Command/definecolor

From ConTeXt wiki
Jump to: navigation, search

\definecolor

Syntax

\definecolor[...][...,...=...,...]
[...] name
r number red channel (RGB)
g number green channel (RGB)
b number blue channel (RGB)
c number cyan channel (CMYK)
m number magenta channel (CMYK)
y number yellow channel (CMYK)
k number black channel (CMYK)
s number gray value (Grayscale), if v isn't set
h number hue (HSB)
s number saturation (HSB)
v number brightness/value (HSB)
t number transparency factor
a number alternative (transparency method)
p number spotcolor percentage
e text spotcolor name
x text Hexadecimal RGB value (like in HTML), only with hex module

Description

\definecolor associates a name with a color, for later use with the \color command.

To use hexadecimal colors in mkii you need to load the proper module first:

\setupcolor[hex]

Then the colors can be specified with

\definecolor[hex-red][h=FF0000]

Regarding the key a, which means transparency alternative method, there are a certain number of values (actually at least 13, from 0 to 12) whose meanings can be seen from below:

\definetransparency [none]        [0]
\definetransparency [normal]      [1]
\definetransparency [multiply]    [2]
\definetransparency [screen]      [3]
\definetransparency [overlay]     [4]
\definetransparency [softlight]   [5]
\definetransparency [hardlight]   [6]
\definetransparency [colordodge]  [7]
\definetransparency [colorburn]   [8]
\definetransparency [darken]      [9]
\definetransparency [lighten]    [10]
\definetransparency [difference] [11]
\definetransparency [exclusion]  [12]

Defining derivative colors

Colors defined in terms of other colors are processed at the Lua end, unless they are direct clones. In that case, the new name is never told to Lua. That means that this does not work:

% direct clone, processed by TeX
\definecolor[ColorA][red]
% fails, ColorA not known to Lua
\definecolor[ColorB][.5(ColorA)]

Writing it as a fake fraction works.

% definition involves a fraction, processed by Lua.
\definecolor[ColorA][1.0(red)]
% succeeds
\definecolor[ColorB][.5(ColorA)]

Example

% mode=mkiv

% rgb
\definecolor[bluu][r=.25, g = .1, b=1]
Hey, \color[bluu]{look at that!}

% hex
%\setupcolor[hex] % needed in mkii only
\definecolor[salmon][h=AB5757]
Hey, \color[salmon]{look at that!}

See also

Help from ConTeXt-Mailinglist/Forum

All issues with:

C O N T E X T G A R D E N

Personal tools
Namespaces
Variants
Actions
Help
External Help
Installation
Navigation
Toolbox