问题 Qt Example callout 展示了在平面直角坐标系中画tips。知识点涉及到QChart/QGraphicsView/QGraphicsItem。如何在平面直角坐标系中画点、折线、圆、长方形? Example路径 D:\Qt\5.15.2\Src\qtcharts\examples\charts\callout\callout.cpp 代码 main #include
缓存模式 QGraphicsView::CacheNone All painting is done directly onto the viewport. 直接在视口上绘制 QGraphicsView::CacheBackground The background is cached. This affects both custom backgrounds, and backgro