color.sr

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

.ds Dc black
.ds Cc \*(Dc
.de CL	\" Color selection macro
.	\"
.	\"	$1=color (e.g. .CL red) or
.	\"	$1=textcolor on backgroundcolor (e.g. .CL "red on blue")
.	\"	$1=red green blue rgb (e.g. .CL ".2 .3 .4 rgb") or
.	\"	$1=hue saturation brightness hsb (e.g. .CL ".5 .6 .7 hsb")
.	\"	$2=text
.	\"
.	\" If no arguments are given the default color (usually black) will be
.	\" restored. If $2 is omitted the color selected by $1 remains in effect
.	\" until another color is selected. If two arguments are given $2 will be
.	\" printed in color $1 and then the default color will be restored.
.	\"
.	\" The color of the text and the background can be selected by setting $1
.	\" to "textcolor on backgroundcolor" where textcolor and backgroundcolor
.	\" can be any of the known colors. For example use .CL "white on black"
.	\" for reverse video printing. Changing color in a word can be accomplished
.	\" by preceeding the characters with a \X'SetColor:val' command, where val
.	\" is the color you wish to use. Named colors are case independent.
.	\"
.	\" Implementation details are device dependent and are handled in the
.	\" appropriate post-processor. Requesting a color that's not available
.	\" (eg. not defined in /usr/lib/postscript/color.ps) results in the use
.	\" of default colors - black or white on black for reverse video mode.
.	\"
.	\" All colors may not be supported on every output device, and the direct
.	\" specification of a color via an explicit rgb or hsb argument may also
.	\" be device dependent. In any case, to be safe on PostScript devices, all
.	\" numeric paramenters in the direct rgb or hsb specifications should lie
.	\" between 0 and 1 (inclusive). The names of the currently available colors
.	\" on PostScript printers are listed in file /usr/lib/postscript/color.ps.
.	\"
.mk Ov
.if \\n(.$=0 .ds Cc \\*(Dc
.if \\n(.$=1 .ds Cc \\$1
.if \\n(.$<2 \\X'SetColor:\\*(Cc'
.if \\n(.$=2 \\X'SetColor:\\$1'\\c
.if \\n(.$=2 'sp |\\n(Ovu
.if \\n(.$=2 \\$2
.if \\n(.$=2 .mk Ov
.if \\n(.$=2 \\X'SetColor:\\*(Cc'\\c
'sp |\\n(Ovu
..