QRegion¶

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

Synopsis¶

Functions¶

def __add__ (r)
def __add__ (r)
def __and__ (r)
def __and__ (r)
def __eq__ (r)
def __iadd__ (r)
def __iadd__ (r)
def __ior__ (r)
def __isub__ (r)
def __ixor__ (r)
def __mul__ (, m)
def __mul__ (, m)
def __ne__ (r)
def __or__ (r)
def __sub__ (r)
def __xor__ (r)
def begin ()
def boundingRect ()
def cbegin ()
def cend ()
def contains (p)
def contains (r)
def end ()
def intersected (r)
def intersected (r)
def intersects (r)
def intersects (r)
def isEmpty ()
def isNull ()
def rectCount ()
def rects ()
def setRects (rect, num)
def subtracted (r)
def swap (other)
def translate (dx, dy)
def translate (p)
def translated (dx, dy)
def translated (p)
def united (r)
def united (r)
def xored (r)

Detailed Description¶

QRegion is used with setClipRegion() to limit the paint area to what needs to be painted. There is also a 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() .

Iteration over the region (with begin() , end() , or C++11 ranged-for loops) gives a decomposition of the region into rectangles.

Example of using complex regions:
class MyWidget (QWidget):
    # ...
    def paintEvent(self):
        r1 = QRegion(QRect(100, 100, 200, 80), QRegion.Ellipse) # r1: elliptic region
                )
        r2 = QRect(100, 120, 90, 30)   # r2: rectangular region
        r3 = r1.intersected(r2)        # r3: intersection

        painter = QPainter(self)
        painter.setClipRegion(r3)
        ...                            # paint clipped graphics
See also

setClipRegion() setClipRect() QPainterPath

class PySide2.QtGui.QRegion¶

PySide2.QtGui.QRegion(bitmap)

PySide2.QtGui.QRegion(pa[, fillRule=Qt.OddEvenFill])

PySide2.QtGui.QRegion(r[, t=Rectangle])

PySide2.QtGui.QRegion(region)

PySide2.QtGui.QRegion(x, y, w, h[, t=Rectangle])

param w:

int

param x:

int

param y:

int

param h:

int

param fillRule:

FillRule

param bitmap:

PySide2.QtGui.QBitmap

param region:

PySide2.QtGui.QRegion

param r:

PySide2.QtCore.QRect

param t:

RegionType

param pa:

PySide2.QtGui.QPolygon

Constructs an empty region.

See also

isEmpty()

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`` ).

PySide2.QtGui.QRegion.RegionType¶

Specifies the shape of the region to be created.

Constant	Description
QRegion.Rectangle	the region covers the entire rectangle.
QRegion.Ellipse	the region is an ellipse inside the rectangle.

PySide2.QtGui.QRegion.begin()¶

Return type:: PySide2.QtCore.QRect

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()

PySide2.QtGui.QRegion.boundingRect()¶

Return type:: PySide2.QtCore.QRect

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

PySide2.QtGui.QRegion.cbegin()¶

Return type:: PySide2.QtCore.QRect

Same as begin() .

PySide2.QtGui.QRegion.cend()¶

Return type:: PySide2.QtCore.QRect

Same as end() .

PySide2.QtGui.QRegion.contains(p)¶

Parameters:: p – PySide2.QtCore.QPoint
Return type:: bool

PySide2.QtGui.QRegion.contains(r)

Parameters:: r – PySide2.QtCore.QRect
Return type:: bool

PySide2.QtGui.QRegion.end()¶

Return type:: PySide2.QtCore.QRect

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()

PySide2.QtGui.QRegion.intersected(r)¶

Parameters:: r – PySide2.QtCore.QRect
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.intersected(r)

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.intersects(r)¶

Parameters:: r – PySide2.QtCore.QRect
Return type:: bool

PySide2.QtGui.QRegion.intersects(r)

Parameters:: r – PySide2.QtGui.QRegion
Return type:: bool

PySide2.QtGui.QRegion.isEmpty()¶

Return type:: bool

Returns true if the region is empty; otherwise returns false . An empty region is a region that contains no points.

Example:

r1 = QRegion(10, 10, 20, 20)
r1.isNull()                // false
r1.isEmpty()               // false

r2 = QRegion(40, 40, 20, 20)
r3 = QRegion()
r3.isNull()                // true
r3.isEmpty()               // true

r3 = r1.intersected(r2)    // r3: intersection of r1 and r2
r3.isNull()                // false
r3.isEmpty()               // true

r3 = r1.united(r2)         // r3: union of r1 and r2
r3.isNull()                // false
r3.isEmpty()               // false

PySide2.QtGui.QRegion.isNull()¶

Return type:: bool

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()

PySide2.QtGui.QRegion.__ne__(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: bool

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

PySide2.QtGui.QRegion.__and__(r)¶

Parameters:: r – PySide2.QtCore.QRect
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.__and__(r)

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.__mul__(m)¶

Parameters:: m – PySide2.QtGui.QMatrix
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.__mul__(m)

Parameters:: m – PySide2.QtGui.QTransform
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.__add__(r)¶

Parameters:: r – PySide2.QtCore.QRect
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.__add__(r)

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.__iadd__(r)¶

Parameters:: r – PySide2.QtCore.QRect
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.__iadd__(r)

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

PySide2.QtGui.QRegion.__sub__(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

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

See also

subtracted()

PySide2.QtGui.QRegion.__isub__(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

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()

PySide2.QtGui.QRegion.__eq__(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: bool

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

PySide2.QtGui.QRegion.__xor__(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

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

See also

xored()

PySide2.QtGui.QRegion.__ixor__(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

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()

PySide2.QtGui.QRegion.__or__(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

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

See also

united() operator+()

PySide2.QtGui.QRegion.__ior__(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

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()

PySide2.QtGui.QRegion.rectCount()¶

Return type:: int

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

PySide2.QtGui.QRegion.rects()¶

Return type:

Note

This function is deprecated.

Use begin() and end() instead.

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()

PySide2.QtGui.QRegion.setRects(rect, num)¶

Parameters:

rect – PySide2.QtCore.QRect
num – int

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()

PySide2.QtGui.QRegion.subtracted(r)¶

Parameters:: r – PySide2.QtGui.QRegion
Return type:: PySide2.QtGui.QRegion

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 ).

See also

intersected() united() xored()

PySide2.QtGui.QRegion.swap(other)¶

Parameters:: other – PySide2.QtGui.QRegion

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

PySide2.QtGui.QRegion.translate(p)¶

Parameters:: p – PySide2.QtCore.QPoint

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 .

PySide2.QtGui.QRegion.translate(dx, dy)

Parameters:

dx – int
dy – int

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

PySide2.QtGui.QRegion.translated(p)¶

Parameters:: p – PySide2.QtCore.QPoint
Return type:: PySide2.QtGui.QRegion

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.

See also

translate()

PySide2.QtGui.QRegion.translated(dx, dy)

Parameters:

dx – int
dy – int

Return type:

PySide2.QtGui.QRegion

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()

PySide2.QtGui.QRegion.united(r)¶