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QRasterPaintEngine Class

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

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QRasterPaintEngine Class

  • Header: QRasterPaintEngine

  • CMake:

    find_package(Qt6 REQUIRED COMPONENTS Gui)

    target_link_libraries(mytarget PRIVATE Qt6::Gui)

  • qmake: QT += gui

  • Inherits: QPaintEngineEx

  • Inherited By:

  • Group: QRasterPaintEngine is part of qws

This class is under development and is subject to change.

Detailed Description

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

In 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 and a custom window surface must be implemented to make Qt for Embedded Linux aware of the accelerated driver.

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.

See Also

See also QPaintEngine

Member Function Documentation

 

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.

[virtual] QRasterPaintEngine::~QRasterPaintEngine()

Destroys this paint engine.

[override virtual] bool QRasterPaintEngine::begin(QPaintDevice *device)

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

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

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

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

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

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

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

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

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

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

[override virtual] void QRasterPaintEngine::drawStaticTextItem(QStaticTextItem *textItem)

 

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

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

[override virtual] bool QRasterPaintEngine::end()

Reimplements: QPaintEngine::end().

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

 

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

 

[override virtual] bool QRasterPaintEngine::shouldDrawCachedGlyphs(QFontEngine *fontEngine, const QTransform &m) const

Returns whether glyph caching is supported by the font engine fontEngine with the given transform m applied.

Related Non-Members

 

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).

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