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XSL Two Processes: Transformation & Formatting

1.1.1 Tree Transformations

Tree transformation constructs the result tree. In XSL,this tree is called theelement and attributetree, with objects primarily in the"formatting object" namespace. In this tree, a formattingobjectis represented as an XML element, with the properties represented by aset of XML attribute-value pairs. The content of the formatting objectis the content of the XML element. Treetransformation is defined in the XSLT Recommendation[XSLT].A diagram depicting this conceptual process isshown below.

The XSL stylesheet is used in tree transformation. A stylesheetcontains a set of tree construction rules. The tree construction ruleshave two parts: a pattern that is matched against elements in thesource tree and a template that constructs a portion of the resulttree. This allows a stylesheet to be applicable to a wide class ofdocuments that have similar source tree structures.

In some implementations of XSL/XSLT,the result of tree constructioncan be output as an XML document. This would allow an XML documentwhich contains formatting objects and formatting properties to beoutput. This capability is neither necessary for an XSL processor noris it encouraged. There are, however, cases where this is important,such as a server preparing input for a known client; for example, the waythat a WAP(http://www.wapforum.org/faqs/index.htm)server prepares specialized input for a WAP capablehand held device. To preserve accessibility, designers of Web systemsshould not develop architectures that require (or use) thetransmission of documents containing formatting objects and propertiesunless either the transmitter knows that the client can acceptformatting objects and properties or the transmitted document containsa reference to the source document(s) used in the construction of thedocument with the formatting objects and properties.

1.1.2 Formatting

Formatting interprets the result tree in its formatting object treeform to produce the presentation intended by the designerof the stylesheet from which the XML element and attributetree in the "fo" namespace was constructed.

The vocabulary of formatting objects supported by XSL - the set offo: element types - represents the set oftypographic abstractions available to thedesigner. Semantically, each formatting object represents aspecification for a part of the pagination, layout, and stylinginformation that will be applied to the content of that formattingobject as a result of formatting the whole result tree. Eachformatting object class represents a particular kind of formattingbehavior. For example, the block formatting object class representsthe breaking of the content of a paragraph into lines. Other parts ofthe specification may come from other formatting objects; forexample, the formatting of a paragraph (block formattingobject)depends on both the specification of properties on the blockformatting object and the specification of the layout structure intowhich the block is placed by the formatter.

The properties associated with an instance of a formatting objectcontrol the formatting of that object. Some of the properties, forexample "color", directly specify the formatted result.Other properties, for example 'space-before', only constrain the setof possible formatted results without specifying any particularformatted result. The formatter may make choices among otherpossible considerations such as esthetics.

Formatting consists of the generation of a treeof geometric areas, called thearea tree. Thegeometric areas arepositioned on a sequence of one or more pages (a browser typicallyuses a single page). Each geometric area has a position on the page, aspecification of what to display in that area and may have abackground, padding, and borders. For example, formatting asinglecharacter generates an area sufficiently large enough to hold theglyph that is used to present the character visually and the glyph iswhat is displayed in this area. These areas may be nested. Forexample, the glyph may be positioned within a line, within ablock, within a page.

Renderingtakes the area tree, the abstract model of the presentation (in termsof pages and their collections of areas), and causes apresentation to appear on the relevant medium, such as a browserwindow on a computer display screen or sheets of paper. The semanticsof rendering are not described in detail in this specification.

The first step in formatting is to "objectify" the elementand attributetree obtained via an XSLT transformation.Objectifying the tree basically consists of turning theelements in thetree into formatting object nodes and theattributes into property specifications. The result of this step istheformatting object tree.

As part of the step of objectifying, the characters that occur inthe result tree are replaced by fo:character nodes.Characters in text nodes which consistsolely of white space characters andwhich are children of elements whose corresponding formatting objects donot permit fo:character nodes as children are ignored. Other characterswithin elements whose corresponding formatting objects do not permitfo:character nodes as children are errors.

The content of the fo:instream-foreign-objectis not objectified;instead the object representing the fo:instream-foreign-objectelement points to the appropriate node in the element andattribute tree.Similarly any non-XSL namespace child elementof fo:declarations is not objectified; instead the object representingthe fo:declarations element points to the appropriate node in theelement and attribute tree.

The second phase in formatting is to refine the formattingobject treeto produce therefined formatting object tree.The refinement process handles the mapping from propertiesto traits. This consists of: (1) shorthand expansion intoindividual properties, (2) mapping of correspondingproperties, (3) determining computed values (may includeexpression evaluation),(4) handling white-space-treatment and linefeed-treatmentproperty effects, and (5) inheritance.Details onrefinement are found in5 Property Refinement / Resolution.

The refinement step is depicted in the diagram below.

The third step in formatting is the construction of the areatree. Thearea tree is generated as described in the semantics of eachformatting object. The traits applicable to each formattingobjectclass control how the areas are generated. Although everyformatting property may be specified on every formatting object, foreach formatting object class, only a subset of the formattingproperties are used to determine the traits for objects ofthat class.

Area generation is depicted in the diagram below.

1.2.1 Paging and Scrolling

Doing both scrollable document windows and pagination introducesnew complexities to the styling (and pagination) of XML content.Because pagination introduces arbitrary boundaries(pages or regions on pages) on the content, concepts such asthe controlof spacing at page, region, and block boundaries becomeextremely important. There are also concepts related toadjusting the spaces between lines (to adjust the pagevertically)and between words and letters (to justify the lines of text).These do not always arise with simple scrollable documentwindows, such as those found in today's browsers. However, thereis a correspondence between a page with multiple regions, such as a body,header, footer, and left and right sidebars, and a Webpresentation using "frames". The distribution of content into the regionsis basically the same in both cases, and XSL handles bothcases in an analogous fashion.

XSL was developed to give designers control over the featuresneeded when documents are paginated as well as to provide anequivalent "frame" based structure for browsing on the Web.To achieve this control, XSL has extended the set of formattingobjects and formatting properties beyond those available ineither CSS2 or DSSSL.In addition, the selectionof XML source components that can be styled (elements,attributes, text nodes, comments, and processinginstructions) is based on XSLT andXPath[XPath],thus providing theuser with an extremely powerful selection mechanism.

The design of the formatting objects and properties extensionswas first inspired by DSSSL. The actual extensions, however, do notalways look like the DSSSL constructs on which they were based. To eitherconform more closely with the CSS2 specification or tohandle cases more simply than in DSSSL, some extensions have diverged from DSSSL.

There are several ways in which extensions were made. In some cases,it sufficed to add new values, as in the case of those added to reflecta variety of writing-modes, such as top-to-bottom and bottom-to-top, ratherthan just left-to-right and right-to-left.

In other cases, common properties that are expressed in CSS2as one property with multiple simultaneous values, were split intoseveral new properties to provide independent control over independentaspects of the property. For example, the "white-space" property wassplit into four properties:a "white-space-treatment" property thatcontrols how white space is processed, a "linefeed-treatment" property that controlshow line feeds are processed,a "white-space-collapse" property that controlshow multiple consecutive spaces are collapsed,and a "wrap-option" propertythat controls whether lines are automatically wrapped whenthey encounter a boundary, such as the edge of a column.The effect of splitting a property into two or more(sub-)properties is to make the equivalent existing CSS2property a "shorthand" for the set of sub-properties it subsumes.

In still other cases, it was necessary to create new properties.For example, there are a number of new properties that control howhyphenation is done. These include identifying the script and countrythe text is from as well as such properties as "hyphenation-character"(which varies from script to script).

Some of the formatting objects and many of the properties in XSLcome from the CSS2 specification, ensuring compatibilitybetween the two.

There are four classes of XSL properties that can be identified as:

1. CSS properties by copy (unchanged from their CSS2semantics)

2. CSS properties with extended values

3. CSS properties broken apart and/or extended

4. XSL-only properties

1.2.2 Selectors and Tree Construction

As mentioned above, XSL uses XSLT and XPath for tree constructionand pattern selection, thus providing a high degree of controlover how portions of the source content are presented, and whatproperties are associated with those content portions, even wheremixed namespaces are involved.

For example, the patterns of XPath allow the selection of a portionof a string or the Nth text node in a paragraph. This allowsusers to have a rule that makes all third paragraphs inprocedural steps appear in bold, for instance. In addition,properties can be associated with a content portion based on thenumeric value of that content portion or attributes on thecontaining element. This allows one to have a style rulethat makes negative values appear in "red" and positivevalues appear in "black". Also, text can be generateddepending on a particular context in the source tree,or portions of the source tree may be presentedmultiple times with different styles.

1.2.3 An Extended Page Layout Model

There is a set of formatting objects in XSL to describe both thelayout structure of a page or "frame"(how big is the body; are there multiple columns;are there headers, footers, or sidebars; how big are these)and the rules by which the XML source content is placed into these "containers".

The layout structure is defined in terms of one or more instancesof a "simple-page-master" formatting object. This formattingobject allows one to define independently filled regions forthe body (with multiple columns), a header, a footer, and sidebarson a page. These simple-page-masters can be used in page sequencesthat specify in which order the various simple-page-masters shall be used.The page sequence also specifies how styled content is to fill those pages.This model allows one to specify a sequence of simple-page-mastersfor a book chapter where the page instances are automaticallygenerated by the formatter or an explicit sequence of pagessuch as used in a magazine layout. Styled content is assignedto the various regions on a page by associating the name of theregion with names attached to styled content in the result tree.

In addition to these layout formatting objects and properties,there are properties designed to provide the level of controlover formatting that is typical of paginated documents.This includes control over hyphenation, and expanding the control overtext that is kept with other text in the same line, column,or on the same page.

1.2.4 A Comprehensive Area Model

The extension of the properties and formatting objects,particularly in the area on control over the spacing of blocks, lines,and page regions and within lines, necessitated an extension of theCSS2 box formatting model. This extended model is describedin4 Area Model of thisspecification. The CSS2 box model is asubset of this model. See the mapping of the CSS2 box modelterminology to the XSL Area Model terminology in7.2 XSL Areas and the CSS Box Model.The area model provides a vocabulary for describingthe relationships and space-adjustment betweenletters, words, lines, and blocks.

1.2.5 Internationalization and Writing-Modes

There are some scripts, in particular in the Far East, that aretypically set with words proceeding from top-to-bottom andlines proceeding either from right-to-left (most common) orfrom left-to-right. Other directions are alsoused. Properties expressed in terms of a fixed,absolute frame of reference (using top, bottom, left, and right)and which apply only to a notion of words proceeding from left to rightor right to left do not generalize well totext written in those scripts.

For this reason XSL (and before it DSSSL) uses a relative frame ofreference for the formatting object and property descriptions. Just asthe CSS2 frame of reference has four directions (top, bottom, left and right),so does the XSL relative frame of reference have four directions(before, after, start, and end), but these are relative to the "writing-mode". The"writing-mode" property is a way of controlling thedirections needed by a formatter to correctly placeglyphs, words, lines, blocks, etc. on the page or screen.The "writing-mode" expresses the basic directions notedabove. There are writing-modes for "left-to-right - top-to-bottom"(denoted as "lr-tb"), "right-to-left - top-to-bottom" (denoted as "rl-tb"),"top-to-bottom - right-to-left" (denoted as "tb-rl") and more. See7.29.7 writing-modefor the description of the "writing-mode" property.Typically, the writing-mode value specifies two directions:the first is the inline-progression-direction which determinesthe direction in which words willbe placed and the second is the block-progression-directionwhich determines the direction in which blocks (and lines)are placed one after another.In addition, the inline-progression-directionfor a sequence of characters may be implicitly determined usingbidirectional character types for those characters from theUnicode Character Database[UNICODE Character Database]for those characters and the Unicode bidirectional (BIDI) algorithm[UNICODE UAX #9].

Besides the directions that are explicit in the name of thevalue of the "writing-mode" property, the writing-mode determinesother directions needed by the formatter, such as theshift-direction (used for subscripts and superscripts), etc.

1.2.6 Linking

Because XML, unlike HTML, has no built-in semantics,there is no built-in notion of a hypertext link.In this context, "link" refersto "hypertext link" as defined inhttp://www.w3.org/TR/html401/struct/links.html#h-12.1as well as some of the aspects of "link" as defined inhttp://www.w3.org/TR/xlink/#intro,where "link is a relationship between two or more resources orportions of resources, made explicit by an XLink linking element".Therefore,XSL has a formatting object that expresses the dual semantics offormatting the content of the link reference and thesemantics of following the link.

XSL provides a few mechanisms for changing the presentationof a link target that is being visited. One of these mechanismspermits indicating the link target as such;another allows for control over the placement of the linktarget in the viewing area; still another permits some degree ofcontrol over the way the link target is displayed in relationshipto the originating link anchor.

XSL also provides a general mechanism for changing the way elementsare formatted depending on their active state. This is particularlyuseful in relation to links, to indicate whether a given linkreference has already been visited, or to apply a given styledepending on whether the mouse, for instance, is hovering overthe link reference or not.

Note:

The1999 in the URI indicates the year in whichthe URI was allocated by the W3C. It does not indicate the version ofXSL being used.

Note:

The conventions used for the names of XSL elements,attributes, and functions are as follows:names are all lowercase,hyphens are used to separate words, dots are used toseparate names for the components of complex datatypes,and abbreviations are used only if they alreadyappear in the syntax of a related language such as XML orHTML.

Note:

The only exceptions to this rule are when several leaf nodes of the formatting objecttree are combinedto generate a single area, for example when several charactersin sequence generate a single ligatureglyph. In all such cases, relevant properties such asfont-family andfont-size must be the same forall the generating formatting objects (see section4.7.2 Line-building).

Note:

Traits are also associated with FOs during the process of refinement.Some traits are assigned during formatting, while others are already present afterrefinement.

4.2.1 Area Types

There are two types of areas:block-areas andinline-areas. These differ according to howthey are typically stacked by the formatter. An area can haveblock-area children or inline-area children as determinedby the generating formatting object, but a given area's children must all be ofone type. Although block-areas and inline-areas aretypically stacked, some areas can be explicitly positioned.

Aline-area is a special kind of block-area whose childrenare all inline-areas. Aglyph-area is a special kind ofinline-area which has no child areas, and has a singleglyph image as its content.

Typical examples of areas are: a paragraph rendered by usingan fo:block formatting object,which generates block-areas,and a character rendered by using an fo:characterformatting object,which generates an inline-area (in fact, a glyph-area).

4.2.2 Common Traits

Associated with any area are two directions, which are derived from thegeneratingformatting object'swriting-mode andreference-orientation properties: theblock-progression-direction is the direction for stacking block-areadescendants of the area, and theinline-progression-direction is the direction for stacking inline-areadescendants of the area. Anothertrait, theshift-direction, is present on inline-areas and refers tothe direction in which baselineshifts are applied. Also theglyph-orientation defines the orientationof glyph-images in the rendered result.

If the reference-orientation for an area is 0, then thetop, bottom, left, and right edges of the content are parallel to those ofthe area's parent and consistent with them. Otherwise the edges are rotatedfrom those of the area's parent as described in7.21.3 reference-orientation.The inline-progression-direction and block-progression-direction are determinedby the location of these edges as described in7.29.7 writing-mode.

The Boolean traitis-reference-area determineswhether or not an area establishes a coordinate system forspecifying indents. An area for which this trait istrueis called areference-area.Only a reference-area may have a block-progression-direction which is different fromthat of its parent.A reference-area may be either ablock-area or an inline-area.Only specific formatting objects generate reference areas.

The Boolean traitis-viewport-area determineswhether or not an area establishes an opening through which itsdescendant areas can be viewed, and can be used topresent clipped or scrolled material; for example, in printingapplications where bleed and trim is desired.An area for which this trait istrueis called aviewport-area.A viewport-area also has the valuetruefor theis-reference-area trait.

A common construct is aviewport/reference pair.This is a viewport-areaV and a block-areareference-areaR, whereR is the sole childofV and where the start-edge and end-edge of thecontent-rectangle ofR are parallel to the start-edge andend-edge of the content-rectangle ofV.

Each area has the traitstop-position,bottom-position,left-position, andright-position which represent the distancefrom the edges of its content-rectangle to the like-named edges of thenearest ancestor reference-area (or the page-viewport-areain thecase of areas generated by descendants of formatting objectswhose absolute-position isfixed); theleft-offsetandtop-offset determine the amount by whicha relatively-positioned area is shifted for rendering. These traits receivetheir values during the formatting process, or in the caseof absolutely positioned areas, during refinement.

Theblock-progression-dimension andinline-progression-dimension of an area represent theextent of the content-rectangle of that area in each of the tworelative directions.

Other traits include:

• theis-first andis-last traits, which are Boolean traitsindicating the order in which areas are generated and returned(See6.1.1 Definitions Common to Many Formatting Objects)by a givenformatting object.is-first istruefor the first area (or only area) generated and returned by a formatting object,andis-lastistrue for the last area (or only area);

• the amount of space outside the border-rectangle:space-before,space-after,space-start, andspace-end(though some of these may be required to be zero on certain classes of area);

  Note:

  "Before", "after", "start",and "end" refer to relative directions and are definedbelow.

• the thickness of each of the four sides of the padding:padding-before,padding-after,padding-start, andpadding-end;

• the style, thickness, and color of each of thefour sides of the border:border-before, etc.;

• the background rendering of thearea:background-color,background-image, andother background traits; and

• thenominal-font for an area, asdetermined by the font properties and the character descendants of thearea's generating formatting object.(see5.5.7 Font Properties)

Unless otherwise specified, the traits of aformatting object are present on each of its generated areas,and with the same value. (However, see sections4.7.2 Line-building and4.9.4 Border, Padding, and Background.)Theid trait is computed for formatting objects butis not present on areas.

4.2.3 Geometric Definitions

As described above, thecontent-rectangle is the rectanglebounding the inside of the padding and is used to describethe constraints on the positions of descendant areas. It is possible thatmarks from descendant glyphs or other areas may appear outside thecontent-rectangle.

Related to this is theallocation-rectangleof an area,which is used to describe the constraints on the position ofthe area within its parent area. For an inline-area this is either thenormal-allocation-rectangle or thelarge-allocation-rectangle.Thenormal-allocation-rectangleextendsto the content-rectanglein the block-progression-direction and to the border-rectangle in theinline-progression-direction. Thelarge-allocation-rectangleis the border-rectangle. Unlessotherwise specified, the allocation-rectangle for an area is thenormal-allocation-rectangle.

For a block-area, the allocation-rectangle extends to the border-rectangle inthe block-progression-direction and outside the content-rectanglein the inline-progression-direction by an amount equal totheend-indent,and in the opposite direction by an amount equal to thestart-indent.

The edges of a rectangle are designated as follows:

• thebefore-edge is the edge occurring first in theblock-progression-direction and perpendicularto it;

• theafter-edge is the edge oppositethe before-edge;

• thestart-edge is the edge occurringfirst in the inline-progression-direction and perpendicularto it,

• theend-edge is the edge opposite thestart-edge.

For purposes of this definition, the content-rectangle of an area uses theinline-progression-direction and block-progression-direction of that area;but the border-rectangle, padding-rectangle, andallocation-rectangle use thedirections of its parent area. Thus the edges designated for thecontent-rectangle may not correspond to the same-named edgeson the padding-, border-,and allocation-rectangles. This is important in the case ofnested areas with different writing-modes or reference-orientation.

The following diagram shows the correspondence between the various edgenames for a mixed writing-mode example:

   [D]

Each inline-area has analignment-point determined by the formatter,on the start-edgeof its allocation-rectangle; for a glyph-area, this isa point on the start-edge of the glyph on its alignment baseline (see below).This is script-dependent and does not necessarily correspond to the(0,0) coordinate point used for the data describing the glyph shape.

4.2.4 Tree Ordering

In the area tree, the set of areas with a given parent is ordered.The termsinitial, final, preceding, andfollowing refer to this ordering.

In any ordered tree, this sibling order extends to an ordering of the entire treein at least two ways.

• In thepre-order traversal order of a tree, the childrenof each node (their order unchanged relative to one another) follow the node, butprecede any following siblings of the node or of its ancestors.

• In thepost-order traversal order of a tree, the children ofeach node precede the node, but follow any preceding siblings of the node or of itsancestors.

"Preceding" and "following", when applied to non-siblings, will depend on theextension order used, which must be specified. However, in either of these given orders,the leaves of the tree (nodes without children) are unambiguously ordered.

4.2.5 Stacking Constraints

This section defines the notion ofblock-stacking constraints andinline-stacking constraints involving areas. These are defined asordered relations, i.e., ifA andBhave a stacking constraintit does not necessarily mean thatB andA have a stackingconstraint. These definitions are recursive in nature and some cases may dependupon simpler cases of the same definition. This is not circularity but rather aconsequence of recursion. The intention of thedefinitions is to identify areas at any level of thetree which may have only space between them.

Thearea-class trait is an enumerated value which isxsl-normal for an area which is stacked withother areas in sequence. Anormal area is anarea for which this trait isxsl-normal. Apage-level-out-of-linearea is an area with area-classxsl-footnote,xsl-before-float,orxsl-fixed; placement of these areas is controlledby the fo:page-sequenceancestor of its generating formatting object. Areference-level-out-of-linearea is an area with area-classxsl-side-float orxsl-absolute;placement of these areas is controlled by the formatting object generatingthe relevant reference-area. Ananchorarea is an area with area-classxsl-anchor;placement of these areas is arbitrary and does not affect stacking.Areas with area-class equal to one ofxsl-normal,xsl-footnote, orxsl-before-float are defined to bestackable,indicating that they are supposed to be properly stacked.

Block-stacking constraints

IfP is a block-area, then there is afence precedingP ifP is a reference-area or if theborder-before-widthor padding-before-width ofP are non-zero.Similarly, there is afence followingP ifP is areference-areaor if the border-after-width or padding-after-width ofP are non-zero.

IfA andB are stackable areas, andS isa sequence of space-specifiers (see4.3 Spaces and Conditionality),it is defined thatA andBhave block-stacking constraintS ifany of the following conditions holds:

1. B is a block-area which is the first normalchild ofA, andS is the sequence consisting of thespace-before ofB.

2. A is a block-area which is the last normalchild ofB, andS is the sequence consisting of thespace-after ofA.

3. A andB are both block-areas, and either

   a.B is the next stackable sibling area ofA, andS is the sequence consisting of the space-after ofA and the space-before ofB;

   b.B is the first normal child of a block-areaP,B is not a line-area, there is no fence precedingP,A andP have a block-stacking constraintS', andS consists ofS' followed by the space-before ofB; or

   c.A is the last normal child of a block-areaP,A is not a line-area, there is no fence followingP,P andB have a block-stacking constraintS'', andS consists of the space-after ofA followed byS''.

   d.A has a block-stacking constraintS' with a block-areaE,E has a block-stacking constraintS'' withB,E isempty (i.e., it has zero border, padding, and block-progression-dimension, and no normal children), andS consists ofS' followed byS''.

WhenA andB have a block-stacking constraint, theadjacent edges ofA andB are an orderedpair recursively defined as:

• In case 1, the before-edge of thecontent-rectangle ofAand the before-edge of the allocation-rectangle ofB.

• In case 2, the after-edge of the allocation-rectangleofA andthe after-edge of the content-rectangle ofB.

• In case 3a, the after-edge of theallocation-rectangle ofAand the before-edge of the allocation-rectangle ofB.

• In case 3b, the first of the adjacent edges ofA andP,and the before-edge of the allocation-rectangle ofB.

• In case 3c, the after-edge of theallocation-rectangle ofAand the second of the adjacent edges ofP andB.

• Incase 3d, the first of the adjacent edges ofA andE,and the second of the adjacent edges ofE andB.

Example. In this diagram each node represents a block-area.Assume that all paddingand border widths are zero, and none of the areas arereference-areas. ThenPandA have a block-stacking constraint, as doAandB,A andC,B andC,C andD,D andB,B andE,D andE, andE andP; theseare the only pairs in the diagram having block-stacking constraints. IfB had non-zero padding-after, thenDandE would not have any block-stacking constraint (thoughBandE would continue to have a block-stacking constraint).

Inline-stacking constraints.

This section will recursively define theinline-stacking constraints between two areas (either two inline-areas or one inline-areaand one line-area),together with the notion offence preceding andfence following; these definitions are interwoven with one another.This parallels the definition for block-stackingconstraints, but with the additional complication that we may have a stackingconstraint between inline-areas which are stacked in opposite inline-progression-directions.(This is not an issue for block-stacking constraints becausea block-area which is not a reference-area may not have ablock-progression-directiondifferent from that of its parent.)

IfP andQ have an inline-stacking constraint, thenP has afence precedingQ ifP isa reference-area or has non-zero border-width or padding-width at the firstadjacent edge ofP andQ. Similarly,Q hasafence followingP ifQ is a reference-areaor has non-zero border-width or padding-width at the secondadjacent edge ofP andQ.

IfA andB are normal areas, andSis a sequence of space-specifiers, it is defined thatA andB have inline-stacking constraintS if any of thefollowing conditions holds:

1. A is an inline-area or line-area,B is an inline-area which is the first normal child ofA, andS is the sequence consisting of the space-start ofB.

2. B is an inline-area or line-area,A is an inline-area which is the last normal child ofB, andS is the sequence consisting of the space-end ofA.

3. A andB are each either an inline-area or a line-area, and either

   a. bothA andB are inline-areas,B is the next normal sibling area ofA, andS is the sequence consisting of the space-end ofA and the space-start ofB;

   b.B is an inline-area which is the first normal child of an inline-areaP,P has no fence followingA,A andP have an inline-stacking constraintS', the inline-progression-direction ofP is the same as the inline-progression-direction of the nearest common ancestor area ofA andP, andS consists ofS' followed by the space-start ofB.

   c.A is an inline-area which is the last normal child of an inline-areaP,P has no fence precedingB,P andB have an inline-stacking constraintS'', the inline-progression-direction ofP is the same as the inline-progression-direction of the nearest common ancestor area ofP andB, andS consists of the space-end ofA followed byS''.

   d.B is an inline-area which is the last normal child of an inline-areaP,P has no fence followingA,A andP have an inline-stacking constraintS', the inline-progression-direction ofP is opposite to the inline-progression-direction of the nearest common ancestor area ofA andP, andS consists ofS' followed by the space-end ofB.

   e.A is an inline-area which is the first normal child of an inline-areaP,P has no fence precedingB,P andB have an inline-stacking constraintS'', the inline-progression-direction ofP is opposite to the inline-progression-direction of the nearest common ancestor area ofP andB, andS consists of the space-start ofA followed byS''.

WhenA andB have an inline-stacking constraint,theadjacent edges ofA andB are an orderedpair defined as:

• In case 1, the start-edge of thecontent-rectangle ofAand the start-edge of the allocation-rectangle ofB.

• In case 2, the end-edge of the allocation-rectangle ofA andthe end-edge of the content-rectangle ofB.

• In case 3a, the end-edge of theallocation-rectangle ofA andthe start-edge of the allocation-rectangle ofB.

• In case 3b, the first of the adjacent edges ofA andP, and the start-edge of the allocation-rectangle ofB.

• In case 3c, the end-edge of theallocation-rectangle ofAand the second of the adjacent edges ofP andB.

• In case 3d, the first of the adjacent edges ofA andP, and the end-edge of the allocation-rectangle ofB.

• In case 3e, the start-edge of theallocation-rectangle ofAand the second of the adjacent edges ofP andB.

Two areas areadjacent if they have a block-stacking constraintor an inline-stacking constraint. It follows from the definitions that areas of the sametype (inline or block) can be adjacent only if all their non-common ancestorsare also of the same type (up to but not including their nearest common ancestor).Thus, for example, two inline-areas which reside in different line-areas are neveradjacent.

An areaAbegins an areaP ifA is adescendant ofP andP andA have either ablock-stacking constraint or an inline-stacking constraint,provided that no descendant ofP which is an ancestorofA has a space-before (in the case of a block-stacking constraint)or a space-start (in the case of an inline-stacking constraint)whose computed minimum, maximum, or optimum valuesare nonzero.In this case thesecond of the adjacent edges ofP andA is definedto bealeading edge inP. A space-specifier whichapplies tothe leading edge is also defined tobeginP.

Similarly, An areaAends an areaP ifA is adescendant ofP andA andP have either ablock-stacking constraint or an inline-stacking constraint,provided that no descendant ofP which is an ancestorofA has a space-after (in the case of a block-stacking constraint)or a space-end (in the case of an inline-stacking constraint)whose computed minimum, maximum, or optimum valuesare nonzero.In this case thefirst of the adjacent edges ofA andP is definedto beatrailing edge inP. A space-specifier whichapplies tothe trailing edge is also defined toendP.

4.2.6 Font Baseline Tables

Each script has its preferred "baseline" for aligning glyphs from that script.Western scripts typically use an "alphabetic" baseline that touches at or near thebottom of capital letters. Further, for each font there is apreferred way of aligning embedded glyphs from different scripts, e.g., for aWestern font there are separate baselines for aligning embedded ideographic or Indicglyphs.

Each block-area and inline-area has adominant-baseline-identifier trait whose value is a baseline identifiercorresponding to the type of alignment expected for inline-area descendants of that area,and each inline-area has analignment-baseline which specifies how thearea is aligned to its parent. These traits are interpreted as described in section7.9.1 Fonts and Font Data.

For each font, anactual-baseline-table maps these identifiersto points on the start-edge of the area. Byabuse of terminology, the line in the inline-progression-directionthrough the point corresponding to the dominant-baseline-identifier is calledthe "dominant baseline."

4.3.1 Space-resolution Rules

Theresolved space-specifier of a given space-specifierS iscomputed as follows. Consider the maximal inline-stacking constraint orblock-stacking constraintS'' containing the space-specifierS as an element of the sequence (S'' is a sequenceof space-specifiers; see4.2.5 Stacking Constraints). DefineS' to be a subsequence ofS'' as follows:

• ifS is the space-before or space-after of a line-area,thenS' is the maximal subsequence ofS'' containingS such that all the space-specifiers inS' are traitsof line-areas,

• ifS is the space-before or space-after of a block-areawhich is not a line-area, thenS' is the maximal subsequenceofS'' containingS such that all the space-specifiersinS' are traits of block-areas which are notline-areas,

• ifS is the space-start or space-end of an inline-area,thenS' is all ofS''.

The resolved space-specifier ofS is a non-conditional,forcing space-specifier computed in terms of thesequenceS'.

1. If any of the space-specifiers inS' is conditional,and begins a reference-area or line-area, then it issuppressed,which means that its resolved space-specifier is zero. Further, any conditionalspace-specifiers which consecutively follow it in the sequence are also suppressed.For purposes of this rule, a space-specifierUconsecutively follows a space-specifierV if itU followsV andU andV are separated inthe sequence only by conditional space-specifiers and/orspace-specifiers whose computed minimum, maximum, and optimum values arezero.

   If a conditional space-specifier ends a reference-area or line-area, then itis suppressed together with any other conditional space-specifiers whichconsecutively precede it in the sequence.For purposes of this rule, a space-specifierUconsecutively precedes a space-specifierV ifitU precedesV andU andVare separated inthe sequence only by conditional space-specifiers and/orspace-specifiers whose computed minimum, maximum, and optimum values arezero.

2. If any of the remaining space-specifiers inS' is forcing, all non-forcingspace-specifiers are suppressed, and the value of each of the forcing space-specifiersis taken as its resolved value.

3. Alternatively if all of the remaining space-specifiers inS' are non-forcing,then the resolved space-specifier is defined in terms of those non-suppressed space-specifierswhose precedence is numerically highest, and among these those whose optimum value is thegreatest. All other space-specifiers are suppressed. If there is only one ofthese then its value is taken as its resolved value.

   Otherwise, follow these rules when there aretwo or morespace-specifiers all of the same highest precedence and the same(largest) optimum: The resolved space-specifier of the lastspace-specifier in the sequence is derived from these spaces bytaking their common optimum value as its optimum. The greatest oftheir minimum values is its minimum. The least of their maximumvalues is its maximum. All other space-specifiers are suppressed.

4. IfS is subject to overconstrainment relaxing,then its maximum value is set to the actual block-progression-dimension of thecontaining block-area. See4.3.2 Overconstrained space-specifiers

Example. Suppose the sequence of space values occurring at thebeginning of a reference-area is:first, a space with value 10 points (that isminimum, optimum, and maximum all equal to 10 points) and conditionalitydiscard; second, a space with value 4 points andconditionalityretain; and third, a spacewith value 5 points and conditionalitydiscard;all three spaces having precedence zero. Then the first (10 point) space issuppressed under rule 1, and thesecond (4 point) space is suppressed under rule 3. The resolved value of thethird space is a non-conditional 5 points, even thoughit originally came from a conditional space.

The padding of a block-area does not interact with anyspace-specifier(except that by definition, the presence of padding at the before- or after-edgeprevents areas on either side of it from having a stacking constraint.)

The border or padding at the before-edge or after-edge of a block-areaB maybe specified as conditional. If so, then it is set to zero if its associatededge is a leading edge in a reference-area, and the is-first trait ofBis false, or if its associatededge is a trailing edge in a reference-area, and the is-last trait ofBis false. In either of these cases, the borderor padding is taken to be zero for purposes of the stacking constraint definitions.

The border or padding at the start-edge or end-edge of an inline-areaI maybe specified as conditional. If so, then it is set to zero if its associatededge is a leading edge in a line-area, and the is-first trait ofIis false, or if its associatededge is a trailing edge in a line-area, and the is-last trait ofIis false. In either of these cases, the borderor padding is taken to be zero for purposes of the stacking constraint definitions.

4.3.2 Overconstrained space-specifiers

Whenan areaP is generated by a formatting object whoseblock-progression-dimensionis "auto", then the constraints involving the before-edge and after-edge ofthe content-rectangle ofP, together with the constraints between thevarious descendants ofP, result in a constraint on the actual valueof the block-progression-dimension. If the block-progression-dimension is insteadspecified as a length, then this might result in an overconstrained area tree,for example an incompletely-filled fo:blockwith a specified size. In that case some constraints betweenP and itsdescendants should be relaxed; those that are eligible for this treatment aresaid to besubject to overconstrainment relaxing, and treated as inthe previous section.

• If the display-align value is "after" or "center" andP is the first normal area generatedby the formatting object, then the space-before of the first normal child ofPis subject to overconstrainment relaxing.

• If the display-align value is "before" or "center" andP is the last normal area generatedby the formatting object, then the space-after of the last normal child ofPis subject to overconstrainment relaxing.

4.4.1 Stacked Block-areas

Block-area children of an area are typically stacked in theblock-progression-directionwithin their parent area, and this is the default method ofpositioning block-areas. However, formatting objectsare free to specify other methods of positioning child areas of areas whichthey generate, for example list-items or tables.

For a parent areaP whose children areblock-areas,P is defined to beproperlystacked if all of the following conditions hold:

1. For each block-areaB which is a descendant ofP,the following hold:

   • the before-edge and after-edgeof its allocation-rectangle are parallel to the before-edge and after-edges of thecontent-rectangle ofP,

   • the start-edge of its allocation-rectangle is parallel to the start-edgeof the content-rectangle ofR (whereR is the closestancestor reference-area ofB), and offset from it inwardby a distance equal tothe block-area's start-indent plus itsstart-intrusion-adjustment(as defined below), minus its border-start,padding-start, and space-start values, and

   • the end-edge of its allocation-rectangle is parallel to theend-edgeof the content-rectangle ofR, and offset from it inwardby a distance equal tothe block-area's end-indent plus itsend-intrusion-adjustment(as defined below),minus its border-end, padding-end, and space-endvalues.

      [D]

   Content Rectangle of Reference Area

   Note:

   The notion of indent is intended to apply to the content-rectangle, butthe constraint is written in terms of theallocation-rectangle, because as noted earlier(4.2.3 Geometric Definitions)the edges of thecontent-rectangle may notcorrespond to like-named edges of theallocation-rectangle.

   Thestart-intrusion-adjustment andend-intrusion-adjustment are traits used todeal with intrusions fromfloats in the inline-progression-direction.

   See also section5.3.2 Margin, Space, and Indent Propertiesfor how the margin properties affect the indents.

2. For each pair of normal areasB andB'in the subtree belowP, ifB andB' have a block-stacking constraintSandB is not empty (see4.2.5 Stacking Constraints),then the distance between the adjacent edges ofB andB'is consistent with theconstraint imposed by theresolved values of the space-specifiers inS.

      [D]

   Example. In the diagram, if areaAhas a space-after value of 3 points,B aspace-beforeof 1 point, andC a space-before of 2 points, allwithprecedence offorce, and with zero border and padding,then the constraints will placeB'sallocation-rectangle4 points below that ofA, andC'sallocation-rectangle6 points below thatofA. Thus the 4-point gap receives thebackground colorfromP, and the 2-point gap beforeCreceives the background color fromB.

4.4.2 Intrusion Adjustments

Intrusion adjustments (both start- and end-) are defined to account for theindentation that occurs as the result of side floats.

IfA andB are areas which have the same nearest reference area ancestor, thenAandB are defined to beinline-overlapping if there is some lineparallel to the inline-progression-direction, which intersects both theallocation-rectangle ofA and the allocation-rectangle ofB.

IfA is an area of classxsl-side-float with float="start", andB is a block-area, andA andBhave the same nearest reference area ancestor, thenA is defined toencroach uponB ifA andBare inline-overlapping and the start-indent ofB is less than the sum of the start-indent ofAand the inline-progression-dimension ofA. Thestart-encroachment ofA onB is then defined tobe amount by which the start-indent ofB is less than the sum of the start-indent ofA andthe inline-progression-dimension ofA.

IfA is an area of classxsl-side-float with float="end", andB is a block-area, andA andBhave the same nearest reference area ancestor, thenA is defined toencroach uponB ifA andBare inline-overlapping and the end-indent ofB is less than the sum of the end-indent ofAand the inline-progression-dimension ofA. Theend-encroachment ofA onB is thendefined to be amount by which the end-indent ofB is less than the sum of the end-indent ofA andthe inline-progression-dimension ofA.

IfB is a block-area which is not a line-area, then itslocal-start-intrusion-adjustment is computed as the maximum ofthe following lengths:

1. zero;

2. if the parent ofB is not a reference area: the start-intrusion-adjustment of the parent ofB;and

3. ifB has intrusion-displace="block",then for each areaA of classxsl-side-floatwith float="start" such that the generating formatting object ofA is not a descendant ofthe generating formatting object ofB, and such thatA encroaches upon some line-area child ofB: the start-encroachment ofA onB;and

4. ifB has intrusion-displace = "block", then for each areaA of classxsl-side-float with float="start"such thatA andB are inline-overlapping, and for each block-area ancestorB' ofB which isa descendant of the nearest reference area ancestor ofB, such thatA encroaches on a line-areachild ofB': the start-encroachment ofA onB'.

The start-intrusion-adjustment of a block-areaB is then defined to bethe maximum of the local-start-intrusion-adjustments of the normal block-areas generatedand returned by the generating formatting object ofB.

IfL is a line-area, then its start-intrusion-adjustment is computed as the maximum ofthe following lengths:

1. the start-intrusion-adjustment of the parent ofL;

2. for each areaA of classxsl-side-float with float="start" such thatA encroaches uponL:the start-encroachment ofA onL; and

3. if the parent ofL has intrusion-displace = "indent",then for each areaA of classxsl-side-float with float="start" such thatA andL are inline-overlapping, and for each block-area ancestorB' ofL which isa descendant of the nearest reference area ancestor ofL, such thatA encroaches on some line-areachildL' ofB': the start-encroachment ofA onB'.

The end-intrusion-adjustment for a block-area is computed in a precisely analogous manner.That is:

IfB is a block-area which is not a line-area, then itslocal-end-intrusion-adjustment is computed as the maximum ofthe following lengths:

1. zero;

2. if the parent ofB is not a reference area: the end-intrusion-adjustment of the parent ofB;and

3. ifB has intrusion-displace="block",then for each areaA of classxsl-side-floatwith float="end" such that the generating formatting object ofA is not a descendant ofthe generating formatting object ofB, and such thatA encroaches upon some line-area child ofB: the end-encroachment ofA onB;and

4. ifB has intrusion-displace = "block", then for each areaA of classxsl-side-float with float="end"such thatA andB are inline-overlapping, and for each block-area ancestorB' ofB which isa descendant of the nearest reference area ancestor ofB, such thatA encroaches on a line-areachild ofB': the end-encroachment ofA onB'.

The end-intrusion-adjustment of a block-areaB is then defined to bethe maximum of the local-end-intrusion-adjustments of the normal block-areas generatedand returned by the generating formatting object ofB.

IfL is a line-area, then its end-intrusion-adjustment is computed as the maximum ofthe following lengths:

1. the end-intrusion-adjustment of the parent ofL;

2. for each areaA of classxsl-side-float with float="end" such thatA encroaches uponL:the end-encroachment ofA onL; and

3. if the parent ofL has intrusion-displace = "indent",then for each areaA of classxsl-side-float with float="end" such thatA andL are inline-overlapping, and for each block-area ancestorB' ofL which isa descendant of the nearest reference area ancestor ofL, such thatA encroaches on some line-areachildL' ofB': the end-encroachment ofA onB'.

   [D]

Nominal and Maximum Line Rectangles

Note:

Using the nominal-requested-line-rectangle allows equal baseline-to-baselinespacing. Using the maximum-line-rectangle allows constant space between line-areas.Using theper-inline-height-rectangle and zero space-before and space-after allowsCSS-style line box stacking. Also, the value of half-leading is included in theexpanded-rectangle regardless of conditionality, and thus a line-height conditionalityof "discard" does not have effect in this case.

Note:

When the line-stacking-strategy isline-height,allocation is done with respect to the expanded-rectangle.

4.6.1 Stacked Inline-areas

Inline-area children of an area are typically stacked in theinline-progression-directionwithin their parent area, and this is the default method ofpositioning inline-areas.

Inline-areas are stacked relative to thedominant baseline,as defined above(4.2.6 Font Baseline Tables).

For a parent areaP whose children are inline-areas,Pis defined to beproperly stacked if all of the following conditionshold:

1. For each inline-area descendantI ofP, thestart-edge, end-edge, before-edge and after-edge of the allocation-rectangleofI are parallel to corresponding edges of the content-rectangleof the nearest ancestor reference-area ofI.

2. For each pair of normal areasI andI'in the subtree belowP, ifI andI' havean inline-stacking constraintS, then the distance between theadjacent edges ofI andI' is consistent with theconstraint imposed by the resolved values of the space-specifiers inS.

3. For any inline-area descendantI ofP, thedistance in the shift-direction from the dominant baseline of the parentQ ofI, to the alignment-point ofIequals the offset between the dominant baseline ofQ andthe baseline ofQ corresponding to the alignment-baselinetrait ofI, plusthe baseline-shift forI.

   The first summand is computed to compensate formixed writing systems with different baseline types, and the othersummands involve deliberate baseline shifts for things like superscriptsand subscripts.

4.6.2 Glyph-areas

The most common inline-area is a glyph-area, which contains therepresentation for a character (or characters) in a particular font.

A glyph-area has an associatednominal-font, determined bythe area's typographic traits, which apply to its character data, andaglyph-orientation determined by its writing-mode andreference-orientation, which determine the orientation of the glyphwhen it is rendered.

The alignment-point and dominant-baseline-identifier of a glyph-area are assignedaccording to the writing-system in use (e.g., the glyph baselinein Western languages), and are used to control placement of inline-areasdescendants of a line-area. The formatter may generate inline-areas withdifferent inline-progression-directions from their parent to accommodatecorrect inline-area stacking in the case of mixed writing systems.

A glyph-area has no children. Its block-progression-dimension andactual-baseline-table are the same for all glyphs in a font.Conforming implementations may choose tocompute the block-progression-dimension for a glyph area based on theactual glyph size rather than using a common size for all glyphsin a font.

4.7.1 General Ordering Constraints

A subsetS of the areas returned to a formatting object iscalledproperly ordered if the areas in thatsubset have thesame order as their generating formatting objects. Specifically, ifA₁andA₂ are areas inS, returned by childformatting objectsF₁ andF₂whereF₁ precedesF₂,thenA₁ must precedeA₂ in thepre-order traversal order of the area tree. IfF₁equalsF₂ andA₁ isreturned prior toA₂, thenA₁must precedeA₂ in the pre-order-traversalof the area tree.

For each formatting objectF and each area-classC,the subset consisting of the areas returned toF with area-classC must be properly ordered, except whereotherwise specified.

4.7.2 Line-building

This section describes the ordering constraints that apply to formattingan fo:block or similar block-level object.

A block-level formatting objectF whichconstructs lines does so byconstructing block-areas which it returns to its parentformatting object, and placing normal areas and/or anchor areas returned toF by its childformatting objects as children of those block-areas or ofline-areaswhich it constructs as children of those block-areas.

For each such formatting objectF, it must bepossible to form anordered partitionP consisting of ordered subsetsS₁,S₂, ...,S_n ofthe normal areas and anchor areas returned by the child formatting objects,such that the following are all satisfied:

1. Each subset consists of a sequence of inline-areas, or of a singleblock-area.

2. The ordering of the partition follows the ordering of theformatting object tree. Specifically, ifA is inS_iandB is inS_j withi <j, or ifA andB are both in the same subsetS_i withA beforeB in thesubset order, then eitherA is returned by a preceding siblingformatting object ofB, orA andB are returned by the sameformatting object withA being returned beforeB.

3. The partitioning occurs at legal line-breaks. Specifically, ifA isthe last area ofS_i andB is the first area ofS_i+1, then the rules ofthe language, script and hyphenation constraints(7.10 Common Hyphenation Properties,7.16.1 hyphenation-keep, and7.16.2 hyphenation-ladder-count)in effect must permit a line-breakbetweenA andB, within the context of all areas inS_iandS_i+1.

4. Forced line-breaks are respected.Specifically, if C is a descendant of F, and C is an fo:characterwhose Unicode character is U+000A, and A is the area generated by C,then either C is a child of F and A is the last area in a subset S_i,or C is a descendant of a child C' of F, and A ends(in the sense of 4.2.5) an area A' returned by C',such that A' is the last area in a subset S_i.

5. The partition follows the ordering of the area tree,except for certain glyph substitutions and deletions.Specifically, if B₁, B₂, ..., B_p arethe normal child areas of the area or areas returned by F,(ordered in the pre-order traversal order of the area tree),then there is a one-to-one correspondence between these child areasand the partition subsets (i.e. n = p), and for each i,

   • S_i consists of a single block-area andB_i is that block-area, or

   • S_i consists of inline-areas and B_i is a line-areawhose child areas are the same as the inline-areas in S_i,and in the same order, except that where the rules of the languageand script in effect call for glyph-areas to be substituted,inserted, or deleted, then the substituted or inserted glyph-areasappear in the area tree in the corresponding place, and thedeleted glyph-areas do not appear in the area tree.For example, insertions and substitutions may occur because ofaddition of hyphens or spelling changes due to hyphenation,or glyph image construction from syllabification, or ligature formation.Deletions occur as specified in6.,below.

6. white-space-treatment is enforced. In particular,deletions in5.occur when there is a glyph area G such that

   (a.) the white-space-treatment of G is "ignore" and the character of Gis classified as white space in XML; or

   (b.) the white-space-treatment of G is "ignore-if-before-linefeed" or"ignore-if-surrounding-linefeed", the suppress-at-line-break of G is"suppress", and G would end a line-area; or

   (c.) the white-space-treatment of G is "ignore-if-after-linefeed" or"ignore-if-surrounding-linefeed", the suppress-at-line-break of G is"suppress", and G would begin a line-area.

   In these cases the area G is deleted; this may cause the condition inclauses (b.) or (c.) to become true and lead to further deletions.

Substitutions that replace a sequence of glyph-areas with a singleglyph-area should only occur when the margin, border, and padding in theinline-progression-direction (start- and end-), baseline-shift, andletter-spacing values are zero, treat-as-word-space isfalse, and thevalues of all other relevant traits match (i.e.,alignment-adjust, alignment-baseline, colortrait, background traits, dominant-baseline-identifier, font traits,text-depth,text-altitude, glyph-orientation-horizontal,glyph-orientation-vertical, line-height, line-height-shift-adjustment,text-decoration, text-shadow).

4.7.3 Inline-building

This section describes the ordering constraints that apply to formattingan fo:inline or similar inline-level object.

An inline-level formatting objectF whichconstructs one or more inline-areas does so byplacing normal inline-areas and/or anchor inline-areas returned toF by its childformatting objects as children of inline-areas which itgenerates.

For each such formatting objectF, it must bepossible to form anordered partitionP consisting of ordered subsetsS₁,S₂, ...,S_n ofthe normal and/or anchor inline-areas and normal block-areasreturned by the child formatting objects,such that the following are all satisfied:

1. Each subset consists of a sequence of inline-areas,or of a single block-area.

2. The ordering of the partition followsthe ordering of the formatting object tree, as defined above.

3. The partitioning occurs at legal line-breaks, as defined above.

4. Forced line-breaks are respected, as defined above.

5. The partition follows the ordering of the area tree,except for certain glyph substitutions and deletions, asdefined above.

4.9.1 Geometry

Each area is rendered in a particular location. Formatting object semanticsdescribe the location of intrinsic marks relative to the object's location,i.e., the left, right, top, and bottom edges of its content-rectangle. Thissection describes how the area's location is determined,which determines the location of its intrinsic marks.

For each page, the page-viewport-area corresponds isometrically to theoutput medium.

The page-reference-area is offset from the page-viewport-area as describedbelow in section4.9.2 Viewport Geometry.

All areas in the tree with an area-class ofxsl-fixedare positioned suchthat the left-, right-, top-, and bottom-edges of itscontent-rectangle areoffset inward from the content-rectangle of its ancestor page-viewport-areaby distances specified by theleft-position,right-position,top-position,andbottom-position traits, respectively.

Any area in the tree which is the child of a viewport-area is renderedas described in section4.9.2 Viewport Geometry.

All other areas in the tree are positioned such that theleft-, right-, top-,and bottom-edges of its content-rectangle are offset inwardfrom thecontent-rectangle of its nearest ancestor reference-area by distancesspecified by theleft-position,right-position,top-position,andbottom-position traits, respectively. These are shifted downand left by the values of thetop-offsetandleft-offset traits, respectively, if the areahas arelative-position ofrelative.

4.9.2 Viewport Geometry

A reference-area which is the child of a viewport-area is positionedsuch thatthe start-edge and end-edge of its content-rectangle areparallel to thestart-edge and end-edge of the content-rectangle of its parentviewport-area. The start-edge of its content-rectangleis offset from the start-edge of the content-rectangle of its parent viewport-areaby aninline-scroll-amount, and the before-edge of its content-rectangle is offset from thebefore-edge ofthe content-rectangle of its parent viewport-area by ablock-scroll-amount.

If the block-progression-dimension of the reference-area is largerthan thatof the viewport-area and theoverflow traitfor the reference-area isscroll,then the inline-scroll-amount and block-scroll-amount aredetermined by a scrolling mechanism, if any,provided by the user agent. Otherwise, both are zero.

4.9.3 Visibility

The visibility of marks depends upon the location of the marks,thevisibility of the area, and theoverflow of any ancestorviewport-areas.

If an area has visibilityhidden it generates no marks.

If an area has anoverflow ofhidden,or when the environment is non-dynamic and theoverflow isscroll then the area determinesaclipping rectangle, which is defined to be therectangle determined by the value of theclip trait of the area, andfor any markgenerated by one of its descendant areas, portions of the marklying outsidethe clipping rectangle do not appear.

4.9.4 Border, Padding, and Background

The border- and padding-rectangles are determined relative to thecontent-rectangle by the values of the common padding and border widthtraits (border-before-width, etc.).

For any area, which is not a child of a viewport-area, the border isrendered between the border-rectangle and the padding-rectangle inaccordance with the common border color and style traits. For a child ofa viewport-area, the border is not rendered.

For an area, which is not part of a viewport/reference pair, thebackground is rendered. For an area that is either a viewport-area or areference-area in a viewport/reference pair, if the refined value ofbackground-attachment isscrolland the block-progression-dimension of the reference-area is larger thanthat of the viewport-area, then the background is rendered on thereference-area and not the viewport-area, and otherwise it is renderedon the viewport-area and not the reference-area.

The background, if any, is rendered in thepadding-rectangle, in accordancewith thebackground-image,background-color,background-repeat,background-position-vertical, andbackground-position-horizontal traits.

4.9.5 Intrinsic Marks

For each class of formatting objects, the marks intrinsic to itsgenerated areas are specified in the formatting object description.For example, an fo:character object generates a glyph-area, and thisis rendered by drawing a glyph within that area'scontent-rectangle in accordance with the area's font traits andglyph-orientationandblink traits.

In addition, other traits (for example the various score and score-color traits) specifyother intrinsicmarks. In the case of score traits (underline-score,overline-score andthrough-score), the score thickness and positionare specified by the nominal-font in effect; where the font fails tospecify these quantities, they are implementation-dependent.

4.9.6 Layering and Conflict of Marks

Marks are layered as described below, which defines a partialordering of which marks arebeneath which other marks.

Two marks are defined toconflict if they apply tothe same pointin the output medium. When two marks conflict, the one which isbeneath the other does not affect points in the output medium wherethey both apply.

Marks generated by the same area are layered as follows: the areabackground is beneath the area's intrinsic marks, and the intrinsicmarks are beneath the border. Layering among the area's intrinsicmarks is defined by the semantics of the area's generating formattingobject and its properties. For example, a glyph-area's glyph drawingcomes beneath the marks generated for text-decoration.

The stacking layer of an area is defined by its stacking context andits z-index value. The stacking layer of an areaA is defined to be lessthan that of an areaB if some ancestor-or-selfA' ofAandB' ofB have the same stacking context andthe z-index ofA' is lessthan the z-index ofB'. If neither stacking layer is less than theother then they are defined to have the same stacking layer.

IfA andB are areas, and the stacking layerofA is less than the stacking layerofB, then all marks generated byAare beneath all marks generated byB.

IfA andB are areas with the samestacking layer, the backgrounds ofA andBcome beneath all other marks generated byA andB. Further, ifA is anancestor ofB (still with the same stacking layer), thenthe background ofAis beneath all the areas ofB, and all the areasofB are beneath the intrinsic areas (and border)ofA.

IfA andB have the same stacking layer andneither is an ancestor of the other,then it is an error if either their backgrounds conflict or if anon-background mark ofA conflicts with anon-background mark ofB.An implementation may recover by proceeding as if the marks from thefirst area in the pre-order traversal order are beneath those of theother area.

   [D]

A Typical Area Tree

5.1.1 Specified Values

The specified value of a property isdetermined using the following mechanisms(in order of precedence):

1. If the tree-construction process placed the propertyon the formatting object, use the value of that propertyas the specified value. This is called "explicitspecification".

2. Otherwise, if the property is inheritable, use the value of thatproperty from the parent formatting object, generally thecomputed value (see below).

3. Otherwise use the property's initial value, if it has one.The initial value of each property is indicated in theproperty's definition. If there is no initial value, thatproperty is not specified on the formatting object.In general, this is an error.

Since it has no parent, the root of the result treecannot use values from a parent formattingobject; in this case, the initial value is used if necessary.

5.1.2 Computed Values

Specified values may be absolute (i.e., they are notspecified relative to another value, as in "red" or "2mm")or relative (i.e., they are specified relative to another value,as in "auto", "2em", and "12%"), or they may be expressions.For most absolute values, nocomputation is needed to find the computed value. Relative values,on the other hand, must be transformed into computed values: percentagesmust be multiplied by a reference value (each property defines which valuethat is), values with a relative unit (em)must be made absolute by multiplying with the appropriate font size,"auto" values must be computed by the formulas given witheach property, certain propertyvalues ("smaller", "bolder") must be replacedaccording to their definitions.The computed value of any property that controls a border widthwhere the style ofthe border is "none" is forced to be "0pt".

Some properties have more than one way in which the property value can be specified.The simplest example of such properties are those which can be specifiedeither in terms of a direction relative to the writing-mode (e.g., padding-before)or a direction in terms of the absolute geometric orientation of the viewport(e.g., padding-top). These two properties are called therelative property and the absolute property, respectively.Collectively, they are called "corresponding properties".

Specifying a value for one property determines both acomputed value for the specified property and a computed valuefor the corresponding property.Which relative property corresponds to which absoluteproperty depends on the writing-mode. For example, ifthe "writing-mode" at the top level of a document is"lr-tb",then "padding-start" corresponds to "padding-left", but ifthe "writing-mode" is "rl-tb", then "padding-start"corresponds to "padding-right".The exact specification of how to compute the values ofcorresponding properties is given in5.3 Computing the Values of Corresponding Properties.

In most cases, elements inherit computed values. However,there are some properties whose specified value may beinherited (e.g., some values for the "line-height"property).In the cases where child elements do not inherit the computed value,this is described in the property definition.

5.1.3 Actual Values

A computed value is in principle ready to beused, but a user agent may not be able to makeuse of the value in a given environment. Forexample, a user agent may only be able to renderborders with integer pixel widths and may, therefore,have to adjust the computed width to an integral numberof media pixels. The actualvalue is the computed value after any such adjustments have been applied.

5.1.4 Inheritance

Some of the properties applicable to formatting objects are "inheritable."Such properties are so identified in the property description.The inheritable properties can be placed on any formattingobject. The inheritable properties are propagated down theformatting object tree from a parent to each child. (These propertiesare given their initial value at the root of the result tree.)For a given inheritable property, if that property is present on achild, then that value of the property is used for that child(and its descendants until explicitly re-set in a lower descendant);otherwise, the specified value of that property on the child is thecomputed value of that property on the parent formattingobject. Hence there is always a specified valuedefined for every inheritable property for everyformatting object.

Note:

Shorthands are included only in the highest XSL conformancelevel: "complete" (see8 Conformance).

The conformance level for each property is shown inB.3 Property Table: Part II.

Note:

For example,if both the "background"and the "background-color" properties are specified on a givenformatting object:process the "background" shorthand, then process the"background-color" property.

Note:

"reference-orientation" is a rotation and does not influencethe correspondence mapping.

5.3.1 Border and Padding Properties

The simplest class of corresponding properties arethose for which there are only two variants in thecorrespondence, an absolute property and a relativeproperty, and the property names differ only in thechoice of absolute orrelative designation; for example, "border-left-color" and"border-start-color".

For this class, the computed values of the correspondingproperties are determined as follows. If the correspondingabsolute variant of the property is specified on the formattingobject, its computed value is used to set the computed value of thecorresponding relative property. If the corresponding absolute propertyis not explicitly specified, then the computedvalue of the absolute property is set to the computed value of thecorresponding relative property.If the corresponding relative property is specified on theformatting object and the absolute property only specified bythe expansion of a shorthand, then the computed value of theabsolute property is set to the computed value of the correspondingrelative property.

Note that if both the absolute and the relativeproperties are notexplicitly specified, then the rules for determining the specifiedvalue will use either inheritance if that is defined for the propertyor the initial value. The initial value must be the same for all possiblecorresponding properties. If both an absolute and a corresponding relativeproperty are explicitly specified, then the above rule gives precedence to theabsolute property, and the specified value of thecorresponding relative propertyis ignored in determining the computed value of the corresponding properties.

The (corresponding) properties that use the above rule todetermine their computed value are:

• border-after-color

• border-before-color

• border-end-color

• border-start-color

• border-after-style

• border-before-style

• border-end-style

• border-start-style

• border-after-width

• border-before-width

• border-end-width

• border-start-width

• padding-after

• padding-before

• padding-end

• padding-start

5.3.2 Margin, Space, and Indent Properties

The "space-before", and "space-after" properties (block-levelformatting objects), "space-start", and "space-end" properties(inline-level formatting objects) are handled in the same way as theproperties immediately above, but the correspondingabsolute properties are in the set: "margin-top","margin-bottom", "margin-left", and "margin-right".The .conditionality component of any space-before or space-after determinedfrom a margin property is set to "retain".

There are two more properties, "end-indent"and "start-indent" (block-levelformatting objects) which correspond to thevarious absolute "margin" properties. For these properties,the correspondence is more complex and involves the corresponding"border-X-width" and "padding-X" properties,where X is one of "left", "right", "top" or "bottom".The computed values of these corresponding properties are determinedas follows:

If the corresponding absolute "margin" property is specified on theformatting object and the formatting object generates a reference areathe computed value of the margin is used to calculate the computedvalue of the corresponding "Y-indent" property,where Y is either "start" or "end".The computed value of the of the absolute "margin" propertyis determined by the CSS descriptions of the propertiesand the relevant sections (in particular section 10.3) of theCSS Recommendation referenced by these properties.The formulae for "start-indent"and "end-indent" are":

start-indent = margin-corresponding+ padding-corresponding + border-corresponding-width

end-indent = margin-corresponding+ padding-corresponding + border-corresponding-width

If the corresponding absolute "margin" property is specified on theformatting object and the formatting object does not generate areference area, the computed value of the margin and the computed valuesof the corresponding "border-X-width" and "padding-X" properties are used tocalculate the computed value of the corresponding "Y-indent" property.The formulae for "start-indent"and "end-indent" are:

start-indent = inherited_value_of(start-indent) +margin-corresponding + padding-corresponding +border-corresponding-width

end-indent = inherited_value_of(end-indent) +margin-corresponding + padding-corresponding +border-corresponding-width

If the corresponding absolute margin property is not explicitlyspecified, or ifthe corresponding relative property is specified on theformatting object and the absolute property only specified bythe expansion of a shorthand,the corresponding absolute margin property is calculatedaccording to the following formulae:

margin-corresponding = start-indent -inherited_value_of(start-indent) - padding-corresponding -border-corresponding-width

margin-corresponding = end-indent -inherited_value_of(end-indent) - padding-corresponding -border-corresponding-width

5.3.3 Height, and Width Properties

Based on the writing-mode in effect for the formatting object,either the "height", "min-height", and "max-height" properties, orthe "width", "min-width", and "max-width" properties are convertedto the corresponding block-progression-dimension, orinline-progression-dimension.

The "height" properties are absolute and indicate the dimensionfrom "top" to "bottom"; the width properties the dimension from"left" to "right".

If the "writing-mode" specifies a block-progression-direction of"top-to-bottom" or "bottom-to-top" the conversion is as follows:

• If any of "height", "min-height", or "max-height" is specified:

  • If "height" is specified then first set:

    block-progression-dimension.minimum=<height>

    block-progression-dimension.optimum=<height>

    block-progression-dimension.maximum=<height>

  • If "height" is not specified, then first set:

    block-progression-dimension.minimum=auto

    block-progression-dimension.optimum=auto

    block-progression-dimension.maximum=auto

  • Then, if "min-height" is specified, reset:

    block-progression-dimension.minimum=<min-height>

  • Then, if "max-height" is specified, reset:

    block-progression-dimension.maximum=<max-height>

  • However, if "max-height" is specifiedas "none", reset:

    block-progression-dimension.maximum=auto

• If any of "width", "min-width", or "min-width" is specified:

  • If "width" is specified then first set:

    inline-progression-dimension.minimum=<width>

    inline-progression-dimension.optimum=<width>

    inline-progression-dimension.maximum=<width>

  • If "width" is not specified, then first set:

    inline-progression-dimension.minimum=auto

    inline-progression-dimension.optimum=auto

    inline-progression-dimension.maximum=auto

  • Then, if "min-width" is specified, reset:

    inline-progression-dimension.minimum=<min-width>

  • Then, if "max-width" is specified, reset:

    inline-progression-dimension.maximum=<max-width>

  • However, if "max-width" is specifiedas "none", reset:

    inline-progression-dimension.maximum=auto

If the "writing-mode" specifies a block-progression-direction of"left-to-right" or "right-to-left" the conversion is as follows:

• If any of "height", "min-height", or "max-height" is specified:

  • If "height" is specified then first set:

    inline-progression-dimension.minimum=<height>

    inline-progression-dimension.optimum=<height>

    inline-progression-dimension.maximum=<height>

  • If "height" is not specified, then first set:

    inline-progression-dimension.minimum=auto

    inline-progression-dimension.optimum=auto

    inline-progression-dimension.maximum=auto

  • Then, if "min-height" is specified, reset:

    inline-progression-dimension.minimum=<min-height>

  • Then, if "max-height" is specified, reset:

    inline-progression-dimension.maximum=<max-height>

  • However, if "max-height" is specifiedas "none", reset:

    inline-progression-dimension.maximum=auto

• If any of "width", "min-width", or "min-width" is specified:

  • If "width" is specified then first set:

    block-progression-dimension.minimum=<width>

    block-progression-dimension.optimum=<width>

    block-progression-dimension.maximum=<width>

  • If "width" is not specified, then first set:

    block-progression-dimension.minimum=auto

    block-progression-dimension.optimum=auto

    block-progression-dimension.maximum=auto

  • Then, if "min-width" is specified, reset:

    block-progression-dimension.minimum=<min-width>

  • Then, if "max-width" is specified, reset:

    block-progression-dimension.maximum=<max-width>

  • However, if "max-width" is specifiedas "none", reset:

    block-progression-dimension.maximum=auto

5.3.4 Overconstrained Geometry

The sum of the start-indent, end-indent, and inline-progression-dimensionof the content-rectangle of an area should be equal to theinline-progression-dimension of the content-rectangle of the closestancestor reference-area. In the case where a specification wouldlead to them being different the end-indent (and thus the correspondingmargin) is adjusted such that the equality is true.

5.4.1 Background-position-horizontal and background-position-vertical Properties

A value of "top", "bottom", "left", "right", or "center" isconverted to a length as specified in the property definition.

5.4.2 Column-number Property

If a value has not been specified on a formatting object to whichthis property applies the initial value is computed as specifiedin the property definition.

5.4.3 Text-align Property

A value of "left", or "right" is converted to the writing-moderelative value as specified in the property definition.

5.4.4 Text-align-last Property

A value of "left", or "right" is converted to the writing-moderelative value as specified in the property definition.

5.4.5 z-index Property

The value is converted to one that is absolute; i.e., the refined valueis the specified value plus the refined value of z-index of its parentformatting object, if any.

5.4.6 Language Property

A value being a 2-letter code in conformance with[ISO639] is converted to the corresponding3-letter[ISO639-2] terminology code,a 3-letter code in conformance with[ISO639-2]bibliographic code is converted to the corresponding 3-letterterminology code, a value of 'none' or 'mul' is converted to 'und'.

5.5.1 Word spacing and Letter spacing Properties

These properties may set values for thespace-startandspace-end traits, as described in the propertydefinitions.

5.5.2 Reference-orientation Property

Thereference-orientation trait is copied fromthe reference-orientation property during refinement. Duringcomposition an absolute orientation is determined(see4.2.2 Common Traits).

5.5.3 Writing-mode and Direction Properties

Thewriting-mode,direction, andunicode-bidi traitsare copied fromthe properties of the same name during refinement.During composition these are used in the determination ofabsolute orientations for theblock-progression-direction,inline-progression-direction, andshift-direction traitsin accordance with4.2.2 Common Traits.

5.5.4 Absolute-position Property

If absolute-position has the value"absolute" or "fixed", the values of theleft-position,top-position, etc. traitsare copied directly from thevalues of the "left", "top", etc. properties. Otherwise these traits'values are left undefined during refinement and determined duringcomposition.

5.5.5 Relative-position Property

If relative-position has the value"relative" then the values of theleft-offset andtop-offset traits are copied directlyfrom the "left" and "top"properties. If the "right" property is specified but "left" is not,thenleft-offset is set to the negative of thevalue of "right". If neither"left" nor "right" is specified theleft-offset is 0.If the "bottom"property is specified but "top" is not, thentop-offset is set to thenegative of the value of "bottom". If neither "top" nor "bottom" isspecified thetop-offset is 0.

5.5.6 Text-decoration Property

The "text-decoration" property value provides values fortheblink trait and a set ofscore and score-color traits. Thespecified color has thevalue of thecolor trait of the formatting objectfor which the "text-decoration" property is being refined.

A property value containing the token "underline" sets a value of"true" to theunderline-score trait, and a value ofspecified color to theunderline-score-colortrait.

A property value containing the token "overline" sets a value of"true" to theoverline-score trait, and a value ofspecified color to theoverline-score-colortrait.

A property value containing the token "line-through" sets a value of"true" to thethrough-score trait, and a value ofspecified color to thethrough-score-colortrait.

A property value containing the token "blink" sets a value of"true" to theblink trait.

A property value containing the token "no-underline" sets a value of"false" to theunderline-score trait, and a value ofspecified color to theunderline-score-colortrait.

A property value containing the token "no-overline" sets a value of"false" to theoverline-score trait, and a value ofspecified color to theoverline-score-colortrait.

A property value containing the token "no-line-through" sets a value of"false" to thethrough-score trait, and a value ofspecified color to thethrough-score-colortrait.

A property value containing the token "no-blink" sets a value of"false" to theblink trait.

5.5.7 Font Properties

The font traits on an area are indirectly derived from the combinationof the font properties, which are used to select a font, and thefont tables from that font.

The abstract model that XSL assumes for a font is described in7.9.1 Fonts and Font Data.

There is no XSL mechanism to specify a particular font; instead,aselected font is chosen from the fonts available to theUser Agent based on a set of selection criteria. Theselectioncriteria are the following font properties:"font-family","font-style","font-variant","font-weight","font-stretch", and"font-size",plus, for some formattingobjects, one or more characters.The details ofhow the selection criteria are used is specified in the"font-selection-strategy" property (see7.9.3 font-selection-strategy).

Thenominal-font trait is set to the selected font. In thecase where there is no selected font and the 'missing character' glyphis displayed, thenominal-font trait is set to the font containingthat glyph, otherwise(i.e., some other mechanism was used to indicate that a characteris not being displayed) thenominal-font is asystem font.

Thedominant-baseline-identifier andactual-baseline-table traits are derived from thevalue of the "dominant-baseline" property. The value of this propertyis a compound value with three components: a baseline-identifier forthe dominant-baseline, a baseline-table and a baseline-tablefont-size. Thedominant-baseline-identifier is set fromthe first component. The baseline-table font-size is used to scale thethe positions of the baselines from the baseline table and, then, theposition of the dominant-baseline is subtracted from the positionsof the other baselines to yield a table of offsets from the dominantbaseline. This table is the value of theactual-baseline-table trait.

5.7.1 Text-transform Property

The case changes specified by this property are carried out duringrefinement by changing the value of the "character" propertyappropriately.

Note:

In most cases, a delimited text range is the maximal sequence ofcharacters that would be formatted into a sequence of one or moreline-areas. For the fo:multi-case and the text with an orientationperpendicular to the dominant-baseline, the delimited range may be asub-sequence of a line or sequence of lines. For example, in Japaneseformatted in a vertical writing-mode, rotated Latin and Arabic textwould be delimited by the vertical Japanese characters thatimmediately surround the Latin and Arabic text. Any formatting objectsthat generated inline-areas would have no affect on the determinationof the delimited text range.

Note:

The expression language supports operations on a limited set ofdatatypes. These do not include <angle>, <time>, and <frequency>.Values of these datatypes must be strings in the expression language.The definition of these datatypes specify the allowed formof these strings.

5.9.1 Property Context

Properties are evaluated against a property-specific context. This context provides:

• A list of allowed resultant types for a property value.

• Conversions from resultant expression value types to an allowed type for the property.

• The current font-size value.

• Conversions from relative numerics by type to absolute numerics within additive expressions.

When a type instance (e.g., a string, a keyword, anumeric, etc.) is recognized in the expression it is evaluated againstthe property context. This provides the ability for specific values to beconverted with the property context's specific algorithms or conversionsfor use in the evaluation of the expression as a whole.

For example, the "auto" enumeration token for certainproperties is a calculated value. Such a token would be convertedinto a specific type instance via an algorithm specified in the property definition.In such a case the resulting value might be an absolute length specifying the widthof some aspect of the formatting object.

In addition, this allows certain types like relative numerics to beresolved into absolute numerics prior to mathematicaloperations.

All property contexts allow conversions as specified in5.9.12 Expression Value Conversions.

5.9.2 Evaluation Order

When a set of properties is being evaluated for aspecific formatting object in the formatting object treethere is a specific order in which properties must be evaluated.Essentially, the "font-size" property must be evaluated first beforeall other properties. Once the "font-size" property has been evaluated,all other properties may be evaluated in any order.

When the "font-size" property is evaluated, the currentfont-size for use in evaluation is the font-size of the parent element.Once the "font-size" property has been evaluated,that value is used as thecurrent font-size for all property contexts of all properties value expressionsbeing further evaluated.

5.9.3 Basics

5.9.4 Function Calls

5.9.5 Numerics

A numeric represents all the types of numbers in an XSL expression.Some of these numbers are absolute values. Others arerelative to some other set of values. All of these values use a floating-point number to represent the number-part of their definition.

A floating-point number can have anydouble-precision 64-bit format IEEE 754 value[IEEE 754].These include a special "Not-a-Number" (NaN) value,positive and negative infinity, and positive and negative zero. SeeSection 4.2.3 of[JLS] for a summary of the keyrules of the IEEE 754 standard.

The following operators may be used with numerics:

+

Performs addition.

-

Performs subtraction or negation.

*

Performs multiplication.

div

Performs floating-point division according to IEEE 754.

mod

Returns the remainder from a truncating division.

Numeric Expressions

If a non-numeric value is used in anAdditiveExpr and there is no property context conversion from that type into an absolute numeric value, the expression is invalid and considered an error.

5.9.6 Absolute Numerics

An absolute numeric is an absolute length which is a pair consisting of aNumber and aUnitName raised to a power. When an absolute length is written without a unit, the unit power is assumed to be zero. Hence, all floating point numbers are a length with a power of zero.

Each unit name has associated with it an internal ratio to some commoninternal unit of measure (e.g., a meter). When a value iswritten in aproperty expression, it is first converted to the internal unit of measureand then mathematical operations are performed.

Inaddition, only the mod,addition, and subtraction operators require that the numerics oneither side of the operation be absolute numerics of the same unit power.For other operations, the unit powers may be different and the resultshould be mathematically consistent as with the handling of powers in algebra.

A property definition may constrain an absolute length to aparticular power.For example, when specifying font-size, the value is expected to be ofpower "one".That is, it is expected to have a single powered unit specified (e.g., 10pt).

When the final value of a property is calculated, the resulting power of theabsolute numeric must be either zero or one. If any other power is specified,the value is an error.

5.9.7 Relative Numerics

Relative lengths are values that arecalculated relative to some other set of values. When written as part of anexpression, they are either converted via the propertycontext into an absolute numeric or passed verbatim as the property value.

It is an error if the property context has no available conversionfor the relative numeric and a conversion is required for expressionevaluation (e.g., within an add operation).

5.9.8 Strings

Strings are represented either asliterals oras anenumeration token.All properties contexts allow conversion from enumeration tokens to strings.See5.9.12 Expression Value Conversions.

5.9.9 Colors

A color is a set of values used to identify a particular color from a color space.Only RGB[sRGB](Red, Green, Blue)and ICC (International Color Consortium)[ICC]colors are included in this Recommendation.

RGB colors are directly represented in the expression language using ahexadecimal notation. ICC colors can be specified through an rgb-iccfunction.Colors can also be specified through the system-colorfunction or through conversion from anEnumerationTokenvia the property context.

5.9.10 Keywords

Keywords are special tokens in the grammar that provide access tocalculated values or other property values.The allowed keywords are defined in the following subsections.

5.9.11 Lexical Structure

When processing an expression,white space (ExprWhitespace) may beallowed before or after any expression token even though it is notexplicitly defined as such in the grammar. In some cases, white spaceis necessary to make tokens in the grammar lexically distinct.Essentially, white space should be treated as if it does not existafter tokenization of the expression has occurred.

The following special tokenization rules must be applied in theorder specified to disambiguate the grammar:

• If the character following anNCName (possibly after interveningExprWhitespace) is"(",then the token must be recognized asFunctionName.

• A number terminates at the first occurrence of a non-digit character otherthan ".". This allows the unit token forlength quantities to parse properly.

• When anNCName immediately follows aNumber, it should be recognized as aUnitName or it is an error.

• TheKeyword values take precedence overEnumerationToken.

• If aNCName follows anumeric,it should be recognized as anOperatorName or it is an error.

Expression Lexical Structure

5.9.12 Expression Value Conversions

Values that are the result of an expression evaluation may be convertedinto property value types. In some instances this is a simple verificationof set membership (e.g., is the value a legal country code). In other cases,the value is expected to be a simple type like an integer and must be converted.

It is not necessary that all types be allowed to be converted. If theexpression value cannot be converted to the necessary type for the property value,it is an error.

The following table indicates what conversions are allowed.

The specific conversion to be applied is property specific and can befound in the definition of each property.

5.9.13 Definitions of Units of Measure

The units of measure in this Recommendation have the following definitions:

5.10.1 Number Functions

numericfloor(numeric)

Thefloor function returns the largest (closest topositive infinity) integer that is not greater than the argument.The numeric argument to this function must be of unit power zero.

numericceiling(numeric)

Theceiling function returns the smallest (closestto negative infinity) integer that is not less than the argument. The numericargument to this function must be of unit power zero.

numericround(numeric)

Theround function returns the integer that isclosest to the argument. If there are two suchnumbers, then the one that is closest to positive infinity isreturned. The numeric argument to this function must be of unit power zero.

numericmin(numeric,numeric)

Themin function returns the minimum of thetwo numeric arguments. These arguments must have the same unit power.

numericmax(numeric,numeric)

Themax function returns the maximum of the twonumeric arguments. These arguments must have the same unit power.

numericabs(numeric)

Theabs functionreturns the absolute value of the numeric argument.That is, if the numeric argument is negative, it returns the negation ofthe argument.

5.10.2 Color Functions

colorrgb(numeric,numeric,numeric)

Thergb function returns a specific color from the RGBcolor space. The parameters to this function must be numerics (real numbers) with alength power of zero.

colorrgb-icc(numeric,numeric,numeric,NCName,numeric,numeric)

Thergb-icc functionreturns a specific color from the ICC Color Profile. The color profile is specified by the name parameter (the fourth parameter). This color profile must have been declared in the fo:declarations formatting object using an fo:color-profile formatting object.

The first three parameters specify a fallback color from the sRGB color space. This color is used when the color profile is not available.

The color is specified by a sequence of one or more color values (real numbers) specified after the name parameter. These values are specific to the color profile.

colorsystem-color(NCName)

Thesystem-color function returns a system definedcolor with a given name.

5.10.3 Font Functions

objectsystem-font(NCName,NCName?)

Thesystem-font function returns acharacteristic of a system font. The first argument is thename of the system font and the second argument, which is optional,names the property that specifies the characteristic. If the secondargument is omitted, then the characteristic returned is the same asthe name of the property to which the expression is being assigned.

For example, the expression"system-font(heading,font-size)" returns the font-sizecharacteristic for the system font named "heading". This is equivalent to theproperty assignment'font-size="system-font(heading)"'.

5.10.4 Property Value Functions

objectinherited-property-value(NCName?)

Theinherited-property-value function returns theinherited value of the property whose name matches the argument specified,or if omitted for the property for whichthe expression is being evaluated.It is an error if this property is not an inherited property.If the argument specifies a shorthand property and if the expressiononly consists of the inherited-property-value function with an argumentmatching the property being computed, it is interpreted as an expansionof the shorthand with each property into which the shorthand expands,each having a value of inherited-property-value with an argumentmatching the property. It is an error if arguments matchinga shorthand property are used in any other way. Similarly,if the argumentspecifies a property of a compound datatype and if the expressiononly consists of the inherited-property-value function withan argument matching the property being computed,it is interpreted as an expansion with each component of thecompound property having a value of inherited-property-valuewith an argument matching the component. It is an error ifarguments matching a property of a compound datatype are usedin any other way.

The returned "inherited value" isthe computed valueof this property on this object's parent. For example,given the following:

<fo:list-block>  ...  <fo:list-item color="red">    <fo:list-item-body background-color="green">      <fo:block background-color="inherited-property-value(color)">      </fo:block>    </fo:list-item-body>  </fo:list-item></fo:list-block>

The background-color property on the fo:block is assignedthe value "red" because the (computed, after inheritance)value of the color (not background-color) property on thefo:list-item-body that is the parent of the fo:block is "red".

numericlabel-end()

Thelabel-end function returns the calculatedlabel-end value for lists. See the definition in7.30.11 provisional-label-separation.

numericbody-start()

Thebody-start function returns thecalculated body-start value for lists.See the definition in7.30.12 provisional-distance-between-starts.

objectfrom-parent(NCName?)

Thefrom-parent functionreturns a computed value (see5.1 Specified, Computed, and Actual Values, and Inheritance)of the property whose name matchesthe argument specified,or if omitted for the property for whichthe expression is being evaluated.The value returned is that for the parent of theformatting object for which the expression is evaluated.If there is no parent, the value returned is the initialvalue. If the argument specifies a shorthand property and ifthe expression only consists of the from-parent function with anargument matching the property being computed, it isinterpretedas an expansion of the shorthand with each property into whichthe shorthand expands, each having a value of from-parent withan argument matching the property.It is an error if arguments matching a shorthand property are usedin any other way.Similarly, if the argument specifies a property of a compound datatypeand if the expression only consists of the from-parent function withan argument matching the property being computed, it is interpretedas an expansion with each component of the compound property havinga value of from-parent with an argument matching the component.It is an error if arguments matching a property of a compound datatypeare used in any other way.

objectfrom-nearest-specified-value(NCName?)

Thefrom-nearest-specified-value functionreturns a computed value of the property whose name matchesthe argument specified,or if omitted for the property for whichthe expression is being evaluated.The value returned is that for the closest ancestor of theformatting object for which the expression is evaluated onwhich thereis an assignment of the property in the XML result tree in thefo namespace.If there is no such ancestor, the value returned is theinitial value.If the argument specifies a shorthand property and ifthe expression only consists of the from-nearest-specified-value function with anargument matching the property being computed, it isinterpretedas an expansion of the shorthand with each property into whichthe shorthand expands, each having a value of from-nearest-specified-value withan argument matching the property.It is an error if arguments matching a shorthand property are usedin any other way.Similarly, if the argument specifies a property ofa compound datatype and if the expression only consists ofthe from-nearest-specified-value function with an argument matchingthe property being computed, it is interpreted as an expansion witheach component of the compound property having a value offrom-nearest-specified-value with an argument matching the component.It is an error if arguments matching a property of a compound datatypeare used in any other way.

objectfrom-page-master-region(NCName?)

Thefrom-page-master-region function returns thecomputed value of the property whose name matches the argument specified,or if omitted for the property for whichthe expression is being evaluated.

In XSL 1.1 this function may only be used as the value of the"writing-mode" and "reference-orientation" properties.In addition the argument of the functionmust be omitted.If an argument is present, it is an error.

The computed value of the designatedproperty is taken from that property on the layout formatting objectbeing used to generate the region viewport/reference area pair.

If this function is used in an expression on a formatting object,F,that is a descendant of an fo:page-sequence, then the computed valueis taken from the region specification that was used to generatethe nearest ancestor region reference area which has asits descendants the areas returned byF.

If the argument specifies a property of a compound datatype andif the expression only consists of the inherited-property-value functionwith an argument matching the property being computed,it is interpreted as an expansion with each component ofthe compound property having a value of inherited-property-value withan argument matching the component. It is an errorif arguments matching a property of a compound datatype are usedin any other way.

<fo:root><fo:layout-master-set>  <fo:simple-page-master master-name="all-pages">    <fo:region-body region-name="xsl-region-body" margin="0.75in"                    writing-mode="tb-rl" />    <fo:region-before region-name="xsl-region-before" extent="0.75in"/>  </fo:simple-page-master>  <fo:page-sequence-master master-name="default-sequence">    <fo:repeatable-page-master-reference master-reference="all-pages"/>  </fo:page-sequence-master></fo:layout-master-set><fo:page-sequence master-name="default-sequence">  <fo:flow flow-name="xsl-region-body">    <fo:block>        [Content in a language which allows either         horizontal or vertical formatting]    </fo:block>  </fo:flow></fo:page-sequence></fo:root>

<fo:page-sequence master-name="default-sequence">

<fo:page-sequence master-name="default-sequence"                  writing-mode="from-page-master-region()">

objectfrom-table-column(NCName?)

Thefrom-table-column functionreturns the inherited value of the property whose name matches theargument specified,or if omitted for the property for whichthe expression is being evaluated,from the fo:table-column whose column-numbermatches the column for which this expression is evaluated andwhose number-columns-spanned also matches any span.If there is no match for the number-columns-spanned, it ismatchedagainst a span of 1. If there is still no match, the initialvalue is returned.If the argument specifies a shorthand property and if the expressiononly consists of the from-table-column function with an argumentmatching the property being computed, it is interpreted asan expansion of the shorthand with each property into whichthe shorthand expands, each having a value of from-table-column withan argument matching the property. It is an error if arguments matchinga shorthand property are used in any other way. Similarly,if the argument specifies aproperty of a compound datatype and if the expression only consists ofthe from-table-column function with an argument matchingthe property being computed, it is interpreted as an expansionwith each component of the compound property having a value offrom-table-column with an argument matching the component.It is an error if arguments matching a property of a compound datatypeare used in any other way.It is also an error to use this function on formatting objectsthat are not an fo:table-cell or its descendants.

numericproportional-column-width(numeric)

Theproportional-column-width functionreturnsN units of proportional measurewhereN is the argument given to this function.The column widths are first determined ignoring the proportionalmeasures. The difference between the table-width and the sum ofthe column widths is the available proportional width. One unitof proportional measure is the available proportional widthdivided by the sum of the proportional factors.It is an error to use this function on formatting objects otherthan an fo:table-column. It is also an error to use this functionif the fixed table layout is not used.

objectmerge-property-values(NCName?)

Themerge-property-values function returns a value of theproperty whose name matches the argument,or if omitted for the property for whichthe expression is being evaluated.The value returned is the specified value on the lastfo:multi-property-set, of the parent fo:multi-properties,that applies to the User Agent state.If there is no such value, the computed value of theparent fo:multi-properties is returned.If the argument specifies a shorthand property and if the expressiononly consists of the merge-property-values function with an argumentmatching the property being computed, it is interpreted as an expansionof the shorthand with each property into which the shorthand expands,each having a value of merge-property-values with an argument matchingthe property. It is an error if arguments matching a shorthand propertyare used in any other way. Similarly, if the argumentspecifies a property of a compound datatype and if the expressiononly consists of the merge-property-values function with an argumentmatching the property being computed, it is interpreted asan expansion with each component of the compound property having avalue of merge-property-values with an argument matching the component.It is an error if arguments matching a property of a compound datatypeare used in any other way.

It is an error to use this function on formatting objects otherthan an fo:wrapper that is the child of an fo:multi-properties.

space-before.minimum="2.0pt"space-before.optimum="3.0pt"space-before.maximum="4.0pt"space-before.precedence="0"space-before.conditionality="discard"

space-before="4.0pt"

space-before.minimum="4.0pt"space-before.optimum="4.0pt"space-before.maximum="4.0pt"space-before.precedence="0"space-before.conditionality="discard"

Note:

Since a <percentage> value,that is not interpreted as "auto",is a valid <length> value it may be used in a short form.

keep-together="always"

keep-together.within-line="always"keep-together.within-column="always"keep-together.within-page="always"

space-before="4.0pt"space-before.maximum="6.0pt"

space-before.minimum="4.0pt"space-before.optimum="4.0pt"space-before.maximum="6.0pt"space-before.precedence="0"space-before.conditionality="discard"

Note:

For example, assuming a block-progression-direction of"top-to-bottom", in a specification of

margin-top="10.0pt"space-before.minimum="4.0pt"

the explicit setting of one of the components of the correspondingrelative property will have no effect.

6.1.1 Definitions Common to Many Formatting Objects

This categorization leads to defining two traits which characterizethe relationship between an area and the formatting objects whichgenerate and return that area. These traits aregenerated-by andreturned-by.

The value of thegenerated-by trait is asingle formattingobject. A formatting objectF is defined togenerate an areaAif the semantics ofF specify the generation ofone or more areas andA is one of the areas thusgenerated, or is a substituted form of one of the areas thusgenerated, as specified in section4.7.2 Line-building.

In the case of substituted glyph-areas, the generating formattingobject is deemed to be the formatting object which generated theglyph-area which comes first in the sequence of substitutedglyph-areas. In the case of an inserted glyph-area (e.g., anautomatically-generated hyphen) the generating formatting object isdeemed to be the generating formatting object of the last glyph-areapreceding the inserted glyph-area in the pre-ordertraversal of the area tree.

The value of thereturned-by trait is a setof pairs, where eachpair consists of a formatting object and a positive integer. Theinteger represents the position of the area in the ordering of allareas returned by the formatting object.

A formatting objectF is defined toreturnthe sequence ofareasA,B,C, ... ifthe pair(F,1) is a member of thereturned-by trait ofA, the pair(F,2) is a member of thereturned-by trait ofB, the pair(F,3) is a member of thereturned-by trait ofC, ...

If an area is a member of the sequence of areas returned by aformatting object, then either it was generated by the formattingobject or it was a member of the sequence of areas returned by a childof that formatting object. Not all areas returned by a child of aformatting object need be returned by that formatting object. Aformatting object may generate an area that has, as some ofits children areas, areas returned by the children of thatformattingobject. These children (in the area tree) of the generated area arenot returned by the formatting object to which they were returned.

A set of nodes in a tree is alineage if:

• there is a nodeN in the set such that all thenodes in the set are ancestors ofN, and

• for every nodeN in the set, if the set containsan ancestor ofN, it also contains the parent ofN.

The set of formatting objects that an area is returned by is alineage.

Areas returned by a formatting object may be eithernormal orout-of-line. Normal areas represent areas inthe"normal flowof text"; that is, they become area children of the areas generated bythe formatting object to which they are returned. Normal areas have areturned-by lineage of size one. There isonly one kind of normal area.

Out-of-line areas are areas used outside the normal flow of texteither because they are absolutely positioned or they are part of afloat or footnote. Out-of-line areas may have areturned-by lineage of size greater than one.

Thearea-class trait indicates which class,normal orout-of-line, an area belongs to. For out-of-line areas, it alsoindicates the subclass of out-of-line area. The values for this traitare: "xsl-normal", "xsl-absolute", "xsl-footnote","xsl-side-float", or "xsl-before-float".An areais normal if and only if the value of thearea-class trait is"xsl-normal"; otherwise, the area is an out-of-linearea. (See section4.2.5 Stacking Constraints.)

The areasreturned-by a given formatting object are ordered asnoted above. This ordering defines an ordering on the sub-sequence ofareas that are of a givenarea-class, such as the sub-sequenceof normal areas. An areaA precedes an areaB in the sub-sequence ifand only if areaA precedes areaB in the areasreturned-by theformatting objects.

Areference-area chainis defined as a sequenceof reference-areas that is either generated by the same formattingobject that is not a page-sequence formatting object, or that consistsof the region reference-areas or normal-flow-reference-areas(see6.4.14 fo:region-body)generated using region formatting objects assigned to the sameflow (see6.4.1.4 Flows and Flow Mapping).The reference-areas in the sequence are saidto be "contained" by the reference-area chain, and they have thesame ordering relative to each other in the sequence as they havein the area tree, using pre-order traversal order of the area tree.

     block     block-container     table-and-caption     table     list-block

     bidi-override     character     external-graphic     instream-foreign-object     inline     inline-container     leader     page-number     page-number-citation     page-number-citation-last     scaling-value-citation     basic-link     multi-toggle     index-page-citation-list

     multi-switch     multi-properties     index-range-begin     index-range-end     wrapper     retrieve-marker

     retrieve-table-marker

     change-bar-begin     change-bar-end

     float

     footnote

6.4.1 Introduction

The root node of the formatting object tree must be anfo:rootformatting object. The children of the fo:root formatting object area single fo:layout-master-set, an optional fo:declarations,an optional fo:bookmark-tree,and a sequence of one or morefo:page-sequences and/or fo:page-sequence-wrapper elements.The fo:layout-master-set defines the geometry andsequencing of the pages; the children of the fo:page-sequences, whichare calledflows (contained in fo:flow andfo:static-content), provide the content that is distributedinto the pages. The fo:declarations object is a wrapper for formatting objectswhose content is to be used as a resource to the formattingprocess. The process of generating the pages is done automaticallyby the XSL processor formatting the result tree.

The children of the fo:layout-master-set are the pagination and layoutspecifications and flow-map specifications.There are two types of pagination and layoutspecifications: page-masters and page-sequence-masters. Page-mastershave the role of describing the intended subdivisions of a page andthe geometry of these subdivisions. Page-sequence-masters have therole of describing the sequence of page-masters that will be used togenerate pages during the formatting of an fo:page-sequence.Flow-maps have the role of assigning flows to regions.

<fo:flow flow-name="A">  <fo:block>In the second century ofthe Christian Aera, the empire of Rome ... </fo:block></fo:flow>

<fo:flow flow-name="B">  <fo:block>Quo usque tandem abutere, Catilina, patientia nostra? ...</fo:block></fo:flow>

<fo:flow-map flow-map-name="E1">  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier flow-name-reference="A"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier region-name-reference="R"/>    </fo:flow-target-list>  </fo:flow-assignment>  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier flow-name-reference="B"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier region-name-reference="S"/>    </fo:flow-target-list>  </fo:flow-assignment></fo:flow-map>

<fo:flow-map flow-map-name="E2">  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier flow-name-reference="A"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier region-name-reference="R1"/>      <fo:region-name-specifier region-name-reference="R2"/>    </fo:flow-target-list>  </fo:flow-assignment></fo:flow-map>

<fo:flow-map flow-map-name="E3">  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier flow-name-reference="A"/>      <fo:flow-name-specifier flow-name-reference="B"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier region-name-reference="R"/>    </fo:flow-target-list>  </fo:flow-assignment></fo:flow-map>

<fo:flow-map flow-map-name="E4">  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier flow-name-reference="A"/>      <fo:flow-name-specifier flow-name-reference="B"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier region-name-reference="R1"/>      <fo:region-name-specifier region-name-reference="R2"/>    </fo:flow-target-list>  </fo:flow-assignment></fo:flow-map>

6.4.2 fo:root

Common Usage:

This is the top node of the formatting object tree. It holds anfo:layout-master-set formatting object (which holds all masters usedin the document), an optional fo:declarations,an optional fo:bookmark-tree,and one or more fo:page-sequence or fo:page-sequence-wrapper objects. Eachfo:page-sequence represents a sequence of pages that result fromformatting the content children of the fo:page-sequence.An fo:page-sequence-wrapper can also occur as the child of fo:root.An fo:page-sequence-wrapper can contain zero or morefo:page-sequence objects or fo:page-sequence-wrappers.The fo:page-sequence-wrapper is used to specify inherited propertiesfor the fo:page-sequence objects it wraps; it has no additionalformatting semantics.

Areas:

Page-viewport-areas are returned by the fo:page-sequence children of thefo:root formatting object. The fo:root does not generate any areas.

Constraints:

The children of the root of the area tree consist solely of, and totally of, thepage-viewport-areas returned by the fo:page-sequence children of thefo:root. The set of all areas returned by the fo:page-sequence childrenisproperly ordered. (See Section4.7.1 General Ordering Constraints.)

Contents:

(layout-master-set,declarations?,bookmark-tree?,(page-sequence|page-sequence-wrapper)+)

It is an error if there is not at least one fo:page-sequencedescendant of fo:root.

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.27.11 media-usage

6.4.3 fo:declarations

Common Usage:

The fo:declarations formatting object is used to group global declarations for a stylesheet.

Areas:

The fo:declarations formatting object does not generateor return any areas.

Constraints:

None.

Contents:

(color-profile)*

The fo:declarations formatting object may haveadditional child elements in a non-XSL namespace. Their presence does not,however, change the semantics of the XSL namespace objects and properties.The permitted structure of these non-XSL namespace elements is defined fortheir namespace(s).

6.4.4 fo:color-profile

Common Usage:

The fo:color-profile formatting object is used to declarean ICC Color Profile for a stylesheet.The color-profile is referenced again via the name specified inthe "color-profile-name" property.

The color-profile is identified by the URI specified in the "src"property value. This URI may identify an internally recognizedcolor-profile or it may point to a ICC Color Profile encodingthat should be loaded and interpreted.

When the color-profile is referenced (e.g., via thergb-icc function5.10.2 Color Functions), the following rules are used:

1. If the color-profile is available, the color valueidentified from the color-profile should be used.

2. If the color-profile is not available,the sRGB([sRGB]) fallback must be used.

Areas:

The fo:color-profile formatting object does not generateor return any areas.

Constraints:

None.

Contents:

EMPTY

The following properties apply to this formatting object:

7.30.16 src
7.18.2 color-profile-name
7.18.3 rendering-intent

6.4.5 fo:page-sequence

Common Usage:

The fo:page-sequence formatting object is used to specify how tocreate a (sub-)sequence of pages within a document; for example, achapter of a report. The content of these pages comes from flowchildren of the fo:page-sequence as assigned by the flow-map in effectfor thatfo:page-sequence. The layout of these pages comes fromthe fo:page-sequence-master or page-masterreferenced by themaster-referencetrait on the fo:page-sequence. The sequence of areas returned byeach of the flow-object children of the fo:page-sequence aremade descendants of the generated pages as described below.

Areas:

The fo:page-sequence formatting object generates a sequence ofviewport/reference pairs, and returns the page-viewport-areas. Foreach page-reference-area, and each region specified in the page-master used togenerate that page-reference-area, the fo:page-sequence object also generatesthe viewport/reference pair for the occurrence of that region in thatpage-reference-area, and may generate a before-float-reference-area,footnote-reference-area,and main-reference-area, and one or more normal-flow-reference-areas.The generation of these further areas is described in the descriptionsof the fo:simple-page-master, region-masters and fo:flow-map.It may also generate a title-area.

All areas generated by an fo:page-sequence havearea-class "xsl-absolute".

The page-viewport-areas identify one of the sides as a page binding edge.This recommendation does not specify the mechanism for selectingwhich side is the page binding edge.

For each formatting object descendantD under the change bar influenceof a given fo:change-bar-begin objectF (as defined in6.13.2 fo:change-bar-begin),the fo:page-sequence generates a "change bar area"for each areaA returned byD, as a child of the ancestor region-area ofA. Each change bar area is of class xsl-absolute, with zero margin andpadding, with border-end-color given by the change-bar-color ofF, withborder-end-style given by the change-bar-style ofF, withborder-end-width given by the change-bar-width ofF, with inlineprogression-dimension equal to zero and block-progression-dimensionequal to the dimension ofA parallel to the block-progression-dimensionof the region-area.

The change bar area is positioned to be adjacent to the nearest ancestorareaC ofA which is either a normal-flow-reference-area orregion-reference-area. The change bar area is aligned withA and liesaway fromC by a distance given by the change-bar-offset ofF, withrespect to the start-edge or the end-edge ofC as determined by thechange-bar-placement trait ofF.

Trait Derivation:

Thereference-orientation andwriting-modeof the region-viewport-areasare determined by the values of the "reference-orientation" and"writing-mode" properties of the fo:page-sequence.

Constraints:

Each page-viewport-area/page-reference-area pair is generated using apage-master that satisfies the constraints of the page-sequence-masteridentified by themaster-reference trait of thefo:page-sequence or a page-master that was directly identified by themaster-reference trait. Theregion-viewport-area children of such a page-reference-area must correspondto the regions that are children of that page-master.

The areas generated by the fo:page-sequence have as theirdescendants the areas returned by the flows that are children of thefo:page-sequence.

The areas returned to the fo:page-sequence by a flow must satisfy fivetypes of constraints:

• Completeness. All areas returned by formatting objectdescendants of the flow children of the fo:page-sequencebecome descendants of areas generated by the fo:page-sequence,with the exception of glyph-areas subject to deletion or substitution as in Sections4.7.2 Line-building and4.7.3 Inline-building.

• Flow-map association. The areas returned from aflow child of thefo:page-sequence must be descendants of region-reference-areas generatedusing regions to which the flow is assigned by the flow-map in effect.

  Areas returned from an fo:static-content with aflow-nameofxsl-before-float-separatorbecome children of thebefore-float-reference-area of an area associated to an fo:region-body,following all sibling areas of area-classxsl-before-float. Areasreturned from an fo:static-content with aflow-name ofxsl-footnote-separator become children ofthe footnote-reference-area of an area associated to an fo:region-body,preceding all sibling areas ofarea-classxsl-footnote.

  If the flow-map-reference is specified, the flow-map in effect is theone described by the fo:flow-map child of the fo:layout-master-sethaving a flow-map-name matching the specified value offlow-map-reference on the fo:page-sequence. If the flow-map-referenceis not specified, the flow-map in effect is the implicit flow-mapshown in6.4.22 fo:flow-map.

• Area-class association. Areas returned byflow children of an fo:page-sequence are distributed as follows:

  • All areas of area-classxsl-footnote,and all areas returned from an fo:static-content with a flow-name ofxsl-footnote-separator,must be descendants of a footnote-reference-area;

  • all areas of area-classxsl-before-float,and all areas returned from an fo:static-content with a flow-name ofxsl-before-float-separator,must be descendants of a before-float-reference-area;

  all other areas must be descendants of a region-reference-area andfurther they must be descendants of a main-reference-area child ofthat region-reference-area if it has one.

• Stacking. The stackable areas of a given class returnedby children of each flow are properly stacked within the appropriate reference-area,as described above.

• Flow-assignment ordering.The default ordering constraint of4.7.1 General Ordering Constraintsdoes not apply to the fo:page-sequence.The default ordering constraint applies to the flow object childreninside each fo:flow; special ordering constraints apply to thechild fo:static-content objects.

  If the flow-map in effect for a page-sequence has aflow-assignment child with flow-source-listS andflow-target-listT and the child flow-name-specifiersofS have flow-name-reference valuesF₁,...,F_m, andthe child region-name-specifiers ofT haveregion-name-reference valuesR₁,...,R_n,then for each area-classC, the areas returned tothe page-sequence belonging to that class have thesame order in the area tree (relative to the region ordering)as their generating formatting objects (relative to the flow ordering).That is, ifA andB are areas ofarea-classC and eitherA andBare returned by the same flow withAreturned prior toB, orAandB are returned by flowswith flow-name valuesF_iandF_j, respectively,for somei andj such thati<j, then one ofthe following conditions must hold:

  • the ancestor page-reference-area ofAprecedes the ancestor page-reference-area ofB, or

  • A andB share the same ancestorpage-reference-area,A is a descendant of aregion-reference-area generated usinga region whose region-name value isR_kandB is a descendant of a region-reference-area generatedusing a region whose region-name value isR_l for somek andl such thatk<l, or

  • A andB are descendants of the sameregion-reference-area andA precedesB in thepre-order-tree traversal of the area tree.

If a title-area is generated the following constraints must besatisfied:

• Completeness. All areas returned by formatting objectdescendants of the fo:title child of the fo:page-sequencebecome descendants of the title-area generated by the fo:page-sequence,with the exception of glyph-areas subject to deletion or substitution as in Sections4.7.2 Line-building and4.7.3 Inline-building.

• Stacking. The areas returnedby children of the fo:title are properly stacked within the title-area.

The default ordering constraint of section4.7.1 General Ordering Constraintsdoes apply to the fo:title.

Contents:

(title?,folio-prefix?,folio-suffix?,static-content*,flow+)

The following properties apply to this formatting object:

7.10.1 country
7.27.19 flow-map-reference
7.26.1 format
7.10.2 language
7.26.4 letter-value
7.26.2 grouping-separator
7.26.3 grouping-size
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.27.7 initial-page-number
7.27.6 force-page-count
7.27.9 master-reference
7.21.3 reference-orientation
7.29.7 writing-mode

6.4.6 fo:page-sequence-wrapper

Common Usage:

The fo:page-sequence-wrapper formatting object is used to specifyinherited properties for a group of fo:page-sequence formatting objects.

Areas:

The fo:page-sequence-wrapper formatting object does not generateany areas. The fo:page-sequence-wrapper formatting object returnsthe sequence of areas created by concatenating the sequences of areasreturned by each of the children of the fo:page-sequence-wrapper.

Trait Derivation:

Except for "id", "index-class", and "index-key",the fo:page-sequence-wrapper has no propertiesthat are directly used by it. However, it does serve as a carrier tohold inheritable properties that are utilized by its children.

Constraints:

The order of concatenation of the sequences of areas returned bythe children of the fo:page-sequence-wrapper is the same order asthe children are ordered under the fo:page-sequence-wrapper.An fo:page-sequence-wrapper that contains no fo:page-sequence objectsas descendants returns no areas.

Contents:

(page-sequence|page-sequence-wrapper)*

The following properties apply to this formatting object:

7.30.8 id
7.24.1 index-class
7.24.2 index-key

6.4.7 fo:layout-master-set

Common Usage:

The fo:layout-master-set is a wrapper around all masters used in thedocument. This includes page-sequence-masters, page-masters, andflow-maps.

Areas:

The fo:layout-master-set formatting object generates no area directly.The masters that are the children of the fo:layout-master-set areused by the fo:page-sequence to generate pages.

Constraints:

The value of themaster-name trait on eachchild of the fo:layout-master-set must be unique within the set.

Contents:

(simple-page-master|page-sequence-master|flow-map)+

6.4.8 fo:page-sequence-master

Common Usage:

The fo:page-sequence-master is used to specify the constraints on andthe order in which a given set of page-masters will be used ingenerating a sequence of pages. Pages are automatically generated whenthe fo:page-sequence-master is used in formatting an fo:page-sequence.

Areas:

The fo:page-sequence-master formatting object generates no area directly.It is used by thefo:page-sequence formatting object to generate pages.

Constraints:

The children of the fo:page-sequence-master are a sequence ofsub-sequence-specifiers. A page-sequencesatisfies the constraintdetermined by an fo:page-sequence-master if(a) it can be partitionedinto a sequence of sub-sequences of pages that map one-to-oneto an initial sub-sequence of the sequence ofsub-sequence-specifiers that are thechildren of thefo:page-sequence-master and, (b) for each sub-sequence of pagesin the partition, thatsub-sequence satisfies the constraints of the correspondingsub-sequence-specifier.Thesequence of sub-sequences of pages can be shorter than the sequence ofsub-sequence-specifiers.

It is an error if the entire sequence of sub-sequence-specifiers children isexhausted while some areas returned by an fo:flow are not placed. Implementationsmay recover, if possible, by re-using the sub-sequence-specifier that was lastused to generate a page.

Contents:

(single-page-master-reference|repeatable-page-master-reference|repeatable-page-master-alternatives)+

The following properties apply to this formatting object:

7.27.8 master-name

6.4.9 fo:single-page-master-reference

Common Usage:

An fo:single-page-master-reference is thesimplest sub-sequence-specifier. It specifies a sub-sequence consistingof a single instance of a single page-master. It is used to specifythe use of a particular page-master at a given point in the sequenceof pages that would be generated using the fo:page-sequence-masterthat is the parent of the fo:single-page-master-reference.

Areas:

The fo:single-page-master-reference formatting object generates no area directly.It is used by the fo:page-sequence formattingobject to generate pages.

Constraints:

The fo:single-page-master-reference has a reference to thefo:simple-page-master which has the same master-name as themaster-reference trait on thefo:single-page-master-reference.

The sub-sequence of pages mapped to thissub-sequence-specifier satisfiesthe constraints of this sub-sequence-specifier if (a) thesub-sequence of pages consists of a single page and (b) that page isconstrained to have been generated using the fo:simple-page-masterreferenced by the fo:single-page-master-reference.

Contents:

EMPTY

The following properties apply to this formatting object:

7.27.9 master-reference

6.4.10 fo:repeatable-page-master-reference

Common Usage:

An fo:repeatable-page-master-reference is the next simplestsub-sequence-specifier. It specifies a sub-sequenceconsisting ofrepeated instances of a single page-master. The number of repetitionsmay be bounded or potentially unbounded.

Areas:

The fo:repeatable-page-master-reference formatting object generates no area directly.It is used by the fo:page-sequence formatting object to generatepages.

Constraints:

The fo:repeatable-page-master-reference has a reference to thefo:simple-page-master which has the same master-name as themaster-reference trait on thefo:repeatable-page-master-reference.

The sub-sequence of pages mapped to thissub-sequence-specifier satisfiesthe constraints of this sub-sequence-specifier if (a) thesub-sequence of pages consists of zero or more pages, (b) each page isgenerated using the fo:simple-page-masterreferenced by the fo:repeatable-page-master-reference, and (c) length ofthe sub-sequence is less than or equal to the value ofmaximum-repeats.

If no region-master child of the page-master referred to by thisformatting object has a region-nameassociated to any flow in an fo:page-sequence, then thesub-sequence is constrained to have length zero.

Contents:

EMPTY

The following properties apply to this formatting object:

7.27.9 master-reference
7.27.10 maximum-repeats

6.4.11 fo:repeatable-page-master-alternatives

Common Usage:

The fo:repeatable-page-master-alternativesformatting object is the most complexsub-sequence-specifier. Itspecifies a sub-sequence consisting of repeated instances of a set ofalternative page-masters. The number of repetitions may be bounded orpotentially unbounded. Which of the alternative page-masters is usedat any point in the sequence depends on the evaluation of a conditionon the use of the alternative. Typical conditions include, testingwhether the page which is generated using the alternative is the firstor last page in a page-sequence or is the page blank. The full set ofconditions allows different page-masters to be used for the firstpage, for odd and even pages, for blank pages, etc.

Areas:

The fo:repeatable-page-master-alternativesformatting object generates no area directly. This formatting objectis used by the fo:page-sequence formatting object to generate pages.

Constraints:

The children of the fo:repeatable-page-master-alternatives arefo:conditional-page-master-references. These children are calledalternatives.

The sub-sequence of pages mapped to thissub-sequence-specifier satisfiesthe constraints of this sub-sequence-specifier if (a) thesub-sequence of pages consists of zero or more pages, (b) each page isgenerated using the fo:simple-page-masterreferenced by the one of the alternatives thatare the children of the fo:repeatable-page-master-alternatives, (c)the conditions on that alternative aretrue, (d) thatalternative is the first alternative in the sequence of children forwhich all the conditions aretrue, and (e) the lengthof the sub-sequence is less than or equal to the value ofmaximum-repeats.

Contents:

(conditional-page-master-reference+)

The following properties apply to this formatting object:

7.27.10 maximum-repeats

6.4.12 fo:conditional-page-master-reference

Common Usage:

The fo:conditional-page-master-reference is used to identify apage-master that is to be used when the conditions on its use aresatisfied. This allows different page-masters to be used, for example,for even and odd pages, for the first page in a page-sequence, or forblank pages. This usage is typical in chapters of a book or reportwhere the first page has a different layout than the rest of thechapter and the headings and footings on even and odd pagesmay be different as well.

Areas:

The fo:conditional-page-master-reference formatting object generates no area directly.It is used bythe fo:page-sequence formatting object to generate pages.

Constraints:

The fo:conditional-page-master-reference has a reference to thefo:simple-page-master which has the same master-name asthemaster-reference trait on the fo:conditional-page-master-reference.

There are three traits,page-position,odd-or-even, andblank-or-not-blank thatspecify thesub-conditions on the use of the referenced page-master. All threesub-conditions must betrue for the condition on thefo:conditional-page-master-reference to betrue.

The sub-condition corresponding to thepage-positiontrait istrue if the page generated using thefo:conditional-page-master-reference has the specified position in thesequence of pages generated by the referencing page-sequence; namely,"first", "last","only" (both first and last),"rest" (not firstnor last) or"any" (all of the previous). Thereferencingpage-sequence is the fo:page-sequence that referenced thefo:page-sequence-master from which thisfo:conditional-page-master-reference is a descendant.

The sub-condition corresponding to theodd-or-eventrait istrue if the value of theodd-or-eventrait is "any" or if the value matches the parity of thepage number of the page generated using thefo:conditional-page-master-reference.

The sub-condition corresponding to theblank-or-not-blank trait istrue, if (1) the value of the trait is"not-blank" and the page generated using thefo:conditional-page-master-reference has areas generated by descendants ofthe fo:flow formatting objects; if (2) the value of the trait is"blank" and the page generated using thefo:conditional-page-master-reference is such that there areno areas from any fo:flow to be put on that page (e.g.,(a) to maintain proper page parity due to (i) a break-afteror break-before value of "even-page" or "odd-page" or (ii) at thestart or end of the page-sequence or (b) because theconstraintson the areas generated by descendants of the fo:flow formatting objects wouldnot be satisfied if they were descendant from this page); or if (3)the value of the trait is "any".

Contents:

EMPTY

The following properties apply to this formatting object:

7.27.9 master-reference
7.27.14 page-position
7.27.12 odd-or-even
7.27.1 blank-or-not-blank

6.4.13 fo:simple-page-master

Common Usage:

The fo:simple-page-master is used in the generation of pages andspecifies the geometry of the page. The page is subdivided intoregions: one or more region-body, and up to four other regions:region-before, region-after,region-start, and region-end.

Areas:

The fo:simple-page-master formatting object generates no area directly.It is used in the generation of pages by anfo:page-sequence.

When the fo:simple-page-master is used to generate a page, a viewport/referencepair is generated, consisting of a page-viewport-area and apage-reference-area. The page-viewport-area represents thephysical bounds of the output medium. The page-reference-arearepresents the portion of the page on which content is intended toappear; that is, the area inside the page margins.

In addition, when the fo:simple-page-master is used to generate apage, viewport/reference pairs that correspond to the regions that are thechildren of the fo:simple-page-master are also generated.(See the formatting object specifications forthe five regions (6.4.14 fo:region-body,6.4.15 fo:region-before,6.4.16 fo:region-after,6.4.17 fo:region-start, and6.4.18 fo:region-end)for the details on the generation of these areas.)The "writing-mode" of the pageis used to determine the placement of the five regions on the master.

Trait Derivation:

Thereference-orientation of the page-reference-areaandwriting-modeof the page-viewport-area are determined by the formatting objectthat generates the area (see6.4.5 fo:page-sequence).Thewriting-mode of thepage-reference-area is set to the same value as that ofthe page-viewport-area.Reference-orientation does not affect the page-viewport-area and itsreference-orientation is set to "0".Borders and padding are notallowed with a page-reference-area.The remaining traits on thepage-reference-area areset according to the normal rules for determining the values oftraits.

Constraints:

When a page-master is used in the generation of a page, theblock-progression-dimension andinline-progression-dimension of thecontent-rectangle of the page-viewport-area are determined using thecomputed values of the"page-height" and "page-width" properties.For sheet media, the computed values of the"page-height" and "page-width" propertiesdetermine the orientation of the sheet;"page-height" is measured from "top" to"bottom". For display media, the display window is alwaysupright; the top of the display screen is "top".

The traits derived from the "margin-top","margin-bottom", "margin-left" and"margin-right" properties are used to indent the page-reference-areacontent-rectangle from the corresponding edge of the content-rectangle of thepage-viewport-area.

   [D]

The value of thefolio-number trait on thefirst page returned by thefo:page-sequence is constrained to equal the value of theinitial-page-number trait. The value of thefolio-numbertrait on subsequent pages is constrained to be one greater than thevalue on the immediately preceding page.

Theformat,letter-value,grouping-separator,grouping-size,country, andlanguage traits are used to format the number into astring form, as specified in[XSLT].This formatted number is used by the fo:page-number flow object.

Constraints applicable to regions:

There are a number of constraints that apply to all theregions that are specified within a given fo:simple-page-master.

   [D]

If the block-progression-dimension of the properly stackedregion-reference-area is greater than the block-progression-dimension of theregion-viewport-area that is its parent, then the constraints onthe relationship between the region-viewport-area and theregion-reference-area depend on values of theoverflow traiton the region-master and the kind of flowsassigned to the region.

If all the flows assigned to the corresponding region arefo:static-content flow objects, then there is no constrainton the block-progression-dimension of the region-reference-area.

If all the flows assigned to the corresponding region are fo:flow formattingobjects, then

• If the value of themedia-usage trait ispaginate,or the value of theoverflow trait isvisible,hidden, orerror-if-overflow,then the block-progression-dimension of the region-reference-area isconstrained to be no greater than the block-progression-dimension ofthe region-viewport-area.

• If the value of themedia-usage trait isbounded-in-one-dimension orunbounded,and the value of theoverflow trait isscroll orauto,then there is no constraint on theblock-progression-dimension of the region-reference-area.

Contents:

(region-body+,region-before?,region-after?,region-start?,region-end?)

The following properties apply to this formatting object:

7.11 Common Margin Properties-Block
7.27.8 master-name
7.27.13 page-height
7.27.15 page-width
7.21.3 reference-orientation
7.29.7 writing-mode

6.4.14 fo:region-body

Common Usage:

Used in constructing a simple-page-master. This region specifies aviewport/reference pair that is located in the "center" of thefo:simple-page-master. Theoverflow trait controls howmuch of the underlying region-reference-area is visible; that is, whetherthe region-reference-area is clipped by its parent region-viewport-area.

The fo:region-body may be also be used to provide multiplecolumns. When thecolumn-count trait is greater than one, thenthe region-body will be subdivided into multiple columns.

Areas:

The fo:region-body formatting object is used to generate oneregion-viewport-area and one region-reference-area whenever anfo:simple-page-master that has an fo:region-body as a childis used togenerate a page.A scrolling mechanism shall be provided, in an implementation-definedmanner, if the value of theoverflow trait is "scroll".

The position and size of the region-viewport-area isspecified relative to the content-rectangle of thepage-reference-area generated by fo:simple-page-master. The content-rectangleof the region-viewport-area is indented from the content-rectangleof the page-reference-area by the values of the "margin-top","margin-bottom", "margin-left" and "margin-right" properties.The values of thepaddingandborder-width traits must be "0".

The region-reference-area generated using an fo:region-body is the childof the region-viewport-area.The "writing-mode" of the fo:region-body definesthe column-progression within the region. The inline-progression-directionis used to determine the stacking direction for columns (and thedefault flow order of text from column-to-column).

In addition to the viewport/reference pair, when theregion-body is used togenerate areas,at least one and up to three additional reference-areas aregenerated. These reference-areas are the optionalbefore-float-reference-area,the optionalfootnote-reference-area, and themain-reference-area. The latter reference-area comprisesthe space left after space is borrowed for the other tworeference-areas. The main-reference-area has nopadding, border, or space associated with it.

The main-reference-area has as its childrena sequence ofspan-reference-areas.These are reference-area block-areas with zero border and padding,whose inline-progression-dimension isequal to that of the main-reference-area,and which are normally stacked within the main-reference-area.

Each span-reference-area has one or more reference-area children,designated asnormal-flow-reference-areas.The number and placement of the children of a span-reference-areadepends on thecolumn-count trait of the span-reference-area.In turn, the formatter must generate precisely enough of thesespan-reference-areas, and so set theircolumn-count traits,that block-areasreturned from the flows with aspan of "all" are children ofspan-reference-areas withcolumn-count equal to 1,and block-areas returned from the flows with aspan of "none"are children of span-reference-areas withcolumn-count equal tothe refined value of the column-count property of theassociated region-reference-area.

For each span-reference-area, the numberNof normal-flow-reference-area children is equal to the value of thecolumn-count trait.

It is an error to specify acolumn-count otherthan 1 if the "overflow" property has the value "scroll".An implementation may recover by behaving as if "1" had been specified.

The inline-progression-dimension of each of thesenormal-flow-reference-areas is determined by subtracting(N-1) times the column-gap trait from theinline-progression-dimension of themain-reference-area and dividing that result byN.Using "body-in-size" for the name of the inline-progression-dimensionof the span-reference-area and "column-in-size" for the name of the sizeof the normal-flow-reference-areas in the inline-progression-direction,the formula is:

column-in-size = (body-in-size - (N - 1)*column-gap)/N

The block-progression-dimension of the normal-flow-reference-areasis the same as that of the parent span-reference-area.

The normal-flow-reference-areas are positioned within thespan-reference-area as follows: The first column is positionedwith the before-edge and start-edge of its content-rectanglecoincident with the before-edge and start-edge of the content-rectangleof the span-reference-area. The content-rectangle of theJthnormal-flow-reference-area child of the span-reference-areais positioned with its before-edge coincident with the before-edgeof the content-rectangle of the span-reference-area and with isstart-edge at ((J-1)*(column-in-size + column-gap))in the inline-progression-direction.This results in the end-edge of the content-rectangle of theNth normal-flow-reference-area being coincident withthe end-edge of the content-rectangle of the span-reference-area.

All areas generated by using the fo:region-body are of area-class "xsl-absolute".

Trait Derivation:

Thereference-orientation andwriting-modeof the region-viewport-area are determined by the formatting objectthat generates the area (see6.4.5 fo:page-sequence).Thereference-orientation of theregion-reference-area is set to "0" and is, therefore, thesame as the orientation established by the region-viewport-area.Thewriting-mode of theregion-reference-area is set to the same value as that ofthe region-viewport-area.

The remaining traits on theregion-viewport-area and region-reference-area areset according to the normal rules for determining the values oftraits.

The traits on the span-reference-areas and on thenormal-flow-reference-areas are determinedin the same manner as described in5 Property Refinement / Resolution.

Constraints:

The constraints applicable to all regions (see6.4.13 fo:simple-page-master) all apply.

The inline-progression-dimension of the region-viewport-area isdetermined by the inline-progression-dimension of thecontent-rectangle of the page-reference-area minus the valuesof thestart-indent andend-indenttraits of the region-master. The start-edge and end-edge of thecontent-rectangle of the region-viewport-area are determined by thereference-orientation trait on the page-master.

The block-progression-dimension of the region-viewport-area isdetermined by the block-progression-dimension of the content-rectanglefor the page-reference-area minus the values of thespace-before andspace-after traits ofthe region-master. The before-edge and after-edge of the content-rectangleof the region-viewport-areaare determined by thereference-orientation trait onthe page-master.

The values of thespace-before andstart-indent traits are used to position theregion-viewport-area relative to the before-edge andstart-edge of the content-rectangle ofthe page-reference-area.

The constraints on the size and position of the region-reference-areagenerated using the fo:region-body are covered in the "Constraintsapplicable to regions" section of6.4.13 fo:simple-page-master.

Contents:

EMPTY

The following properties apply to this formatting object:

7.8 Common Border, Padding, and Background Properties
7.11 Common Margin Properties-Block
7.21.1 clip
7.27.2 column-count
7.27.3 column-gap
7.14.4 display-align
7.21.2 overflow
7.27.17 region-name
7.21.3 reference-orientation
7.29.7 writing-mode

6.4.15 fo:region-before

Common Usage:

Used in constructing a simple-page-master. This region specifiesa viewport/reference pair that is located on the "before" side ofthe page-reference-area.In lr-tb writing-mode, this region corresponds tothe headerregion. Theoverflow trait controls howmuch of the underlying region-reference-area is visible; that is, whetherthe region-reference-area is clipped by its parent region-viewport-area.

Areas:

The fo:region-before formatting object is used to generate oneregion-viewport-areaand one region-reference-area.

The values of thepaddingandborder-width traits must be "0".

The before-edge of the content-rectangle of thisregion-viewport-area is positioned coincident with thebefore-edge of the content-rectangle of the page-reference-areagenerated using the parent fo:simple-page-master. The block-progression-dimensionof the region-viewport-area isdetermined by theextent trait on the fo:region-beforeformatting object.

The inline-progression-dimension of the region-viewport-area is determined by theprecedence trait on the fo:region-before. If the valueof theprecedence trait istrue, then theinline-progression-dimension extends up to the start-edge andend-edge of thecontent-rectangle of the page-reference-area. In this case, the region-beforeregion-viewport-area acts like a float into areasgenerated by the region-start and region-end. If thevalue of theprecedence trait on the fo:region-beforeisfalse, then these adjacent regions float into the areagenerated by the fo:region-before and the extent of thefo:region-before is (effectively) reduced by the incursions of theadjacent regions.

The region-reference-area lies on a canvasunderneath the region-viewport-area.

The size of the region-reference-area depends on the setting of theoverflow trait on the region. If the value of thattraitis "auto", "hidden", "error-if-overflow", "paginate",or "visible" then the size of thereference-areais the same as the size of the viewport. If the value of theoverflowtrait is "scroll", the size of the reference-area isequalto the size of the viewport in theinline-progression-direction in thewriting-mode for the region and has no constraint in theblock-progression-direction (which implies that it grows tohold the distribution of all the content bound to the region).

Trait Derivation:

Thereference-orientation andwriting-modeof the region-viewport-area are determined by the formatting objectthat generates the area (see6.4.5 fo:page-sequence).Thereference-orientation of theregion-reference-area is set to "0" and is, therefore, thesame as the orientation established by the region-viewport-area.Thewriting-mode of theregion-reference-area is set to the same value as that ofthe region-viewport-area.

The remaining traits on theregion-viewport-area and region-reference-area areset according to the normal rules for determining the values oftraits.

Constraints:

The constraints on the size and position of the region-reference-areagenerated using the fo:region-before are covered in the "Constraintsapplicable to regions" section of6.4.13 fo:simple-page-master.

Contents:

EMPTY

The following properties apply to this formatting object:

7.8 Common Border, Padding, and Background Properties
7.21.1 clip
7.14.4 display-align
7.27.4 extent
7.21.2 overflow
7.27.16 precedence
7.27.17 region-name
7.21.3 reference-orientation
7.29.7 writing-mode

6.4.16 fo:region-after

Common Usage:

Used in constructing a simple-page-master. This region specifiesa viewport/reference pair that is located on the "after" side ofthe page-reference-area.In lr-tb writing-mode, this region corresponds tothe footerregion. Theoverflow trait controls howmuch of the underlying region-reference-area is visible; that is, whetherthe region-reference-area is clipped by its parent region-viewport-area.

Areas:

The fo:region-after formatting object is used to generate oneregion-viewport-areaand one region-reference-area.

The values of thepaddingandborder-width traits must be "0".

The after-edge of the content-rectangle of thisregion-viewport-area is positioned coincident with theafter-edge of the content-rectangle of the page-reference-areagenerated using the parent fo:simple-page-master. The block-progression-dimensionof the region-viewport-area isdetermined by theextent trait on the fo:region-afterformatting object.

The inline-progression-dimension of the region-viewport-area is determined by theprecedence trait on the fo:region-after. If the valueof theprecedence trait istrue, then theinline-progression-dimension extends up to the start-edge andend-edge of thecontent-rectangle of the page-reference-area. In this case, the region-afterregion-viewport-area acts like a float into areasgenerated by the region-start and region-end. If thevalue of theprecedence trait on the fo:region-afterisfalse, then these adjacent regions float into the areagenerated by the fo:region-after and the extent of thefo:region-after is (effectively) reduced by the incursions of theadjacent regions.

The region-reference-area lies on a canvasunderneath the region-viewport-area.

The size of the region-reference-area depends on the setting of theoverflow trait on the region. If the value of thattraitis "auto", "hidden", "error-if-overflow", "paginate",or "visible" then the size of thereference-areais the same as the size of the viewport. If the value of theoverflowtrait is "scroll", the size of the reference-area isequalto the size of the viewport in theinline-progression-direction in thewriting-mode for the region and has no constraint in theblock-progression-direction (which implies that it grows tohold the distribution of all the content bound to the region).

Trait Derivation:

Thereference-orientation andwriting-modeof the region-viewport-area are determined by the formatting objectthat generates the area (see6.4.5 fo:page-sequence).Thereference-orientation of theregion-reference-area is set to "0" and is, therefore, thesame as the orientation established by the region-viewport-area.Thewriting-mode of theregion-reference-area is set to the same value as that ofthe region-viewport-area.

The remaining traits on theregion-viewport-area and region-reference-area areset according to the normal rules for determining the values oftraits.

Constraints:

The constraints on the size and position of the region-reference-areagenerated using the fo:region-after are covered in the "Constraintsapplicable to regions" section of6.4.13 fo:simple-page-master.

Contents:

EMPTY

The following properties apply to this formatting object:

7.8 Common Border, Padding, and Background Properties
7.21.1 clip
7.14.4 display-align
7.27.4 extent
7.21.2 overflow
7.27.16 precedence
7.27.17 region-name
7.21.3 reference-orientation
7.29.7 writing-mode

6.4.17 fo:region-start

Common Usage:

Used in constructing a simple-page-master. This region specifiesa viewport/reference pair that is located on the "start" side ofthe page-reference-area.In lr-tb writing-mode, this region corresponds to a leftsidebar. Theoverflow trait controls howmuch of the underlying region-reference-area is visible; that is, whetherthe region-reference-area is clipped by its parent region-viewport-area.

Areas:

The fo:region-start formatting object is used to generate oneregion-viewport-areaand one region-reference-area.

The values of thepaddingandborder-width traits must be "0".

The start-edge of the content-rectangle of thisregion-viewport-area is positioned coincident with thestart-edge of the content-rectangle of the page-reference-areagenerated using the parent fo:simple-page-master. The inline-progression-dimensionof the region-viewport-area isdetermined by theextent trait on the fo:region-startformatting object.

The block-progression-dimension of the region-viewport-area isdetermined by theprecedence trait on theadjacent fo:region-before and the fo:region-after, if these exist;otherwise it is determined as if the value of theprecedencetrait wasfalse.If the value of theprecedence trait of the fo:region-before (or, respectively,fo:region-after) isfalse, then theblock-progression-dimensionextends up to the before- (or, respectively, after-) edge of thecontent-rectangle of the page-reference-area. In this case, theregion-start acts like a float into areasgenerated by the region-before (respectively, the region-after). Ifthe value of theprecedence trait on the adjacent regions istrue, then these adjacent regions float intothe area generated bythe fo:region-start and the extent of the fo:region-start is(effectively) reduced by the incursions of the adjacent regions withthe value of theprecedence trait equal totrue.

The region-reference-area lies on a canvasunderneath the region-viewport-area.

The size of the region-reference-area depends on the setting of theoverflow trait on the region. If the value of thattraitis "auto", "hidden", "error-if-overflow", "paginate",or "visible" then the size of thereference-areais the same as the size of the viewport. If the value of theoverflowtrait is "scroll", the size of the reference-area isequalto the size of the viewport in theinline-progression-direction in thewriting-mode for the region and has no constraint in theblock-progression-direction (which implies that it grows tohold the distribution of all the content bound to the region).

Trait Derivation:

Thereference-orientation andwriting-modeof the region-viewport-area are determined by the formatting objectthat generates the area (see6.4.5 fo:page-sequence).Thereference-orientation of theregion-reference-area is set to "0" and is, therefore, thesame as the orientation established by the region-viewport-area.Thewriting-mode of theregion-reference-area is set to the same value as that ofthe region-viewport-area.

The remaining traits on theregion-viewport-area and region-reference-area areset according to the normal rules for determining the values oftraits.

Constraints:

The constraints on the size and position of the region-reference-areagenerated using the fo:region-start are covered in the "Constraintsapplicable to regions" section of6.4.13 fo:simple-page-master.

Contents:

EMPTY

The following properties apply to this formatting object:

7.8 Common Border, Padding, and Background Properties
7.21.1 clip
7.14.4 display-align
7.27.4 extent
7.21.2 overflow
7.27.17 region-name
7.21.3 reference-orientation
7.29.7 writing-mode

6.4.18 fo:region-end

Common Usage:

Used in constructing a simple-page-master. This region specifiesa viewport/reference pair that is located on the "end" side ofthe page-reference-area.In lr-tb writing-mode, this region corresponds to a right sidebar.Theoverflow trait controls howmuch of the underlying region-reference-area is visible; that is, whetherthe region-reference-area is clipped by its parent region-viewport-area.

Areas:

The fo:region-end formatting object is used to generate oneregion-viewport-areaand one region-reference-area.

The values of thepaddingandborder-width traits must be "0".

The end-edge of the content-rectangle of thisregion-viewport-area is positioned coincident with theend-edge of the content-rectangle of the page-reference-areagenerated using the parent fo:simple-page-master. The inline-progression-dimensionof the region-viewport-area isdetermined by theextent trait on the fo:region-endformatting object.

The block-progression-dimension of the region-viewport-area isdetermined by theprecedence trait on theadjacent fo:region-before and the fo:region-after, if these exist;otherwise it is determined as if the value of theprecedencetrait wasfalse.If the value of theprecedence trait of the fo:region-before (or, respectively,fo:region-after) isfalse, then theblock-progression-dimensionextends up to the before- (or, respectively, after-) edge of thecontent-rectangle of the page-reference-area. In this case, theregion-end acts like a float into areasgenerated by the region-before (respectively, the region-after). Ifthe value of theprecedence trait on the adjacent regions istrue, then these adjacent regions float intothe area generated bythe fo:region-end and the extent of the fo:region-end is(effectively) reduced by the incursions of the adjacent regions withthe value of theprecedence trait equal totrue.

The region-reference-area lies on a canvasunderneath the region-viewport-area.

The size of the region-reference-area depends on the setting of theoverflow trait on the region. If the value of thattraitis "auto", "hidden", "error-if-overflow", "paginate",or "visible" then the size of thereference-areais the same as the size of the viewport. If the value of theoverflowtrait is "scroll", the size of the reference-area isequalto the size of the viewport in theinline-progression-direction in thewriting-mode for the region and has no constraint in theblock-progression-direction (which implies that it grows tohold the distribution of all the content bound to the region).

Trait Derivation:

Thereference-orientation andwriting-modeof the region-viewport-area are determined by the formatting objectthat generates the area (see6.4.5 fo:page-sequence).Thereference-orientation of theregion-reference-area is set to "0" and is, therefore, thesame as the orientation established by the region-viewport-area.Thewriting-mode of theregion-reference-area is set to the same value as that ofthe region-viewport-area.

The remaining traits on theregion-viewport-area and region-reference-area areset according to the normal rules for determining the values oftraits.

Constraints:

The constraints on the size and position of the region-reference-areagenerated using the fo:region-end are covered in the "Constraintsapplicable to regions" section of6.4.13 fo:simple-page-master.

Contents:

EMPTY

The following properties apply to this formatting object:

7.8 Common Border, Padding, and Background Properties
7.21.1 clip
7.14.4 display-align
7.27.4 extent
7.21.2 overflow
7.27.17 region-name
7.21.3 reference-orientation
7.29.7 writing-mode

6.4.19 fo:flow

Common Usage:

The content of the fo:flow formatting object is asequence offlow objects that provides the flowing text content that isdistributed into pages.

Areas:

The fo:flow formatting object does not generate any areas. Thefo:flow formatting object returns a sequence of areas created byconcatenating the sequences of areas returned by each of the childrenof the fo:flow. The order of concatenation is the same order as thechildren are ordered under the fo:flow.

Constraints:

The flow-map determines the assignment of the contentof the fo:flow to a region.

Contents:

(%block;)+

In addition this formatting object may have a sequence ofzero or more fo:markers as its initial children.

The following properties apply to this formatting object:

7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.27.5 flow-name

6.4.20 fo:static-content

Common Usage:

Thefo:static-content formatting object holds a sequence or atree offormatting objects that is to be presented in a singleregionor repeated in like-named regions on one or more pages in the page-sequence.Its common use is for repeating or running headers and footers.

This content is repeated, in itsentirety, on every page to which it is assigned.

Areas:

The fo:static-content formatting object does not generate any areas.The fo:static-content formatting object returns the sequence of areascreated by concatenating the sequences of areas returned by each ofthe children of the fo:static-content. The order of concatenation is the sameorder as the children are ordered under the fo:static-content.

Constraints:

The flow-map determines the assignment of the contentof the fo:static-content to a region.

The fo:static-content may be processed multiple times and thus thedefault ordering constraint of section4.7.1 General Ordering Constraintsdoes not apply to the fo:static-content. Instead, it must satisfy theconstraint on a per-page basis. Specifically, ifP is a page-reference-area,C is an area-class, andS is the set of all descendants ofPof area-classC returned to the fo:static-content descendant, thenSmust be properly ordered.

Contents:

(%block;)+

The following properties apply to this formatting object:

7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.27.5 flow-name

6.4.21 fo:title

Common Usage:

The fo:title formatting object is used to associate a title with agiven page-sequence. This title may be used by an interactive User Agent toidentify the pages. For example, the content of the fo:title can beformatted and displayed in a "title" window or in a "tool tip".

Areas:

This formatting object returns the sequence of areas returned by thechildren of this formatting object.

Constraints:

The sequence of returned areas must be the concatenation of thesub-sequences of areas returned by each of the flow children of thefo:title formatting object in the order in which the children occur.

Contents:

(#PCDATA|%inline;)*

An fo:title is not permitted tohave an fo:float, fo:footnote or fo:marker as a descendant.

Additionally, an fo:title is not permitted to have as a descendantan fo:block-container that generates an absolutely positioned area.

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.9 Common Font Properties
7.12 Common Margin Properties-Inline
7.18.1 color
7.16.4 line-height
7.30.17 visibility

6.4.22 fo:flow-map

Common Usage:

The fo:flow-map is used to specify the assignment of flows toregions.

Areas:

The fo:flow-map formatting object generates no area directly. Itis used by the fo:page-sequence formatting object to assign flowsto regions.

Each fo:flow-assignment child of the fo:flow map defines a source listand a target list. The source list is a sequence of flow names whosecorresponding fo:flow objects (in the referring fo:page-sequence) aretreated as a single fo:flow for composition purposes. The target list isa sequence of region-names which identify the region or regions on eachpage which are used for the source content.

For each fo:flow-assignment child of the fo:flow-map, having anfo:flow-source-list child S and an fo:flow-target-list child T,we say that thefo:flow-mapassigns each of the flows referenced by thefo:flow-name-specifier children of S to the regions referenced by thefo:region-name-specifier children of T.

Constraints:

Many of the constraints that a flow-map induces are expressed in6.4.5 fo:page-sequence.

The children of the fo:flow-map are fo:flow-assignment objects containingparallel constraints for assigning flows to regions. It is an error for aflow-name to appear in the source list of more than onefo:flow-assignmentchild of a given fo:flow-map. It is also an error for a region-name toappear in the target list of more than one fo:flow-assignmentchild of agiven fo:flow-map.

Implicit flow-map:

<fo:flow-map>  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier        flow-name-reference="xsl-region-body"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier        region-name-reference="xsl-region-body"/>    </fo:flow-target-list>  </fo:flow-assignment>  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier        flow-name-reference="xsl-region-before"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier        region-name-reference="xsl-region-before"/>    </fo:flow-target-list>  </fo:flow-assignment>  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier        flow-name-reference="xsl-region-after"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier        region-name-reference="xsl-region-after"/>    </fo:flow-target-list>  </fo:flow-assignment>  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier        flow-name-reference="xsl-region-start"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier        region-name-reference="xsl-region-start"/>    </fo:flow-target-list>  </fo:flow-assignment>  <fo:flow-assignment>    <fo:flow-source-list>      <fo:flow-name-specifier        flow-name-reference="xsl-region-end"/>    </fo:flow-source-list>    <fo:flow-target-list>      <fo:region-name-specifier        region-name-reference="xsl-region-end"/>     </fo:flow-target-list>  </fo:flow-assignment></fo:flow-map>

Contents:

(flow-assignment+)

The following properties apply to this formatting object:

7.27.18 flow-map-name

6.4.23 fo:flow-assignment

Common Usage:

The fo:flow-assignment is used to specify the assignment of onesequence of flows to a sequenceof regions.

Areas:

The fo:flow-assignment formattingobject generates no area directly. It is used by the fo:page-sequenceformattingobject to assign flows to regions.

Constraints:

The children of the fo:flow-assignmentare a source-list and target-list containing constraints for assigningone sequence of flows to a sequence of regions.

Contents:

(flow-source-list,flow-target-list)

6.4.24 fo:flow-source-list

Common Usage:

The fo:flow-source-list isused to specify the sequence of flows to assign in a particularfo:flow-assignment.

Areas:

The fo:flow-source-list formattingobject generates no area directly. It is used by the fo:page-sequenceformattingobject to assign flows to regions.

Constraints:

The children of the fo:flow-source-listare a sequence of flow-name-specifiers identifying flows of the sequence.These flows must be either all fo:flow formatting objects or allfo:static-content formatting objects.It is an error if they are a mixture.

Contents:

(flow-name-specifier+)

6.4.25 fo:flow-name-specifier

Common Usage:

The fo:flow-name-specifieris used to specify one flow in a source-list.

Areas:

The fo:flow-name-specifierformatting object generates no area directly. It is used by thefo:page-sequenceformatting object to assign flows to regions.

Constraints:

The flow-name-reference propertyspecifies the name of a flow in the source sequence.

Contents:

EMPTY

The following properties apply to this formatting object:

7.27.20 flow-name-reference

6.4.26 fo:flow-target-list

Common Usage:

The fo:flow-target-list isused to specify the sequence of regions to which flows are assigned ina particular fo:flow-assignment.

Areas:

The fo:flow-target-list formattingobject generates no area directly. It is used by the fo:page-sequenceformattingobject to assign flows to regions.

Constraints:

The children of the fo:flow-target-listare a sequence of region-name-specifiers identifying regions in thesequence.

Contents:

(region-name-specifier+)

6.4.27 fo:region-name-specifier

Common Usage:

The fo:region-name-specifieris used to specify one region in a target-list.

Areas:

The fo:region-name-specifierformatting object generates no area directly. It is used by thefo:page-sequenceformatting object to assign flows to regions.

Constraints:

The region-name-referenceproperty specifies the name of a region in the target sequence.

Contents:

EMPTY

The following properties apply to this formatting object:

7.27.21 region-name-reference

6.5.1 Introduction

The fo:block formatting object is used for formattingparagraphs, titles, figure captions, table titles, etc. Thefollowing example illustrates the usage of fo:block in astylesheet.

<doc>  <chapter>    <title>Chapter title</title>    <section>      <title>First section title</title>      <paragraph>Section one's first paragraph.</paragraph>      <paragraph>Section one's second paragraph.</paragraph>    </section>    <section>      <title>Second section title</title>      <paragraph>Section two's only paragraph.</paragraph>    </section>  </chapter></doc>

<?xml version="1.0" encoding="utf-8"?><xsl:stylesheet    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"    xmlns:fo="http://www.w3.org/1999/XSL/Format"><xsl:template match="chapter">  <fo:block break-before="page">    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="chapter/title">  <fo:block text-align="center" space-after="8pt"            space-before="16pt" space-after.precedence="3">    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="section">  <xsl:apply-templates/></xsl:template><xsl:template match="section/title">  <fo:block text-align="center" space-after="6pt"            space-before="12pt" space-before.precedence="0"            space-after.precedence="3">    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="paragraph[1]" priority="1">  <fo:block text-indent="0pc" space-after="7pt"            space-before.minimum="6pt" space-before.optimum="8pt"            space-before.maximum="10pt">    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="paragraph">  <fo:block text-indent="2pc" space-after="7pt"            space-before.minimum="6pt" space-before.optimum="8pt"            space-before.maximum="10pt">    <xsl:apply-templates/>  </fo:block></xsl:template></xsl:stylesheet>

<fo:block break-before="page">  <fo:block text-align="center" space-after="8pt"    space-before="16pt"    space-after.precedence="3">Chapter title  </fo:block>  <fo:block text-align="center" space-after="6pt"    space-before="12pt" space-before.precedence="0"    space-after.precedence="3">First section title  </fo:block>  <fo:block text-indent="0pc" space-after="7pt"    space-before.minimum="6pt" space-before.optimum="8pt"    space-before.maximum="10pt">Section one's first paragraph.  </fo:block>  <fo:block text-indent="2pc" space-after="7pt"    space-before.minimum="6pt" space-before.optimum="8pt"    space-before.maximum="10pt">Section one's second paragraph.  </fo:block>  <fo:block text-align="center" space-after="6pt"    space-before="12pt" space-before.precedence="0"    space-after.precedence="3">Second section title  </fo:block>  <fo:block text-indent="0pc" space-after="7pt"    space-before.minimum="6pt" space-before.optimum="8pt"    space-before.maximum="10pt">Section two's only paragraph.  </fo:block></fo:block>

6.5.2 fo:block

Common Usage:

The fo:block formatting object is commonly used for formatting paragraphs,titles, headlines, figure and table captions, etc.

Areas:

The fo:block formatting object generates one or morenormal block-areas.The fo:block returns these areas, anypage-level-out-of-line areas, andanyreference-level-out-of-line areasreturned by the children of the fo:block.The fo:block also generates zero or more line-areas as children of thenormal block-areas it returns, in accordance with4.7.2 Line-building.

Trait Derivation:

The .minimum, .optimum, and .maximum components of thehalf-leading traitare set to 1/2 the difference ofthe computed value of theline-height property and thecomputed value of the sum of thetext-altitude andtext-depth properties.The .precedence and .conditionality components are copied from theline-height property.

Constraints:

No area may have more than one normal child areareturned by the same fo:block formatting object.

The children of each normal area generated by an fo:blockmust satisfy the constraints specified in4.7.2 Line-building.

In addition the constraints imposed by the traits derived from theproperties applicable to this formatting object must be satisfied.The geometric constraints are rigorously defined in4 Area Model.

Contents:

(#PCDATA|%inline;|%block;)*

In addition this formatting object may have a sequence ofzero or more fo:markers as its initial children,optionally followed by an fo:initial-property-set.

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.9 Common Font Properties
7.10 Common Hyphenation Properties
7.11 Common Margin Properties-Block
7.13 Common Relative Position Properties
7.20.1 break-after
7.20.2 break-before
7.19.1 clear
7.18.1 color
7.29.5 text-depth
7.29.4 text-altitude
7.16.1 hyphenation-keep
7.16.2 hyphenation-ladder-count
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.19.3 intrusion-displace
7.20.3 keep-together
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.16.3 last-line-end-indent
7.16.7 linefeed-treatment
7.16.4 line-height
7.16.5 line-height-shift-adjustment
7.16.6 line-stacking-strategy
7.20.6 orphans
7.16.8 white-space-treatment
7.21.4 span
7.16.9 text-align
7.16.10 text-align-last
7.16.11 text-indent
7.30.17 visibility
7.16.12 white-space-collapse
7.20.7 widows
7.16.13 wrap-option

6.5.3 fo:block-container

Common Usage:

The fo:block-container flow object is used togenerate a block-level reference-area, typically containingtext blocks with a different writing-mode. In addition, itcan also be used with a different reference-orientation torotate its content.

Areas:

The fo:block-container formatting object generates one or moreviewport/reference pairs.All generated viewport-areas aresubject to the constraints given by the block-progression-dimension andinline-progression-dimension traits of the fo:block-container. Thefo:block-container returns these areas and any page-level-out-of-lineareas returned by the children of the fo:block-container.

If the absolute-position trait is "auto", these areas all have anarea-class of "xsl-normal". If the absolution-position trait is"absolute" or "fixed" then there is one viewport/reference pair, and itsarea-class is "xsl-absolute" or "xsl-fixed", respectively.

Trait Derivation:

The reference-orientation and writing-mode traits of the viewport-areaand reference-area come from the fo:block-container. These determine theorientation of the start-edge, end-edge, before-edge and after-edge ofthe content-rectangle of the viewport-area, and of the padding-,border-, and content-rectangles of the reference-area.Thereference-orientation of thereference-area is set to "0" and is, therefore, thesame as the orientation established by the viewport-area.The inline-progression-dimension of the reference-area is the same as thatof the viewport-area, and may not be "auto" if theinline-progression-direction is different from that of the parent of thefo:block-container. The block-progression-dimension of thereference-area is not constrained; thus the reference-area may be largerthan the viewport-area and this may cause the "overflow" property tooperate.

Constraints:

The children of each reference-area generatedby an fo:block-container formatting objectmust be normalblock-areas returned by the children of the fo:block-container,must beproperly stacked, andmust beproperly ordered.

Anyreference-level-out-of-lineareas returned by the children of the fo:block-containerare handled as described in6.12.2 fo:float.

Contents:

(%block;)+

In addition an fo:block-container that does not generateanabsolutely positioned areamay have a sequence ofzero or more fo:markers as its initial children.

The following properties apply to this formatting object:

7.6 Common Absolute Position Properties
7.8 Common Border, Padding, and Background Properties
7.11 Common Margin Properties-Block
7.15.3 block-progression-dimension
7.20.1 break-after
7.20.2 break-before
7.19.1 clear
7.21.1 clip
7.14.4 display-align
7.15.6 height
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.15.7 inline-progression-dimension
7.19.3 intrusion-displace
7.20.3 keep-together
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.21.2 overflow
7.21.3 reference-orientation
7.21.4 span
7.15.14 width
7.29.7 writing-mode
7.30.18 z-index

6.6.1 Introduction

Inline-level formatting objects are most commonly used toformata portion of text or for generating rules and leaders. Thereare many other uses. The following examples illustratesome of these uses of inline-level formatting objects.

• putting the first line of a paragraph intosmall-caps,

• turning a normally inline formatting object, fo:external-graphic, intoa block by "wrapping" with an fo:block formattingobject,

• formatting a running footer containing the word"Page" followed by a page number.

<doc><p>This is the text of a paragraph that is going to bepresented with the first line in small-caps.</p></doc>

<?xml version='1.0'?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"                xmlns:fo="http://www.w3.org/1999/XSL/Format"                version='1.0'><xsl:template match="p">  <fo:block>    <fo:initial-property-set font-variant="small-caps"/>    <xsl:apply-templates/>  </fo:block></xsl:template></xsl:stylesheet>

<fo:block>  <fo:initial-property-set font-variant="small-caps">  </fo:initial-property-set>This is the text of a paragraph that is going to bepresented with the first line in small-caps.</fo:block>

<doc>  <figure>    <photo image="TH0317A.jpg"/>    <caption>C'ieng Tamlung of C'ieng Mai</caption>  </figure></doc>

<?xml version='1.0'?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"                xmlns:fo="http://www.w3.org/1999/XSL/Format"                version='1.0'><xsl:template match="figure">  <fo:block>    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="photo">  <fo:block text-align="center">    <fo:external-graphic src="'url({@image})'"/>  </fo:block></xsl:template><xsl:template match="caption">  <fo:block space-before="3pt" text-align="center"    start-indent="10mm" end-indent="10mm">    <xsl:apply-templates/>  </fo:block></xsl:template></xsl:stylesheet>

<fo:block>  <fo:block text-align="center">    <fo:external-graphic src="'url(TH0317A.jpg)'"/>  </fo:block>  <fo:block space-before="3pt" text-align="center" start-indent="10mm"    end-indent="10mm">C'ieng Tamlung of C'ieng Mai</fo:block></fo:block>

<!DOCTYPE doc SYSTEM "pgref.dtd"><doc>  <chapter><title>Chapter</title>    <p>Text</p>  </chapter>  <chapter><title>Chapter</title>    <p>For a description of X see <ref refid="x"/>.</p>  </chapter></doc>

<?xml version='1.0'?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"                xmlns:fo="http://www.w3.org/1999/XSL/Format"                version='1.0'><xsl:template match="doc">  <fo:root>    <fo:layout-master-set>      <fo:simple-page-master master-name="page"        page-height="297mm" page-width="210mm"        margin-top="20mm" margin-bottom="10mm"        margin-left="25mm" margin-right="25mm">        <fo:region-body          margin-top="0mm" margin-bottom="15mm"          margin-left="0mm" margin-right="0mm"/>        <fo:region-after extent="10mm"/>      </fo:simple-page-master>    </fo:layout-master-set>    <fo:page-sequence master-reference="page">      <fo:static-content flow-name="xsl-region-after">        <fo:block>          <xsl:text>Page </xsl:text>          <fo:page-number/>        </fo:block>      </fo:static-content>      <fo:flow flow-name="xsl-region-body">        <xsl:apply-templates/>      </fo:flow>    </fo:page-sequence>  </fo:root></xsl:template><xsl:template match="chapter/title">  <fo:block>    <xsl:number level="multiple" count="chapter" format="1. "/>    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="p">  <fo:block>    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="ref">  <xsl:text>page </xsl:text>  <fo:page-number-citation refid="{generate-id(id(@refid)/title)}"/></xsl:template></xsl:stylesheet>

<fo:root>  <fo:layout-master-set>    <fo:simple-page-master master-name="page"      page-height="297mm" page-width="210mm"      margin-top="20mm" margin-bottom="10mm"      margin-left="25mm" margin-right="25mm">      <fo:region-body margin-top="0mm" margin-bottom="15mm"        margin-left="0mm" margin-right="0mm"/>      <fo:region-after extent="10mm"/>    </fo:simple-page-master>  </fo:layout-master-set>  <fo:page-sequence master-reference="page">    <fo:static-content flow-name="xsl-region-after">      <fo:block>Page <fo:page-number/>      </fo:block>    </fo:static-content>    <fo:flow flow-name="xsl-region-body">      <fo:block>1. Chapter</fo:block>      <fo:block>Text</fo:block>      <fo:block>2. Chapter</fo:block>      <fo:block>For a description of X see page <fo:page-number-citation refid="N5"/>      </fo:block>    </fo:flow>  </fo:page-sequence></fo:root>

<doc>  <chapter><title>Chapter</title>    <p>Text</p>    <section><title>Section</title>    <p>Text</p>    </section>    <section><title>Section</title>    <p>Text</p>    </section>  </chapter>  <chapter><title>Chapter</title>    <p>Text</p>    <section><title>Section</title>    <p>Text</p>    </section>    <section><title>Section</title>    <p>Text</p>    </section>  </chapter></doc>

<?xml version='1.0'?><xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"                xmlns:fo="http://www.w3.org/1999/XSL/Format"                version='1.0'><xsl:template match="doc">  <!-- create the table of contents -->  <xsl:apply-templates select="chapter/title" mode="toc"/>  <!-- do the document -->  <xsl:apply-templates/></xsl:template><xsl:template match="chapter/title" mode="toc">  <fo:block text-align-last="justify">    <fo:basic-link internal-destination="{generate-id(.)}">      <xsl:number level="multiple" count="chapter" format="1. "/>      <xsl:apply-templates/>    </fo:basic-link>    <xsl:text> </xsl:text>    <fo:leader leader-length.minimum="12pt" leader-length.optimum="40pt"               leader-length.maximum="100%" leader-pattern="dots"/>    <xsl:text> </xsl:text>    <fo:page-number-citation ref-id="{generate-id(.)}"/>  </fo:block>  <xsl:apply-templates select="../section/title" mode="toc"/></xsl:template><xsl:template match="section/title" mode="toc">  <fo:block start-indent="10mm" text-align-last="justify">    <fo:basic-link internal-destination="{generate-id(.)}">      <xsl:number level="multiple" count="chapter|section" format="1.1 "/>      <xsl:apply-templates/>    </fo:basic-link>    <xsl:text> </xsl:text>    <fo:leader leader-length.minimum="12pt" leader-length.optimum="40pt"               leader-length.maximum="100%" leader-pattern="dots"/>    <xsl:text> </xsl:text>    <fo:page-number-citation ref-id="{generate-id(.)}"/>  </fo:block></xsl:template><xsl:template match="chapter/title">  <fo:block>    <xsl:number level="multiple" count="chapter" format="1. "/>    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="section/title">  <fo:block>    <xsl:number level="multiple" count="chapter|section" format="1.1 "/>    <xsl:apply-templates/>  </fo:block></xsl:template><xsl:template match="p">  <fo:block>    <xsl:apply-templates/>  </fo:block></xsl:template></xsl:stylesheet>

<fo:block text-align-last="justify">  <fo:basic-link internal-destination="N4">1. Chapter  </fo:basic-link>  <fo:leader leader-length.minimum="12pt" leader-length.optimum="40pt"    leader-length.maximum="100%" leader-pattern="dots">  </fo:leader>  <fo:page-number-citation ref-id="N4">  </fo:page-number-citation></fo:block><fo:block start-indent="10mm" text-align-last="justify">  <fo:basic-link internal-destination="N11">1.1 Section  </fo:basic-link>  <fo:leader leader-length.minimum="12pt" leader-length.optimum="40pt"    leader-length.maximum="100%" leader-pattern="dots">  </fo:leader>  <fo:page-number-citation ref-id="N11">  </fo:page-number-citation></fo:block><fo:block start-indent="10mm" text-align-last="justify">  <fo:basic-link internal-destination="N19">1.2 Section  </fo:basic-link>  <fo:leader leader-length.minimum="12pt" leader-length.optimum="40pt"    leader-length.maximum="100%" leader-pattern="dots">  </fo:leader>  <fo:page-number-citation ref-id="N19">  </fo:page-number-citation></fo:block><fo:block text-align-last="justify">  <fo:basic-link internal-destination="N28">2. Chapter  </fo:basic-link>  <fo:leader leader-length.minimum="12pt" leader-length.optimum="40pt"    leader-length.maximum="100%" leader-pattern="dots">  </fo:leader>  <fo:page-number-citation ref-id="N28">  </fo:page-number-citation></fo:block><fo:block start-indent="10mm" text-align-last="justify">  <fo:basic-link internal-destination="N35">2.1 Section  </fo:basic-link>  <fo:leader leader-length.minimum="12pt" leader-length.optimum="40pt"    leader-length.maximum="100%" leader-pattern="dots">  </fo:leader>  <fo:page-number-citation ref-id="N35">  </fo:page-number-citation></fo:block><fo:block start-indent="10mm" text-align-last="justify">  <fo:basic-link internal-destination="N43">2.2 Section  </fo:basic-link>  <fo:leader leader-length.minimum="12pt" leader-length.optimum="40pt"    leader-length.maximum="100%" leader-pattern="dots">  </fo:leader>  <fo:page-number-citation ref-id="N43">  </fo:page-number-citation></fo:block><fo:block>1. Chapter</fo:block><fo:block>Text</fo:block><fo:block>1.1 Section</fo:block><fo:block>Text</fo:block><fo:block>1.2 Section</fo:block><fo:block>Text</fo:block><fo:block>2. Chapter</fo:block><fo:block>Text</fo:block><fo:block>2.1 Section</fo:block><fo:block>Text</fo:block><fo:block>2.2 Section</fo:block><fo:block>Text</fo:block>

6.6.2 fo:bidi-override

Common Usage:

The fo:bidi-override formatting object is used when the Unicode BIDIalgorithm fails. It forces a string of text to be written in a specificdirection.

Areas:

The fo:bidi-override formatting object generates one or morenormalinline-areas.The fo:bidi-override returns these areas,together with anynormal block-areas,page-level-out-of-line areas,andreference-level-out-of-lineareas returned by the children of the fo:bidi-override.

Trait Derivation:

The direction traits are derived from the "writing-mode","direction", and "unicode-bidi" properties as described in5.5.3 Writing-mode and Direction Properties.

Constraints:

No area may have more than one normal child areareturned by the same fo:bidi-override formatting object.

The children of each normal area returned by an fo:bidi-overridemust satisfy the constraints specified in4.7.3 Inline-building.

Contents:

(#PCDATA|%inline;|%block;)*

In addition this formatting object may have a sequence ofzero or more fo:markers as its initial children.

An fo:bidi-override that is a descendant of an fo:leader or ofthe fo:inline childof an fo:footnote may not have block-level children,unless it has a nearer ancestor that is an fo:inline-container.

The following properties apply to this formatting object:

7.7 Common Aural Properties
7.9 Common Font Properties
7.13 Common Relative Position Properties
7.18.1 color
7.29.1 direction
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.17.2 letter-spacing
7.16.4 line-height
7.30.15 score-spaces
7.29.6 unicode-bidi
7.17.8 word-spacing

6.6.3 fo:character

Common Usage:

The fo:character flow object represents a character thatis mapped toa glyph for presentation. It is an atomic unit to the formatter.

When the result tree is interpreted as a tree of formatting objects,a character in the result tree is treated as if it were an emptyelement of type fo:character with a character attributeequal to the Unicode representation of the character.The semantics of an "auto" value for character properties, which istypically their initial value,are based on the Unicode code point. Overrides may be specified inan implementation-specific manner.

Unicode Tag Characters need not be supported.

Areas:

The fo:character formatting object generates and returnsone or morenormalinline-area.

Constraints:

The dimensions of the areas are determined by the font metrics forthe glyph.

When formatting an fo:character with a "treat-as-word-space" valueof "true", the User Agent may use a different method for determiningtheinline-progression-dimension of the area.

Contents:

EMPTY

The following properties apply to this formatting object:

7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.9 Common Font Properties
7.10 Common Hyphenation Properties
7.12 Common Margin Properties-Inline
7.13 Common Relative Position Properties
7.14.1 alignment-adjust
7.17.7 treat-as-word-space
7.14.2 alignment-baseline
7.14.3 baseline-shift
7.17.1 character
7.18.1 color
7.14.5 dominant-baseline
7.29.5 text-depth
7.29.4 text-altitude
7.29.2 glyph-orientation-horizontal
7.29.3 glyph-orientation-vertical
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.17.2 letter-spacing
7.16.4 line-height
7.30.15 score-spaces
7.17.3 suppress-at-line-break
7.17.4 text-decoration
7.17.5 text-shadow
7.17.6 text-transform
7.30.17 visibility
7.17.8 word-spacing

6.6.4 fo:initial-property-set

Common Usage:

The fo:initial-property-set auxiliary formatting objectspecifies formatting propertiesfor the first line of an fo:block.

Areas:

The fo:initial-property-set formatting object does not generateor return any areas. It simply holds a set of traits that are applicableto the first line-area of the area thathas a value of "true" for theis-first trait and that wasgenerated by the parent fo:block of the fo:initial-property-set.

Trait Derivation:

The traits on the fo:initial-property-set are taken intoaccount as traits constraining the first line as ifthe child inline formatting objects of the fo:block,or parts of them in thecase of a line-break, that were used in formattingthe first line were enclosed by an fo:inline, as a directchild of the fo:block, with those traits.

Constraints:

None.

Contents:

EMPTY

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.9 Common Font Properties
7.13 Common Relative Position Properties
7.18.1 color
7.17.2 letter-spacing
7.16.4 line-height
7.30.15 score-spaces
7.17.4 text-decoration
7.17.5 text-shadow
7.17.6 text-transform
7.17.8 word-spacing

6.6.5 fo:external-graphic

Common Usage:

The fo:external-graphic flow object is used for agraphic where the graphics data resides outside of the fo:element tree.

Areas:

The fo:external-graphicformatting object generates and returns one inline-levelviewport-area and one reference-area containing the external graphic.The inline-level area uses thelarge-allocation-rectangleas defined in4.2.3 Geometric Definitions.

Constraints:

The viewport's size is determined by theblock-progression-dimension andinline-progression-dimension traits.For values of "auto", the content size of the graphic is used.

The content size of a graphic is determined by taking theintrinsic size of the graphic and scaling as specified by thecontent-height,content-width,scaling,allowed-height-scale,andallowed-width-scale traits.If one of the content-height orcontent-width is not "auto", the same scale factor(as calculated from the specified non-auto value) is applied equally toboth directions.

Once scaled, the reference-areais aligned with respect to the viewport-areausing thetext-align anddisplay-aligntraits. If it is too large for the viewport-area,the graphic is aligned as if it would fit and theoverflowtrait controls the clipping, scroll bars, etc.

In the case when the graphics format does not specify an intrinsicsize of the graphic the size is determined in an implementation-definedmanner.

Contents:

EMPTY

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.12 Common Margin Properties-Inline
7.13 Common Relative Position Properties
7.14.1 alignment-adjust
7.14.2 alignment-baseline
7.15.1 allowed-height-scale
7.15.2 allowed-width-scale
7.14.3 baseline-shift
7.15.3 block-progression-dimension
7.21.1 clip
7.15.4 content-height
7.30.7 content-type
7.15.5 content-width
7.14.4 display-align
7.14.5 dominant-baseline
7.15.6 height
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.15.7 inline-progression-dimension
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.16.4 line-height
7.21.2 overflow
7.15.12 scaling
7.15.13 scaling-method
7.30.16 src
7.16.9 text-align
7.15.14 width

6.6.6 fo:instream-foreign-object

Common Usage:

The fo:instream-foreign-object flow object is used for an inlinegraphic or other "generic" objectwhere the object data resides as descendants of thefo:instream-foreign-object, typically as an XML element subtree ina non-XSL namespace.

Areas:

The fo:instream-foreign-objectformatting object generates and returns one inlineviewport-area and one reference-area containing the instream-foreign-object.The inline-level area uses thelarge-allocation-rectangleas defined in4.2.3 Geometric Definitions.

Constraints:

The viewport's size is determined by theblock-progression-dimension andinline-progression-dimension traits.For values of "auto", the content size of the instream foreign object is used.

The content size of an instream-foreign-object is determined by taking theintrinsic size of the object and scaling as specified by thecontent-height,content-width,scaling,allowed-height-scale,andallowed-width-scale traits.If one of the content-height orcontent-width is not "auto", the same scale factor(as calculated from the specified non-auto value) is applied equally toboth directions.

Once scaled, the reference-areais aligned with respect to the viewport-areausing thetext-align anddisplay-aligntraits. If it is too large for the viewport-area,the instream-foreign-object is aligned as if it would fit and theoverflowtrait controls the clipping, scroll bars, etc.

In the case when the instream-foreign-object does not specify an intrinsicsize of the object, the size is determined in an implementation definedmanner.

Contents:

The fo:instream-foreign-object flow object hasa child from a non-XSLnamespace. The permitted structure of this child is thatdefined for that namespace.

The fo:instream-foreign-object flow object may have additional attributesin the non-XSL namespace. These,as well as the xsl defined properties,are made available to the processorof the content of the flow object. Their semantics are defined by thatnamespace.

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.12 Common Margin Properties-Inline
7.13 Common Relative Position Properties
7.14.1 alignment-adjust
7.14.2 alignment-baseline
7.15.1 allowed-height-scale
7.15.2 allowed-width-scale
7.14.3 baseline-shift
7.15.3 block-progression-dimension
7.21.1 clip
7.15.4 content-height
7.30.7 content-type
7.15.5 content-width
7.14.4 display-align
7.14.5 dominant-baseline
7.15.6 height
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.15.7 inline-progression-dimension
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.16.4 line-height
7.21.2 overflow
7.15.12 scaling
7.15.13 scaling-method
7.16.9 text-align
7.15.14 width

6.6.7 fo:inline

Common Usage:

The fo:inline formatting object is commonly used for formattinga portion of text with a background or enclosing it in a border.

Areas:

The fo:inline formatting object generates one or morenormalinline-areas.The fo:inline returns these areas,together with anynormal block-areas,page-level-out-of-line areas,andreference-level-out-of-lineareas returned by the children of the fo:inline.

Constraints:

No area may have more than one normal child areareturned by the same fo:inline formatting object.

The children of each normal area returned by an fo:inlinemust satisfy the constraints specified in4.7.3 Inline-building.

In addition the constraints imposed by the traits derived from theproperties applicable to this formatting object must be satisfied.The geometric constraints are rigorously defined in4 Area Model.

Contents:

(#PCDATA|%inline;|%block;)*

In addition this formatting object may have a sequence ofzero or more fo:markers as its initial children.

An fo:inline that is a child of an fo:footnote may not haveblock-level children.An fo:inline that is a descendant of an fo:leader or of thefo:inline child of an fo:footnotemay not have block-level children, unless it has a nearer ancestor thatis an fo:inline-container.

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.9 Common Font Properties
7.12 Common Margin Properties-Inline
7.13 Common Relative Position Properties
7.14.1 alignment-adjust
7.14.2 alignment-baseline
7.14.3 baseline-shift
7.15.3 block-progression-dimension
7.18.1 color
7.14.5 dominant-baseline
7.15.6 height
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.15.7 inline-progression-dimension
7.20.3 keep-together
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.16.4 line-height
7.17.4 text-decoration
7.30.17 visibility
7.15.14 width
7.16.13 wrap-option

6.6.8 fo:inline-container

Common Usage:

The fo:inline-container flow object is used togenerate an inline reference-area, typically containingtext blocks with a different writing-mode.

Areas:

The fo:inline-container formatting object generates one or moreviewport/reference pairs.All generated viewport-areas aresubject to the constraints given by the block-progression-dimension andinline-progression-dimension traits of the fo:inline-container. Thefo:inline-container returns these areas and any page-level-out-of-lineareas returned by the children of the fo:inline-container.

If the absolute-position trait is "auto", these areas all have anarea-class of "xsl-normal". If the absolution-position trait is"absolute" or "fixed" then there is one viewport/reference pair, and itsarea-class is "xsl-absolute" or "xsl-fixed", respectively.

Trait Derivation:

The reference-orientation and writing-mode traits of the viewport-areaand reference-area come from the fo:inline-container. These determinethe orientation of the start-edge, end-edge, before-edge and after-edgeof the content-rectangle of the viewport-area, and of the padding-,border-, and content-rectangles of the reference-area.Thereference-orientation of thereference-area is set to "0" and is, therefore, thesame as the orientation established by the viewport-area.The inline-progression-dimension of the reference-area is the same as thatof the viewport-area, and may not be "auto" if theinline-progression-direction is different from that of the parent of thefo:inline-container. The block-progression-dimension of thereference-area is not constrained; thus the reference-area may be largerthan the viewport-area and this may cause the "overflow" property tooperate.

The values in the baseline-table ofthis object are calculated as follows:

baseline

If the writing mode has a block-progression-direction thatis parallel to the block-progression-direction of the parent:the alignment-point is at the position of the dominant-baselineof the first descendant line-area. If there is no such line-areathe alignment-point is at the position of the after-edge of the allocation rectangle.

If the writing mode has a block-progression-direction thatis not parallel to the block-progression-direction of the parent:the alignment-point is at the position that is half way betweenthe before-edge and after-edge of the content rectangle.

before-edge

The alignment-point is at the position of the before-edge ofthe allocation rectangle.

text-before-edge

The alignment-point is at the position that is the closestto the before-edge of the allocation rectangle selected from thetwo candidate edges.If the writing mode has a block-progression-direction thatis parallel to the block-progression-direction of the parentthe candidate edges are the before-edge andthe after-edge of the content rectangle; if it is not, the candidateedges are the start-edge and the end-edge of the content rectangle.

middle

The alignment-point is at the position that is half way betweenthe before-edge and after-edge of the allocation rectangle.

after-edge

The alignment-point is at the position of the after-edge ofthe allocation rectangle.

text-after-edge

The alignment-point is at the position that is the closestto the after-edge of the allocation rectangle selected from thetwo candidate edges.If the writing mode has a block-progression-direction thatis parallel to the block-progression-direction of the parentthe candidate edges are the before-edge andthe after-edge of the content rectangle; if it is not, the candidateedges are the start-edge and the end-edge of the content rectangle.

ideographic

The alignment-point is at the position that is7/10 of the distance from the before-edge of the allocation rectangleto the after-edge of the allocation rectangle.

alphabetic

The alignment-point is at the position that is6/10 of the distance from the before-edge of the allocation rectangleto the after-edge of the allocation rectangle.

hanging

The alignment-point is at the position that is2/10 of the distance from the before-edge of the allocation rectangleto the after-edge of the allocation rectangle.

mathematical

The alignment-point is at the position that is5/10 of the distance from the before-edge of the allocation rectangleto the after-edge of the allocation rectangle.

Constraints:

No area may have more than one normal child areareturned by the same fo:inline-container formatting object.

The children of each reference-area generated by an fo:inline-containerformatting objectmust be normalblock-areas returned by the children of the fo:inline-container,must beproperly stacked, andmust beproperly ordered.

Anyreference-level-out-of-lineareas returned by the children of the fo:inline-containerare handled as described in6.12.2 fo:float.

Contents:

(%block;)+

In addition this formatting object may have a sequence ofzero or more fo:markers as its initial children.

The following properties apply to this formatting object:

7.8 Common Border, Padding, and Background Properties
7.12 Common Margin Properties-Inline
7.13 Common Relative Position Properties
7.14.1 alignment-adjust
7.14.2 alignment-baseline
7.14.3 baseline-shift
7.15.3 block-progression-dimension
7.21.1 clip
7.14.4 display-align
7.14.5 dominant-baseline
7.15.6 height
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.15.7 inline-progression-dimension
7.20.3 keep-together
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.16.4 line-height
7.21.2 overflow
7.21.3 reference-orientation
7.15.14 width
7.29.7 writing-mode

6.6.9 fo:leader

Common Usage:

The fo:leader formatting object is often used:

• in table-of-contentsto generate sequences of "." glyphs that separatetitles from page numbers

• to create entry fields in fill-in-the-blank forms

• to create horizontal rules for use as separators

Areas:

The fo:leader formatting object generates and returnsa single normalinline-area.

Trait Derivation:

If the value of theleader-pattern is "use-content"theblock-progression-dimension of the content-rectangle is determinedin the same manner as for inline-areas; otherwise it is determined bytherule-thickness trait.

Constraints:

If the leader's minimum length is too long to place in theline-area, the leader will begin a new line. If it is too long to beplaced in a line by itself, it will overflow the line and potentiallyoverflow the reference-area in accordance with that container'soverflow trait.

The fo:leader formatting object can have any inline formatting objects andcharacters as its children, except that fo:leaders may not be nested.Its childrenare ignored unless the value of theleader-pattern trait is "use-content".

The inline-area generated by the fo:leader has a dimension in theinline-progression-direction which shall be at least theleader-length.minimum and at most theleader-length.maximum.

For lines-areas that have been specified to be justified, the justifiedline-area must honor theleader-alignment trait of any inline-areasgenerated by fo:leaders.

If the value of theleader-pattern trait is "dots" or "use-content",the following constraint applies:

The inline-area generated by the fo:leader has as its children the areasreturned by children of the fo:leader, or obtained by formatting the patternspecified in theleader-pattern trait, repeated an integral number oftimes. If the width of even a single repetition is larger than the dimensionof the inline-area in the inline-progression-direction, the inline-area shallbe filled with blank space. The space-start and space-end of the child areasis set to account for the constraints specified in theleader-pattern-widthandleader-alignment traits.

Contents:

(#PCDATA|%inline;)*

The content must not contain an fo:leader, fo:inline-container,fo:block-container,fo:float, fo:footnote, or fo:markereither as a direct child or as a descendant.

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.9 Common Font Properties
7.12 Common Margin Properties-Inline
7.13 Common Relative Position Properties
7.14.1 alignment-adjust
7.14.2 alignment-baseline
7.14.3 baseline-shift
7.18.1 color
7.14.5 dominant-baseline
7.29.5 text-depth
7.29.4 text-altitude
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.22.1 leader-alignment
7.22.4 leader-length
7.22.2 leader-pattern
7.22.3 leader-pattern-width
7.22.5 rule-style
7.22.6 rule-thickness
7.17.2 letter-spacing
7.16.4 line-height
7.17.5 text-shadow
7.30.17 visibility
7.17.8 word-spacing

6.6.10 fo:page-number

Common Usage:

The fo:page-number formatting object is used to obtain aninline-areawhose content isthe page-number for the page on which the inline-area isplaced.

Areas:

The fo:page-number formatting object generates and returnsa single normalinline-area.

Constraints:

The content of the inline-area depends on thereference-page and thereference-page-sequence.For the fo:page-number thereference-page is the pageon which the inline-area is placed and thereference-page-sequence is the ancestor fo:page-sequenceof the fo:page-number.

The child areas of this inline-area are the same as the result offormatting a result-tree fragment consisting ofthe content of any fo:folio-prefix child of thereference-page-sequence,followed by fo:character flowobjects; one for each character in the folio-number string andwith only the "character" property specified,followed by thecontent of any fo:folio-suffix child of thereference-page-sequence.

The folio-number string is obtained by converting the folio-numberfor thereference-page in accordance with thenumber to string conversion properties of thereference-page-sequence.

Contents:

EMPTY

The following properties apply to this formatting object:

7.5 Common Accessibility Properties
7.7 Common Aural Properties
7.8 Common Border, Padding, and Background Properties
7.9 Common Font Properties
7.12 Common Margin Properties-Inline
7.13 Common Relative Position Properties
7.14.1 alignment-adjust
7.14.2 alignment-baseline
7.14.3 baseline-shift
7.14.5 dominant-baseline
7.30.8 id
7.24.1 index-class
7.24.2 index-key
7.20.4 keep-with-next
7.20.5 keep-with-previous
7.17.2 letter-spacing
7.16.4 line-height
7.30.15 score-spaces
7.29.4 text-altitude
7.17.4 text-decoration
7.29.5 text-depth
7.17.5 text-shadow
7.17.6 text-transform
7.30.17 visibility
7.17.8 word-spacing
7.16.13 wrap-option