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QPaintEngine

Inheritance diagram of QPaintEngine

Synopsis

Functions

Virtual functions

Detailed Description

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

Qt 4.0 provides several premade implementations of PySide.QtGui.QPaintEngine for the different painter backends we support. We provide one paint engine for each window system and painting framework we support. This includes X11 on Unix/Linux and CoreGraphics on Mac OS X. In addition we provide PySide.QtGui.QPaintEngine implementations for OpenGL (accessible through PySide.QtOpenGL.QGLWidget ) and PostScript (accessible through QPSPrinter on X11). Additionally there is a raster-based paint engine that is a fallback for when an engine does not support a certain capability.

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

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

The big advantage of the PySide.QtGui.QPaintEngine approach opposed to Qt 3’s PySide.QtGui.QPainter /QPaintDevice::cmd() approach is that it is now possible to adapt to multiple technologies on each platform and take advantage of each to the fullest.

class PySide.QtGui.QPaintEngine([features=0])
Parameters:featuresPySide.QtGui.QPaintEngine.PaintEngineFeatures
PySide.QtGui.QPaintEngine.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.
PySide.QtGui.QPaintEngine.Type
Constant Description
QPaintEngine.X11  
QPaintEngine.Windows  
QPaintEngine.MacPrinter  
QPaintEngine.CoreGraphics Mac OS X’s Quartz2D ( CoreGraphics )
QPaintEngine.QuickDraw Mac OS X’s QuickDraw
QPaintEngine.QWindowSystem Qt for Embedded Linux
QPaintEngine.PostScript  
QPaintEngine.OpenGL  
QPaintEngine.Picture PySide.QtGui.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  
PySide.QtGui.QPaintEngine.PaintEngineFeature

This enum is used to describe the features or capabilities that the paint engine has. If a feature is not supported by the engine, PySide.QtGui.QPainter will do a best effort to emulate that feature through other means and pass on an alpha blended PySide.QtGui.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 antialising 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 QPainter.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 QGradient.ObjectBoundingMode . Otherwise, if QPaintEngine.PatternTransform is supported, object bounding mode gradients are converted to gradients with coordinate mode QGradient.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.
PySide.QtGui.QPaintEngine.DirtyFlag
Constant Description
QPaintEngine.DirtyPen 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 QPaintEngine.updateState() .
QPaintEngine.AllDirty Convenience enum used internally.

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

A paint engine must update every dirty state.

PySide.QtGui.QPaintEngine.extended
PySide.QtGui.QPaintEngine.selfDestruct
PySide.QtGui.QPaintEngine.active
PySide.QtGui.QPaintEngine.state
PySide.QtGui.QPaintEngine.gccaps
PySide.QtGui.QPaintEngine.autoDestruct()
Return type:PySide.QtCore.bool
PySide.QtGui.QPaintEngine.begin(pdev)
Parameters:pdevPySide.QtGui.QPaintDevice
Return type:PySide.QtCore.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.

PySide.QtGui.QPaintEngine.clearDirty(df)
Parameters:dfPySide.QtGui.QPaintEngine.DirtyFlags
PySide.QtGui.QPaintEngine.coordinateOffset()
Return type:PySide.QtCore.QPoint

Returns the offset from the painters origo to the engines origo. This value is used by PySide.QtGui.QPainter for engines who have internal double buffering.

This function only makes sense when the engine is active.

PySide.QtGui.QPaintEngine.drawEllipse(r)
Parameters:rPySide.QtCore.QRectF

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

The default implementation calls PySide.QtGui.QPaintEngine.drawPolygon() .

PySide.QtGui.QPaintEngine.drawEllipse(r)
Parameters:rPySide.QtCore.QRect

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

PySide.QtGui.QPaintEngine.drawImage(r, pm, sr[, flags=Qt.AutoColor])
Parameters:
PySide.QtGui.QPaintEngine.drawLines(lines, lineCount)
Parameters:

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

PySide.QtGui.QPaintEngine.drawLines(lines, lineCount)
Parameters:

This is an overloaded function.

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

PySide.QtGui.QPaintEngine.drawPath(path)
Parameters:pathPySide.QtGui.QPainterPath

The default implementation ignores the path and does nothing.

PySide.QtGui.QPaintEngine.drawPixmap(r, pm, sr)
Parameters:

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

PySide.QtGui.QPaintEngine.drawPoints(points, pointCount)
Parameters:

Draws the first pointCount points in the buffer points

PySide.QtGui.QPaintEngine.drawPoints(points, pointCount)
Parameters:

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.

PySide.QtGui.QPaintEngine.drawPolygon(points, pointCount, mode)
Parameters:

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 PySide.QtGui.QPaintEngine.drawPolygon() functions must be reimplemented.

PySide.QtGui.QPaintEngine.drawPolygon(points, pointCount, mode)
Parameters:

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 PySide.QtGui.QPaintEngine.drawPolygon() functions must be reimplemented.

PySide.QtGui.QPaintEngine.drawRects(rects, rectCount)
Parameters:

This is an overloaded function.

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

PySide.QtGui.QPaintEngine.drawRects(rects, rectCount)
Parameters:

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

PySide.QtGui.QPaintEngine.drawTextItem(p, textItem)
Parameters:

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

PySide.QtGui.QPaintEngine.drawTiledPixmap(r, pixmap, s)
Parameters:

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.

PySide.QtGui.QPaintEngine.end()
Return type:PySide.QtCore.bool

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

PySide.QtGui.QPaintEngine.hasFeature(feature)
Parameters:featurePySide.QtGui.QPaintEngine.PaintEngineFeatures
Return type:PySide.QtCore.bool
PySide.QtGui.QPaintEngine.isActive()
Return type:PySide.QtCore.bool

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

PySide.QtGui.QPaintEngine.isExtended()
Return type:PySide.QtCore.bool

Returns true if the paint engine is a QPaintEngineEx derivative.

PySide.QtGui.QPaintEngine.paintDevice()
Return type:PySide.QtGui.QPaintDevice

Returns the device that this engine is painting on, if painting is active; otherwise returns 0.

PySide.QtGui.QPaintEngine.painter()
Return type:PySide.QtGui.QPainter

Returns the paint engine’s painter.

PySide.QtGui.QPaintEngine.setActive(newState)
Parameters:newStatePySide.QtCore.bool

Sets the active state of the paint engine to state .

PySide.QtGui.QPaintEngine.setAutoDestruct(autoDestr)
Parameters:autoDestrPySide.QtCore.bool
PySide.QtGui.QPaintEngine.setDirty(df)
Parameters:dfPySide.QtGui.QPaintEngine.DirtyFlags
PySide.QtGui.QPaintEngine.setSystemClip(baseClip)
Parameters:baseClipPySide.QtGui.QRegion

Sets the system clip for this engine. The system clip defines the basis area that the engine has to draw in. All clips that are set will be be an intersection with the system clip.

Reset the systemclip to no clip by setting an empty region.

PySide.QtGui.QPaintEngine.setSystemRect(rect)
Parameters:rectPySide.QtCore.QRect

Sets the target rect for drawing within the backing store. This function should ONLY be used by the backing store.

PySide.QtGui.QPaintEngine.syncState()

Updates all dirty states in this engine. This function should ONLY be used when drawing with native handles directly and immediate sync from QPainters state to the native state is required.

PySide.QtGui.QPaintEngine.systemClip()
Return type:PySide.QtGui.QRegion

Returns the system clip. The system clip is read only while the painter is active. An empty region indicates that system clip is not in use.

PySide.QtGui.QPaintEngine.systemRect()
Return type:PySide.QtCore.QRect

Retrieves the rect for drawing within the backing store. This function should ONLY be used by the backing store.

PySide.QtGui.QPaintEngine.testDirty(df)
Parameters:dfPySide.QtGui.QPaintEngine.DirtyFlags
Return type:PySide.QtCore.bool
PySide.QtGui.QPaintEngine.type()
Return type:PySide.QtGui.QPaintEngine.Type

Reimplement this function to return the paint engine QPaintEngine.Type .

PySide.QtGui.QPaintEngine.updateState(state)
Parameters:statePySide.QtGui.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 QPaintEngineState.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.