We bake cookies in your browser for a better experience. Using this site means that you consent.Read More
We bake cookies in your browser for a better experience. Using this site means that you consent.Read More
TheQRegion class specifies a clip region for a painter.More...
| Header: | #include <QRegion> |
| enum | RegionType { Rectangle, Ellipse } |
| QRegion() | |
| QRegion(int x, int y, int w, int h, RegionType t = Rectangle) | |
| QRegion(const QPolygon & a, Qt::FillRule fillRule = Qt::OddEvenFill) | |
| QRegion(const QRegion & r) | |
| QRegion(const QBitmap & bm) | |
| QRegion(const QRect & r, RegionType t = Rectangle) | |
| QRect | boundingRect() const |
| bool | contains(const QPoint & p) const |
| bool | contains(const QRect & r) const |
| Handle | handle() const |
| QRegion | intersected(const QRegion & r) const |
| QRegion | intersected(const QRect & rect) const |
| bool | intersects(const QRegion & region) const |
| bool | intersects(const QRect & rect) const |
| bool | isEmpty() const |
| int | rectCount() const |
| QVector<QRect> | rects() const |
| void | setRects(const QRect * rects, int number) |
| QRegion | subtracted(const QRegion & r) const |
| void | swap(QRegion & other) |
| void | translate(int dx, int dy) |
| void | translate(const QPoint & point) |
| QRegion | translated(int dx, int dy) const |
| QRegion | translated(const QPoint & p) const |
| QRegion | united(const QRegion & r) const |
| QRegion | united(const QRect & rect) const |
| QRegion | xored(const QRegion & r) const |
| operator QVariant() const | |
| bool | operator!=(const QRegion & other) const |
| const QRegion | operator&(const QRegion & r) const |
| const QRegion | operator&(const QRect & r) const |
| QRegion & | operator&=(const QRegion & r) |
| QRegion & | operator&=(const QRect & r) |
| const QRegion | operator+(const QRegion & r) const |
| const QRegion | operator+(const QRect & r) const |
| QRegion & | operator+=(const QRegion & r) |
| QRegion & | operator+=(const QRect & rect) |
| const QRegion | operator-(const QRegion & r) const |
| QRegion & | operator-=(const QRegion & r) |
| QRegion & | operator=(const QRegion & r) |
| QRegion & | operator=(QRegion && other) |
| bool | operator==(const QRegion & r) const |
| const QRegion | operator^(const QRegion & r) const |
| QRegion & | operator^=(const QRegion & r) |
| const QRegion | operator|(const QRegion & r) const |
| QRegion & | operator|=(const QRegion & r) |
| QDataStream & | operator<<(QDataStream & s, const QRegion & r) |
| QDataStream & | operator>>(QDataStream & s, QRegion & r) |
TheQRegion class specifies a clip region for a painter.
QRegion is used withQPainter::setClipRegion() to limit the paint area to what needs to be painted. There is also aQWidget::repaint() function that takes aQRegion parameter.QRegion is the best tool for minimizing the amount of screen area to be updated by a repaint.
This class is not suitable for constructing shapes for rendering, especially as outlines. UseQPainterPath to create paths and shapes for use withQPainter.
QRegion is animplicitly shared class.
A region can be created from a rectangle, an ellipse, a polygon or a bitmap. Complex regions may be created by combining simple regions usingunited(),intersected(),subtracted(), orxored() (exclusive or). You can move a region usingtranslate().
You can test whether a regionisEmpty() or if itcontains() aQPoint orQRect. The bounding rectangle can be found withboundingRect().
The functionrects() gives a decomposition of the region into rectangles.
Example of using complex regions:
void MyWidget::paintEvent(QPaintEvent*){QRegion r1(QRect(100,100,200,80),// r1: elliptic regionQRegion::Ellipse);QRegion r2(QRect(100,120,90,30));// r2: rectangular regionQRegion r3= r1.intersected(r2);// r3: intersectionQPainter painter(this); painter.setClipRegion(r3);...// paint clipped graphics}
On Embedded Linux, Windows CE and X11 platforms, parts of this class rely on code obtained under the following licenses:
Copyright (c) 1987 X Consortium
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of the X Consortium shall not be used in advertising or otherwise to promote the sale, use or other dealings in this Software without prior written authorization from the X Consortium.
Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
All Rights Reserved
Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation, and that the name of Digital not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission.
DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
See alsoQPainter::setClipRegion(),QPainter::setClipRect(), andQPainterPath.
Specifies the shape of the region to be created.
| Constant | Value | Description |
|---|---|---|
QRegion::Rectangle | 0 | the region covers the entire rectangle. |
QRegion::Ellipse | 1 | the region is an ellipse inside the rectangle. |
Constructs an empty region.
See alsoisEmpty().
Constructs a rectangular or elliptic region.
Ift isRectangle, the region is the filled rectangle (x,y,w,h). Ift isEllipse, the region is the filled ellipse with center at (x +w / 2,y +h / 2) and size (w ,h).
Constructs a polygon region from the point arraya with the fill rule specified byfillRule.
IffillRule isQt::WindingFill, the polygon region is defined using the winding algorithm; if it isQt::OddEvenFill, the odd-even fill algorithm is used.
Warning: This constructor can be used to create complex regions that will slow down painting when used.
Constructs a new region which is equal to regionr.
Constructs a region from the bitmapbm.
The resulting region consists of the pixels in bitmapbm that areQt::color1, as if each pixel was a 1 by 1 rectangle.
This constructor may create complex regions that will slow down painting when used. Note that drawing masked pixmaps can be done much faster usingQPixmap::setMask().
This is an overloaded function.
Create a region based on the rectanger with region typet.
If the rectangle is invalid a null region will be created.
See alsoQRegion::RegionType.
Returns the bounding rectangle of this region. An empty region gives a rectangle that isQRect::isNull().
Returns true if the region contains the pointp; otherwise returns false.
This is an overloaded function.
Returns true if the region overlaps the rectangler; otherwise returns false.
Returns a platform-specific region handle. TheHandle type isHRGN on Windows,Region on X11, andRgnHandle on Mac OS X. OnQt for Embedded Linux it isvoid *.
Warning: This function is not portable.
Returns a region which is the intersection of this region andr.
The figure shows the intersection of two elliptical regions.
This function was introduced in Qt 4.2.
See alsosubtracted(),united(), andxored().
Returns a region which is the intersection of this region and the givenrect.
This function was introduced in Qt 4.4.
See alsosubtracted(),united(), andxored().
Returns true if this region intersects withregion, otherwise returns false.
This function was introduced in Qt 4.2.
Returns true if this region intersects withrect, otherwise returns false.
This function was introduced in Qt 4.2.
Returns true if the region is empty; otherwise returns false. An empty region is a region that contains no points.
Example:
QRegion r1(10,10,20,20);r1.isEmpty();// falseQRegion r3;r3.isEmpty();// trueQRegion r2(40,40,20,20);r3= r1.intersected(r2);// r3: intersection of r1 and r2r3.isEmpty();// truer3= r1.united(r2);// r3: union of r1 and r2r3.isEmpty();// false
Returns the number of rectangles that will be returned inrects().
This function was introduced in Qt 4.6.
Returns an array of non-overlapping rectangles that make up the region.
The union of all the rectangles is equal to the original region.
See alsosetRects().
Sets the region using the array of rectangles specified byrects andnumber. The rectanglesmust be optimally Y-X sorted and follow these restrictions:
See alsorects().
Returns a region which isr subtracted from this region.
The figure shows the result when the ellipse on the right is subtracted from the ellipse on the left (left - right).
This function was introduced in Qt 4.2.
See alsointersected(),united(), andxored().
Swaps regionother with this region. This operation is very fast and never fails.
This function was introduced in Qt 4.8.
Translates (moves) the regiondx along the X axis anddy along the Y axis.
This is an overloaded function.
Translates the regionpoint.x() along the x axis andpoint.y() along the y axis, relative to the current position. Positive values move the region to the right and down.
Translates to the givenpoint.
Returns a copy of the region that is translateddx along the x axis anddy along the y axis, relative to the current position. Positive values move the region to the right and down.
This function was introduced in Qt 4.1.
See alsotranslate().
This is an overloaded function.
Returns a copy of the regtion that is translatedp.x() along the x axis andp.y() along the y axis, relative to the current position. Positive values move the rectangle to the right and down.
This function was introduced in Qt 4.1.
See alsotranslate().
Returns a region which is the union of this region andr.
The figure shows the union of two elliptical regions.
This function was introduced in Qt 4.2.
See alsointersected(),subtracted(), andxored().
Returns a region which is the union of this region and the givenrect.
This function was introduced in Qt 4.4.
See alsointersected(),subtracted(), andxored().
Returns a region which is the exclusive or (XOR) of this region andr.
The figure shows the exclusive or of two elliptical regions.
This function was introduced in Qt 4.2.
See alsointersected(),united(), andsubtracted().
Returns the region as aQVariant
Returns true if this region is different from theother region; otherwise returns false.
Applies theintersected() function to this region andr.r1&r2 is equivalent tor1.intersected(r2).
See alsointersected().
This is an overloaded function.
This function was introduced in Qt 4.4.
Applies theintersected() function to this region andr and assigns the result to this region.r1&=r2 is equivalent tor1 = r1.intersected(r2).
See alsointersected().
This is an overloaded function.
This function was introduced in Qt 4.4.
Applies theunited() function to this region andr.r1+r2 is equivalent tor1.united(r2).
See alsounited() andoperator|().
This is an overloaded function.
This function was introduced in Qt 4.4.
Applies theunited() function to this region andr and assigns the result to this region.r1+=r2 is equivalent tor1 = r1.united(r2).
See alsointersected().
Returns a region that is the union of this region with the specifiedrect.
See alsounited().
Applies thesubtracted() function to this region andr.r1-r2 is equivalent tor1.subtracted(r2).
See alsosubtracted().
Applies thesubtracted() function to this region andr and assigns the result to this region.r1-=r2 is equivalent tor1 = r1.subtracted(r2).
See alsosubtracted().
Assignsr to this region and returns a reference to the region.
Returns true if the region is equal tor; otherwise returns false.
Applies thexored() function to this region andr.r1^r2 is equivalent tor1.xored(r2).
See alsoxored().
Applies thexored() function to this region andr and assigns the result to this region.r1^=r2 is equivalent tor1 = r1.xored(r2).
See alsoxored().
Applies theunited() function to this region andr.r1|r2 is equivalent tor1.united(r2).
See alsounited() andoperator+().
Applies theunited() function to this region andr and assigns the result to this region.r1|=r2 is equivalent tor1 = r1.united(r2).
See alsounited().
Writes the regionr to the streams and returns a reference to the stream.
See alsoFormat of the QDataStream operators.
Reads a region from the streams intor and returns a reference to the stream.
See alsoFormat of the QDataStream operators.
© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of theGNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.