| [347] | 1 | Troubleshooting GNU FreeFont
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| 2 |
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| 3 | So your text looks lousy, although you installed FreeFont and you seem to be
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| 4 | using it. What do you do?
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| 5 |
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| 6 | Before you blame the problem on FreeFont, take the time to double-check that
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| 7 | the text you are looking at is really rendered with FreeFont.
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| 8 |
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| 9 | Be aware that not all Unicode characters are supported by FreeFont, and
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| 10 | even characters supported by one face, such as Serif, might not be
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| 11 | supported by other faces such as Sans.
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| 12 |
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| 13 | Also, some systems have settings that strongly affect the rendering
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| 14 | of fonts. It may be worth tweaking these.
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| 15 |
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| 16 | glyph substitution
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| 17 | ==================
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| 18 |
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| 19 | When given the task of displaying characters in text, modern font rendering
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| 20 | software usually tries to display *something*, even if the font it is
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| 21 | *supposed* to be using does not contain glyphs for all the characters in the
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| 22 | text. The software will snoop through all the fonts on the system to find
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| 23 | one that has a glyph for the one missing in the desired font. So although
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| 24 | you have specified FreeSans-bold, you may be looking at a letter from quite
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| 25 | a different font.
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| 26 |
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| 27 | First double-check that the font in question really contains the character
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| 28 | in question. If you don't have font development software, this can be
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| 29 | tricky. In the case of FreeFont, you can check if a given character
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| 30 | range is supported: <http://www.gnu.org/software/freefont/coverage.html>
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| 31 |
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| 32 | Next double-check that your application (web browser, text editor, etc)
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| 33 | has indeed been properly instructed to use the font.
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| 34 |
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| 35 | Then double-check that the font is really installed in the system.
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| 36 | (This depends on the operating system, of course.)
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| 37 |
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| 38 | Linux and Unix
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| 39 | ==============
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| 40 |
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| 41 | Modern Linux systems use a system called fontconfig, which maintains a font
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| 42 | cache, for efficiency.
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| 43 |
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| 44 | The font cache can really complicate font installation and troubleshooting
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| 45 | however. It can happen that when a font is newly installed, what is
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| 46 | displayed is coming out of an old cache entry rather than the new font.
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| 47 |
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| 48 | Just what to do depends on how and where the font was installed.
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| 49 |
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| 50 | Fonts installed system-wide are usually put in a directory such as
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| 51 | /usr/share/fonts/
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| 52 | the font cache for these might be in
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| 53 | /var/cache/fontconfig/
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| 54 | Fonts installed just for one user account will typically be in
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| 55 | ~/.fonts/
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| 56 | and the cache will be
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| 57 | ~/.fontconfig/
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| 58 |
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| 59 | You can clean your local cache merely by emptying the directory
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| 60 | ~/.fontconfig/
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| 61 | In any case, to clean the cache, you can use the fontconfig command
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| 62 | fc-cache -vf
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| 63 | If run as root, it will clean the system cache, if run as a normal user,
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| 64 | it cleans only the normal user's cache.
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| 65 |
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| 66 | The procedure for local fonts is:
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| 67 | 1) shut off any program using the fonts in question
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| 68 | 2) clean the cache
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| 69 | 3) re-start the program
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| 70 | The procedure for system-wide fonts is:
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| 71 | 1) log out of the X Windows session
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| 72 | 2) in a console, clean the cache
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| 73 | 3) log in to an X Windows session
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| 74 |
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| 75 | LibreOffice / OpenOffice
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| 76 | ========================
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| 77 | These products have their own font rendering libraries, which have
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| 78 | idiosyncratic behavior.
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| 79 |
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| 80 | It has recently been reported that as of LibreOffice 3.5.1, font features
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| 81 | are disabled for OpenType fonts. If you use FreeFont with these products,
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| 82 | you may want to install the TrueType versions of the fonts.
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| 83 |
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| 84 | Windows
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| 85 | =======
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| 86 |
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| 87 | The most common complaint has to do with "blurry text". There are two
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| 88 | causes.
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| 89 |
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| 90 | The first is that ClearType smoothing is turned off. The best way to check
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| 91 | is to use the native Windows Web browser. Do a search for "ClearType Tuner".
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| 92 | The Microsoft pages install a tuner for ClearType. A security block notice
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| 93 | will appear at the top of the window--you have to allow the installation.
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| 94 | Then check the box "Turn on ClearType". The change happens immediately.
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| 95 |
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| 96 | The secont cause is that the FreeFont version with cubic spline outlines is
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| 97 | installed. As of the 2012 GNU FreeFont release, the TrueType builds have
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| 98 | quadratic splines, which work best with Windows' rendering software.
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| 99 | TTF (TrueType) quadratic splines Windows 7, Vista, Windows XP.
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| 100 | OTF (OpenType) cubic splines Linux, Mac
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| 101 |
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| 102 | Note also: Firefox has a setting for ClearType:
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| 103 | gfx.font_rendering.cleartype_params.rendering_mode
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| 104 | A value of 2 sets it to old-style GDI rendering, while -1 is the default.
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| 105 |
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| 106 | reporting problems
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| 107 | ==================
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| 108 |
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| 109 | If you really think you're seeing a bug in FreeFont, or if you have
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| 110 | a suggestion, consider opening a problem report at
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| 111 | https://savannah.gnu.org/bugs/?group=freefont
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| 112 | It is best that you make a Savannah account and log in with that, so
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| 113 | you can be e-mailed whenever changes are made to your report.
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| 114 |
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| 115 | $Id: troubleshooting.txt,v 1.10 2011-07-16 08:38:06 Stevan_White Exp $
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