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  1. Qt
  2. QTBUG-64239

Displaying coloured emojis with emojione in a QLabel causes segfault on linux with hidpi

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P1: Critical
    • Resolution: Done
    • Affects Version/s: 5.9.2
    • Fix Version/s: 5.9.3
    • Component/s: GUI: Font handling
    • Labels:
      None
    • Environment:

      Description

      Setting the contents of a QLabel to display colored emojis using emojione with HTML span attributes causes issues on linux with hidpi displays: emojis images are corrupted (only displaying a quarter of the full emoji) and the program quickly crashes with a segfault.

      Disabling HiDpi scaling with `Qt::AA_DisableHighDpiScaling` prevents both the crash and the rendering issues. So does using system fonts instead of emojione (but thus emojis are displayed non-colored).

      Small reproducing example:

      #include <QApplication>
      #include <QFontDatabase>
      #include <QLabel>
      
      int main(int argc, char *argv[])
      {
          //QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
          QApplication a(argc, argv);
          QFontDatabase::addApplicationFont("./emojione-android.ttf");
          QLabel   label;
          label.setText("Hello world <span style=\"font-family: Noto Color Emoji;\">\U0001F609</span>");
          label.show();
          return a.exec();
      }
      

      (this example uses the emojione android font ("Noto Color Emoji") that can be downloaded here: https://github.com/emojione/emojione-assets/releases/download/3.1.2/emojione-android.ttf )

      On the above example, uncommenting the first line of main prevents the crash.

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              Assignee:
              allan.jensen Allan Sandfeld Jensen
              Reporter:
              levans levans
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                Resolved:

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