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==Background Directives==
The shapes rendered by Context Free/CFDG are drawn on a canvas that starts out with a background color. The default color is opaque white, but this can be changed using a background directive.

A background directive is a line in the CFDG file that starts with the word 'background' that is followed by set of [[Shape_adjustments#Color_Adjustments|color adjustments]] in curly braces. The adjustments are relative to the default background color of opaque white (hue = 0, saturation = 0, brightness = 1, alpha = 1). If there are more than one background directive then only the first is used.

Here are some useful background directives:
<code cfdg>background { b -1 }        // opaque black
 
background { a -1 }        // transparent </code>

Here is another background directive example:
<code cfdg>background { hue -180 saturation 0.4 brightness -0.1}        // sky-blue</code>