com.trolltech.qt.gui
Class QPaintEngine

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.gui.QPaintEngine
All Implemented Interfaces:
QtJambiInterface

public abstract class QPaintEngine
extends QtJambiObject

The QPaintEngine class provides an abstract definition of how QPainter draws to a given device on a given platform. Qt 4.0 provides several premade implementations of 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 QPaintEngine implementations for OpenGL (accessible through 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 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 QPaintDevice::paintEngine().

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

The big advantage of the QPaintEngine approach opposed to Qt 3's 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.

See also:
QPainter, QPaintDevice::paintEngine(), and The Paint System.


Nested Class Summary
static class QPaintEngine.DirtyFlag
          These types are used by QPainter to trigger lazy updates of the various states in the QPaintEngine using QPaintEngine::updateState().
static class QPaintEngine.DirtyFlags
           
static class QPaintEngine.PaintEngineFeature
          This enum is used to describe the features or capabilities that the paint engine has.
static class QPaintEngine.PaintEngineFeatures
           
static class QPaintEngine.PolygonDrawMode
           
static class QPaintEngine.Type
           
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QPaintEngine()
          Creates a paint engine with the featureset specified by caps.
QPaintEngine(QPaintEngine.PaintEngineFeature[] features)
           
QPaintEngine(QPaintEngine.PaintEngineFeatures features)
          Creates a paint engine with the featureset specified by caps.
 
Method Summary
protected  int active()
          Returns the active state of this paint engine.
abstract  boolean begin(QPaintDeviceInterface pdev)
          Reimplement this function to initialise your paint engine when painting is to start on the paint device pdev.
 void clearDirty(QPaintEngine.DirtyFlag[] df)
           
 void drawEllipse(QRect r)
          The default implementation of this function calls the floating point version of this function
 void drawEllipse(QRectF r)
          Reimplement this function to draw the largest ellipse that can be contained within rectangle rect.
 void drawImage(QRectF r, QImage pm, QRectF sr)
          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.
 void drawImage(QRectF r, QImage pm, QRectF sr, Qt.ImageConversionFlag[] flags)
           
 void drawImage(QRectF r, QImage pm, QRectF sr, Qt.ImageConversionFlags flags)
          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.
 void drawLines(QLine[] lines)
          This is an overloaded member function, provided for convenience.
 void drawLines(QLineF[] lines)
          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.
 void drawPath(QPainterPath path)
          The default implementation ignores the path and does nothing.
abstract  void drawPixmap(QRectF r, QPixmap pm, QRectF sr)
          Reimplement this function to draw the part of the pm specified by the sr rectangle in the given r.
 void drawPoints(QPoint[] points)
          Draws the first pointCount points in the buffer points
 void drawPoints(QPointF[] points)
          Draws the first pointCount points in the buffer points
 void drawPolygon(QPoint[] points, QPaintEngine.PolygonDrawMode mode)
           
 void drawPolygon(QPointF[] points, QPaintEngine.PolygonDrawMode mode)
          This is an overloaded member function, provided for convenience.
 void drawRects(QRect[] rects)
          This is an overloaded member function, provided for convenience.
 void drawRects(QRectF[] rects)
          Draws the first rectCount rectangles in the buffer rects.
 void drawTextItem(QPointF p, QTextItem textItem)
          This function draws the text item textItem at position p.
 void drawTiledPixmap(QRectF r, QPixmap pixmap, QPointF s)
          Reimplement this function to draw the pixmap in the given rect, starting at the given p.
abstract  boolean end()
          Reimplement this function to finish painting on the current paint device.
protected  int extended()
           
protected  QPaintEngine.PaintEngineFeatures gccaps()
           
 boolean hasFeature(QPaintEngine.PaintEngineFeature[] feature)
           
 boolean hasFeature(QPaintEngine.PaintEngineFeatures feature)
          Returns true if the paint engine supports the specified feature; otherwise returns false.
 boolean isActive()
          Returns true if the paint engine is actively drawing; otherwise returns false.
 QPaintDeviceInterface paintDevice()
          Returns the device that this engine is painting on, if painting is active; otherwise returns 0.
 QPainter painter()
          Returns the paint engine's painter.
protected  int selfDestruct()
           
 void setActive(boolean newState)
          Sets the active state of the paint engine to state.
protected  void setActive(int active)
          Sets the active state of the paint engine to active.
 void setDirty(QPaintEngine.DirtyFlag[] df)
           
protected  void setExtended(int extended)
           
protected  void setGccaps(QPaintEngine.PaintEngineFeature[] gccaps)
           
protected  void setGccaps(QPaintEngine.PaintEngineFeatures gccaps)
           
protected  void setSelfDestruct(int selfDestruct)
           
 boolean testDirty(QPaintEngine.DirtyFlag[] df)
           
abstract  QPaintEngine.Type type()
          Reimplement this function to return the paint engine Type .
abstract  void updateState(QPaintEngineState state)
          Reimplement this function to update the state of a paint engine.
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QPaintEngine

public QPaintEngine(QPaintEngine.PaintEngineFeature[] features)

QPaintEngine

public QPaintEngine()
Creates a paint engine with the featureset specified by caps.


QPaintEngine

public QPaintEngine(QPaintEngine.PaintEngineFeatures features)
Creates a paint engine with the featureset specified by caps.

Method Detail

clearDirty

public final void clearDirty(QPaintEngine.DirtyFlag[] df)

hasFeature

public final boolean hasFeature(QPaintEngine.PaintEngineFeature[] feature)

hasFeature

public final boolean hasFeature(QPaintEngine.PaintEngineFeatures feature)
Returns true if the paint engine supports the specified feature; otherwise returns false.


isActive

public final boolean isActive()
Returns true if the paint engine is actively drawing; otherwise returns false.

See also:
setActive().


paintDevice

public final QPaintDeviceInterface paintDevice()
Returns the device that this engine is painting on, if painting is active; otherwise returns 0.


painter

public final QPainter painter()
Returns the paint engine's painter.


setActive

public final void setActive(boolean newState)
Sets the active state of the paint engine to state.

See also:
isActive().


setDirty

public final void setDirty(QPaintEngine.DirtyFlag[] df)

testDirty

public final boolean testDirty(QPaintEngine.DirtyFlag[] df)

begin

public abstract boolean begin(QPaintDeviceInterface pdev)
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(), and isActive().


drawEllipse

public void drawEllipse(QRect r)
The default implementation of this function calls the floating point version of this function


drawEllipse

public void drawEllipse(QRectF r)
Reimplement this function to draw the largest ellipse that can be contained within rectangle rect.

The default implementation calls drawPolygon().


drawImage

public final void drawImage(QRectF r,
                            QImage pm,
                            QRectF sr,
                            Qt.ImageConversionFlag[] flags)

drawImage

public final void drawImage(QRectF r,
                            QImage pm,
                            QRectF sr)
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.


drawImage

public void drawImage(QRectF r,
                      QImage pm,
                      QRectF sr,
                      Qt.ImageConversionFlags flags)
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

public void drawLines(QLine[] lines)
This is an overloaded member function, provided for convenience.

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


drawLines

public void drawLines(QLineF[] lines)
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

public void drawPath(QPainterPath path)
The default implementation ignores the path and does nothing.


drawPixmap

public abstract void drawPixmap(QRectF r,
                                QPixmap pm,
                                QRectF sr)
Reimplement this function to draw the part of the pm specified by the sr rectangle in the given r.


drawPoints

public void drawPoints(QPoint[] points)
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

public void drawPoints(QPointF[] points)
Draws the first pointCount points in the buffer points


drawPolygon

public void drawPolygon(QPoint[] points,
                        QPaintEngine.PolygonDrawMode mode)

drawPolygon

public void drawPolygon(QPointF[] points,
                        QPaintEngine.PolygonDrawMode mode)
This is an overloaded member function, provided for convenience.

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

public void drawRects(QRect[] rects)
This is an overloaded member function, provided for convenience.

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

public void drawRects(QRectF[] rects)
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

public void drawTextItem(QPointF p,
                         QTextItem textItem)
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

public void drawTiledPixmap(QRectF r,
                            QPixmap pixmap,
                            QPointF s)
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.


end

public abstract boolean end()
Reimplement this function to finish painting on the current paint device. Return true if painting was finished successfully; otherwise return false.

See also:
begin(), and isActive().


type

public abstract QPaintEngine.Type type()
Reimplement this function to return the paint engine Type .


updateState

public abstract void updateState(QPaintEngineState state)
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.

See also:
QPaintEngineState.


setExtended

protected final void setExtended(int extended)

extended

protected final int extended()

setSelfDestruct

protected final void setSelfDestruct(int selfDestruct)

selfDestruct

protected final int selfDestruct()

setActive

protected final void setActive(int active)
Sets the active state of the paint engine to active.


active

protected final int active()
Returns the active state of this paint engine.


setGccaps

protected final void setGccaps(QPaintEngine.PaintEngineFeature[] gccaps)

setGccaps

protected final void setGccaps(QPaintEngine.PaintEngineFeatures gccaps)

gccaps

protected final QPaintEngine.PaintEngineFeatures gccaps()