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  1. Qt
  2. QTBUG-13934

QFontMetric::height() causes crash when QApplication::GUIenabled == false

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P2: Important
    • Resolution: Duplicate
    • Affects Version/s: 4.6.3
    • Fix Version/s: 4.7.0
    • Component/s: None
    • Labels:
      None
    • Environment:
      ubuntu 2.6.32-24-generic #39-Ubuntu SMP Wed Jul 28 06:07:29 UTC 2010 i686 GNU/Linux
      gcc (Ubuntu 4.4.3-4ubuntu5) 4.4.3)

      Description

      When using QFontMetrics in a non-GUI application on X11:

      XListFonts is called with an invalid X11 display which leads to a crash. XListFonts should not be called if there is no valid X11 display (since GUIEnbaled == false)

      The following code reproduces the error:

      #include <QApplication>
      #include <QFont>
      #include <QFontMetrics>
      
      void testFontHeight()
      {
      #if defined(QT_CORE_LIB)
      QFont font("Courier New", 10);
      font.setFixedPitch(true);
      
      QFontMetrics fontMetrics(font);
      
      int iHeight = fontMetrics.height();
      int iAscent = fontMetrics.ascent();
      int iDescent = fontMetrics.descent();
      
      Q_ASSERT( iHeight == iAscent + iDescent + 1 );
      #endif
      }
      
      int main(int argc, char *argv[])
      {
          QApplication a(argc, argv, false);
      
          testFontHeight();
      
          return 0;
      }
      
      

      Here is the backtrace:

      #0 XListFonts (dpy=0x0, 
      pattern=0x9114108 "-*-Courier New-*-*-*-*-*-*-*-*-*-*-*-*", 
      maxNames=65535, actualCount=0xbfffe8c8) at ../../src/FontNames.c:52 
      #1 0x08509b39 in loadXlfds(char const*, int) () 
      #2 0x0850a3d0 in load(QString const&, int, bool) () 
      #3 0x0850e187 in QFontDatabase::loadXlfd(int, int, QFontDef const&, int) () 
      #4 0x0850fbf7 in QFontDatabase::load(QFontPrivate const*, int) () 
      #5 0x084f304c in QFontPrivate::engineForScript(int) const () 
      #6 0x08502ef2 in QFontMetrics::height() const () 
      

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              Assignee:
              earthdomain Earth Domain (Inactive)
              Reporter:
              janichol Andy Nichols
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                Dates

                Created:
                Updated:
                Resolved:

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