QQuickPaintedItem¶
The QQuickPaintedItem
class provides a way to use the QPainter
API in the QML Scene Graph. More…

Synopsis¶
Functions¶
def
contentsBoundingRect
()def
contentsScale
()def
contentsScaleChanged
()def
contentsSize
()def
contentsSizeChanged
()def
fillColor
()def
fillColorChanged
()def
mipmap
()def
opaquePainting
()def
performanceHints
()def
renderTarget
()def
renderTargetChanged
()def
resetContentsSize
()def
setContentsScale
(arg__1)def
setContentsSize
(arg__1)def
setFillColor
(arg__1)def
setMipmap
(enable)def
setOpaquePainting
(opaque)def
setPerformanceHint
(hint[, enabled=true])def
setPerformanceHints
(hints)def
setRenderTarget
(target)def
setTextureSize
(size)def
textureSize
()def
textureSizeChanged
()def
update
([rect=QRect()])
Detailed Description¶
The QQuickPaintedItem
makes it possible to use the QPainter
API with the QML Scene Graph. It sets up a textured rectangle in the Scene Graph and uses a QPainter
to paint onto the texture. The render target in Qt 6 is always a QImage
. When the render target is a QImage
, QPainter
first renders into the image then the content is uploaded to the texture. Call update()
to trigger a repaint.
To enable QPainter
to do anti-aliased rendering, use setAntialiasing()
.
To write your own painted item, you first create a subclass of QQuickPaintedItem
, and then start by implementing its only pure virtual public function: paint()
, which implements the actual painting. The painting will be inside the rectangle spanning from 0,0 to width()
, height()
.
Note
It important to understand the performance implications such items can incur. See RenderTarget
and renderTarget
.
-
class
PySide6.QtQuick.
QQuickPaintedItem
([parent=None])¶ - Parameters
parent –
PySide6.QtQuick.QQuickItem
Constructs a QQuickPaintedItem
with the given parent
item.
-
PySide6.QtQuick.QQuickPaintedItem.
RenderTarget
¶
This enum describes QQuickPaintedItem
‘s render targets. The render target is the surface QPainter
paints onto before the item is rendered on screen.
Constant
Description
QQuickPaintedItem.Image
The default;
QPainter
paints into aQImage
using the raster paint engine. The image’s content needs to be uploaded to graphics memory afterward, this operation can potentially be slow if the item is large. This render target allows high quality anti-aliasing and fast item resizing.QQuickPaintedItem.FramebufferObject
As of Qt 6.0, this value is ignored.
QQuickPaintedItem.InvertedYFramebufferObject
As of Qt 6.0, this value is ignored.
See also
-
PySide6.QtQuick.QQuickPaintedItem.
PerformanceHint
¶
This enum describes flags that you can enable to improve rendering performance in QQuickPaintedItem
. By default, none of these flags are set.
Constant
Description
QQuickPaintedItem.FastFBOResizing
As of Qt 6.0, this value is ignored.
-
PySide6.QtQuick.QQuickPaintedItem.
contentsBoundingRect
()¶ - Return type
This function is provided for compatibility, use size in combination with textureSize
to decide the size of what you are drawing.
See also
-
PySide6.QtQuick.QQuickPaintedItem.
contentsScale
()¶ - Return type
float
See also
-
PySide6.QtQuick.QQuickPaintedItem.
contentsScaleChanged
()¶
-
PySide6.QtQuick.QQuickPaintedItem.
contentsSize
()¶ - Return type
See also
-
PySide6.QtQuick.QQuickPaintedItem.
contentsSizeChanged
()¶
-
PySide6.QtQuick.QQuickPaintedItem.
fillColor
()¶ - Return type
See also
-
PySide6.QtQuick.QQuickPaintedItem.
fillColorChanged
()¶
-
PySide6.QtQuick.QQuickPaintedItem.
mipmap
()¶ - Return type
bool
Returns true if mipmaps are enabled; otherwise, false is returned.
By default, mipmapping is not enabled.
See also
-
PySide6.QtQuick.QQuickPaintedItem.
opaquePainting
()¶ - Return type
bool
Returns true if this item is opaque; otherwise, false is returned.
By default, painted items are not opaque.
See also
-
PySide6.QtQuick.QQuickPaintedItem.
paint
(painter)¶ - Parameters
painter –
PySide6.QtGui.QPainter
This function, which is usually called by the QML Scene Graph, paints the contents of an item in local coordinates.
The underlying texture will have a size defined by textureSize
when set, or the item’s size, multiplied by the window’s device pixel ratio.
The function is called after the item has been filled with the fillColor
.
Reimplement this function in a QQuickPaintedItem
subclass to provide the item’s painting implementation, using painter
.
Note
The QML Scene Graph uses two separate threads, the main thread does things such as processing events or updating animations while a second thread does the actual issuing of graphics resource updates and the recording of draw calls. As a consequence, is not called from the main GUI thread but from the GL enabled renderer thread. At the moment is called, the GUI thread is blocked and this is therefore thread-safe.
Warning
Extreme caution must be used when creating QObjects, emitting signals, starting timers and similar inside this function as these will have affinity to the rendering thread.
See also
-
PySide6.QtQuick.QQuickPaintedItem.
performanceHints
()¶ - Return type
PerformanceHints
Returns the performance hints.
By default, no performance hint is enabled.
-
PySide6.QtQuick.QQuickPaintedItem.
renderTarget
()¶ - Return type
See also
-
PySide6.QtQuick.QQuickPaintedItem.
renderTargetChanged
()¶
-
PySide6.QtQuick.QQuickPaintedItem.
resetContentsSize
()¶
This convenience function is equivalent to calling setContentsSize
(QSize()).
-
PySide6.QtQuick.QQuickPaintedItem.
setContentsScale
(arg__1)¶ - Parameters
arg__1 – float
See also
-
PySide6.QtQuick.QQuickPaintedItem.
setContentsSize
(arg__1)¶ - Parameters
arg__1 –
PySide6.QtCore.QSize
See also
-
PySide6.QtQuick.QQuickPaintedItem.
setFillColor
(arg__1)¶ - Parameters
arg__1 –
PySide6.QtGui.QColor
See also
-
PySide6.QtQuick.QQuickPaintedItem.
setMipmap
(enable)¶ - Parameters
enable – bool
If enable
is true, mipmapping is enabled on the associated texture.
Mipmapping increases rendering speed and reduces aliasing artifacts when the item is scaled down.
By default, mipmapping is not enabled.
See also
-
PySide6.QtQuick.QQuickPaintedItem.
setOpaquePainting
(opaque)¶ - Parameters
opaque – bool
If opaque
is true, the item is opaque; otherwise, it is considered as translucent.
Opaque items are not blended with the rest of the scene, you should set this to true if the content of the item is opaque to speed up rendering.
By default, painted items are not opaque.
See also
-
PySide6.QtQuick.QQuickPaintedItem.
setPerformanceHint
(hint[, enabled=true])¶ - Parameters
hint –
PerformanceHint
enabled – bool
Sets the given performance hint
on the item if enabled
is true; otherwise clears the performance hint.
By default, no performance hint is enabled/
See also
-
PySide6.QtQuick.QQuickPaintedItem.
setPerformanceHints
(hints)¶ - Parameters
hints –
PerformanceHints
Sets the performance hints to hints
By default, no performance hint is enabled/
See also
-
PySide6.QtQuick.QQuickPaintedItem.
setRenderTarget
(target)¶ - Parameters
target –
RenderTarget
See also
-
PySide6.QtQuick.QQuickPaintedItem.
setTextureSize
(size)¶ - Parameters
size –
PySide6.QtCore.QSize
See also
-
PySide6.QtQuick.QQuickPaintedItem.
textureSize
()¶ - Return type
See also
-
PySide6.QtQuick.QQuickPaintedItem.
textureSizeChanged
()¶
-
PySide6.QtQuick.QQuickPaintedItem.
update
([rect=QRect()])¶ - Parameters
rect –
PySide6.QtCore.QRect
Schedules a redraw of the area covered by rect
in this item. You can call this function whenever your item needs to be redrawn, such as if it changes appearance or size.
This function does not cause an immediate paint; instead it schedules a paint request that is processed by the QML Scene Graph when the next frame is rendered. The item will only be redrawn if it is visible.
See also
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