QPaintEngine Class

成员函数文档编制

QPaintEngine:: QPaintEngine ( QPaintEngine::PaintEngineFeatures caps = PaintEngineFeatures())

Creates a paint engine with the featureset specified by caps .

[virtual] QPaintEngine:: ~QPaintEngine ()

Destroys the paint engine.

[pure virtual] bool QPaintEngine:: begin ( QPaintDevice * 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.

另请参阅 end () 和 isActive ().

[virtual] void QPaintEngine:: drawEllipse (const QRectF & rect )

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

默认实现调用 drawPolygon ().

[virtual] void QPaintEngine:: drawEllipse (const QRect & rect )

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

[virtual] void QPaintEngine:: drawImage (const QRectF & rectangle , const QImage & image , const QRectF & sr , Qt::ImageConversionFlags flags = Qt::AutoColor)

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.

[virtual] void QPaintEngine:: drawLines (const QLineF * lines , int lineCount )

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

[virtual] void QPaintEngine:: drawLines (const QLine * lines , int lineCount )

这是重载函数。

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

[virtual] void QPaintEngine:: drawPath (const QPainterPath & path )

The default implementation ignores the path and does nothing.

[pure virtual] void QPaintEngine:: drawPixmap (const QRectF & r , const QPixmap & pm , const QRectF & sr )

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

[virtual] void QPaintEngine:: drawPoints (const QPointF * points , int pointCount )

Draws the first pointCount points in the buffer points

[virtual] void QPaintEngine:: drawPoints (const QPoint * points , int pointCount )

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 .

[virtual] void QPaintEngine:: drawPolygon (const QPointF * points , int pointCount , QPaintEngine::PolygonDrawMode mode )

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

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

[virtual] void QPaintEngine:: drawPolygon (const QPoint * points , int pointCount , QPaintEngine::PolygonDrawMode mode )

这是重载函数。

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

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

[virtual] void QPaintEngine:: drawRects (const QRectF * rects , int rectCount )

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

[virtual] void QPaintEngine:: drawRects (const QRect * rects , int rectCount )

这是重载函数。

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

[virtual] void QPaintEngine:: drawTextItem (const QPointF & p , const QTextItem & textItem )

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

[virtual] void QPaintEngine:: drawTiledPixmap (const QRectF & rect , const QPixmap & pixmap , const QPointF & p )

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.

[pure virtual] bool QPaintEngine:: end ()

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

另请参阅 begin () 和 isActive ().

bool QPaintEngine:: hasFeature ( QPaintEngine::PaintEngineFeatures feature ) const

返回 true if the paint engine supports the specified feature ；否则返回 false .

bool QPaintEngine:: isActive () const

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

另请参阅 setActive ().

QPaintDevice *QPaintEngine:: paintDevice () const

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

QPainter *QPaintEngine:: painter () const

Returns the paint engine's painter.

void QPaintEngine:: setActive ( bool state )

Sets the active state of the paint engine to state .

另请参阅 isActive ().

[pure virtual] QPaintEngine::Type QPaintEngine:: type () const

Reimplement this function to return the paint engine Type .

[pure virtual] void QPaintEngine:: updateState (const 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.

另请参阅 QPaintEngineState .