class QPaintEngine¶

The QPaintEngine class provides an abstract definition of how QPainter draws to a given device on a given platform. More…

Synopsis¶

Methods¶

def __init__()
def clearDirty()
def hasFeature()
def isActive()
def isExtended()
def paintDevice()
def painter()
def setActive()
def setDirty()
def setSystemClip()
def setSystemRect()
def syncState()
def systemClip()
def systemRect()
def testDirty()

Virtual methods¶

def begin()
def coordinateOffset()
def createPixmap()
def createPixmapFromImage()
def drawEllipse()
def drawImage()
def drawLines()
def drawPath()
def drawPixmap()
def drawPoints()
def drawPolygon()
def drawRects()
def drawTextItem()
def drawTiledPixmap()
def end()
def type()
def updateState()

Note

This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE

Detailed Description¶

Qt provides several premade implementations of QPaintEngine for the different painter backends we support. The primary paint engine provided is the raster paint engine, which contains a software rasterizer which supports the full feature set on all supported platforms. This is the default for painting on QWidget-based classes in e.g. on Windows, X11 and macOS, it is the backend for painting on QImage and it is used as a fallback for paint engines that do not support a certain capability. In addition we provide QPaintEngine implementations for OpenGL (accessible through QOpenGLWidget) and printing (which allows using QPainter to draw on a QPrinter object).

If one wants to use QPainter to draw to a different backend, one must subclass QPaintEngine and reimplement all its virtual functions. The QPaintEngine implementation is then made available by subclassing QPaintDevice and reimplementing the virtual function paintEngine() .

QPaintEngine is created and owned by the QPaintDevice that created it.

See also

QPainter paintEngine() Paint System

class PaintEngineFeature¶

(inherits enum.Flag) This enum is used to describe the features or capabilities that the paint engine has. If a feature is not supported by the engine, QPainter will do a best effort to emulate that feature through other means and pass on an alpha blended QImage to the engine with the emulated results. Some features cannot be emulated: AlphaBlend and PorterDuff.

Constant

Description

QPaintEngine.AlphaBlend

The engine can alpha blend primitives.

QPaintEngine.Antialiasing

The engine can use antialiasing to improve the appearance of rendered primitives.

QPaintEngine.BlendModes

The engine supports blending modes.

QPaintEngine.BrushStroke

The engine supports drawing strokes that contain brushes as fills, not just solid colors (e.g. a dashed gradient line of width 2).

QPaintEngine.ConicalGradientFill

The engine supports conical gradient fills.

QPaintEngine.ConstantOpacity

The engine supports the feature provided by setOpacity() .

QPaintEngine.LinearGradientFill

The engine supports linear gradient fills.

QPaintEngine.MaskedBrush

The engine is capable of rendering brushes that has a texture with an alpha channel or a mask.

QPaintEngine.ObjectBoundingModeGradients

The engine has native support for gradients with coordinate mode ObjectBoundingMode . Otherwise, if QPaintEngine::PatternTransform is supported, object bounding mode gradients are converted to gradients with coordinate mode LogicalMode and a brush transform for the coordinate mapping.

QPaintEngine.PainterPaths

The engine has path support.

QPaintEngine.PaintOutsidePaintEvent

The engine is capable of painting outside of paint events.

QPaintEngine.PatternBrush

The engine is capable of rendering brushes with the brush patterns specified in Qt::BrushStyle.

QPaintEngine.PatternTransform

The engine has support for transforming brush patterns.

QPaintEngine.PerspectiveTransform

The engine has support for performing perspective transformations on primitives.

QPaintEngine.PixmapTransform

The engine can transform pixmaps, including rotation and shearing.

QPaintEngine.PorterDuff

The engine supports Porter-Duff operations

QPaintEngine.PrimitiveTransform

The engine has support for transforming drawing primitives.

QPaintEngine.RadialGradientFill

The engine supports radial gradient fills.

QPaintEngine.RasterOpModes

The engine supports bitwise raster operations.

QPaintEngine.AllFeatures

All of the above features. This enum value is usually used as a bit mask.

Constant	Description
QPaintEngine.AlphaBlend	The engine can alpha blend primitives.
QPaintEngine.Antialiasing	The engine can use antialiasing to improve the appearance of rendered primitives.
QPaintEngine.BlendModes	The engine supports blending modes.
QPaintEngine.BrushStroke	The engine supports drawing strokes that contain brushes as fills, not just solid colors (e.g. a dashed gradient line of width 2).
QPaintEngine.ConicalGradientFill	The engine supports conical gradient fills.
QPaintEngine.ConstantOpacity	The engine supports the feature provided by `setOpacity()` .
QPaintEngine.LinearGradientFill	The engine supports linear gradient fills.
QPaintEngine.MaskedBrush	The engine is capable of rendering brushes that has a texture with an alpha channel or a mask.
QPaintEngine.ObjectBoundingModeGradients	The engine has native support for gradients with coordinate mode `ObjectBoundingMode` . Otherwise, if QPaintEngine::PatternTransform is supported, object bounding mode gradients are converted to gradients with coordinate mode `LogicalMode` and a brush transform for the coordinate mapping.
QPaintEngine.PainterPaths	The engine has path support.
QPaintEngine.PaintOutsidePaintEvent	The engine is capable of painting outside of paint events.
QPaintEngine.PatternBrush	The engine is capable of rendering brushes with the brush patterns specified in Qt::BrushStyle.
QPaintEngine.PatternTransform	The engine has support for transforming brush patterns.
QPaintEngine.PerspectiveTransform	The engine has support for performing perspective transformations on primitives.
QPaintEngine.PixmapTransform	The engine can transform pixmaps, including rotation and shearing.
QPaintEngine.PorterDuff	The engine supports Porter-Duff operations
QPaintEngine.PrimitiveTransform	The engine has support for transforming drawing primitives.
QPaintEngine.RadialGradientFill	The engine supports radial gradient fills.
QPaintEngine.RasterOpModes	The engine supports bitwise raster operations.
QPaintEngine.AllFeatures	All of the above features. This enum value is usually used as a bit mask.

class DirtyFlag¶

Constant

Description

QPaintEngine.DirtyPen

(inherits enum.Flag) The pen is dirty and needs to be updated.

QPaintEngine.DirtyBrush

The brush is dirty and needs to be updated.

QPaintEngine.DirtyBrushOrigin

The brush origin is dirty and needs to updated.

QPaintEngine.DirtyFont

The font is dirty and needs to be updated.

QPaintEngine.DirtyBackground

The background is dirty and needs to be updated.

QPaintEngine.DirtyBackgroundMode

The background mode is dirty and needs to be updated.

QPaintEngine.DirtyTransform

The transform is dirty and needs to be updated.

QPaintEngine.DirtyClipRegion

The clip region is dirty and needs to be updated.

QPaintEngine.DirtyClipPath

The clip path is dirty and needs to be updated.

QPaintEngine.DirtyHints

The render hints is dirty and needs to be updated.

QPaintEngine.DirtyCompositionMode

The composition mode is dirty and needs to be updated.

QPaintEngine.DirtyClipEnabled

Whether clipping is enabled or not is dirty and needs to be updated.

QPaintEngine.DirtyOpacity

The constant opacity has changed and needs to be updated as part of the state change in updateState() .

QPaintEngine.AllDirty

Convenience enum used internally.

Constant	Description
QPaintEngine.DirtyPen	(inherits `enum.Flag`) The pen is dirty and needs to be updated.
QPaintEngine.DirtyBrush	The brush is dirty and needs to be updated.
QPaintEngine.DirtyBrushOrigin	The brush origin is dirty and needs to updated.
QPaintEngine.DirtyFont	The font is dirty and needs to be updated.
QPaintEngine.DirtyBackground	The background is dirty and needs to be updated.
QPaintEngine.DirtyBackgroundMode	The background mode is dirty and needs to be updated.
QPaintEngine.DirtyTransform	The transform is dirty and needs to be updated.
QPaintEngine.DirtyClipRegion	The clip region is dirty and needs to be updated.
QPaintEngine.DirtyClipPath	The clip path is dirty and needs to be updated.
QPaintEngine.DirtyHints	The render hints is dirty and needs to be updated.
QPaintEngine.DirtyCompositionMode	The composition mode is dirty and needs to be updated.
QPaintEngine.DirtyClipEnabled	Whether clipping is enabled or not is dirty and needs to be updated.
QPaintEngine.DirtyOpacity	The constant opacity has changed and needs to be updated as part of the state change in `updateState()` .
QPaintEngine.AllDirty	Convenience enum used internally.

These types are used by QPainter to trigger lazy updates of the various states in the QPaintEngine using updateState() .

A paint engine must update every dirty state.

class PolygonDrawMode¶

Constant	Description
QPaintEngine.OddEvenMode	The polygon should be drawn using OddEven fill rule.
QPaintEngine.WindingMode	The polygon should be drawn using Winding fill rule.
QPaintEngine.ConvexMode	The polygon is a convex polygon and can be drawn using specialized algorithms where available.
QPaintEngine.PolylineMode	Only the outline of the polygon should be drawn.

class Type¶

Constant	Description
QPaintEngine.X11
QPaintEngine.Windows
QPaintEngine.MacPrinter
QPaintEngine.CoreGraphics	macOS’s Quartz2D (CoreGraphics)
QPaintEngine.QuickDraw	macOS’s QuickDraw
QPaintEngine.QWindowSystem	Qt for Embedded Linux
QPaintEngine.OpenGL
QPaintEngine.Picture	`QPicture` format
QPaintEngine.SVG	Scalable Vector Graphics XML format
QPaintEngine.Raster
QPaintEngine.Direct3D	Windows only, Direct3D based engine
QPaintEngine.Pdf	Portable Document Format
QPaintEngine.OpenVG
QPaintEngine.User	First user type ID
QPaintEngine.MaxUser	Last user type ID
QPaintEngine.OpenGL2
QPaintEngine.PaintBuffer
QPaintEngine.Blitter
QPaintEngine.Direct2D	Windows only, Direct2D based engine

PySide6.QtGui.QPaintEngine.state¶

PySide6.QtGui.QPaintEngine.gccaps¶

PySide6.QtGui.QPaintEngine.active¶

PySide6.QtGui.QPaintEngine.selfDestruct¶

PySide6.QtGui.QPaintEngine.extended¶

__init__([features=QPaintEngine.PaintEngineFeatures()])¶

Parameters:: features – Combination of PaintEngineFeature

Creates a paint engine with the featureset specified by caps.

abstract begin(pdev)¶

Parameters:: pdev – QPaintDevice
Return type:: bool

Reimplement this function to initialise your paint engine when painting is to start on the paint device pdev. Return true if the initialization was successful; otherwise return false.

See also

end() isActive()

clearDirty(df)¶

Parameters:: df – Combination of DirtyFlag

coordinateOffset()¶

Return type:: QPoint

createPixmap(size)¶

Parameters:: size – QSize
Return type:: QPixmap

createPixmapFromImage(image[, flags=Qt.AutoColor])¶

Parameters:

image – QImage
flags – Combination of ImageConversionFlag

Return type:

QPixmap

drawEllipse(r)¶

Parameters:: r – QRect

This is an overloaded function.

The default implementation of this function calls the floating point version of this function

drawEllipse(r)

Parameters:: r – QRectF

Reimplement this function to draw the largest ellipse that can be contained within rectangle rect.

The default implementation calls drawPolygon() .

drawImage(r, pm, sr[, flags=Qt.AutoColor])¶

Parameters:

r – QRectF
pm – QImage
sr – QRectF
flags – Combination of ImageConversionFlag

Reimplement this function to draw the part of the image specified by the sr rectangle in the given rectangle using the given conversion flags flags, to convert it to a pixmap.

drawLines(lines, lineCount)¶

Parameters:

lines – QLine
lineCount – int

This is an overloaded function.

The default implementation converts the first lineCount lines in lines to a QLineF and calls the floating point version of this function.

drawLines(lines, lineCount)

Parameters:

lines – QLineF
lineCount – int

The default implementation splits the list of lines in lines into lineCount separate calls to drawPath() or drawPolygon() depending on the feature set of the paint engine.

drawPath(path)¶

Parameters:: path – QPainterPath

The default implementation ignores the path and does nothing.

abstract drawPixmap(r, pm, sr)¶

Parameters:

r – QRectF
pm – QPixmap
sr – QRectF

Reimplement this function to draw the part of the pm specified by the sr rectangle in the given r.

drawPoints(points, pointCount)¶

Parameters:

points – QPoint
pointCount – int

Draws the first pointCount points in the buffer points

The default implementation converts the first pointCount QPoints in points to QPointFs and calls the floating point version of drawPoints.

drawPoints(points, pointCount)

Parameters:

points – QPointF
pointCount – int

Draws the first pointCount points in the buffer points

drawPolygon(points, pointCount, mode)¶

Parameters:

points – QPoint
pointCount – int
mode – PolygonDrawMode

This is an overloaded function.

Reimplement this virtual function to draw the polygon defined by the pointCount first points in points, using mode mode.

Note

At least one of the drawPolygon() functions must be reimplemented.

drawPolygon(points, pointCount, mode)

Parameters:

points – QPointF
pointCount – int
mode – PolygonDrawMode

Reimplement this virtual function to draw the polygon defined by the pointCount first points in points, using mode mode.

Note

At least one of the drawPolygon() functions must be reimplemented.

drawRects(rects, rectCount)¶

Parameters:

rects – QRect
rectCount – int

This is an overloaded function.

The default implementation converts the first rectCount rectangles in the buffer rects to a QRectF and calls the floating point version of this function.

drawRects(rects, rectCount)

Parameters:

rects – QRectF
rectCount – int

Draws the first rectCount rectangles in the buffer rects. The default implementation of this function calls drawPath() or drawPolygon() depending on the feature set of the paint engine.

drawTextItem(p, textItem)¶

Parameters:

p – QPointF
textItem – QTextItem

This function draws the text item textItem at position p. The default implementation of this function converts the text to a QPainterPath and paints the resulting path.

drawTiledPixmap(r, pixmap, s)¶

Parameters:

r – QRectF
pixmap – QPixmap
s – QPointF

Reimplement this function to draw the pixmap in the given rect, starting at the given p. The pixmap will be drawn repeatedly until the rect is filled.

abstract end()¶

Return type:: bool

Reimplement this function to finish painting on the current paint device. Return true if painting was finished successfully; otherwise return false.

See also

begin() isActive()

hasFeature(feature)¶

Parameters:: feature – Combination of PaintEngineFeature
Return type:: bool

Returns true if the paint engine supports the specified feature; otherwise returns false.

isActive()¶

Return type:: bool

Returns true if the paint engine is actively drawing; otherwise returns false.

See also

setActive()

isExtended()¶

Return type:: bool

paintDevice()¶

Return type:: QPaintDevice

Returns the device that this engine is painting on, if painting is active; otherwise returns None.

painter()¶

Return type:: QPainter

Returns the paint engine’s painter.

setActive(newState)¶

Parameters:: newState – bool

Sets the active state of the paint engine to state.

See also

isActive()

setDirty(df)¶

Parameters:: df – Combination of DirtyFlag

setSystemClip(baseClip)¶

Parameters:: baseClip – QRegion

setSystemRect(rect)¶

Parameters:: rect – QRect

syncState()¶

systemClip()¶

Return type:: QRegion

systemRect()¶

Return type:: QRect

testDirty(df)¶

Parameters:: df – Combination of DirtyFlag
Return type:: bool

abstract type()¶

Return type:: Type

Reimplement this function to return the paint engine Type .

abstract updateState(state)¶

Parameters:: state – QPaintEngineState

Reimplement this function to update the state of a paint engine.

When implemented, this function is responsible for checking the paint engine’s current state and update the properties that are changed. Use the state() function to find out which properties that must be updated, then use the corresponding get function to retrieve the current values for the given properties.

See also

QPaintEngineState