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Eneboo - Documentación para desarrolladores
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Eneboo - Documentación para desarrolladores
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The QRegion class specifies a clip region for a painter. Más...
#include <qregion.h>
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() that takes a QRegion parameter. QRegion is the best tool for reducing flicker.
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 unite(), intersect(), subtract() or eor() (exclusive or). You can move a region using translate().
You can test whether a region isNull(), isEmpty() or if it contains() a QPoint or QRect. The bounding rectangle is given by boundingRect().
The function rects() gives a decomposition of the region into rectangles.
Example of using complex regions:
void MyWidget::paintEvent( QPaintEvent * ) { QPainter p; // our painter 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( this ); // start painting widget p.setClipRegion( r3 ); // set clip region ... // paint clipped graphics p.end(); // painting done }
QRegion is an implicitly shared class.
| enum QRegion::RegionType |
| enum QRegion::RegionType |
| QRegion::QRegion | ( | ) |
Constructs a null region.
| 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 ).
| QRegion::QRegion | ( | const QRect & | r, |
| RegionType | t = Rectangle |
||
| ) |
Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. If the rectangle is invalid, the rectangle will be normalized() before the region is created. This semantics will change in Qt-3 and an invalid rectangle will construct an empty region.
Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Create a region based on the rectange r with region type t.
If the rectangle is invalid a null region will be created.
| QRegion::QRegion | ( | const QPointArray & | a, |
| bool | winding = FALSE |
||
| ) |
Constructs a polygon region from the point array a.
If winding is TRUE, the polygon region is filled using the winding algorithm, otherwise the default even-odd fill algorithm is used.
This constructor may create complex regions that will slow down painting when used.
| QRegion::QRegion | ( | const QRegion & | r | ) |
Constructs a new region which is equal to r.
Constructs a new region which is equal to region r.
| QRegion::QRegion | ( | const QBitmap & | bm | ) |
Constructs a region from the bitmap bm.
The resulting region consists of the pixels in bm that are 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().
Constructs a region from the bitmap bm.
The resulting region consists of the pixels in bitmap bm that are 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 | ( | ) |
Destructs the region.
Destroys the region.
| QRegion::QRegion | ( | ) |
| QRegion::QRegion | ( | int | x, |
| int | y, | ||
| int | w, | ||
| int | h, | ||
| RegionType | = Rectangle |
||
| ) |
| QRegion::QRegion | ( | const QRect & | , |
| RegionType | = Rectangle |
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| ) |
| QRegion::QRegion | ( | const QPointArray & | , |
| bool | winding = FALSE |
||
| ) |
| QRegion::QRegion | ( | const QRegion & | ) |
| QRegion::QRegion | ( | const QBitmap & | ) |
| QRegion::~QRegion | ( | ) |
| QRect QRegion::boundingRect | ( | ) | const |
Returns the bounding rectangle of this region. An empty region gives a rectangle that is QRect::isNull().
| QRect QRegion::boundingRect | ( | ) | const |
Returns TRUE if the region contains the point p; otherwise returns FALSE.
Esta es una función miembro sobrecargada que se suministra por conveniencia. Difiere de la anterior función solamente en los argumentos que acepta. Returns TRUE if the region overlaps the rectangle r; otherwise returns FALSE.
Returns a region which is the exclusive or (XOR) of this region and r.
rxor.png Region XORed
The figure shows the exclusive or of two elliptical regions.
Returns a region which is the intersection of this region and r.
rintersect.png Region Intersection
The figure shows the intersection of two elliptical regions.
| bool QRegion::isEmpty | ( | void | ) | 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 ); QRegion r2( 40, 40, 20, 20 ); QRegion r3; r1.isNull(); // FALSE r1.isEmpty(); // FALSE r3.isNull(); // TRUE r3.isEmpty(); // TRUE r3 = r1.intersect( r2 ); // r3 = intersection of r1 and r2 r3.isNull(); // FALSE r3.isEmpty(); // TRUE r3 = r1.unite( r2 ); // r3 = union of r1 and r2 r3.isNull(); // FALSE r3.isEmpty(); // FALSE
| bool QRegion::isEmpty | ( | ) | const |
| bool QRegion::isNull | ( | ) | const |
| bool QRegion::isNull | ( | ) | const |
Returns TRUE if the region is a null region; otherwise returns FALSE.
A null region is a region that has not been initialized. A null region is always empty.
Returns TRUE if the region is different from r; otherwise returns FALSE.
Applies the intersect() function to this region and r. r1&r2 is equivalent to r1.intersect(r2)
Applies the intersect() function to this region and r and assigns the result to this region. r1&=r2 is equivalent to r1=r1.intersect(r2)
Applies the unite() function to this region and r. r1+r2 is equivalent to r1.unite(r2)
Applies the unite() function to this region and r and assigns the result to this region. r1+=r2 is equivalent to r1=r1.unite(r2)
Applies the subtract() function to this region and r. r1-r2 is equivalent to r1.subtract(r2)
Applies the subtract() function to this region and r and assigns the result to this region. r1-=r2 is equivalent to r1=r1.subtract(r2)
Assigns r to this region and returns a reference to the region.
Returns TRUE if the region is equal to r; otherwise returns FALSE.
Applies the unite() function to this region and r. r1|r2 is equivalent to r1.unite(r2)
Returns an array of non-overlapping rectangles that make up the region.
The union of all the rectangles is equal to the original region.
Sets the region to be the given set of rectangles. The rectangles must be optimal Y-X sorted bands as follows:
Returns a region which is r subtracted from this region.
rsubtract.png Region Subtraction
The figure shows the result when the ellipse on the right is subtracted from the ellipse on the left. (left-right )
Translates (moves) the region dx along the X axis and dy along the Y axis.
Returns a region which is the union of this region and r.
runion.png Region Union
The figure shows the union of two elliptical regions.
| QDataStream & operator<< | ( | QDataStream & | s, |
| const QRegion & | r | ||
| ) | [friend] |
Writes the region r to the stream s and returns a reference to the stream.
| Q_EXPORT QDataStream& operator<< | ( | QDataStream & | , |
| const QRegion & | |||
| ) | [friend] |
| Q_EXPORT QDataStream& operator>> | ( | QDataStream & | , |
| QRegion & | |||
| ) | [friend] |
| QDataStream & operator>> | ( | QDataStream & | s, |
| QRegion & | r | ||
| ) | [friend] |
Reads a region from the stream s into r and returns a reference to the stream.
1.7.4
