The QRegion class specified a clip region for the painter. (details) (complete member list)
#include <qregion.h>
A region defines a clip region for a QPainter. A region can be a rectangle, an ellipse, a polygon or a combination of these.
Regions are combined by creating a new region which is a union, intersection or difference between any two regions.
The region XOR operation is defined as:
a XOR b = (a UNION b) - (a INTERSECTION b)
Example of use:
QWidget w;
QPainter p;
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.intersect( r2 ); // r3 = intersection
p.begin( &w ); // start painting widget
p.setClipRegion( r3 ); // set clip region
... // paint clipped graphics
p.end(); // painting done
Constructs an empty region.
Constructs a rectangular or elliptic region.
Arguments:
Constructs a polygon region from the point array a.
Constructs a region which is a shallow copy of r.
Destroys the region.
Returns TRUE if the region contains the point p, or FALSE if p is outside the region.
Returns TRUE if the region contains the rectangle r, or FALSE if r is outside the region.
Returns a deep copy of the region.
Returns a region which is the intersection of this region and r.
Returns TRUE if the region is empty, or FALSE if it is non-empty.
Returns TRUE if the region is a null region.
Changes the offset of the region dx along the X axis and dy along the Y axis.
Returns TRUE if the region is different from r, or FALSE if the regions are equal.
Assigns a shallow copy of r to this region and returns a reference to the region.
Returns TRUE if the region is equal to r, or FALSE if the regions are different.
Returns a region which is r subtracted from this region.
Returns a region which is the union of this region and r.
Returns a region which is this region XOR r.
This file is part of the Qt toolkit, copyright 1995 Troll Tech, all rights reserved.
It was generated from the following files: