The history of luaTEX 2006–2009 / v 0.50 - Pragma ADE

XIV
Colors redone
introduction
Color support has been present in ConTEXt right from the start and support has been gradualy
extended, for instance with transparency and spot colors. About 10 years later we
have the rst major rewrite of this mechanism using attributes as implemented in LuaTEX.
Because I needed a test le to check if all things still work as expected, I decided to recap
the most important commands in this chapter.
color support
The core command is \definecolor, so let's dene a few colors:
\definecolor [red] [r=1]
\definecolor [green] [g=1]
\definecolor [blue] [b=1]
\definecolor [yellow] [y=1]
\definecolor [magenta] [m=1]
\definecolor [cyan] [c=1]
This gives us the following colors:
color name transparency specification
white black red r=1.000 g=0.000 b=0.000
white black green r=0.000 g=1.000 b=0.000
white black blue r=0.000 g=0.000 b=1.000
white black yellow c=0.000 m=0.000 y=1.000 k=0.000
white black magenta c=0.000 m=1.000 y=0.000 k=0.000
white black cyan c=1.000 m=0.000 y=0.000 k=0.000
As you can see in this table, transparency is part of a color specication, so let's dene a
few transparent colors:
\definecolor [t-red] [r=1,a=1,t=.5]
\definecolor [t-green] [g=1,a=1,t=.5]
\definecolor [t-blue] [b=1,a=1,t=.5]
color name transparency specification
white black t-red a=1.000 t=0.500 r=1.000 g=0.000 b=0.000
Colors redone 107