Font configuration (简体中文)

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摘要 help replacing me
An overview of font configuration options and various techniques for improving the readability of fonts
相关页面
Fonts: Information on adding fonts and font recommendations
Java Runtime Environment Fonts: Fonts specific to Sun's Java machine
MS Fonts: Adding Microsoft fonts and mimicking Windows' font settings
Font Configuration/fontconfig Examples

Fontconfig是一个库,它被设计用来为应用程序提供可用字体,或者用来配置字体渲染效果,参见包fontconfigWikipedia:Fontconfig。 Free type库(freetype2包)就是以此为配置基础来渲染字体。

尽管Fontconfig已经是当今Linux的标准库,但是仍有一部分应用程序构建在更加原始的字体分类法上:Xorg server配置。

Arch Linux包含的字体渲染包支持有字节码解释器(BCI)的freetype2。为了更好的字体渲染,特别是在LCD显示器上,一些补丁包也添加到库中,参见下面的#补丁包#Infinality包同时支持自动微调和亚像素渲染,允许在无须重新编译的情况下微调LCD滤光器,而且在粗体字下自动微调仍然表现良好。

字体路径

由于应用程序需要知道它们所使用的字体的位置,所以必须对字体做良好的编目,以便于应用程序更好更快的访问它们。

Fontconfig包含的字体路径是/usr/share/fonts/~/.fonts/(Fontconfig会递归访问刚刚提到的目录)。为了简化管理和安装过程,当需要添加字体时,推荐使用之前提到的路径。

查看Fontconfig所包含的字体:

$ fc-list : file

参见man fc-list以获得更多输出格式方面的信息。

通过考察Xorg的log文件来检查Xorg包含的字体路径:

$ grep /fonts /var/log/Xorg.0.log
小贴士: 你也可以通过命令xset q检查Xorg包含的字体路径。

需要明确的是,Xorg不会像Fontconfig一样递归搜索/usr/share/fonts/目录。如果要增加一个目录,必须使用一个完整目录:

Section "Files"
    FontPath     "/usr/share/fonts/local/"
EndSection

如果你想把字体路径设置到每一位用户,你可以通过添加下面的配置代码到文件~/.xinitrc,这样可以将字体路径添加进或者移除出默认的路径中:

xset +fp /usr/share/fonts/local/           # Prepend a custom font path to Xorg's list of known font paths
xset -fp /usr/share/fonts/sucky_fonts/     # Remove the specified font path from Xorg's list of known font paths

如果要查看Xorg包含的字体,可以使用这个命令xlsfonts, 这个命令来自包xorg-xlsfonts

Fontconfig配置

Fontconfig的文档在fonts.confman页面中。

Configuration can be done per-user through $XDG_CONFIG_HOME/fontconfig/fonts.conf, and globally with /etc/fonts/local.conf. The settings in the per-user configuration have precedence over the global configuration. Both these files use the same syntax.

Note: Configuration files and directories: ~/.fonts.conf, ~/.fonts.conf.d and ~/.fontconfig/*.cache-* are deprecated since fontconfig 2.10.1 (upstream commit) and will not be read by default in the future versions of package. Use instead $XDG_CONFIG_HOME/fontconfig/fonts.conf, $XDG_CONFIG_HOME/fontconfig/conf.d and $XDG_CACHE_HOME/fontconfig/*.cache-* respectively.

Fontconfig gathers all its configurations in a central file (/etc/fonts/fonts.conf). This file is replaced during fontconfig updates and shouldn't be edited. Fontconfig-aware applications source this file to know available fonts and how they get rendered. This file is a conglomeration of rules from the global configuration (/etc/fonts/local.conf), the configured presets in /etc/fonts/conf.d/, and the user configuration file ($XDG_CONFIG_HOME/fontconfig/fonts.conf).

Note: For some desktop environments (such as GNOME and KDE) using the Font Control Panel will automatically create or overwrite the user font configuration file. For these desktop environments, it is best to match your already defined font configurations to get the expected behavior.

Fontconfig configuration files use XML format and need these headers:

<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>

  <!-- settings go here -->

</fontconfig>

The configuration examples in this article omit these tags.

预设

There are presets installed in the directory /etc/fonts/conf.avail. They can be enabled by creating symbolic links to them, both per-user and globally, as described in /etc/fonts/conf.d/README. These presets will override matching settings in their respective configuration files.

For example, to enable sub-pixel RGB rendering globally:

# cd /etc/fonts/conf.d
# ln -s ../conf.avail/10-sub-pixel-rgb.conf

To do the same but instead for a per-user configuration:

$ mkdir $XDG_CONFIG_HOME/fontconfig/conf.d
$ ln -s /etc/fonts/conf.avail/10-sub-pixel-rgb.conf $XDG_CONFIG_HOME/fontconfig/conf.d

反锯齿

Font rasterization converts vector font data to bitmap data so that it can be displayed. The result can appear jagged due to aliasing. anti-aliasing is enabled by default and increases the apparent resolution of font edges.

  <match target="font">
    <edit name="antialias" mode="assign">
      <bool>true</bool>
    </edit>
  </match>

微调

Font hinting (also known as instructing) is the use of mathematical instructions to adjust the display of an outline font so that it lines up with a rasterized grid, such as the pixel grid in a display. Fonts will not line up correctly without hinting until displays have 300 DPI or greater. Two types of hinting are available.

字节码解释器(BCI)

Using normal hinting, TrueType hinting instructions in the font are interpreted by freetype's Byte-Code Interpreter. This works best for fonts with good hinting instructions.

To enable normal hinting:

  <match target="font">
    <edit name="hinting" mode="assign">
      <bool>true</bool>
    </edit>
  </match>

自动微调器

Auto-discovery for hinting. This looks worse than normal hinting for fonts with good instructions, but better for those with poor or no instructions. The autohinter and subpixel rendering are not designed to work together and should not be used in combination.

To enable auto-hinting:

  <match target="font">
    <edit name="autohint" mode="assign">
      <bool>true</bool>
    </edit>
  </match>

微调字体

Hint style is the amount of influence the hinting mode has. Hinting can be set to: hintfull, hintmedium, hintslight and hintnone. With BCI hinting, hintfull should work best for most fonts. With the autohinter, hintslight is recommended.

  <match target="font">
    <edit name="hintstyle" mode="assign">
      <const>hintfull</const>
    </edit>
  </match>

亚像素渲染

Subpixel rendering effectively triples the horizontal (or vertical) resolution for fonts by making use of subpixels. The autohinter and subpixel rendering are not designed to work together and should not be used in combination without the #Infinality patch set.

Most monitors manufactured today use the Red, Green, Blue (RGB) specification. Fontconfig will need to know your monitor type to be able to display your fonts correctly.

RGB (most common), BGR, V-RGB (vertical), or V-BGR

To enable subpixel rendering:

  <match target="font">
    <edit name="rgba" mode="assign">
      <const>rgb</const>
    </edit>
  </match>

If you notice unusual colors around font's borders, the wrong subpixel arrangement might be configured. The Lagom subpixel layout test web page can help identify it.

LCD滤光器

When using subpixel rendering, you should enable the LCD filter, which is designed to reduce colour fringing. This is described under LCD filtering in the FreeType 2 API reference. Different options are described under FT_LcdFilter, and are illustrated by this LCD filter test page.

The lcddefault filter will work for most users. Other filters are available that can be used in special situations: lcdlight; a lighter filter ideal for fonts that look too bold or fuzzy, lcdlegacy, the original Cairo filter; and lcdnone to disable it entirely.

  <match target="font">
    <edit mode="assign" name="lcdfilter">
      <const>lcddefault</const>
    </edit>
  </match>

高级LCD滤光器说明

If the available, built-in LCD filters are not satisfactory, it is possible to tweak the font rendering very specifically by building a custom freetype2 package and modifying the hardcoded filters. The Arch Build System can be used to build and install packages from source.

First, refresh the freetype2 PKGBUILD as root:

# abs extra/freetype2

This example uses /var/abs/build as the build directory, substitute it according to your personal ABS setup. Download and extract the freetype2 package as a regular user:

$ cd /var/abs/build
$ cp -r ../extra/freetype2 .
$ cd freetype2
$ makepkg -o

Edit the file src/freetype-VERSION/src/base/ftlcdfil.c and look up the definition of the constant default_filter[5]:

static const FT_Byte  default_filter[5] =
    { 0x10, 0x40, 0x70, 0x40, 0x10 };

This constant defines a low-pass filter applied to the rendered glyph. Modify it as needed. Save the file, build and install the custom package:

$ makepkg -e
$ sudo pacman -Rd freetype2
$ sudo pacman -U freetype2-VERSION-ARCH.pkg.tar.xz

Reboot or restart X. The lcddefault filter should now render fonts differently.

取消粗体字的自动微调功能

The auto-hinter uses sophisticated methods for font rendering, but often makes bold fonts too wide. Fortunately, a solution can be turning off the autohinter for bold fonts while leaving it on for the rest:

...
<match target="font">
    <test name="weight" compare="more">
        <const>medium</const>
    </test>
    <edit name="autohint" mode="assign">
        <bool>false</bool>
    </edit>
</match>
...

只对较大的字体打开反锯齿功能

See also sharpfonts.co.cc for related information.

Some users prefer the sharper rendering that anti-aliasing does not offer:

...
<match target="font">
    <edit name="antialias" mode="assign">
        <bool>false</bool>
    </edit>
</match>

<match target="font" >
    <test name="size" qual="any" compare="more">
        <double>12</double>
    </test>
    <edit name="antialias" mode="assign">
        <bool>true</bool>
    </edit>
</match>

<match target="font" >
    <test name="pixelsize" qual="any" compare="more">
        <double>16</double>
    </test>
    <edit name="antialias" mode="assign">
        <bool>true</bool>
    </edit>
</match>
...

替换字体

The most reliable way to do this is to add an XML fragment similar to the one below. This will cause Bitstream Vera Sans to be used in place of Helvetica:

...
<match target="pattern" name="family" >
    <test name="family" qual="any" >
        <string>Helvetica</string>
    </test>
    <edit name="family" mode="assign">
        <string>Bitstream Vera Sans</string>
    </edit>
</match>
...

An alternate approach is to set the "preferred" font, but this only works if the original font is not on the system, in which case the one specified will be substituted:

...
< !-- Replace Helvetica with Bitstream Vera Sans Mono -->
< !-- Note, an alias for Helvetica should already exist in default conf files -->
<alias>
    <family>Helvetica</family>
    <prefer><family>Bitstream Vera Sans Mono</family></prefer>
    <default><family>fixed</family></default>
</alias>
...

禁用点阵字型

To disable bitmap fonts in fontconfig, use 70-no-bitmaps.conf (which is not placed by fontconfig by default):

# cd /etc/fonts/conf.d
# rm 70-yes-bitmaps.conf
# ln -s ../conf.avail/70-no-bitmaps.conf

You may not need to remove 70-yes-bitmaps.conf if it does not exist. You can choose which fonts to replace bitmaps fonts with (Helvetica, Courier and Times bitmap mapts to TTF fonts) by:

# cd /etc/fonts/conf.d
# ln -s ../conf.avail/29-replace-bitmap-fonts.conf

To disable embedded bitmap fonts for a specific font:

<match target="font">
  <test qual="any" name="family">
    <string>Monaco</string>
  </test>
  <edit name="embeddedbitmap"><bool>false</bool></edit>
</match>

为不完善的字体构建粗体风格和意大利体风格

Freetype has the ability to automatically create italic and bold styles for fonts that do not have them, but only if explicitly required by the application. Given programs rarely send these requests, this section covers manually forcing generation of missing styles.

Start by editing /usr/share/fonts/fonts.cache-1 as explained below. Store a copy of the modifications on another file, because a font update with fc-cache will overwrite /usr/share/fonts/fonts.cache-1.

Assuming the Dupree font is installed:

"dupree.ttf" 0 "Dupree:style=Regular:slant=0:weight=80:width=100:foundry=unknown:index=0:outline=True:etc...

Duplicate the line, change style=Regular to style=Bold or any other style. Also change slant=0 to slant=100 for italic, weight=80 to weight=200 for bold, or combine them for bold italic:

"dupree.ttf" 0 "Dupree:style=Bold Italic:slant=100:weight=200:width=100:foundry=unknown:index=0:outline=True:etc...

Now add necessary modifications to $XDG_CONFIG_HOME/fontconfig/fonts.conf:

...
<match target="font">
    <test name="family" qual="any">
        <string>Dupree</string>
         <!-- other fonts here .... -->
     </test>
     <test name="weight" compare="more_eq"><int>140</int></test>
     <edit name="embolden" mode="assign"><bool>true</bool></edit>
</match>

<match target="font">
    <test name="family" qual="any">
        <string>Dupree</string>
        <!-- other fonts here .... -->
    </test>
    <test name="slant" compare="more_eq"><int>80</int></test>
    <edit name="matrix" mode="assign">
        <times>
            <name>matrix</name>
                <matrix>
                    <double>1</double><double>0.2</double>
                    <double>0</double><double>1</double>
                </matrix>
        </times>
    </edit>
</match>
...
Tip: Use the value 'embolden' for existing bold fonts in order to make them even bolder.

改变规则重定义机制

Fontconfig processes files in /etc/fonts/conf.d in reverse numerical order. This enables rules or files to override one another, but often confuses users about what file gets parsed last.

To guarantee that personal settings take precedence over any other rules, change their ordering:

# cd /etc/fonts/conf.d
# mv 50-user.conf 00-user.conf

This change seems however to be unnecessary for the most of the cases, because a user is given enough control by default to set up own font preferences, hinting and antialiasing properties, alias new fonts to generic font families, etc.

fontconfig配置的例子

Example fontconfig configurations can be found on this page.

A simple starting point:

/etc/fonts/local.conf
<?xml version='1.0'?>
<!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
<fontconfig>
 <match target="font">
  
  <edit mode="assign" name="rgba">
   <const>rgb</const>
  </edit>

  <edit mode="assign" name="hinting">
   <bool>true</bool>
  </edit>

  <edit mode="assign" name="hintstyle">
   <const>hintfull</const>
  </edit>

  <edit mode="assign" name="antialias">
   <bool>true</bool>
  </edit>

  <edit mode="assign" name="lcdfilter">
    <const>lcddefault</const>
  </edit>
 
 </match>
</fontconfig>

补丁包

These patched packages are available in the AUR. A few considerations:

  • Configuration is usually necessary.
  • The new font rendering will not kick in until applications restart.
  • Applications which statically link to a library will not be affected by patches applied to the system library.

Infinality

Warning: Since the Fontconfig 2.10.1 update, Infinality users will receive multiple warnings similar to:

Fontconfig warning: "/etc/fonts/infinality/conf.d/60-group-non-tt-fonts.conf", line 483: Having multiple values in <test> isn't supported and may not works as expected

Rule adjustments are currently being worked on. See: this article for more information.

The infinality patchset aims to greatly improve freetype2 font rendering. It adds multiple new capabilities.

Infinality's settings are all configurable at runtime via environment variables in /etc/profile.d/infinality-settings.sh, and include the following:

  • Emboldening Enhancement: Disables Y emboldening, producing a much nicer result on fonts without bold versions. Works on native TT hinter and autohinter.
  • Auto-Autohint: Automatically forces autohint on fonts that contain no TT instructions.
  • Autohint Enhancement: Makes autohint snap horizontal stems to pixels. Gives a result that appears like a well-hinted truetype font, but is 100% patent-free (as far as I know).
  • Customized FIR Filter: Select your own filter values at run-time. Works on native TT hinter and autohinter.
  • Stem Alignment: Aligns bitmap glyphs to optimized pixel boundaries. Works on native TT hinter and autohinter.
  • Pseudo Gamma Correction: Lighten and darken glyphs at a given value, below a given size. Works on native TT hinter and autohinter.
  • Embolden Thin Fonts: Embolden thin or light fonts so that they are more visible. Works on autohinter.
  • Force Slight Hinting: Force slight hinting even when programs want full hinting. If you use the local.conf I provide (included in infinality-settings fedora package) you will notice nice improvements on @font-face fonts.
  • ChromeOS Style Sharpening: ChromeOS uses a patch to sharpen the look of fonts. This is now included in the infinality patchset.

A number of presets are included and can be used by setting the USE_STYLE variable in /etc/profile.d/infinality-settings.sh.

freetype2-infinalityAUR can be installed from the AUR. Additionally, if you are using lib32-freetype2 from [multilib], replace it with lib32-freetype2-infinalityAUR from the AUR. The AUR also contains a Git version of freetype2 that builds the latest development snapshot of freetype2 with the Infinality patchset: freetype2-git-infinalityAUR, lib32-freetype2-git-infinalityAUR.

It is recommended to also install fontconfig-infinalityAUR to enable selection of predefined font substitution styles and antialiasing settings, apart from the rendering settings of the engine itself. After doing so, you can select the font style (win7, winxp, osx, linux, ...) with:

# infctl setstyle

If you set e.g. win7 or osx you need the corresponding fonts installed.

Note: Default infinality settings can cause some programs to display fonts at 72 DPI instead of 96. If you notice a problem open /etc/fonts/infinality/infinality.conf search for the section on DPI and change 72 to 96. This problem can specifically affect conky causing the fonts to appear smaller than they should. Thus not aligning properly with images.
Note: The README for fontconfig-infinalityAUR says that /etc/fonts/local.conf should either not exist, or have no infinality-related configurations in it. The local.conf is now obsolete and completely replaced by this configuration.

for more information see this article: http://www.infinality.net/forum/viewtopic.php?f=2&t=77

Ubuntu

Ubuntu adds extra configurations, and occasionally patches to the font rendering libraries.

Install the patched packages from the AUR, the package names are: freetype2-ubuntuAUR fontconfig-ubuntuAUR libxft-ubuntuAUR cairo-ubuntuAUR.

The global configuration will need to be added. See #Example fontconfig configurations for a starting point.

恢复到未打补丁的包

To restore the unpatched packages, reinstall the originals:

# pacman -S --asdeps freetype2 libxft cairo fontconfig

没有fontconfig支持的应用程序

Some applications like URxvt will ignore fontconfig settings. This is very apparent when using the infinality patches which are heavily reliant on proper configuration. You can work around this by using ~/.Xresources, but it is not nearly as flexible as fontconfig. Example (see #Fontconfig configuration for explanations of the options):

~/.Xresources
Xft.autohint: 0
Xft.lcdfilter:  lcddefault
Xft.hintstyle:  hintfull
Xft.hinting: 1
Xft.antialias: 1
Xft.rgba: rgb

Make sure the settings are loaded properly when X starts with xrdb -q (see Xresources for more information).

字体问题解决方法

字体扭曲

Note: 96 DPI is not a standard. You should use your monitor's actual DPI to get proper font rendering, especially when using subpixel rendering.

If fonts are still unexpectedly large or small, poorly proportioned or simply rendering poorly, fontconfig may be using the incorrect DPI.

Fontconfig should be able to detect DPI parameters as discovered by the Xorg server. You can check the automatically discovered DPI with xdpyinfo:

$ xdpyinfo | grep dots
  resolution:    102x102 dots per inch
Note: To use the xdpyinfo command, you must install the package xorg-xdpyinfo.

If the DPI is detected incorrectly (usually due to an incorrect monitor EDID), you can specify it manually in the Xorg configuration, see Xorg#Display Size and DPI. This is the recommended solution, but it may not work with buggy drivers.

Fontconfig will default to the Xft.dpi variable if it is set. Xft.dpi is usually set by desktop environments (usually to Xorg's DPI setting) or manually in ~/.Xdefaults or ~/.Xresources. Use xrdb to query for the value:

$ xrdb -query | grep dpi
Xft.dpi:	102

Those still having problems can fall back to manually setting the DPI used by fontconfig:

...
<match target="pattern">
   <edit name="dpi" mode="assign"><double>102</double></edit>
</match>
...

较旧的GTK和QT应用程序

Modern GTK apps enable Xft by default but this was not the case before version 2.2. If it is not possible to update these applications, force Xft for old GNOME applications by adding to ~/.bashrc:

export GDK_USE_XFT=1

For older QT applications:

export QT_XFT=true

资源