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  1. Qt
  2. QTBUG-93092

QGraphicsObject bad performance on Windows compared to Linux and macOS

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2: Important
    • Resolution: Cannot Reproduce
    • Affects Version/s: 5.15.1, 6.1
    • Fix Version/s: None
    • Environment:

      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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            Assignee:
            qt.team.graphics.and.multimedia Qt Graphics Team
            Reporter:
            kosadev Łukasz Kosiński
            Votes:
            6 Vote for this issue
            Watchers:
            7 Start watching this issue

              Dates

              Created:
              Updated:
              Resolved:

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