内容

• 公共函数
• 重实现公共函数
• 相关非成员
• 详细描述

QRasterPaintEngine 类

The QRasterPaintEngine class enables hardware acceleration of painting operations in Qt for Embedded Linux. 更多...

头：	#include <QRasterPaintEngine>
Since:	Qt 4.2
继承：	QPaintEngine

该类在开发且可能改变。

• 所有成员列表，包括继承成员

公共函数

	QRasterPaintEngine (QPaintDevice * device )
	~QRasterPaintEngine ()
virtual void	drawBufferSpan (const uint * buffer , int size , int x , int y , int length , uint alpha )
virtual void	drawColorSpans (const QSpan * spans , int count , uint color )
bool	supportsTransformations (const QFontEngine * fontEngine ) const

重实现公共函数

virtual bool	begin (QPaintDevice * device )
virtual void	drawEllipse (const QRectF & rect )
virtual void	drawEllipse (const QRect & rect )
virtual void	drawImage (const QRectF & r , const QImage & img , const QRectF & sr , Qt::ImageConversionFlags falgs = Qt::AutoColor)
virtual void	drawLines (const QLine * lines , int lineCount )
virtual void	drawLines (const QLineF * lines , int lineCount )
virtual void	drawPixmap (const QRectF & r , const QPixmap & pixmap , const QRectF & sr )
virtual void	drawPoints (const QPointF * points , int pointCount )
virtual void	drawPoints (const QPoint * points , int pointCount )
virtual void	drawPolygon (const QPointF * points , int pointCount , PolygonDrawMode mode )
virtual void	drawPolygon (const QPoint * points , int pointCount , PolygonDrawMode mode )
virtual void	drawRects (const QRect * rects , int rectCount )
virtual void	drawRects (const QRectF * rects , int rectCount )
virtual void	drawStaticTextItem (QStaticTextItem * textItem )
virtual void	drawTextItem (const QPointF & p , const QTextItem & textItem )
virtual void	drawTiledPixmap (const QRectF & r , const QPixmap & pixmap , const QPointF & sr )
virtual bool	end ()
virtual void	fillRect (const QRectF & r , const QBrush & brush )
virtual void	fillRect (const QRectF & r , const QColor & color )
virtual bool	supportsTransformations (qreal pixelSize , const QTransform & m ) const
virtual Type	type () const

• 24 公共函数继承自 QPaintEngine

相关非成员

typedef

QSpan

详细描述

The QRasterPaintEngine class enables hardware acceleration of painting operations in Qt for Embedded Linux.

Note that this functionality is only available in Qt for Embedded Linux .

在 Qt for Embedded Linux , painting is a pure software implementation. But starting with Qt 4.2, it is possible to add an accelerated graphics driver to take advantage of available hardware resources.

Hardware acceleration is accomplished by creating a custom screen driver, accelerating the copying from memory to the screen, and implementing a custom paint engine accelerating the various painting operations. Then a custom paint device (derived from the QCustomRasterPaintDevice class) and a custom window surface (derived from QWSWindowSurface) must be implemented to make Qt for Embedded Linux aware of the accelerated driver.

注意： The QRasterPaintEngine class does not support 8-bit images. Instead, they need to be converted to a supported format, such as QImage::Format_ARGB32_Premultiplied .

见 Adding an Accelerated Graphics Driver to Qt for Embedded Linux 文档编制了解细节。

另请参阅 QCustomRasterPaintDevice and QPaintEngine .

成员函数文档编制

QRasterPaintEngine:: QRasterPaintEngine ( QPaintDevice * device )

Creates a raster based paint engine for operating on the given device , with the complete set of paint engine features and capabilities .

该函数在 Qt 4.5 引入。

QRasterPaintEngine:: ~QRasterPaintEngine ()

销毁此描绘引擎。

[虚拟] bool QRasterPaintEngine:: begin ( QPaintDevice * device )

重实现自 QPaintEngine::begin ().

[虚拟] void QRasterPaintEngine:: drawBufferSpan (const uint * buffer , int size , int x , int y , int length , uint alpha )

绘制给定 buffer .

The default implementation does nothing; reimplement this function to draw a buffer that contains more than one color. Note that this function must be reimplemented if the framebuffer is not memory-mapped.

The size parameter specifies the total size of the given buffer , while the length parameter specifies the number of pixels to draw. The buffer's position is given by ( x , y ). The provided alpha value is added to each pixel in the buffer when drawing.

另请参阅 drawColorSpans ().

[虚拟] void QRasterPaintEngine:: drawColorSpans (const QSpan * spans , int count , uint color )

Draws the given color spans 采用指定 color 。 count parameter specifies the number of spans.

The default implementation does nothing; reimplement this function to draw the given color spans 采用指定 color . Note that this function must be reimplemented if the framebuffer is not memory-mapped.

另请参阅 drawBufferSpan ().

[虚拟] void QRasterPaintEngine:: drawEllipse (const QRectF & rect )

重实现自 QPaintEngine::drawEllipse ().

[虚拟] void QRasterPaintEngine:: drawEllipse (const QRect & rect )

重实现自 QPaintEngine::drawEllipse ().

这是重载函数。

重实现此函数以绘制可以包含的最大椭圆，在矩形 rect .

[虚拟] void QRasterPaintEngine:: drawImage (const QRectF & r , const QImage & img , const QRectF & sr , Qt::ImageConversionFlags falgs = Qt::AutoColor)

重实现自 QPaintEngine::drawImage ().

[虚拟] void QRasterPaintEngine:: drawLines (const QLine * lines , int lineCount )

重实现自 QPaintEngine::drawLines ().

[虚拟] void QRasterPaintEngine:: drawLines (const QLineF * lines , int lineCount )

重实现自 QPaintEngine::drawLines ().

[虚拟] void QRasterPaintEngine:: drawPixmap (const QRectF & r , const QPixmap & pixmap , const QRectF & sr )

重实现自 QPaintEngine::drawPixmap ().

[虚拟] void QRasterPaintEngine:: drawPoints (const QPointF * points , int pointCount )

重实现自 QPaintEngine::drawPoints ().

[虚拟] void QRasterPaintEngine:: drawPoints (const QPoint * points , int pointCount )

重实现自 QPaintEngine::drawPoints ().

这是重载函数。

绘制第一 pointCount 点在缓冲 points

默认实现转换第一 pointCount QPoints 在 points 成 QPointF 并调用浮点版本的 drawPoints .

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

重实现自 QPaintEngine::drawPolygon ().

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

重实现自 QPaintEngine::drawPolygon ().

[虚拟] void QRasterPaintEngine:: drawRects (const QRect * rects , int rectCount )

重实现自 QPaintEngine::drawRects ().

[虚拟] void QRasterPaintEngine:: drawRects (const QRectF * rects , int rectCount )

重实现自 QPaintEngine::drawRects ().

[虚拟] void QRasterPaintEngine:: drawStaticTextItem ( QStaticTextItem * textItem )

[虚拟] void QRasterPaintEngine:: drawTextItem (const QPointF & p , const QTextItem & textItem )

重实现自 QPaintEngine::drawTextItem ().

[虚拟] void QRasterPaintEngine:: drawTiledPixmap (const QRectF & r , const QPixmap & pixmap , const QPointF & sr )

重实现自 QPaintEngine::drawTiledPixmap ().

[虚拟] bool QRasterPaintEngine:: end ()

重实现自 QPaintEngine::end ().

[虚拟] void QRasterPaintEngine:: fillRect (const QRectF & r , const QBrush & brush )

[虚拟] void QRasterPaintEngine:: fillRect (const QRectF & r , const QColor & color )

bool QRasterPaintEngine:: supportsTransformations (const QFontEngine * fontEngine ) const

[虚拟] bool QRasterPaintEngine:: supportsTransformations ( qreal pixelSize , const QTransform & m ) const

[虚拟] Type QRasterPaintEngine:: type () const

重实现自 QPaintEngine::type ().

相关非成员

typedef QSpan

A struct equivalent to QT_FT_Span, containing a position (x, y), the span's length in pixels and its color/coverage (a value ranging from 0 to 255).