Getting Standard Fonts

[Radek]

I would like to use standard fonts in my app. I need the standard (in KDE, configured in the System Settings) proportional and fixed pitch fonts. I haven't detected a Qt-way, how to get proportional and fixed QFonts corresponding to the ones configured in default font settings - or some info which allows getting these QFonts. Perhaps, I am overlooking something.

The default font seems to be the "desktop font". It is, perhaps always, a proportional font but suppose purely theoretically that a user configured his desktop so that the desktop font is fixed pitch. What font do I get as a default font? And How to get the fixed pitch font? QTextCharFormat::setFontFixedPitch(true) seems to be ignored in my app. In fact, no wonder, fonts are usually either proportional or fixed pitch.

Debian Wheezy, KDE, Qt 4.8.4

[ChrisW67]

If you want to know what KDE settings have stored then you need to ask KDE. You might be able to rely on using QSettings to read the "~.kde4/share/config/kdeglobals" file for this information but I do not know how stable this would be and there may be a "correct" KDE API to use.

The default font in a Qt application UI is a suitable generic font for the platform. The formatting of characters in a QTextDocument is a different matter. You can QTextDocument::setDefaultFont() any way you like and set the font used for particular characters using QTextCharFormat::setFont(). As you point out, calling setFixedPitch() on a font with only proportional spacing will probably not work, but create a QFont with a suitable font and setting that should. You can inspect all the available fonts in the system using QFontDatabase.

[Radek]

The Debian KDE solution: The KGlobalSettings KDE object contains static members returning the needed QFonts:

QFont  KGlobalSettings::generalFont() const;                 // the general proportional font
QFont  KGlobalSettings::fixedFont() const;                     // the fixed pitch font
QFont  KGlobalSettings::toolbarFont() const;                  // the toolbar font
QFont  KGlobalSettings::menuFont() const;                    // the menu font
QFont  KGlobalSettings::windowTitleFont() const;            // the titlebar font
QFont  KGlobalSettings::largeFont() const;                      // the 48 pts font
QFont  KGlobalSettings::smallestReadableFont() const;   // the smallest readable font

QFont  KGlobalSettings::generalFont() const;                 // the general proportional font
QFont  KGlobalSettings::fixedFont() const;                     // the fixed pitch font
QFont  KGlobalSettings::toolbarFont() const;                  // the toolbar font
QFont  KGlobalSettings::menuFont() const;                    // the menu font
QFont  KGlobalSettings::windowTitleFont() const;            // the titlebar font
QFont  KGlobalSettings::largeFont() const;                      // the 48 pts font
QFont  KGlobalSettings::smallestReadableFont() const;   // the smallest readable font

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Add the libkdeui library to the .pro file (I have noticed that the library is kdeui on Ubuntu). My current font setting procedure:

#include <kglobalsettings.h>
#include <text.hpp>
 
 
bool Text::FontConf( const fontconf_t& fc )                       //  Text is "public QPlainTextEdit"  
{
  QColor co(currfmt.foreground().color());                           //  currfmt is QTextCharFormat of the current text char format
  int    fs = currfmt.font().pointSize();
  bool   bo = (currfmt.fontWeight() == QFont::Bold);
  bool   bb = false;
 
  if( currfmt.fontFixedPitch() != fc.isfixed )
  {
    currfmt.setFont(fc.isfixed ? KGlobalSettings::fixedFont() : KGlobalSettings::generalFont());
    currfmt.setFontFixedPitch(fc.isfixed);
    bb = true;
  }
 
  if( fs != fc.psize )
  {
    currfmt.font().setPointSize(fc.psize);
    bb = true;
  }
 
  if( bo != fc.isbold )
  {
    currfmt.setFontWeight(fc.isbold ? QFont::Bold : QFont::Normal);
    bb = true;
  }
 
  if( currfmt.fontItalic() != fc.isitalic )
  {
    currfmt.setFontItalic(fc.isitalic);
    bb = true;
  }
 
  if( co != fc.color )
  {
    QBrush  newcolor(fc.color);
 
    currfmt.setForeground(newcolor);
    bb = true;
  }
 
  if( bb ) setCurrentCharFormat(currfmt);
 
  return bb;
}

#include <kglobalsettings.h>
#include <text.hpp>


bool Text::FontConf( const fontconf_t& fc )                       //  Text is "public QPlainTextEdit"  
{
  QColor co(currfmt.foreground().color());                           //  currfmt is QTextCharFormat of the current text char format
  int    fs = currfmt.font().pointSize();
  bool   bo = (currfmt.fontWeight() == QFont::Bold);
  bool   bb = false;

  if( currfmt.fontFixedPitch() != fc.isfixed )
  {
    currfmt.setFont(fc.isfixed ? KGlobalSettings::fixedFont() : KGlobalSettings::generalFont());
    currfmt.setFontFixedPitch(fc.isfixed);
    bb = true;
  }

  if( fs != fc.psize )
  {
    currfmt.font().setPointSize(fc.psize);
    bb = true;
  }

  if( bo != fc.isbold )
  {
    currfmt.setFontWeight(fc.isbold ? QFont::Bold : QFont::Normal);
    bb = true;
  }

  if( currfmt.fontItalic() != fc.isitalic )
  {
    currfmt.setFontItalic(fc.isitalic);
    bb = true;
  }

  if( co != fc.color )
  {
    QBrush  newcolor(fc.color);

    currfmt.setForeground(newcolor);
    bb = true;
  }

  if( bb ) setCurrentCharFormat(currfmt);

  return bb;
}

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It works in simple tests on fixed font. Possible minor problems ahead: what all is reset by setFont()? In the other words, what all do I need to set unconditionally in FontConf() after setFont() (point size, bold/italic, etc.)? Note: the FontFixedPitch() seems to be only a flag unrelated to the font. If I set a fixed font, the flag returned by FontFixedPitch() does not change. Therefore, setFontFixedPitch() along with the font to keep consistency.