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  1. Qt
  2. QTBUG-126771

Noticeably laggy while zooming particular SVG file

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Details

    • Bug
    • Resolution: Unresolved
    • P2: Important
    • None
    • 6.7.1, 6.8.0
    • SVG Support
    • None
    • The lag might be hardware-related. My laptop is using an Intel i7-8750H CPU with 16G memory available.
    • All

    Description

      Somewhat related to QTBUG-124287. After load preferences-desktop-appearance-symbolic.svg (you can get this file at that QTBUG or inside the demo project that I attached here) to a QGraphicsScene, when attempting to zoom in the view several times, there will be noticeably lagging, and once we zoom beyond a curtain threshold, it no longer lag if we attempt to continue zoom in. At that time, if we attempt to zoom out, it will become laggy again.

      Steps to reproduce this issue:

      There are two ways to reproduce this issue:

      Method 1

      1. Open a Qt Creator instance (make sure Qt Creator itself is built against Qt 6.7.1)
      2. Drag and drop the preferences-desktop-appearance-symbolic.svg file to the editor area
      3. Use Ctrl+MouseWheelUp to zoom in, and Ctrl+MouseWheelDown to zoom out. The lag will be quite noticeable at a curtain threshold

      Method 2

      1. Use the test-svg-laggy-bug.zip project (see attachment) to test. Once compiled, run it
      2. Click the "Zoom in" button quickly for 15 times, you'll notice the laggy once you done that.
      3. Once step 2 is done and the program no longer laggy, click the "Zoom out" button quickly for 15 times. You will notice the lag happens at the same zoom-level again.

      Attachments

        1. image-2024-07-08-15-37-55-222.png
          11 kB
          Matthias Rauter
        2. test-svg-laggy-bug.zip
          3 kB
          Gary Wang
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          People

            matthias_rauter Matthias Rauter
            blumia Gary Wang
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            Dates

              Created:
              Updated:

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