![]() Paint devices access window system resources, and these resources are not initialized before an application object is created. Warning: Qt requires that a QGuiApplication object exists before any paint devices can be created. ![]() Note that you also must create a corresponding paint engine to be able to draw on the device, i.e derive from QPaintEngine and reimplement its virtual functions. To implement support for a new backend, you must derive from QPaintDevice and reimplement the virtual paintEngine() function to tell QPainter which paint engine should be used to draw on this particular device. The drawing capabilities of QPaintDevice are currently implemented by the QWidget, QImage, QPixmap, QGLPixelBuffer, QPicture, and QPrinter subclasses. X increases to the right and Y increases downwards. Its default coordinate system has its origin located at the top-left position. ![]() A paint device is an abstraction of a two-dimensional space that can be drawn on using a QPainter. ![]()
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