Contents

• Public Types
• Public Functions
• Reimplemented Public Functions
• Protected Functions
• Detailed Description

Detailed Description

TheQPrinter class is a paint device that paints on a printer.

This device represents a series of pages of printed output, and is used in almost exactly the same way as other paint devices such asQWidget andQPixmap. A set of additional functions are provided to manage device-specific features, such as orientation and resolution, and to step through the pages in a document as it is generated.

When printing directly to a printer on Windows or Mac OS X,QPrinter uses the built-in printer drivers. On X11,QPrinter uses theCommon Unix Printing System (CUPS) or the standard Unixlpr utility to send PostScript or PDF output to the printer. As an alternative, theprintProgram() function can be used to specify the command or utility to use instead of the system default.

Note that setting parameters like paper size and resolution on an invalid printer is undefined. You can useQPrinter::isValid() to verify this before changing any parameters.

QPrinter supports a number of parameters, most of which can be changed by the end user through aprint dialog. In general,QPrinter passes these functions onto the underlyingQPrintEngine.

The most important parameters are:

• setOrientation() tellsQPrinter which page orientation to use.
• setPaperSize() tellsQPrinter what paper size to expect from the printer.
• setResolution() tellsQPrinter what resolution you wish the printer to provide, in dots per inch (DPI).
• setFullPage() tellsQPrinter whether you want to deal with the full page or just with the part the printer can draw on.
• setCopyCount() tellsQPrinter how many copies of the document it should print.

Many of these functions can only be called before the actual printing begins (i.e., beforeQPainter::begin() is called). This usually makes sense because, for example, it's not possible to change the number of copies when you are halfway through printing. There are also some settings that the user sets (through the printer dialog) and that applications are expected to obey. SeeQAbstractPrintDialog's documentation for more details.

WhenQPainter::begin() is called, theQPrinter it operates on is prepared for a new page, enabling theQPainter to be used immediately to paint the first page in a document. Once the first page has been painted,newPage() can be called to request a new blank page to paint on, orQPainter::end() can be called to finish printing. The second page and all following pages are prepared using a call tonewPage() before they are painted.

The first page in a document does not need to be preceded by a call tonewPage(). You only need to callingnewPage() afterQPainter::begin() if you need to insert a blank page at the beginning of a printed document. Similarly, callingnewPage() after the last page in a document is painted will result in a trailing blank page appended to the end of the printed document.

If you want to abort the print job,abort() will try its best to stop printing. It may cancel the entire job or just part of it.

SinceQPrinter can print to anyQPrintEngine subclass, it is possible to extend printing support to cover new types of printing subsystem by subclassingQPrintEngine and reimplementing its interface.

Member Type Documentation

enum QPrinter::ColorMode

This enum type is used to indicate whetherQPrinter should print in color or not.

enum QPrinter::DuplexMode

This enum is used to indicate whether printing will occur on one or both sides of each sheet of paper (simplex or duplex printing).

This enum was introduced or modified in Qt 4.4.

enum QPrinter::Orientation

This enum type (not to be confused withOrientation) is used to specify each page's orientation.

This type interacts withQPrinter::PaperSize andQPrinter::setFullPage() to determine the final size of the page available to the application.

enum QPrinter::OutputFormat

The OutputFormat enum is used to describe the formatQPrinter should use for printing.

See alsooutputFormat(),setOutputFormat(), andsetOutputFileName().

enum QPrinter::PageOrder

This enum type is used byQPrinter to tell the application program how to print.

enum QPrinter::PaperSize

This enum type specifies what paper sizeQPrinter should use.QPrinter does not check that the paper size is available; it just uses this information, together withQPrinter::Orientation andQPrinter::setFullPage(), to determine the printable area.

The defined sizes (withsetFullPage(true)) are:

WithsetFullPage(false) (the default), the metrics will be a bit smaller; how much depends on the printer in use.

This enum was introduced or modified in Qt 4.4.

enum QPrinter::PaperSource

This enum type specifies what paper sourceQPrinter is to use.QPrinter does not check that the paper source is available; it just uses this information to try and set the paper source. Whether it will set the paper source depends on whether the printer has that particular source.

Warning: This is currently only implemented for Windows.

enum QPrinter::PrintRange

Used to specify the print range selection option.

See alsoQAbstractPrintDialog::PrintRange.

enum QPrinter::PrinterMode

This enum describes the mode the printer should work in. It basically presets a certain resolution and working mode.

Note:When rendering text on aQPrinter device, it is important to realize that the size of text, when specified in points, is independent of the resolution specified for the device itself. Therefore, it may be useful to specify the font size in pixels when combining text with graphics to ensure that their relative sizes are what you expect.

enum QPrinter::PrinterState

enum QPrinter::Unit

This enum type is used to specify the measurement unit for page and paper sizes.

Note the difference between Point and DevicePixel. The Point unit is defined to be 1/72th of an inch, while the DevicePixel unit is resolution dependant and is based on the actual pixels, or dots, on the printer.

This enum was introduced or modified in Qt 4.4.

Member Function Documentation

QPrinter::QPrinter(PrinterMode mode = ScreenResolution)

Creates a new printer object with the givenmode.

QPrinter::QPrinter(constQPrinterInfo & printer,PrinterMode mode = ScreenResolution)

Creates a new printer object with the givenprinter andmode.

This function was introduced in Qt 4.4.

QPrinter::~QPrinter()

Destroys the printer object and frees any allocated resources. If the printer is destroyed while a print job is in progress this may or may not affect the print job.

bool QPrinter::abort()

Aborts the current print run. Returns true if the print run was successfully aborted andprinterState() will returnQPrinter::Aborted; otherwise returns false.

It is not always possible to abort a print job. For example, all the data has gone to the printer but the printer cannot or will not cancel the job when asked to.

bool QPrinter::collateCopies() const

Returns true if collation is turned on when multiple copies is selected. Returns false if it is turned off when multiple copies is selected. When collating is turned off the printing of each individual page will be repeated the numCopies() amount before the next page is started. With collating turned on all pages are printed before the next copy of those pages is started.

This function was introduced in Qt 4.1.

See alsosetCollateCopies().

ColorMode QPrinter::colorMode() const

Returns the current color mode.

See alsosetColorMode().

int QPrinter::copyCount() const

Returns the number of copies that will be printed. The default value is 1.

This function was introduced in Qt 4.7.

See alsosetCopyCount() andsupportsMultipleCopies().

QString QPrinter::creator() const

Returns the name of the application that created the document.

See alsosetCreator().

QString QPrinter::docName() const

Returns the document name.

See alsosetDocName() andQPrintEngine::PrintEnginePropertyKey.

bool QPrinter::doubleSidedPrinting() const

Returns true if double side printing is enabled.

Currently this option is only supported on X11.

This function was introduced in Qt 4.2.

See alsosetDoubleSidedPrinting().

DuplexMode QPrinter::duplex() const

Returns the current duplex mode.

Currently this option is only supported on X11.

This function was introduced in Qt 4.4.

See alsosetDuplex().

bool QPrinter::fontEmbeddingEnabled() const

Returns true if font embedding is enabled.

Currently this option is only supported on X11.

This function was introduced in Qt 4.1.

See alsosetFontEmbeddingEnabled().

int QPrinter::fromPage() const

Returns the number of the first page in a range of pages to be printed (the "from page" setting). Pages in a document are numbered according to the convention that the first page is page 1.

By default, this function returns a special value of 0, meaning that the "from page" setting is unset.

Note:If fromPage() andtoPage() both return 0, this indicates thatthe whole document will be printed.

This function was introduced in Qt 4.1.

See alsosetFromTo() andtoPage().

bool QPrinter::fullPage() const

Returns true if the origin of the printer's coordinate system is at the corner of the page and false if it is at the edge of the printable area.

SeesetFullPage() for details and caveats.

See alsosetFullPage() andPaperSize.

void QPrinter::getPageMargins(qreal * left,qreal * top,qreal * right,qreal * bottom,Unit unit) const

Returns the page margins for this printer inleft,top,right,bottom. The unit of the returned margins are specified with theunit parameter.

This function was introduced in Qt 4.4.

bool QPrinter::isValid() const

Returns true if the printer currently selected is a valid printer in the system, or a pure PDF/PostScript printer; otherwise returns false.

To detect other failures check the output ofQPainter::begin() orQPrinter::newPage().

QPrinter printer;    printer.setOutputFormat(QPrinter::PdfFormat);    printer.setOutputFileName("/foobar/nonwritable.pdf");QPainter painter;if (! painter.begin(&printer)) {// failed to open fileqWarning("failed to open file, is it writable?");return1;    }    painter.drawText(10,10,"Test");if (! printer.newPage()) {qWarning("failed in flushing page to disk, disk full?");return1;    }    painter.drawText(10,10,"Test 2");    painter.end();

This function was introduced in Qt 4.4.

See alsosetPrinterName().

bool QPrinter::newPage()

Tells the printer to eject the current page and to continue printing on a new page. Returns true if this was successful; otherwise returns false.

Calling newPage() on an inactiveQPrinter object will always fail.

Orientation QPrinter::orientation() const

Returns the orientation setting. This is driver-dependent, but is usuallyQPrinter::Portrait.

See alsosetOrientation().

QString QPrinter::outputFileName() const

Returns the name of the output file. By default, this is an empty string (indicating that the printer shouldn't print to file).

See alsosetOutputFileName() andQPrintEngine::PrintEnginePropertyKey.

OutputFormat QPrinter::outputFormat() const

Returns the output format for this printer.

This function was introduced in Qt 4.1.

See alsosetOutputFormat().

PageOrder QPrinter::pageOrder() const

Returns the current page order.

The default page order isFirstPageFirst.

See alsosetPageOrder().

QRect QPrinter::pageRect() const

Returns the page's rectangle; this is usually smaller than thepaperRect() since the page normally has margins between its borders and the paper.

The unit of the returned rectangle isDevicePixel.

See alsopaperSize().

QRectF QPrinter::pageRect(Unit unit) const

Returns the page's rectangle inunit; this is usually smaller than thepaperRect() since the page normally has margins between its borders and the paper.

This function was introduced in Qt 4.4.

See alsopaperSize().

[virtual]QPaintEngine * QPrinter::paintEngine() const

Reimplemented fromQPaintDevice::paintEngine().

Returns the paint engine used by the printer.

QRect QPrinter::paperRect() const

Returns the paper's rectangle; this is usually larger than thepageRect().

The unit of the returned rectangle isDevicePixel.

See alsopageRect().

QRectF QPrinter::paperRect(Unit unit) const

Returns the paper's rectangle inunit; this is usually larger than thepageRect().

This function was introduced in Qt 4.4.

See alsopageRect().

PaperSize QPrinter::paperSize() const

Returns the printer paper size. The default value is driver-dependent.

This function was introduced in Qt 4.4.

See alsosetPaperSize(),pageRect(), andpaperRect().

QSizeF QPrinter::paperSize(Unit unit) const

Returns the paper size inunit.

This function was introduced in Qt 4.4.

See alsosetPaperSize().

PaperSource QPrinter::paperSource() const

Returns the printer's paper source. This isManual or a printer tray or paper cassette.

See alsosetPaperSource().

QPrintEngine * QPrinter::printEngine() const

Returns the print engine used by the printer.

This function was introduced in Qt 4.1.

QString QPrinter::printProgram() const

Returns the name of the program that sends the print output to the printer.

The default is to return an empty string; meaning thatQPrinter will try to be smart in a system-dependent way. On X11 only, you can set it to something different to use a specific print program. On the other platforms, this returns an empty string.

See alsosetPrintProgram() andsetPrinterSelectionOption().

PrintRange QPrinter::printRange() const

Returns the page range of theQPrinter. After the print setup dialog has been opened, this function returns the value selected by the user.

This function was introduced in Qt 4.1.

See alsosetPrintRange().

QString QPrinter::printerName() const

Returns the printer name. This value is initially set to the name of the default printer.

See alsosetPrinterName().

QString QPrinter::printerSelectionOption() const

Returns the printer options selection string. This is useful only if the print command has been explicitly set.

The default value (an empty string) implies that the printer should be selected in a system-dependent manner.

Any other value implies that the given value should be used.

Warning: This function is not available on Windows.

See alsosetPrinterSelectionOption().

PrinterState QPrinter::printerState() const

Returns the current state of the printer. This may not always be accurate (for example if the printer doesn't have the capability of reporting its state to the operating system).

int QPrinter::resolution() const

Returns the current assumed resolution of the printer, as set bysetResolution() or by the printer driver.

See alsosetResolution().

void QPrinter::setCollateCopies(bool collate)

Sets the default value for collation checkbox when the print dialog appears. Ifcollate is true, it will enablesetCollateCopiesEnabled(). The default value is false. This value will be changed by what the user presses in the print dialog.

This function was introduced in Qt 4.1.

See alsocollateCopies().

void QPrinter::setColorMode(ColorMode newColorMode)

Sets the printer's color mode tonewColorMode, which can be eitherColor orGrayScale.

See alsocolorMode().

void QPrinter::setCopyCount(int count)

Sets the number of copies to be printed tocount.

The printer driver reads this setting and prints the specified number of copies.

This function was introduced in Qt 4.7.

See alsocopyCount() andsupportsMultipleCopies().

void QPrinter::setCreator(constQString & creator)

Sets the name of the application that created the document tocreator.

This function is only applicable to the X11 version of Qt. If no creator name is specified, the creator will be set to "Qt" followed by some version number.

See alsocreator().

void QPrinter::setDocName(constQString & name)

Sets the document name toname.

On X11, the document name is for example used as the default output filename inQPrintDialog. Note that the document name does not affect the file name if the printer is printing to a file. Use the setOutputFile() function for this.

See alsodocName() andQPrintEngine::PrintEnginePropertyKey.

void QPrinter::setDoubleSidedPrinting(bool doubleSided)

Enables double sided printing ifdoubleSided is true; otherwise disables it.

Currently this option is only supported on X11.

This function was introduced in Qt 4.2.

See alsodoubleSidedPrinting().

void QPrinter::setDuplex(DuplexMode duplex)

Enables double sided printing based on theduplex mode.

Currently this option is only supported on X11.

This function was introduced in Qt 4.4.

See alsoduplex().

[protected]void QPrinter::setEngines(QPrintEngine * printEngine,QPaintEngine * paintEngine)

This function is used by subclasses ofQPrinter to specify custom print and paint engines (printEngine andpaintEngine, respectively).

QPrinter does not take ownership of the engines, so you need to manage these engine instances yourself.

Note that changing the engines will reset the printer state and all its properties.

This function was introduced in Qt 4.1.

See alsoprintEngine(),paintEngine(), andsetOutputFormat().

void QPrinter::setFontEmbeddingEnabled(bool enable)

Enabled or disables font embedding depending onenable.

Currently this option is only supported on X11.

This function was introduced in Qt 4.1.

See alsofontEmbeddingEnabled().

void QPrinter::setFromTo(int from,int to)

Sets the range of pages to be printed to cover the pages with numbers specified byfrom andto, wherefrom corresponds to the first page in the range andto corresponds to the last.

Note:Pages in a document are numbered according to the convention that the first page is page 1. However, iffrom andto are both set to 0, thewhole document will be printed.

This function is mostly used to set a default value that the user can override in the print dialog when you callsetup().

This function was introduced in Qt 4.1.

See alsofromPage() andtoPage().

void QPrinter::setFullPage(bool fp)

Iffp is true, enables support for painting over the entire page; otherwise restricts painting to the printable area reported by the device.

By default, full page printing is disabled. In this case, the origin of theQPrinter's coordinate system coincides with the top-left corner of the printable area.

If full page printing is enabled, the origin of theQPrinter's coordinate system coincides with the top-left corner of the paper itself. In this case, thedevice metrics will report the exact same dimensions as indicated byPaperSize. It may not be possible to print on the entire physical page because of the printer's margins, so the application must account for the margins itself.

See alsofullPage(),setPaperSize(),width(),height(), andPrinting with Qt.

void QPrinter::setOrientation(Orientation orientation)

Sets the print orientation toorientation.

The orientation can be eitherQPrinter::Portrait orQPrinter::Landscape.

The printer driver reads this setting and prints using the specified orientation.

On Windows, this option can be changed while printing and will take effect from the next call tonewPage().

On Mac OS X, changing the orientation during a print job has no effect.

See alsoorientation().

void QPrinter::setOutputFileName(constQString & fileName)

Sets the name of the output file tofileName.

Setting a null or empty name (0 or "") disables printing to a file. Setting a non-empty name enables printing to a file.

This can change the value ofoutputFormat(). If the file name has the suffix ".ps" then PostScript is automatically selected as output format. If the file name has the ".pdf" suffix PDF is generated. If the file name has a suffix other than ".ps" and ".pdf", the output format used is the one set withsetOutputFormat().

QPrinter uses Qt's cross-platform PostScript or PDF print engines respectively. If you can produce this format natively, for example Mac OS X can generate PDF's from its print engine, set the output format back toNativeFormat.

See alsooutputFileName(),setOutputToFile(), andsetOutputFormat().

void QPrinter::setOutputFormat(OutputFormat format)

Sets the output format for this printer toformat.

This function was introduced in Qt 4.1.

See alsooutputFormat().

void QPrinter::setPageMargins(qreal left,qreal top,qreal right,qreal bottom,Unit unit)

This function sets theleft,top,right andbottom page margins for this printer. The unit of the margins are specified with theunit parameter.

This function was introduced in Qt 4.4.

void QPrinter::setPageOrder(PageOrder pageOrder)

Sets the page order topageOrder.

The page order can beQPrinter::FirstPageFirst orQPrinter::LastPageFirst. The application is responsible for reading the page order and printing accordingly.

This function is mostly useful for setting a default value that the user can override in the print dialog.

This function is only supported under X11.

See alsopageOrder().

void QPrinter::setPaperSize(PaperSize newPaperSize)

Sets the printer paper size tonewPaperSize if that size is supported. The result is undefined ifnewPaperSize is not supported.

The default paper size is driver-dependent.

This function is useful mostly for setting a default value that the user can override in the print dialog.

This function was introduced in Qt 4.4.

See alsopaperSize(),PaperSize,setFullPage(),setResolution(),pageRect(), andpaperRect().

void QPrinter::setPaperSize(constQSizeF & paperSize,Unit unit)

Sets the paper size based onpaperSize inunit.

This function was introduced in Qt 4.4.

See alsopaperSize().

void QPrinter::setPaperSource(PaperSource source)

Sets the paper source setting tosource.

Windows only: This option can be changed while printing and will take effect from the next call tonewPage()

See alsopaperSource().

void QPrinter::setPrintProgram(constQString & printProg)

Sets the name of the program that should do the print job toprintProg.

On X11, this function sets the program to call with the PostScript output. On other platforms, it has no effect.

See alsoprintProgram().

void QPrinter::setPrintRange(PrintRange range)

Sets the print range option in to berange.

This function was introduced in Qt 4.1.

See alsoprintRange().

void QPrinter::setPrinterName(constQString & name)

Sets the printer name toname.

See alsoprinterName() andisValid().

void QPrinter::setPrinterSelectionOption(constQString & option)

Sets the printer to useoption to select the printer.option is null by default (which implies that Qt should be smart enough to guess correctly), but it can be set to other values to use a specific printer selection option.

If the printer selection option is changed while the printer is active, the current print job may or may not be affected.

Warning: This function is not available on Windows.

See alsoprinterSelectionOption().

void QPrinter::setResolution(int dpi)

Requests that the printer prints atdpi or as near todpi as possible.

This setting affects the coordinate system as returned by, for exampleQPainter::viewport().

This function must be called beforeQPainter::begin() to have an effect on all platforms.

See alsoresolution() andsetPaperSize().

void QPrinter::setWinPageSize(int pageSize)

Sets the page size to be used by the printer under Windows topageSize.

Warning: This function is not portable so you may prefer to usesetPaperSize() instead.

See alsowinPageSize().

QList<PaperSource> QPrinter::supportedPaperSources() const

Returns the supported paper sizes for this printer.

The values will be either a value that matches an entry in theQPrinter::PaperSource enum or a driver spesific value. The driver spesific values are greater than the constant DMBIN_USER declared in wingdi.h.

Warning: This function is only available in windows.

QList<int> QPrinter::supportedResolutions() const

Returns a list of the resolutions (a list of dots-per-inch integers) that the printer says it supports.

For X11 where all printing is directly to postscript, this function will always return a one item list containing only the postscript resolution, i.e., 72 (72 dpi -- but seePrinterMode).

bool QPrinter::supportsMultipleCopies() const

Returns true if the printer supports printing multiple copies of the same document in one job; otherwise false is returned.

On most systems this function will return true. However, on X11 systems that do not support CUPS, this function will return false. That means the application has to handle the number of copies by printing the same document the required number of times.

This function was introduced in Qt 4.7.

See alsosetCopyCount() andcopyCount().

int QPrinter::toPage() const

Returns the number of the last page in a range of pages to be printed (the "to page" setting). Pages in a document are numbered according to the convention that the first page is page 1.

By default, this function returns a special value of 0, meaning that the "to page" setting is unset.

Note:IffromPage() and toPage() both return 0, this indicates thatthe whole document will be printed.

The programmer is responsible for reading this setting and printing accordingly.

This function was introduced in Qt 4.1.

See alsosetFromTo() andfromPage().

int QPrinter::winPageSize() const

Returns the page size used by the printer under Windows.

Warning: This function is not portable so you may prefer to usepaperSize() instead.

See alsosetWinPageSize().