QQuickPaintedItem

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

Inheritance diagram of PySide6.QtQuick.QQuickPaintedItem

Synopsis

Functions

Virtual functions

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 a QImage 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

setRenderTarget()

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

PySide6.QtCore.QRectF

This function is provided for compatibility, use size in combination with textureSize to decide the size of what you are drawing.

PySide6.QtQuick.QQuickPaintedItem.contentsScale()
Return type

float

See also

setContentsScale()

PySide6.QtQuick.QQuickPaintedItem.contentsScaleChanged()
PySide6.QtQuick.QQuickPaintedItem.contentsSize()
Return type

PySide6.QtCore.QSize

See also

setContentsSize()

PySide6.QtQuick.QQuickPaintedItem.contentsSizeChanged()
PySide6.QtQuick.QQuickPaintedItem.fillColor()
Return type

PySide6.QtGui.QColor

See also

setFillColor()

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

setMipmap()

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.

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

width() height() textureSize

PySide6.QtQuick.QQuickPaintedItem.performanceHints()
Return type

PerformanceHints

Returns the performance hints.

By default, no performance hint is enabled.

PySide6.QtQuick.QQuickPaintedItem.renderTarget()
Return type

RenderTarget

See also

setRenderTarget()

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

contentsScale()

PySide6.QtQuick.QQuickPaintedItem.setContentsSize(arg__1)
Parameters

arg__1 – PySide6.QtCore.QSize

See also

contentsSize()

PySide6.QtQuick.QQuickPaintedItem.setFillColor(arg__1)
Parameters

arg__1 – PySide6.QtGui.QColor

See also

fillColor()

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

mipmap()

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

opaquePainting()

PySide6.QtQuick.QQuickPaintedItem.setPerformanceHint(hint[, enabled=true])
Parameters

Sets the given performance hint on the item if enabled is true; otherwise clears the performance hint.

By default, no performance hint is enabled/

PySide6.QtQuick.QQuickPaintedItem.setPerformanceHints(hints)
Parameters

hints – PerformanceHints

Sets the performance hints to hints

By default, no performance hint is enabled/

PySide6.QtQuick.QQuickPaintedItem.setRenderTarget(target)
Parameters

target – RenderTarget

See also

renderTarget()

PySide6.QtQuick.QQuickPaintedItem.setTextureSize(size)
Parameters

size – PySide6.QtCore.QSize

See also

textureSize()

PySide6.QtQuick.QQuickPaintedItem.textureSize()
Return type

PySide6.QtCore.QSize

See also

setTextureSize()

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

paint()