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Currently, Qt supports blur, drop shadow, colorize, and opacity effects. These effects can be used by calling the following classes: QGraphicsBlurEffect, QGraphicsDropShadowEffect, QGraphicsColorizeEffect, and QGraphicsOpacityEffect. All these classes are inherited from the QGraphicsEffect class. You can also create your own custom image effect by creating a subclass of QGrapicsEffect (or any other existing effects) and re-implementing the draw() function.

The graphics effect changes only the bounding rectangle of the source. If you want to increase the margin of the bounding rectangle, re-implement the virtual boundingRectFor() function, and call updateBoundingRect() to notify the framework whenever this rectangle changes.