|(require (planet dsheap/color-utils:1:=0))|
These are some convenience tools to transform images in the 2htdp/image library. The convenience consists of producing new colors by changing a single intensity by name, and a for-like comprehension for images.
Produces band portion old’s color.
Produces color based on old, but using intensity val in band corresponding to component.
Produces color based on col, but with the green intensity to val. , , are analogous.
(for/image ([id image-expr] ...) body ...+)
Produce new image by binding id to each element of image-expr’s color-list in turn.