[英]QPainter performance high frame rate
I am trying to show video at 60fps in a QPainter (in an OpenGLwidget) 我试图在QPainter中显示60fps的视频(在OpenGLwidget中)
I am having an issue that sometimes the drawing takes too long and the next repaint event happens while QPainter is in use - which generates a warning and random crashes. 我遇到一个问题,有时候绘图需要太长时间,并且在使用QPainter时会发生下一次重绘事件 - 这会产生警告和随机崩溃。
A couple of questions: 几个问题:
Is there a 'Qt way' to efficently interlock calls to repaint, since presumably QPainter knows it is being used - or do I just use my platforms mutex support? 有没有'Qt方式'有效地将重复调用联系起来,因为可能是QPainter知道它正被使用 - 或者我只是使用我的平台互斥支持?
Is there a better way to draw at high frame rates (which of course also needs to be locked to VSync) than just a timer calling repaint()? 是否有更好的方法来绘制高帧率(当然也需要锁定到VSync)而不仅仅是一个调用repaint()的计时器?
Try to use update()
instead of repaint()
. 尝试使用
update()
而不是repaint()
。
This function does not cause an immediate repaint;
此功能不会立即重新绘制; instead it schedules a paint event for processing when Qt returns to the main event loop.
相反,当Qt返回主事件循环时,它会调度一个paint事件进行处理。 This permits Qt to optimize for more speed and less flicker than a call to repaint() does.
这允许Qt优化以获得比调用repaint()更快的速度和更少的闪烁。
Calling update() several times normally results in just one paintEvent() call.
多次调用update()通常只会导致一次paintEvent()调用。
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