Unicode has plenty of symbols in addition to the ordinary ASCII. I've been browsing thru them at http://www.iam.uni-bonn.de/~alt/html/unicode_3.html and would like to use some in my Qt programs.

Qt Code: 
  1. #include <QApplication>
  2. #include <QFont>
  3. #include <QFontInfo>
  4. #include <QLabel>
  5.  
  6. int main( int argc, char **argv )
  7. {
  8.     QApplication app( argc, argv );
  9.  
  10.     QFont f = app.font();
  11.     QFontInfo fi(f);
  12.     QLabel *lab = new QLabel;
  13.     QChar sym1(0xba, 0x25);   // filled rightpointing triangle  http://www.iam.uni-bonn.de/~alt/html/unicode_63.html
  14.     QChar sym2(0x00, 0x22);   // upside-down "A"                http://www.iam.uni-bonn.de/~alt/html/unicode_56.html
  15.  
  16.     QFontMetrics fm(f);
  17.  
  18.     QString txt = "QFont: " + f.toString() + "\n" +
  19.             "QFontInfo: " + fi.family() + " " + QString::number(fi.pointSize()) + "\n" +
  20.             "Substitute list:  " + QFont::substitutions().join(", ") +
  21.             "\n\nNext" + sym1 + sym2 +
  22.             "  widths:" + QString::number(fm.width(sym1)) +
  23.             "    " + QString::number(fm.width(sym2));
  24.     lab->setText(txt);
  25.     lab->show();
  26.  
  27.     return app.exec();
  28. }
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The above program shows the default font and the font actually used. After the word "Next" is inserted two symbols (a filled triangle and and upside-down "A"). This works fine when run on my Ubuntu 8.10 system.

A friend though, tested the same program on Debian Lenny, and there the two special characters were not shown.

Using qtconfig-qt4, we have both set the default font to "DejaVu Sans 9", and that is displayed on the first line when we run the program.
The QFontInfo object differs though: it displays the same "DejaVu Sans 9" font on the machine where the symbols shows correctly, but becomes "Bitstream Charter 9" on the other.

I don't think the problem is that the bitstream font lacks the special characters as I tried with that font as the default on my machine and the special symbols still shows.

My questions are:
1) Why does the QFontInfo-object on the Debian Lenny-machine pick another font, when DejaVu Sans is installed (i.e. it was available from the dropdown-menu in qtconfig-qt4 and he has the same files under /usr/share/fonts/truetype/ttf-dejavu as I have)
2) Why doesn't the symbols show up on the Debian Lenny machine (There are no problems inserting such symbols in an openoffice-document).

The "width" of the invisible symbols, as displayed by the program above, is non-zero. The substitute-lists are the same.