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  1. Qt
  2. QTBUG-8389

slow painting of long highlighted lines due to QTextEngine::format()

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    • Icon: Bug Bug
    • Resolution: Done
    • Icon: P3: Somewhat important P3: Somewhat important
    • 4.8.x
    • 4.6.1
    • GUI: Painting, GUI: Text handling
    • None
    • Linux 2.6.31-19
      Qt 4.6.1
      KDE 4.4.0
      Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller
      4GB Ram, Intel Centrino Duo
    • I10c9fca72343f46db24b1d4f519f7747188d4009 I89c18b804111edfab6254442cbee33da39d1a273

      The Kate editor for KDE has serious performance problems with files that contain very long lines with highlights. Attached you find a callgrind output and a file with such a long line.

      As you will see, more than 70% is spent in QTextEngine::format() alone. Can this be improved?

      If you need more information, please let me know.

        1. long_lines_profile.tar.bz2
          1.24 MB
        2. qt-textdocument-boundaryAt_and_format-bottlenecks.tar.bz2
          178 kB
        3. callgrind.out.relwithdebinfo.bz2
          185 kB
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            ogoffart Olivier Goffart (Woboq GmbH)
            milianw Milian Wolff
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              Created:
              Updated:
              Resolved: