| 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 $
|
|---|
