wasting time and storage space.
2.7.1.6. Configuring font rendering options
Font rendering can be tuned to adjust the font appearance to suit user preferences and the display hardware in use. Both GNOME and KDE provide configuration tools to configure font rendering.
The GNOME configuration window shown in Figure 2-28 is accessed from the menu item System>Preferences>Font. The KDE rendering configuration panel shown in Figure 2-29 is accessed through the KDE Control Panel under Appearance & Themes>Fonts.
Figure 2-28. GNOME font-rendering preferences tool
Figure 2-29. KDE font rendering preferences tool
In both cases, you can enable or disable antialiasing, adjust the level of antialiasing hinting, and set subpixel order.
On an older system with a slow CPU and/or low memory resources, turning off antialiasing can make enough of a performance difference to turn an unbearably slow system into one that performs reasonably.
When antialiasing is enabled, the hinting level can be set according to user preferenceexperiment and see what looks best.
If you have an LCD screen, select 'Smoothing: Subpixel (LCD)' in GNOME or 'Use Subpixel Smoothing' in KDE. You'll also need to select the order of the red, green, and blue elements on your screen; since this information is almost never documented in the hardware specifications, use a large magnifying glass or experiment until you find the setting that looks the best.
2.7.2. How Does It Work?
X Window System programs use one of two different font systems. The old system, known as
FreeType's sub-pixel rendering capability is, by and large, useful only on LCDs. It involves treating each of the RGB color elements in a pixel as a partial pixel. Figure 2-30 shows an enlarged diagonal line border between black and white regions on an LCD screen, rendered using subpixel hinting.
Figure 2-30. Subpixel rendering on an LCD panel
Note that each pixel is comprised of a red, green, and a blue element; on this display, they are arranged horizontally in R-G-B order. In the first row, there is one white pixel. In the second row, there is a white pixel followed by one-third of a white pixelwhich, in this case, means a red pixel. The third row consists of a white pixel followed by two-thirds of a pixela red-plus-green pixel, which displays as yellow. The fourth row contains two white pixels.
It seems odd that a color pixel would be perceived as a partial pixel, but it works because of sophisticated algorithms and the fact that the subpixels are a continuation of the R-G-B element pattern on the line.
2.7.3. What About...
2.7.3.1. ...getting a list of available fonts?
The
$ fc-list
Luxi Serif:style=Regular
MiscFixed:style=Regular
Utopia:style=Bold Italic
Nimbus Sans L:style=Regular Italic
Bitstream Vera Sans Mono:style=Bold
Webdings:style=Regular
Console:style=Regular
URW Palladio L:style=Roman
Century Schoolbook L:style=Bold Italic
Luxi Serif:style=Bold
...(snip)...
The list isn't in any sort of order, and it contains a lot of information about the styles available for each font, so it's not very readable. Using some arguments and the sort command will produce a much more readable list of available font faces:
$ fc-list : family|sort -u
Andale Mono
Arial
Arial Black
Bitstream Charter
Bitstream Vera Sans
Bitstream Vera Sans Mono
Bitstream Vera Serif
Century Schoolbook L
Comic Sans MS
Console
console8x8
Courier
...(snip)..
2.7.3.2. ...specifying a font name?
Fontconfig font names are very easy to use: just specify the font face you wish to use. You can optionally include a size (separated by a hyphen) or font attribute name/value pairs (after a colon).
For matching purposes, you can specify multiple values for the font name or size, separated by commas.
