Before I try to code a stripped-down version of my issue I would like to describe it in case I'm missing something obvious.
I have an app with a QGraphicsScene that holds a vehicle which is constantly moving at a fixed rate (~10 times per second). Every time it moves it draws some polygons behind (the path it went trough). Up to that point, everything is ok. Now if I add a lot of straight lines (QGraphicsLineItem instances) performance (number of movements seen on screen per second) varies according the zoom. If I zoom in I get to a point in which everything is too slow. If I zoom out things go back to normal. Note that once the lines are generated they are not changed in any way. I understand that performance might decrease if those lines are near 45º due to bounding boxes, but I fail to understand why it varies with zoom. I'm using Qt 5.5 on Linux. Thanks in advance, Lisandro. -- Lisandro Damián Nicanor Pérez Meyer http://perezmeyer.com.ar/ http://perezmeyer.blogspot.com/
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