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   1      Troubleshooting GNU FreeFont
   2  
   3  So your text looks lousy, although you installed FreeFont and you seem to be
   4  using it.  What do you do?
   5  
   6  Before you blame the problem on FreeFont, take the time to double-check that
   7  the text you are looking at is really rendered with FreeFont.
   8  
   9  Be aware that not all Unicode characters are supported by FreeFont, and
  10  even characters supported by one face, such as Serif, might not be
  11  supported by other faces such as Sans.
  12  
  13  Also, some systems have settings that strongly affect the rendering
  14  of fonts.  It may be worth tweaking these.
  15  
  16  glyph substitution
  17  ==================
  18  
  19  When given the task of displaying characters in text, modern font rendering
  20  software usually tries to display *something*, even if the font it is
  21  *supposed* to be using does not contain glyphs for all the characters in the
  22  text.  The software will snoop through all the fonts on the system to find
  23  one that has a glyph for the one missing in the desired font.  So although
  24  you have specified FreeSans-bold, you may be looking at a letter from quite
  25  a different font.
  26  
  27  First double-check that the font in question really contains the character
  28  in question.  If you don't have font development software, this can be
  29  tricky.  In the case of FreeFont, you can check if a given character 
  30  range is supported: <http://www.gnu.org/software/freefont/coverage.html>
  31  
  32  Next double-check that your application (web browser, text editor, etc)
  33  has indeed been properly instructed to use the font.
  34  
  35  Then double-check that the font is really installed in the system.
  36  (This depends on the operating system, of course.)
  37  
  38  Linux and Unix
  39  ==============
  40  
  41  Modern Linux systems use a system called fontconfig, which maintains a font
  42  cache, for efficiency.
  43  
  44  The font cache can really complicate font installation and troubleshooting
  45  however.  It can happen that when a font is newly installed, what is 
  46  displayed is coming out of an old cache entry rather than the new font.
  47  
  48  Just what to do depends on how and where the font was installed.
  49  
  50  Fonts installed system-wide are usually put in a directory such as
  51      /usr/share/fonts/
  52  the font cache for these might be in
  53      /var/cache/fontconfig/
  54  Fonts installed just for one user account will typically be in
  55      ~/.fonts/
  56  and the cache will be
  57      ~/.fontconfig/
  58  
  59  You can clean your local cache merely by emptying the directory 
  60      ~/.fontconfig/
  61  In any case, to clean the cache, you can use the fontconfig command
  62      fc-cache -vf
  63  If run as root, it will clean the system cache, if run as a normal user,
  64  it cleans only the normal user's cache.
  65  
  66  The procedure for local fonts is:
  67      1) shut off any program using the fonts in question
  68      2) clean the cache
  69      3) re-start the program
  70  The procedure for system-wide fonts is:
  71      1) log out of the X Windows session
  72      2) in a console, clean the cache
  73      3) log in to an X Windows session
  74  
  75  LibreOffice / OpenOffice
  76  ========================
  77  These products have their own font rendering libraries, which have 
  78  idiosyncratic behavior.
  79  
  80  It has recently been reported that as of LibreOffice 3.5.1, font features
  81  are disabled for OpenType fonts.  If you use FreeFont with these products,
  82  you may want to install the TrueType versions of the fonts.
  83  
  84  Windows
  85  =======
  86  
  87  The most common complaint has to do with "blurry text".  There are two
  88  causes.
  89  
  90  The first is that ClearType smoothing is turned off.  The best way to check
  91  is to use the native Windows Web browser. Do a search for "ClearType Tuner".
  92  The Microsoft pages install a tuner for ClearType. A security block notice
  93  will appear at the top of the window--you have to allow the installation.
  94  Then check the box "Turn on ClearType".  The change happens immediately.
  95  
  96  The secont cause is that the FreeFont version with cubic spline outlines is
  97  installed.  As of the 2012 GNU FreeFont release, the TrueType builds have
  98  quadratic splines, which work best with Windows' rendering software.
  99      TTF (TrueType)  quadratic splines Windows 7, Vista, Windows XP.
 100      OTF (OpenType)  cubic splines     Linux, Mac
 101  
 102  Note also: Firefox has a setting for ClearType:
 103      gfx.font_rendering.cleartype_params.rendering_mode
 104  A value of 2 sets it to old-style GDI rendering, while -1 is the default.
 105  
 106  reporting problems
 107  ==================
 108  
 109  If you really think you're seeing a bug in FreeFont, or if you have
 110  a suggestion, consider opening a problem report at
 111      https://savannah.gnu.org/bugs/?group=freefont
 112  It is best that you make a Savannah account and log in with that, so 
 113  you can be e-mailed whenever changes are made to your report.
 114  
 115  $Id: troubleshooting.txt,v 1.10 2011-07-16 08:38:06 Stevan_White Exp $