should be the colormap for the graphics context and
drawable you're using to draw. If you're drawing to a ,
call .
should have its red, green, and blue fields initialized;
this method will fill in 's pixel field with the best
matching pixel from a color cube. The color is then ready to be
used for drawing, e.g. you can call which
expects "pixel" to be initialized.
In many cases, you can avoid this whole issue by setting
or , which
do not expect "pixel" to be initialized in advance. If you use those
mutators, there's no need for calling this method.