QRegion Class Reference

The QRegion class specifies a clip region for a painter. More...

#include <qregion.h>

Collaboration diagram for QRegion:

Public Types
enum	RegionType { Rectangle , Ellipse }
	Specifies the shape of the region to be created. More...
typedef const QRect *	const_iterator
typedef std::reverse_iterator< const_iterator >	const_reverse_iterator

Public Member Functions
	QRegion ()
	Constructs an empty region.
	QRegion (int x, int y, int w, int h, RegionType t=Rectangle)
	Constructs a rectangular or elliptic region.
	QRegion (const QRect &r, RegionType t=Rectangle)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Create a region based on the rectangle r with region type t.
	QRegion (const QPolygon &pa, Qt::FillRule fillRule=Qt::OddEvenFill)
	Constructs a polygon region from the point array a with the fill rule specified by fillRule.
	QRegion (const QRegion &region)
	Constructs a new region which is equal to region r.
	QRegion (QRegion &&other) noexcept
	QRegion (const QBitmap &bitmap)
	Constructs a region from the bitmap bm.
	~QRegion ()
QRegion &	operator= (const QRegion &)
	Assigns r to this region and returns a reference to the region.
void	swap (QRegion &other) noexcept
bool	isEmpty () const
	Returns true if the region is empty; otherwise returns false.
bool	isNull () const
const_iterator	begin () const noexcept
const_iterator	cbegin () const noexcept
const_iterator	end () const noexcept
const_iterator	cend () const noexcept
const_reverse_iterator	rbegin () const noexcept
const_reverse_iterator	crbegin () const noexcept
const_reverse_iterator	rend () const noexcept
const_reverse_iterator	crend () const noexcept
bool	contains (const QPoint &p) const
	Returns true if the region contains the point p; otherwise returns false.
bool	contains (const QRect &r) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns true if the region overlaps the rectangle r; otherwise returns false.
void	translate (int dx, int dy)
	Translates (moves) the region dx along the X axis and dy along the Y axis.
void	translate (const QPoint &p)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Translates the region {point}{.x()} along the x axis and {point}{.y()} along the y axis, relative to the current position.
QRegion	translated (int dx, int dy) const
QRegion	translated (const QPoint &p) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
QRegion	united (const QRegion &r) const
QRegion	united (const QRect &r) const
QRegion	intersected (const QRegion &r) const
QRegion	intersected (const QRect &r) const
QRegion	subtracted (const QRegion &r) const
QRegion	xored (const QRegion &r) const
bool	intersects (const QRegion &r) const
bool	intersects (const QRect &r) const
QRect	boundingRect () const noexcept
	Returns the bounding rectangle of this region.
void	setRects (const QRect *rect, int num)
	Sets the region using the array of rectangles specified by rects and number.
int	rectCount () const noexcept
QRegion	operator| (const QRegion &r) const
	Applies the united() function to this region and r.
QRegion	operator+ (const QRegion &r) const
	Applies the united() function to this region and r.
QRegion	operator+ (const QRect &r) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
QRegion	operator& (const QRegion &r) const
	Applies the intersected() function to this region and r.
QRegion	operator& (const QRect &r) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
QRegion	operator- (const QRegion &r) const
	Applies the subtracted() function to this region and r.
QRegion	operator^ (const QRegion &r) const
	Applies the xored() function to this region and r.
QRegion &	operator|= (const QRegion &r)
	Applies the united() function to this region and r and assigns the result to this region.
QRegion &	operator+= (const QRegion &r)
	Applies the united() function to this region and r and assigns the result to this region.
QRegion &	operator+= (const QRect &r)
	Returns a region that is the union of this region with the specified rect.
QRegion &	operator&= (const QRegion &r)
	Applies the intersected() function to this region and r and assigns the result to this region.
QRegion &	operator&= (const QRect &r)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.
QRegion &	operator-= (const QRegion &r)
	Applies the subtracted() function to this region and r and assigns the result to this region.
QRegion &	operator^= (const QRegion &r)
	Applies the xored() function to this region and r and assigns the result to this region.
bool	operator== (const QRegion &r) const
	Returns true if the region is equal to r; otherwise returns false.
bool	operator!= (const QRegion &r) const
	Returns true if this region is different from the other region; otherwise returns false.
	operator QVariant () const
	Returns the region as a QVariant.

Friends
struct	QRegionPrivate
Q_GUI_EXPORT QDataStream &	operator<< (QDataStream &, const QRegion &)
	Writes the region r to the stream s and returns a reference to the stream.
Q_GUI_EXPORT QDataStream &	operator>> (QDataStream &, QRegion &)
	Reads a region from the stream s into r and returns a reference to the stream.
Q_GUI_EXPORT friend bool	qt_region_strictContains (const QRegion &region, const QRect &rect)

Related Symbols
(Note that these are not member symbols.)
QDataStream &	operator<< (QDataStream &s, const QRegion &r)
	Writes the region r to the stream s and returns a reference to the stream.
QDataStream &	operator>> (QDataStream &s, QRegion &r)
	Reads a region from the stream s into r and returns a reference to the stream.

Detailed Description

The QRegion class specifies a clip region for a painter.

\inmodule QtGui

QRegion is used with QPainter::setClipRegion() to limit the paint area to what needs to be painted. There is also a QWidget::repaint() function that takes a QRegion 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. Use QPainterPath to create paths and shapes for use with QPainter.

QRegion is an \l{implicitly shared} class.

Definition at line 26 of file qregion.h.

Member Typedef Documentation

const_iterator

QRegion::const_iterator

Since

5.8

An iterator over the non-overlapping rectangles that make up the region.

The union of all the rectangles is equal to the original region.

QRegion does not offer mutable iterators.

See also

begin(), end()

Definition at line 46 of file qregion.h.

const_reverse_iterator

QRegion::const_reverse_iterator

Since

5.8

A reverse iterator over the non-overlapping rectangles that make up the region.

The union of all the rectangles is equal to the original region.

QRegion does not offer mutable iterators.

See also

rbegin(), rend()

Definition at line 47 of file qregion.h.

Member Enumeration Documentation

RegionType

enum QRegion::RegionType

Specifies the shape of the region to be created.

\value Rectangle the region covers the entire rectangle. \value Ellipse the region is an ellipse inside the rectangle.

Enumerator
Rectangle
Ellipse

Definition at line 29 of file qregion.h.

Constructor & Destructor Documentation

QRegion() [1/7]

QRegion::QRegion

(

)

Constructs an empty region.

See also

isEmpty()

Referenced by operator&=(), and operator+=().

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QRegion() [2/7]

QRegion::QRegion	(	int	x,
		int	y,
		int	w,
		int	h,
		RegionType	t = Rectangle
	)

Constructs a rectangular or elliptic region.

If t is Rectangle, the region is the filled rectangle (x, y, w, h). If t is Ellipse, the region is the filled ellipse with center at (x + w / 2, y + h / 2) and size (w ,h).

Definition at line 160 of file qregion.cpp.

QRegion() [3/7]

QRegion::QRegion	(	const QRect &	r,
		RegionType	t = Rectangle
	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Create a region based on the rectangle r with region type t.

If the rectangle is invalid a null region will be created.

See also

QRegion::RegionType

QRegion() [4/7]

QRegion::QRegion	(	const QPolygon &	a,
		Qt::FillRule	fillRule = Qt::OddEvenFill
	)

Constructs a polygon region from the point array a with the fill rule specified by fillRule.

If fillRule is \l{Qt::WindingFill}, the polygon region is defined using the winding algorithm; if it is \l{Qt::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.

QRegion() [5/7]

QRegion::QRegion

(

const QRegion &

region

)

Constructs a new region which is equal to region r.

QRegion() [6/7]

QRegion::QRegion ( QRegion &&  other )

inlinenoexcept

Since

5.7

Move-constructs a new region from region other. After the call, other is null.

See also

isNull()

Definition at line 36 of file qregion.h.

QRegion() [7/7]

QRegion::QRegion

(

const QBitmap &

bm

)

Constructs a region from the bitmap bm.

The resulting region consists of the pixels in bitmap bm that are Qt::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 using QPixmap::setMask().

~QRegion()

QRegion::~QRegion

(

)

Destroys the region.

Member Function Documentation

begin()

QRegion::begin ( ) const

noexcept

Since

5.8

Returns a const_iterator pointing to the beginning of the range of non-overlapping rectangles that make up the region.

The union of all the rectangles is equal to the original region.

See also

rbegin(), cbegin(), end()

Referenced by QPaintEngineEx::clip(), QXcbBackingStore::endPaint(), QClipData::initialize(), qRegionToWinRegion(), qt_regionToPath(), QTest::toString(), and QSGSoftwareRenderableNode::update().

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boundingRect()

QRect QRegion::boundingRect ( ) const

noexcept

Returns the bounding rectangle of this region.

An empty region gives a rectangle that is QRect::isNull().

Referenced by _q_paintIntoCache(), QWindowsDirect2DPaintEngine::begin(), QRasterPaintEngine::clip(), QWindowsVistaStylePrivate::drawBackgroundDirectly(), QQC2::QWindowsXPStylePrivate::drawBackgroundDirectly(), QGraphicsScenePrivate::drawItems(), QTreeView::drawTree(), QWidgetPrivate::drawWidget(), QWidgetPrivate::effectiveRectFor(), fillRegion(), QGraphicsViewPrivate::findItems(), QBackingStore::flush(), QOffscreenBackingStore::flush(), QWindowsBackingStore::flush(), QXcbNativeBackingStore::flush(), QXcbBackingStore::flush(), QCocoaWindow::handleExposeEvent(), intersects(), QWidgetPrivate::paintSiblingsRecursive(), QQnxRasterWindow::post(), QWindowsDirect2DWindow::present(), QXcbBackingStoreImage::put(), qt_hrgn_from_qregion(), QQC2::qt_hrgn_from_qregion(), qt_regionToPath(), QWidgetPrivate::render(), QXcbSystemTrayBackingStore::render(), QWidgetPrivate::render_helper(), QAndroidPlatformOpenGLWindow::repaint(), QXcbNativeBackingStore::resize(), QRasterBackingStore::scroll(), QCALayerBackingStore::scroll(), QClipData::setClipRegion(), QQC2_NAMESPACE::QMacStyle::sizeFromContents(), QMacStyle::sizeFromContents(), QWidgetPrivate::subtractOpaqueSiblings(), QWaylandSurfacePrivate::surface_commit(), QRasterPaintEnginePrivate::systemStateChanged(), QOpenGL2PaintEngineExPrivate::systemStateChanged(), QPicturePaintEngine::updateClipRegion(), QOpenGL2PaintEngineExPrivate::updateClipScissorTest(), QGraphicsViewPrivate::updateRegion(), and QPaintEnginePrivate::updateSystemClip().

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cbegin()

QRegion::cbegin ( ) const

inlinenoexcept

Since

5.8

Same as begin().

Definition at line 50 of file qregion.h.

References begin().

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cend()

QRegion::cend ( ) const

inlinenoexcept

Since

5.8

Same as end().

Definition at line 52 of file qregion.h.

contains() [1/2]

bool QRegion::contains

(

const QPoint &

p

)

const

Returns true if the region contains the point p; otherwise returns false.

Referenced by QSGAbstractSoftwareRenderer::optimizeRenderList(), QDockAreaLayoutInfo::paintSeparators(), QDockAreaLayout::paintSeparators(), and QFlickGestureRecognizer::recognize().

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contains() [2/2]

bool QRegion::contains

(

const QRect &

r

)

const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns true if the region overlaps the rectangle r; otherwise returns false.

crbegin()

QRegion::crbegin ( ) const

inlinenoexcept

Since

5.8

Same as rbegin().

Definition at line 54 of file qregion.h.

crend()

QRegion::crend ( ) const

inlinenoexcept

Since

5.8

Same as rend().

Definition at line 56 of file qregion.h.

end()

QRegion::end ( ) const

noexcept

Since

5.8

Returns a const_iterator pointing to one past the end of non-overlapping rectangles that make up the region.

The union of all the rectangles is equal to the original region.

See also

rend(), cend(), begin()

Referenced by QXcbBackingStore::endPaint(), qRegionToWinRegion(), and qt_regionToPath().

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intersected() [1/2]

QRegion QRegion::intersected

(

const QRect &

rect

)

const

Since

4.4

Returns a region which is the intersection of this region and the given rect.

See also

subtracted(), united(), xored()

intersected() [2/2]

QRegion QRegion::intersected

(

const QRegion &

r

)

const

Since

4.2

Returns a region which is the intersection of this region and r.

Region Intersection

The figure shows the intersection of two elliptical regions.

See also

subtracted(), united(), xored()

Referenced by QSGSoftwareRenderableNode::addDirtyRegion(), QBlitterPaintEngine::fillRect(), QOpenGL2PaintEngineExPrivate::fillStencilWithVertexArray(), QAlphaPaintEnginePrivate::fullyContained(), operator&(), operator&(), QXcbBackingStoreImage::scroll(), QWidgetPrivate::scrollRect(), QX11PaintEngine::updateClipRegion_dev(), and QSGSoftwareRenderableNodeUpdater::visit().

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intersects() [1/2]

bool QRegion::intersects

(

const QRect &

rect

)

const

Since

4.2

Returns true if this region intersects with rect, otherwise returns false.

intersects() [2/2]

bool QRegion::intersects

(

const QRegion &

region

)

const

Since

4.2

Returns true if this region intersects with region, otherwise returns false.

Definition at line 613 of file qregion.cpp.

References boundingRect(), isEmpty(), rect_intersects(), and rectCount().

Referenced by QSGSoftwareRenderableNode::addDirtyRegion(), QWidgetRepaintManager::bltRect(), QAlphaPaintEnginePrivate::canSeeTroughBackground(), QFbScreen::doRedraw(), QGraphicsScenePrivate::drawSubtreeRecursive(), QOpenGL2PaintEngineExPrivate::fillStencilWithVertexArray(), QXcbBackingStoreImage::flushScrolledRegion(), QWidgetPrivate::overlappedRegion(), QXcbBackingStoreImage::preparePaint(), and QSGSoftwareRenderableNode::subtractDirtyRegion().

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isEmpty()

bool QRegion::isEmpty

(

)

const

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();               // false
 
QRegion r3;
r3.isEmpty();               // true
 
QRegion r2(40, 40, 20, 20);
r3 = r1.intersected(r2);    // r3: intersection of r1 and r2
r3.isEmpty();               // true
 
r3 = r1.united(r2);         // r3: union of r1 and r2
r3.isEmpty();               // false

Referenced by _q_paintIntoCache(), QOpenGL2PaintEngineEx::begin(), QQnxRasterWindow::blitPreviousToCurrent(), QFbScreen::doRedraw(), QBsdFbScreen::doRedraw(), QIntegrityFbScreen::doRedraw(), QLinuxFbDrmScreen::doRedraw(), QLinuxFbScreen::doRedraw(), QVncScreen::doRedraw(), QWindowsVistaStylePrivate::drawBackgroundDirectly(), QQC2::QWindowsXPStylePrivate::drawBackgroundDirectly(), QWindowsVistaStylePrivate::drawBackgroundThruNativeBuffer(), QQC2::QWindowsXPStylePrivate::drawBackgroundThruNativeBuffer(), QGraphicsScenePrivate::drawItemHelper(), QWidgetPrivate::drawWidget(), QtWaylandClient::QWaylandXdgSurface::handleExpose(), QCocoaWindow::handleExposeEvent(), QBackingStore::hasStaticContents(), intersects(), QWidgetPrivate::invalidateBackingStore(), QWidgetPrivate::invalidateBackingStore_resizeHelper(), QWidgetRepaintManager::isDirty(), QSGSoftwareRenderableNode::isDirtyRegionEmpty(), QCocoaWindow::isOpaque(), QWidgetRepaintManager::markDirty(), QWidgetRepaintManager::markNeedsFlush(), QMdiSubWindow::mouseMoveEvent(), QWidgetPrivate::moveRect(), QSGAbstractSoftwareRenderer::optimizeRenderList(), QPaintDeviceWindowPrivate::paint(), QTabBar::paintEvent(), QQnxRasterWindow::post(), QWidgetPrivate::prepareToRender(), qt_mac_clip_cg(), QQuickShapeSoftwareRenderNode::render(), QWidgetPrivate::render(), QWidget::render(), QWidgetPrivate::render_helper(), QSGSoftwareRenderableNode::renderNode(), QQuickWidgetPrivate::renderSceneGraph(), QWindowsBackingStore::resize(), scaleRegion(), QQC2::scaleRegion(), QCALayerBackingStore::scroll(), QWidgetPrivate::scrollRect(), QCoreGraphicsPaintEnginePrivate::setClip(), QWidget::setMask(), QWasmWindow::setMask(), QCocoaWindow::setMask(), QWindowsWindow::setMask(), QXcbWindow::setMask(), QPaintEnginePrivate::setSystemTransformAndViewport(), QPaintEnginePrivate::setSystemViewport(), QWidgetRepaintManager::staticContents(), QSGSoftwareRenderableNode::subtractDirtyRegion(), QWidgetPrivate::subtractOpaqueSiblings(), QWidgetRepaintManager::sync(), QRasterPaintEnginePrivate::systemStateChanged(), QOpenGL2PaintEngineExPrivate::systemStateChanged(), QTest::toString(), QSGSoftwareRenderableNode::update(), QX11PaintEngine::updateBrush(), QX11PaintEngine::updateClipRegion_dev(), QMdiSubWindowPrivate::updateMask(), QX11PaintEngine::updatePen(), QPaintEnginePrivate::updateSystemClip(), QApplication::widgetAt(), src_gui_painting_qregion_unix::wrapper(), and QtWaylandClient::QWaylandXdgSurface::xdg_surface_configure().

isNull()

bool QRegion::isNull

(

)

const

Since

5.0

Returns true if the region is empty; otherwise returns false. An empty region is a region that contains no points. This function is the same as isEmpty

See also

isEmpty()

Referenced by QSGSoftwareRenderableNodeUpdater::endVisit(), QXcbBackingStoreImage::flushScrolledRegion(), QSGAbstractSoftwareRenderer::optimizeRenderList(), QCALayerBackingStore::resize(), QTest::toString(), QWasmBackingStore::updateTexture(), and QSGSoftwareRenderableNodeUpdater::visit().

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operator QVariant()

QRegion::operator QVariant

(

)

const

Returns the region as a QVariant.

Definition at line 549 of file qregion.cpp.

References QVariant::fromValue().

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operator!=()

bool QRegion::operator!= ( const QRegion &  r ) const

inline

Returns true if this region is different from the other region; otherwise returns false.

Definition at line 97 of file qregion.h.

References operator==().

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operator&() [1/2]

QRegion QRegion::operator&

(

const QRect &

r

)

const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since

4.4

Definition at line 433 of file qregion.cpp.

References intersected().

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operator&() [2/2]

QRegion QRegion::operator&

(

const QRegion &

r

)

const

Applies the intersected() function to this region and r.

r1&r2 is equivalent to r1.intersected(r2).

See also

intersected()

Definition at line 426 of file qregion.cpp.

References intersected().

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operator&=() [1/2]

QRegion & QRegion::operator&=

(

const QRect &

r

)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since

4.4

Definition at line 511 of file qregion.cpp.

References QRegion().

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operator&=() [2/2]

QRegion & QRegion::operator&=

(

const QRegion &

r

)

Applies the intersected() function to this region and r and assigns the result to this region.

r1&=r2 is equivalent to r1 = r1.intersected(r2).

See also

intersected()

Definition at line 498 of file qregion.cpp.

operator+() [1/2]

QRegion QRegion::operator+

(

const QRect &

r

)

const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since

4.4

Definition at line 417 of file qregion.cpp.

References united().

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operator+() [2/2]

QRegion QRegion::operator+

(

const QRegion &

r

)

const

Applies the united() function to this region and r.

r1+r2 is equivalent to r1.united(r2).

See also

united(), operator|()

Definition at line 410 of file qregion.cpp.

References united().

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operator+=() [1/2]

QRegion & QRegion::operator+=

(

const QRect &

rect

)

Returns a region that is the union of this region with the specified rect.

See also

united()

Definition at line 483 of file qregion.cpp.

References QRegion(), and operator+=().

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operator+=() [2/2]

QRegion & QRegion::operator+=

(

const QRegion &

r

)

Applies the united() function to this region and r and assigns the result to this region.

r1+=r2 is equivalent to {r1 = r1.united(r2)}.

See also

intersected()

Referenced by operator+=().

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operator-()

QRegion QRegion::operator-

(

const QRegion &

r

)

const

Applies the subtracted() function to this region and r.

r1-r2 is equivalent to r1.subtracted(r2).

See also

subtracted()

Definition at line 444 of file qregion.cpp.

References subtracted().

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operator-=()

QRegion & QRegion::operator-=

(

const QRegion &

r

)

Applies the subtracted() function to this region and r and assigns the result to this region.

r1-=r2 is equivalent to {r1 = r1.subtracted(r2)}.

See also

subtracted()

Definition at line 526 of file qregion.cpp.

operator=()

QRegion & QRegion::operator=

(

const QRegion &

r

)

Assigns r to this region and returns a reference to the region.

Move-assigns other to this QRegion instance.

Since

5.2

operator==()

bool QRegion::operator==

(

const QRegion &

r

)

const

Returns true if the region is equal to r; otherwise returns false.

operator^()

QRegion QRegion::operator^

(

const QRegion &

r

)

const

Applies the xored() function to this region and r.

r1^r2 is equivalent to r1.xored(r2).

See also

xored()

Definition at line 453 of file qregion.cpp.

References xored().

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operator^=()

QRegion & QRegion::operator^=

(

const QRegion &

r

)

Applies the xored() function to this region and r and assigns the result to this region.

r1^=r2 is equivalent to {r1 = r1.xored(r2)}.

See also

xored()

Definition at line 536 of file qregion.cpp.

operator|()

QRegion QRegion::operator|

(

const QRegion &

r

)

const

Applies the united() function to this region and r.

r1|r2 is equivalent to r1.united(r2).

See also

united(), operator+()

Definition at line 401 of file qregion.cpp.

References united().

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operator|=()

QRegion & QRegion::operator|=

(

const QRegion &

r

)

Applies the united() function to this region and r and assigns the result to this region.

r1|=r2 is equivalent to {r1 = r1.united(r2)}.

See also

united()

Definition at line 463 of file qregion.cpp.

rbegin()

QRegion::rbegin ( ) const

inlinenoexcept

Since

5.8

Returns a const_reverse_iterator pointing to the beginning of the range of non-overlapping rectangles that make up the region.

The union of all the rectangles is equal to the original region.

See also

begin(), crbegin(), rend()

Definition at line 53 of file qregion.h.

Referenced by QQnxRasterWindow::blitPreviousToCurrent().

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rectCount()

int QRegion::rectCount ( ) const

noexcept

Since

4.6

Returns the number of rectangles that this region is composed of. Same as {end() - begin()}.

Referenced by _q_paintIntoCache(), QPaintEngineEx::clip(), QRasterPaintEngine::clip(), QTreeView::drawTree(), QGraphicsViewPrivate::findItems(), QClipData::initialize(), intersects(), qRegionToXcbRectangleList(), qt_hrgn_from_qregion(), QQC2::qt_hrgn_from_qregion(), qt_mac_scale_region(), qt_regionToPath(), QSGSoftwareRenderableNode::renderNode(), scaledRegion(), QClipData::setClipRegion(), QOpenGL2PaintEngineExPrivate::systemStateChanged(), QTest::toString(), QSGSoftwareRenderableNode::update(), and QRfbRawEncoder::write().

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rend()

QRegion::rend ( ) const

inlinenoexcept

Since

5.8

Returns a const_reverse_iterator pointing to one past the end of the range of non-overlapping rectangles that make up the region.

The union of all the rectangles is equal to the original region.

See also

end(), crend(), rbegin()

Definition at line 55 of file qregion.h.

References begin().

Referenced by QQnxRasterWindow::blitPreviousToCurrent().

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setRects()

void QRegion::setRects	(	const QRect *	rects,
		int	number
	)

Sets the region using the array of rectangles specified by rects and number.

The rectangles must be optimally Y-X sorted and follow these restrictions:

\list

• The rectangles must not intersect.
• All rectangles with a given top coordinate must have the same height.
• No two rectangles may abut horizontally (they should be combined into a single wider rectangle in that case).
• The rectangles must be sorted in ascending order, with Y as the major sort key and X as the minor sort key. \endlist \omit Only some platforms have these restrictions (Qt for Embedded Linux, X11 and \macos). \endomit

Referenced by QAlphaPaintEnginePrivate::canSeeTroughBackground(), qt_mac_scale_region(), and scaledRegion().

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subtracted()

QRegion QRegion::subtracted

(

const QRegion &

r

)

const

Since

4.2

Returns a region which is r subtracted from this region.

Region Subtraction

The figure shows the result when the ellipse on the right is subtracted from the ellipse on the left ({left - right}).

See also

intersected(), united(), xored()

Referenced by operator-(), QSGAbstractSoftwareRenderer::optimizeRenderList(), and QSGSoftwareRenderableNode::previousDirtyRegion().

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swap()

void QRegion::swap ( QRegion &  other )

inlinenoexcept

Since

4.8

Swaps region other with this region. This operation is very fast and never fails.

Definition at line 42 of file qregion.h.

References d, other(), and qt_ptr_swap().

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translate() [1/2]

void QRegion::translate ( const QPoint &  point )

inline

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Translates the region {point}{.x()} along the x axis and {point}{.y()} along the y axis, relative to the current position.

Positive values move the region to the right and down.

Translates to the given point.

Definition at line 62 of file qregion.h.

References translate().

Referenced by translate().

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translate() [2/2]

void QRegion::translate	(	int	dx,
		int	dy
	)

Translates (moves) the region dx along the X axis and dy along the Y axis.

Referenced by QBackingStore::flush(), QWidgetPrivate::moveRect(), QWidgetPrivate::paintSiblingsRecursive(), QGraphicsItem::scroll(), QWidgetPrivate::scrollRect(), QWidget::setMask(), QWidgetRepaintManager::staticContents(), QWidgetPrivate::subtractOpaqueSiblings(), and QPaintEnginePrivate::updateSystemClip().

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translated() [1/2]

QRegion QRegion::translated ( const QPoint &  p ) const

inline

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since

4.1

Returns a copy of the regtion that is translated {p}{.x()} along the x axis and {p}{.y()} along the y axis, relative to the current position. Positive values move the rectangle to the right and down.

See also

translate()

Definition at line 64 of file qregion.h.

References translated().

Referenced by translated().

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translated() [2/2]

QRegion QRegion::translated	(	int	dx,
		int	dy
	)		const

Since

4.1

Returns a copy of the region that is translated dx along the x axis and dy along the y axis, relative to the current position. Positive values move the region to the right and down.

See also

translate()

Definition at line 593 of file qregion.cpp.

References ret.

Referenced by QWidget::childrenRegion(), QWindowsVistaStylePrivate::drawBackgroundDirectly(), QQC2::QWindowsXPStylePrivate::drawBackgroundDirectly(), QtWaylandClient::QWaylandShmBackingStore::flush(), QWidgetRepaintManager::markDirty(), QWidgetRepaintManager::markNeedsFlush(), QWidgetPrivate::overlappedRegion(), QTableView::paintEvent(), QXcbBackingStoreImage::put(), QFlickGestureRecognizer::recognize(), QWidgetPrivate::render(), QHighDpi::scale(), QCALayerBackingStore::scroll(), QPixmap::scroll(), QGraphicsView::scrollContentsBy(), QWidgetPrivate::subtractOpaqueSiblings(), and QGraphicsPixmapItemPrivate::updateShape().

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united() [1/2]

QRegion QRegion::united

(

const QRect &

rect

)

const

Since

4.4

Returns a region which is the union of this region and the given rect.

See also

intersected(), subtracted(), xored()

united() [2/2]

QRegion QRegion::united

(

const QRegion &

r

)

const

Since

4.2

Returns a region which is the union of this region and r.

Region Union

The figure shows the union of two elliptical regions.

See also

intersected(), subtracted(), xored()

Referenced by operator+(), operator+(), and operator|().

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xored()

QRegion QRegion::xored

(

const QRegion &

r

)

const

Since

4.2

Returns a region which is the exclusive or (XOR) of this region and r.

Region XORed

The figure shows the exclusive or of two elliptical regions.

See also

intersected(), united(), subtracted()

Referenced by operator^().

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Friends And Related Symbol Documentation

operator<< [1/2]

QDataStream & operator<< ( QDataStream &  s, const QRegion &  r  )

friend

Writes the region r to the stream s and returns a reference to the stream.

See also

{Serializing Qt Data Types}{Format of the QDataStream operators}

Definition at line 313 of file qregion.cpp.

operator<<() [2/2]

QDataStream & operator<< ( QDataStream &  s, const QRegion &  r  )

related

Writes the region r to the stream s and returns a reference to the stream.

See also

{Serializing Qt Data Types}{Format of the QDataStream operators}

Definition at line 313 of file qregion.cpp.

operator>> [1/2]

QDataStream & operator>> ( QDataStream &  s, QRegion &  r  )

friend

Reads a region from the stream s into r and returns a reference to the stream.

See also

{Serializing Qt Data Types}{Format of the QDataStream operators}

Definition at line 347 of file qregion.cpp.

operator>>() [2/2]

QDataStream & operator>> ( QDataStream &  s, QRegion &  r  )

related

Reads a region from the stream s into r and returns a reference to the stream.

See also

{Serializing Qt Data Types}{Format of the QDataStream operators}

Definition at line 347 of file qregion.cpp.

QRegionPrivate

friend struct QRegionPrivate

friend

Definition at line 116 of file qregion.h.

qt_region_strictContains

Q_GUI_EXPORT friend bool qt_region_strictContains ( const QRegion &  region, const QRect &  rect  )

friend

---

The documentation for this class was generated from the following files:

• qtbase/src/gui/painting/qregion.h
• qtbase/src/gui/painting/qregion.cpp