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  1. Qt
  2. QTBUG-7768

fontMetrics.boundingRect() and drawText(boundingRect) disagree about text width metrics

    XMLWordPrintable

Details

    • Bug
    • Resolution: Done
    • P2: Important
    • 6.3.0 Alpha
    • 4.6.1, 6.2.0
    • GUI: Text handling
    • None
    • 4748369eb2e458e12f5228a113b9a6dda440b24b (qt/tqtc-qtbase/dev)

    Description

      When I use

      QRect bounds = QFontMetrics.boundingRect(0, 0, maxWidth, 0, Qt::TextWordWrap, string);

      the resulting bounds rectangle is not always big enough to render the same string using the call

      drawText(bounds, Qt::TextWordWrap, string);

      because those two functions use different algorithms to calculate the font width metrics that affect the word break position.

      In the first attached screen shot, the bounding rectangle of the string "Effets de bureau" is used to draw the text, which gets then cropped to "Effets de".

      In the second screen shot, the bounding rectangle returned by QFontMetrics is enlarged by 2 pixels in width, and drawText() now renders the string
      correctly.

      This bug depends on used font, font size, server DPI, and actual text, so no test case to reproduce.

      Attachments

        1. fontmetrics-width-italicfont.cpp
          3 kB
          David Faure
        2. qtbug-7768-qt6.tgz
          1 kB
          Shawn Rutledge
        3. Screenshot_20210514_003635.png
          98 kB
          David Faure
        4. Screenshot_20211014_120927.png
          92 kB
          Allan Sandfeld Jensen
        5. text1.jpeg
          10 kB
          Christoph Feck
        6. text2.jpeg
          11 kB
          Christoph Feck

        Issue Links

          is duplicated by

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-15974 QFontMetrics::boundingRect() returns too-small result

          • P3: Somewhat important - Should be fixed, but doesn't affect the release in any way.
          • Closed
          relates to

          Task - A task that needs to be done. QTBUG-79144 FontMetrics and Text element report different width for the same text

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-73002 QLabel::fontMetrics().boundingRect(text) != rendered width for some fonts

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-85936 TextMetrics.width does not always give a correct width for the given text and is sometimes too short depending on the font used

          • P2: Important - Urgent, should be fixed, but will not stop the release.
          • Closed
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          Activity

            People

              allan.jensen Allan Sandfeld Jensen
              cfeck Christoph Feck
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              5 Vote for this issue
              Watchers:
              12 Start watching this issue

              Dates

                Created:
                Updated:
                Resolved:

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