Colors

8.12

Colors🔗ℹ

package: colors

1 Colors🔗ℹ

the colors library provides alternatives to rgb color representations. it current supports hsl (hue, saturation, luminosity), hsi (hue, saturation, intensity), and hsv (hue, saturation, value).

For a full introduction to hsl and hsv color systems see Wikipedia.

2 structures and contracts🔗ℹ

value
h**/c : contract?

Contract that accepts hsl?, hsv?, or hsi? values.

procedure
(hsl? it) → boolean?
it : any/c

is it an hsl color type?

procedure
(hsi? it) → boolean?
it : any/c

is it an hsi color type?

procedure
(hsv? it) → boolean?
it : any/c

is it an hsv color type?

value
color/c : contract?

Contract which accepts any color like type: color%’s, strings, or h**/c values.

value
%/c : contract?

Contract for value percentages. Equivalent to (real-in 0 1).

value
hue/c : contract?

Contract for value hues. Equivalent to (or/c (real-in 0 1) +nan.0). This contract is similar to %/c except +nan.0 is use for colors which do not have a defined hue.

3 Color Construction🔗ℹ

procedure
(color->hsl color) → hsl?
color : color/c

Convert to an HSL color.

procedure
(hsl->color hsl) → (is-a/c color%)
hsl : hsl?

Convert back to an RGB Color.

procedure
(color->hsv color) → hsv?
color : color/c

Convert to an HSV color.

procedure
(hsv->color hsv) → (is-a/c color%)
hsv : hsv?

Convert back to an RGB Color.

procedure
(color->hsi color) → hsi?
color : color/c

Convert to an HSI color.

procedure
(hsi->color hsi) → (is-a/c color%)
hsi : hsi?

Convert back to an RGB Color.

procedure
(hsl hue saturation lightness [alpha]) → hsl?
  hue : hue/c
  saturation : %/c
  lightness : %/c
  alpha : %/c = 1.0

Directly construct an HSL color.

procedure
(hsv hue saturation value [alpha]) → hsv?
  hue : hue/c
  saturation : %/c
  value : %/c
  alpha : %/c = 1.0

Directly construct an HSV color.

procedure
(hsi hue saturation intensity [alpha]) → hsi?
  hue : hue/c
  saturation : %/c
  intensity : %/c
  alpha : %/c = 1.0

Directly construct an HSI color.

4 Color manipulation🔗ℹ

procedure
(complement color) → h**/c
color : h**/c

Get the complement of a color. The resulting color has the same type as color.

procedure
(set-hue color hue) → h**/c
color : h**/c
hue : hue/c

Construct a color like color but with the given hue. The resulting color has the same type as color.

procedure
(set-saturation color saturation) → h**/c
color : h**/c
saturation : %/c

Construct a color like color but with the given saturation. The resulting color has the same type as color.

procedure
(set-brightness color brightness) → h**/c
color : h**/c
brightness : %/c

Construct a color like color but with the given brightness. The resulting color has the same type as color.

1	Colors
2	structures and contracts
3	Color Construction
4	Color manipulation