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  1. Qt
  2. QTBUG-93092

QGraphicsObject bad performance on Windows compared to Linux and macOS

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Details

    • Bug
    • Resolution: Cannot Reproduce
    • P2: Important
    • None
    • 5.15.1, 6.1
    • Windows

    Description

      I noticed a significant difference in graphics drawing performance on Windows compared to Linux and macOS.

      Attached is a simple app with custom QGraphicsObject. Object paints a lot of ellipses and lines which is unusual of course. Adding simple QElapsedTimers showed a striking difference in time spent by QPainter in drawing.

      Results of drawing 13000 points & lines:
      Linux:
      Drawing lines: 2ms
      Drawing points: 3ms
       
      macOS:
      Drawing lines: 1ms
      Drawing points: 4-5ms

      Windows:
      Drawing lines: 35ms
      Drawing points: 38ms
       
      If a view is static it doesn't make any problems, but if there is more stuff to draw or it's often repainted (for example while resizing) it makes apps a bit unresponsive.

      Is it a known issue? Is there any chance for improvement? Maybe that's related to underlying graphics driver.

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            qt.team.graphics.and.multimedia Qt Graphics Team
            kosadev Łukasz Kosiński
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            Dates

              Created:
              Updated:
              Resolved:

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