create_colormap_and_alloc/[1,2,3]
     create_colormap_and_alloc(-Colormap)
     create_colormap_and_alloc(+Visual, -Colormap)
     create_colormap_and_alloc(+Screen, +Visual, -Colormap)
     

Colormap is a newly created colormap on Screen using Visual. All of the color cells in Colormap are allocated for your use. Screen defaults to the default screen. Visual defaults to the default screen's default visual.