The engine is capable of painting outside of paint events. 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. The engine has native support for gradients with coordinate mode QGradient::ObjectBoundingMode. The engine is capable of rendering brushes that has a texture with an alpha channel or a mask. The engine supports linear gradient fills. The engine supports the feature provided by QPainter::setOpacity(). The engine supports conical gradient fills. The engine supports drawing strokes that contain brushes as fills, not just solid colors (e.g. The engine can use antialising to improve the appearance of rendered primitives. Some features cannot be emulated: AlphaBlend and PorterDuff. If a feature is not supported by the engine, QPainter will do a best effort to emulate that feature through other means and pass on an alpha blended QImage to the engine with the emulated results.
-1200x675.jpg "quickdraw engines")
This enum is used to describe the features or capabilities that the paint engine has. enum QPaintEngine:: PaintEngineFeature flags QPaintEngine:: PaintEngineFeatures It stores an OR combination of DirtyFlag values. The DirtyFlags type is a typedef for QFlags.
#Quickdraw engines update#
These types are used by QPainter to trigger lazy updates of the various states in the QPaintEngine using QPaintEngine::updateState().Ī paint engine must update every dirty state. The constant opacity has changed and needs to be updated as part of the state change in QPaintEngine::updateState(). Whether clipping is enabled or not is dirty and needs to be updated. The composition mode is dirty and needs to be updated. The render hints is dirty and needs to be updated. The clip path is dirty and needs to be updated. The clip region is dirty and needs to be updated. The transform is dirty and needs to be updated. The background mode is dirty and needs to be updated. The background is dirty and needs to be updated. The font is dirty and needs to be updated. The brush origin is dirty and needs to updated. The brush is dirty and needs to be updated. The pen is dirty and needs to be updated. See also QPainter, QPaintDevice::paintEngine(), and Paint System. QPaintEngine is created and owned by the QPaintDevice that created it.
The QPaintEngine implementation is then made available by subclassing QPaintDevice and reimplementing the virtual function QPaintDevice::paintEngine(). If one wants to use QPainter to draw to a different backend, one must subclass QPaintEngine and reimplement all its virtual functions. In addition we provide QPaintEngine implementations for OpenGL (accessible through QOpenGLWidget) and printing (which allows using QPainter to draw on a QPrinter object). on Windows, X11 and macOS, it is the backend for painting on QImage and it is used as a fallback for paint engines that do not support a certain capability. This is the default for painting on QWidget-based classes in e.g.
#Quickdraw engines full#
The primary paint engine provided is the raster paint engine, which contains a software rasterizer which supports the full feature set on all supported platforms. Qt provides several premade implementations of QPaintEngine for the different painter backends we support. UpdateState(const QPaintEngineState & state) = 0 HasFeature(QPaintEngine::PaintEngineFeatures feature) const QPaintEngine(QPaintEngine::PaintEngineFeatures caps = PaintEngineFeatures())ĭrawImage(const QRectF & rectangle, const QImage & image, const QRectF & sr, Qt::ImageConversionFlags flags = Qt::AutoColor)ĭrawLines(const QLineF * lines, int lineCount)ĭrawLines(const QLine * lines, int lineCount)ĭrawPixmap(const QRectF & r, const QPixmap & pm, const QRectF & sr) = 0ĭrawPoints(const QPointF * points, int pointCount)ĭrawPoints(const QPoint * points, int pointCount)ĭrawPolygon(const QPointF * points, int pointCount, QPaintEngine::PolygonDrawMode mode)ĭrawPolygon(const QPoint * points, int pointCount, QPaintEngine::PolygonDrawMode mode)ĭrawRects(const QRectF * rects, int rectCount)ĭrawRects(const QRect * rects, int rectCount)ĭrawTextItem(const QPointF & p, const QTextItem & textItem)ĭrawTiledPixmap(const QRectF & rect, const QPixmap & pixmap, const QPointF & p)
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