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  1. Qt
  2. QTBUG-104986

QTextLayout::maximumWidth() is not correct for multi-line text

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Details

    • Bug
    • Resolution: Fixed
    • P2: Important
    • 6.5.0 Beta1
    • 5.15.2, 6.2.4, 6.3.1
    • GUI: Text handling
    • None
    • All
    • 013c346a8d (qt/qtbase/dev) 013c346a8d (qt/tqtc-qtbase/dev) 70e33a585c (qt/qtbase/6.4) 70e33a585c (qt/tqtc-qtbase/6.4) 07bde1cadf (qt/tqtc-qtbase/6.2) 991c056438 (qt/tqtc-qtbase/dev)

    Description

      Found this while investigating QTBUG-89557.

      QTextLayout::maximumWidth() doesn't take into account line separator for multi-line text.
      Reproduced on the current Dev as well.

      Code sample:

      #include <QGuiApplication>
#include <QTextLayout>

qreal layoutMaximumWidth(const QString &text)
{
    QTextLayout layout(text);
    layout.beginLayout();
    while (layout.createLine().isValid()) { }
    layout.endLayout();

    return layout.maximumWidth();
}

int main(int argc, char *argv[])
{
    QGuiApplication app(argc, argv);

    qreal w1 = layoutMaximumWidth("test");
    qDebug() << "singleline maxwidth:" << w1;

    qreal w2 = layoutMaximumWidth("test\ntest");
    qDebug() << "multiline maxwidth:" << w2;

    Q_ASSERT(qFuzzyCompare(w1, w2));

    return 0;
}

      Output:

      singleline maxwidth: 19.4688
multiline maxwidth: 38.9375
ASSERT: "qFuzzyCompare(w1, w2)" in file ..\textLayout\main.cpp, line 24

      For the test case above w1 should be equal to w2, and the ASSERT should not fire.
      See full example textLayout.zip
       

      Attachments

        Issue Links

          relates to

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-95853 QTextLayout detecting new line in text

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

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-106909 QML Text's implicit size is not correct for an item with fixed size

          • Not Evaluated - Not yet evaluated/prioritized
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. QTBUG-89557 QML Text's implicitWidth is wrong when wrapMode is set for multiline text.

          • 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-106947 QTextLayout::maximumWidth() doesn't handle spaces correctly

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

            People

              esabraha Eskil Abrahamsen Blomfeldt
              studiosus Vladimir Belyavsky
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              Dates

                Created:
                Updated:
                Resolved: