During a paint event, How can I reuse previous paintings so that I can just paint on top of the previous result. Right now the whole rendering area needs repainting.
gonna try QPixmap.
Do I absolutely need to use update?
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During a paint event, How can I reuse previous paintings so that I can just paint on top of the previous result. Right now the whole rendering area needs repainting.
gonna try QPixmap.
Do I absolutely need to use update?
You want to cache the painting in a
QImageorQPixmap(probably aQPixmap). If you do this a lot, you might also want to look atQPixmapCache.Additionally, a lot of drawing can be calculated beforehand, then fairly quickly done using
QPainterPaths. I will often use them and recalculate when necessary, rather than caching the whole paint event in a pixmap.Edit:
I also ran into a brief mention of QPicture, which might also be something you want to look at: