|
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 $
|
