QtGui.QRegion Class Reference

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

Inheritance diagram for QtGui.QRegion:

Collaboration diagram for QtGui.QRegion:

Public Types
enum	RegionType { Ellipse = 1, Rectangle = 0 }
	More...

Public Member Functions
override bool	Equals (object o)
override int	GetHashCode ()
	QRegion ()
	QRegion (QRegion region)
	QRegion (QBitmap bitmap)
	QRegion (QRect r, QRegion.RegionType t=QRegion.RegionType.Rectangle)
	QRegion (QPolygon pa, Qt.FillRule fillRule=Qt.FillRule.OddEvenFill)
	QRegion (int x, int y, int w, int h, QRegion.RegionType t=QRegion.RegionType.Rectangle)
virtual void	CreateProxy ()
new QRect	BoundingRect ()
new bool	Contains (QPoint p)
new bool	Contains (QRect r)
new QRegion	Eor (QRegion r)
new System.IntPtr	Handle ()
new QRegion	Intersect (QRegion r)
new QRegion	Intersect (QRect r)
new QRegion	Intersected (QRegion r)
new QRegion	Intersected (QRect r)
new bool	Intersects (QRegion r)
new bool	Intersects (QRect r)
new bool	IsEmpty ()
new int	NumRects ()
new int	RectCount ()
new System.Collections.Generic.List < QRect >	Rects ()
new void	SetRects (QRect rect, int num)
new QRegion	Subtract (QRegion r)
new QRegion	Subtracted (QRegion r)
new void	Swap (QRegion other)
new void	Translate (QPoint p)
new void	Translate (int dx, int dy)
new QRegion	Translated (QPoint p)
new QRegion	Translated (int dx, int dy)
new QRegion	Unite (QRegion r)
new QRegion	Unite (QRect r)
new QRegion	United (QRegion r)
new QRegion	United (QRect r)
new QRegion	Xored (QRegion r)
new void	Dispose ()

Static Public Member Functions
static QRegion	operator* (QRegion arg1, QTransform arg2)
static QRegion	operator* (QRegion arg1, QMatrix arg2)
static bool	operator!= (QRegion arg1, QRegion arg2)
static QRegion	operator& (QRegion arg1, QRegion arg2)
static QRegion	operator& (QRegion arg1, QRect arg2)
static QRegion	operator+ (QRegion arg1, QRegion arg2)
static QRegion	operator+ (QRegion arg1, QRect arg2)
static QRegion	operator- (QRegion arg1, QRegion arg2)
static bool	operator== (QRegion arg1, QRegion arg2)
static QRegion	operator^ (QRegion arg1, QRegion arg2)
static QRegion	operator| (QRegion arg1, QRegion arg2)

Protected Member Functions
	QRegion (System.Type dummy)

Protected Attributes
SmokeInvocation	interceptor

Properties
virtual System.IntPtr	SmokeObject [get, set]

Detailed Description

The QRegion class specifies a clip region for a painter.

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 implicitly shared class.

Creating and Using Regions

A region can be created from a rectangle, an ellipse, a polygon or a bitmap. Complex regions may be created by combining simple regions using united(), intersected(), subtracted(), or xored() (exclusive or). You can move a region using translate().

You can test whether a region isEmpty() or if it contains() a QPoint or QRect. The bounding rectangle can be found with boundingRect().

The function rects() 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 region

QRegion::Ellipse);

QRegion r2(QRect(100, 120, 90, 30)); // r2: rectangular region

QRegion r3 = r1.intersected(r2); // r3: intersection

QPainter painter(this);

painter.setClipRegion(r3);

... // paint clipped graphics

}

Additional License Information

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 also QPainter::setClipRegion(), QPainter::setClipRect(), and QPainterPath.

Member Enumeration Documentation

enum QtGui.QRegion.RegionType

Specifies the shape of the region to be created.

Enumerator:

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

Constructor & Destructor Documentation

QtGui.QRegion.QRegion ( System.Type  dummy )

protected

QtGui.QRegion.QRegion

(

)

Constructs an empty region.

See also isEmpty().

QtGui.QRegion.QRegion

(

QRegion

region

)

Constructs a new region which is equal to region r.

QtGui.QRegion.QRegion

(

QBitmap

bitmap

)

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().

QtGui.QRegion.QRegion	(	QRect	r,
		QRegion.RegionType	t = QRegion.RegionType.Rectangle
	)

This is an overloaded function.

Create a region based on the rectange r with region type t.

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

See also QRegion::RegionType.

QtGui.QRegion.QRegion	(	QPolygon	pa,
		Qt.FillRule	fillRule = Qt.FillRule.OddEvenFill
	)

Constructs an empty region.

See also isEmpty().

QtGui.QRegion.QRegion	(	int	x,
		int	y,
		int	w,
		int	h,
		QRegion.RegionType	t = QRegion.RegionType.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).

Member Function Documentation

new QRect QtGui.QRegion.BoundingRect

(

)

Returns the bounding rectangle of this region. An empty region gives a rectangle that is QRect::isNull().

new bool QtGui.QRegion.Contains

(

QPoint

p

)

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

new bool QtGui.QRegion.Contains

(

QRect

r

)

This is an overloaded function.

Returns true if the region overlaps the rectangle r; otherwise returns false.

virtual void QtGui.QRegion.CreateProxy ( )

virtual

new void QtGui.QRegion.Dispose

(

)

new QRegion QtGui.QRegion.Eor

(

QRegion

r

)

Use xored(r) instead.

override bool QtGui.QRegion.Equals

(

object

o

)

override int QtGui.QRegion.GetHashCode

(

)

new System.IntPtr QtGui.QRegion.Handle

(

)

Returns a platform-specific region handle. The Handle type is HRGN on Windows, Region on X11, and RgnHandle on Mac OS X. On Qt for Embedded Linux it is void *.

Warning: This function is not portable.

new QRegion QtGui.QRegion.Intersect

(

QRegion

r

)

Use intersected(r) instead.

new QRegion QtGui.QRegion.Intersect

(

QRect

r

)

Use intersected(r) instead.

new QRegion QtGui.QRegion.Intersected

(

QRegion

r

)

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

The figure shows the intersection of two elliptical regions.

This function was introduced in Qt 4.2.

See also subtracted(), united(), and xored().

new QRegion QtGui.QRegion.Intersected

(

QRect

r

)

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

This function was introduced in Qt 4.4.

See also subtracted(), united(), and xored().

new bool QtGui.QRegion.Intersects

(

QRegion

r

)

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

This function was introduced in Qt 4.2.

new bool QtGui.QRegion.Intersects

(

QRect

r

)

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

This function was introduced in Qt 4.2.

new bool QtGui.QRegion.IsEmpty

(

)

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

new int QtGui.QRegion.NumRects

(

)

static bool QtGui.QRegion.operator!= ( QRegion  arg1, QRegion  arg2  )

static

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

static QRegion QtGui.QRegion.operator& ( QRegion  arg1, QRegion  arg2  )

static

Applies the intersected() function to this region and r. r1&r2 is equivalent to r1.intersected(r2).

See also intersected().

static QRegion QtGui.QRegion.operator& ( QRegion  arg1, QRect  arg2  )

static

This is an overloaded function.

This function was introduced in Qt 4.4.

static QRegion QtGui.QRegion.operator* ( QRegion  arg1, QTransform  arg2  )

static

static QRegion QtGui.QRegion.operator* ( QRegion  arg1, QMatrix  arg2  )

static

static QRegion QtGui.QRegion.operator+ ( QRegion  arg1, QRegion  arg2  )

static

Applies the united() function to this region and r. r1+r2 is equivalent to r1.united(r2).

See also united() and operator|().

static QRegion QtGui.QRegion.operator+ ( QRegion  arg1, QRect  arg2  )

static

This is an overloaded function.

This function was introduced in Qt 4.4.

static QRegion QtGui.QRegion.operator- ( QRegion  arg1, QRegion  arg2  )

static

Applies the subtracted() function to this region and r. r1-r2 is equivalent to r1.subtracted(r2).

See also subtracted().

static bool QtGui.QRegion.operator== ( QRegion  arg1, QRegion  arg2  )

static

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

static QRegion QtGui.QRegion.operator^ ( QRegion  arg1, QRegion  arg2  )

static

Applies the xored() function to this region and r. r1^r2 is equivalent to r1.xored(r2).

See also xored().

static QRegion QtGui.QRegion.operator| ( QRegion  arg1, QRegion  arg2  )

static

Applies the united() function to this region and r. r1|r2 is equivalent to r1.united(r2).

See also united() and operator+().

new int QtGui.QRegion.RectCount

(

)

Returns the number of rectangles that will be returned in rects().

This function was introduced in Qt 4.6.

new System.Collections.Generic.List<QRect> QtGui.QRegion.Rects

(

)

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 also setRects().

new void QtGui.QRegion.SetRects	(	QRect	rect,
		int	num
	)

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:

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.

See also rects().

new QRegion QtGui.QRegion.Subtract

(

QRegion

r

)

Use subtracted(r) instead.

new QRegion QtGui.QRegion.Subtracted

(

QRegion

r

)

Returns a region which is r 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 also intersected(), united(), and xored().

new void QtGui.QRegion.Swap

(

QRegion

other

)

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

This function was introduced in Qt 4.8.

new void QtGui.QRegion.Translate

(

QPoint

p

)

This is an overloaded function.

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.

new void QtGui.QRegion.Translate	(	int	dx,
		int	dy
	)

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

new QRegion QtGui.QRegion.Translated

(

QPoint

p

)

This is an overloaded function.

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.

This function was introduced in Qt 4.1.

See also translate().

new QRegion QtGui.QRegion.Translated	(	int	dx,
		int	dy
	)

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.

This function was introduced in Qt 4.1.

See also translate().

new QRegion QtGui.QRegion.Unite

(

QRegion

r

)

Use united(r) instead.

new QRegion QtGui.QRegion.Unite

(

QRect

r

)

Use united(r) instead.

new QRegion QtGui.QRegion.United

(

QRegion

r

)

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

The figure shows the union of two elliptical regions.

This function was introduced in Qt 4.2.

See also intersected(), subtracted(), and xored().

new QRegion QtGui.QRegion.United

(

QRect

r

)

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

This function was introduced in Qt 4.4.

See also intersected(), subtracted(), and xored().

new QRegion QtGui.QRegion.Xored

(

QRegion

r

)

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

The figure shows the exclusive or of two elliptical regions.

This function was introduced in Qt 4.2.

See also intersected(), united(), and subtracted().

Member Data Documentation

SmokeInvocation QtGui.QRegion.interceptor

protected

Property Documentation

virtual System.IntPtr QtGui.QRegion.SmokeObject

getset