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  1. Qt
  2. QTBUG-109838

QFontMetricsF::horizontalAdvance seems to do unnecessary scanning

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Details

    • Linux/X11
    • 7c84550f3 (dev), 708a48a0b (6.5), 802dfb187 (6.4), 4d3daea33 (tqtc/lts-6.2), bea15cdfa (dev), cc473646e (6.5)

    Description

      For very long input strings, but still with limited length, it will scan the whole input for 0x9c. However it looks like it would use qMin() to limit it to the length anyway:

      https://code.qt.io/cgit/qt/qtbase.git/tree/src/gui/text/qfontmetrics.cpp#n496

      This scanning results in a performance issue in laying out some text which has very long lines, like some logs.

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          relates to

          Suggestion - Public suggestions QTBUG-109717 Q(Any)StringView support for QFontMetrics

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              allan.jensen Allan Sandfeld Jensen
              poikelin Joni Poikelin
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              Dates

                Created:
                Updated:
                Resolved:

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