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  1. Qt
  2. QTBUG-30324

Webkit text rendering performance

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2: Important
    • Resolution: Cannot Reproduce
    • Affects Version/s: 5.0.1, 5.0.2
    • Fix Version/s: None
    • Component/s: GUI: Font handling, WebKit
    • Labels:
      None
    • Environment:
      Windows, MSVC/MinGW, 32/64bit

      Description

      I ran into a problem while using the QWebView to display text, which can be moved around in the view. After adding quite some text (some thousand characters) performance drops significantly. Movement become choppy, and the processor core is fully utilized. Some digging around using vtune, narrows down the problem to QWindowsFontEngine::getOutlineMetrics(...) in the windows call getGlyphOutline.

      This has been tested on:

      • Windows 8 Qt MSVC 2010 32bit - 5.0.1
      • Windows 7 Qt MinGW 32bit - 5.0.1
      • Windows 7 Qt MSVC 2012 64bit - 5.0.2 latest
      • Linux GCC 64bit Qt 5.0.1

      The problem persists on all windows versions, while it performs nicely on linux (no surprise since the problem seems to be in the QWindowsFontEngine).

        Attachments

        1. TextWebviewTest.rar
          2 kB
        2. vtune_bottom_up.png
          vtune_bottom_up.png
          284 kB
        3. vtune_test_caller_callee.png
          vtune_test_caller_callee.png
          361 kB
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          Activity

            People

            Assignee:
            allan.jensen Allan Sandfeld Jensen
            Reporter:
            djuvsland Stian Djuvsland
            Votes:
            1 Vote for this issue
            Watchers:
            6 Start watching this issue

              Dates

              Created:
              Updated:
              Resolved:

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