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- Troubleshooting GNU FreeFont
- So your text looks lousy, although you installed FreeFont and you seem to be
- using it. What do you do?
- Before you blame the problem on FreeFont, take the time to double-check that
- the text you are looking at is really rendered with FreeFont.
- Be aware that not all Unicode characters are supported by FreeFont, and
- even characters supported by one face, such as Serif, might not be
- supported by other faces such as Sans.
- Also, some systems have settings that strongly affect the rendering
- of fonts. It may be worth tweaking these.
- glyph substitution
- ==================
- When given the task of displaying characters in text, modern font rendering
- software usually tries to display *something*, even if the font it is
- *supposed* to be using does not contain glyphs for all the characters in the
- text. The software will snoop through all the fonts on the system to find
- one that has a glyph for the one missing in the desired font. So although
- you have specified FreeSans-bold, you may be looking at a letter from quite
- a different font.
- First double-check that the font in question really contains the character
- in question. If you don't have font development software, this can be
- tricky. In the case of FreeFont, you can check if a given character
- range is supported: <http://www.gnu.org/software/freefont/coverage.html>
- Next double-check that your application (web browser, text editor, etc)
- has indeed been properly instructed to use the font.
- Then double-check that the font is really installed in the system.
- (This depends on the operating system, of course.)
- Linux and Unix
- ==============
- Modern Linux systems use a system called fontconfig, which maintains a font
- cache, for efficiency.
- The font cache can really complicate font installation and troubleshooting
- however. It can happen that when a font is newly installed, what is
- displayed is coming out of an old cache entry rather than the new font.
- Just what to do depends on how and where the font was installed.
- Fonts installed system-wide are usually put in a directory such as
- /usr/share/fonts/
- the font cache for these might be in
- /var/cache/fontconfig/
- Fonts installed just for one user account will typically be in
- ~/.fonts/
- and the cache will be
- ~/.fontconfig/
- You can clean your local cache merely by emptying the directory
- ~/.fontconfig/
- In any case, to clean the cache, you can use the fontconfig command
- fc-cache -vf
- If run as root, it will clean the system cache, if run as a normal user,
- it cleans only the normal user's cache.
- The procedure for local fonts is:
- 1) shut off any program using the fonts in question
- 2) clean the cache
- 3) re-start the program
- The procedure for system-wide fonts is:
- 1) log out of the X Windows session
- 2) in a console, clean the cache
- 3) log in to an X Windows session
- LibreOffice / OpenOffice
- ========================
- These products have their own font rendering libraries, which have
- idiosyncratic behavior.
- It has recently been reported that as of LibreOffice 3.5.1, font features
- are disabled for OpenType fonts. If you use FreeFont with these products,
- you may want to install the TrueType versions of the fonts.
- Windows
- =======
- The most common complaint has to do with "blurry text". There are two
- causes.
- The first is that ClearType smoothing is turned off. The best way to check
- is to use the native Windows Web browser. Do a search for "ClearType Tuner".
- The Microsoft pages install a tuner for ClearType. A security block notice
- will appear at the top of the window--you have to allow the installation.
- Then check the box "Turn on ClearType". The change happens immediately.
- The secont cause is that the FreeFont version with cubic spline outlines is
- installed. As of the 2012 GNU FreeFont release, the TrueType builds have
- quadratic splines, which work best with Windows' rendering software.
- TTF (TrueType) quadratic splines Windows 7, Vista, Windows XP.
- OTF (OpenType) cubic splines Linux, Mac
- Note also: Firefox has a setting for ClearType:
- gfx.font_rendering.cleartype_params.rendering_mode
- A value of 2 sets it to old-style GDI rendering, while -1 is the default.
- reporting problems
- ==================
- If you really think you're seeing a bug in FreeFont, or if you have
- a suggestion, consider opening a problem report at
- https://savannah.gnu.org/bugs/?group=freefont
- It is best that you make a Savannah account and log in with that, so
- you can be e-mailed whenever changes are made to your report.
- $Id: troubleshooting.txt,v 1.10 2011-07-16 08:38:06 Stevan_White Exp $
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