8.12
2 RYB Color Model
Produces a color% object given a coordinate in the
red-yellow-blue (RYB) color space. The RYB color model is
a subtractive model used for painting and art education.
This function produces an approximation in the RGB color
model.
Examples:
> (colorize (disk 50) (make-color/ryb 0 1 1))
> (colorize (filled-rectangle 40 40) (make-color/ryb 1 0.5 1))
procedure
(ryb-series red-1 yellow-1 blue-1 red-2 yellow-2 blue-3 #:midpoints midpoints) → (listof color%) red-1 : (real-in 0 1) yellow-1 : (real-in 0 1) blue-1 : (real-in 0 1) red-2 : (real-in 0 1) yellow-2 : (real-in 0 1) blue-3 : (real-in 0 1) midpoints : 1
Produces a list of color% objects that represent
averages (or mixtures) of the two input colors in the RYB
model.
The midpoints argument controls how many recursive averagings to perform. A midpoints of 1 produces three colors, 2 produces five, and so on.
Examples:
> (map (λ (c) (colorize (filled-rounded-rectangle 50 50) c)) (ryb-series 0.2 0.1 0.3 0 0 0.8 #:midpoints 2)) '(
)
> (map (λ (c) (colorize (filled-rounded-rectangle 50 50) c)) (ryb-series 0 1 0 0 0 0.8 #:midpoints 3)) '(
)
> (plot (contour-intervals (λ (x y) (+ x y)) -2 2 -2 2 #:levels 4 #:contour-styles '(transparent) #:colors (ryb-series 0 0.3 0.3 0.5 0.3 0.2 #:midpoints 2)))
