- color-set! color #!optional r g b asetter
- colour-set! color #!optional r g b asetter
Efficient and convenient way of setting multiple fields of the sdl2:color. Any arguments that are #f will cause no change to that field. E.g. (color-set! my-color 42 #f 255 #f) will set the "r" field to 42 and the "b" field to 255, but will not change the "g" or "a" fields. Returns color after it is modified.