Color addon

al_color_cmyk

ALLEGRO_COLOR al_color_cmyk(float c, float m, float y, float k)

al_color_cmyk_to_rgb

void al_color_cmyk_to_rgb(float cyan, float magenta, float yellow,
    float key, float *red, float *green, float *blue)

al_color_hsl

ALLEGRO_COLOR al_color_hsl(float h, float s, float l)

al_color_hsl_to_rgb

void al_color_hsl_to_rgb(float hue, float saturation, float lightness,
   float *red, float *green, float *blue)

Parameters:

  • hue - Color hue angle in the range 0..360.
  • saturation - Color saturation in the range 0..1.
  • lightness - Color lightness in the range 0..1.
  • red, green, blue - returned RGB values in the range 0..1.

al_color_hsv

ALLEGRO_COLOR al_color_hsv(float h, float s, float v)

al_color_hsv_to_rgb

void al_color_hsv_to_rgb(float hue, float saturation, float value,
   float *red, float *green, float *blue)

Parameters:

  • hue - Color hue angle in the range 0..360.
  • saturation - Color saturation in the range 0..1.
  • value - Color value in the range 0..1.
  • red, green, blue - returned RGB values in the range 0..1.

al_color_html

ALLEGRO_COLOR al_color_html(char const *string)

Interprets an HTML styled hex number (e.g. #00faff) as a color. Components that are malformed are set to 0.

al_color_html_to_rgb

void al_color_html_to_rgb(char const *string,
   float *red, float *green, float *blue)

Interprets an HTML styled hex number (e.g. #00faff) as a color. Components that are malformed are set to 0.

al_color_rgb_to_html

void al_color_rgb_to_html(float red, float green, float blue,
    char *string)

Parameters:

  • red, green, blue - The color components in the range 0..1.
  • string - A string with a size of 8 bytes into which the result will be written.

Example:

char html[8];
al_color_rgb_to_html(1, 0, 0, html);

Now html will contain "#ff0000".

al_color_name

ALLEGRO_COLOR al_color_name(char const *name)

al_color_name_to_rgb

int al_color_name_to_rgb(char const *name, float *r, float *g, float *b)

Parameters:

  • name - The (lowercase) name of the color.
  • r, g, b - If one of the recognized color names below is passed, the corresponding RGB values in the range 0..1 are written.

The recognized names are:

aliceblue, antiquewhite, aqua, aquamarine, azure, beige, bisque, black, blanchedalmond, blue, blueviolet, brown, burlywood, cadetblue, chartreuse, chocolate, coral, cornflowerblue, cornsilk, crimson, cyan, darkblue, darkcyan, darkgoldenrod, darkgray, darkgreen, darkkhaki, darkmagenta, darkolivegreen, darkorange, darkorchid, darkred, darksalmon, darkseagreen, darkslateblue, darkslategray, darkturquoise, darkviolet, deeppink, deepskyblue, dimgray, dodgerblue, firebrick, floralwhite, forestgreen, fuchsia, gainsboro, ghostwhite, goldenrod, gold, gray, green, greenyellow, honeydew, hotpink, indianred, indigo, ivory, khaki, lavenderblush, lavender, lawngreen, lemonchiffon, lightblue, lightcoral, lightcyan, lightgoldenrodyellow, lightgreen, lightgrey, lightpink, lightsalmon, lightseagreen, lightskyblue, lightslategray, lightsteelblue, lightyellow, lime, limegreen, linen, magenta, maroon, mediumaquamarine, mediumblue, mediumorchid, mediumpurple, mediumseagreen, mediumslateblue, mediumspringgreen, mediumturquoise, mediumvioletred, midnightblue, mintcream, mistyrose, moccasin, avajowhite, navy, oldlace, olive, olivedrab, orange, orangered, orchid, palegoldenrod, palegreen, paleturquoise, palevioletred, papayawhip, peachpuff, peru, pink, plum, powderblue, purple, purwablue, red, rosybrown, royalblue, saddlebrown, salmon, sandybrown, seagreen, seashell, sienna, silver, skyblue, slateblue, slategray, snow, springgreen, steelblue, tan, teal, thistle, tomato, turquoise, violet, wheat, white, whitesmoke, yellow, yellowgreen

They are taken from http://en.wikipedia.org/wiki/X11_color_names, with CSS names being preferred over X11 ones where there is overlap.

Returns: 0 if a name from the list above was passed, else 1.

al_color_rgb_to_cmyk

void al_color_rgb_to_cmyk(float red, float green, float blue,
   float *cyan, float *magenta, float *yellow, float *key)

Each RGB color can be represented in CMYK with a K component of 0 with the following formula:

C = 1 - R
M = 1 - G
Y = 1 - B
K = 0

This function will instead find the representation with the maximal value for K and minimal color components.

al_color_rgb_to_hsl

void al_color_rgb_to_hsl(float red, float green, float blue,
   float *hue, float *saturation, float *lightness)

Given an RGB triplet with components in the range 0..1, return the hue in degrees from 0..360 and saturation and lightness in the range 0..1.

al_color_rgb_to_hsv

void al_color_rgb_to_hsv(float red, float green, float blue,
   float *hue, float *saturation, float *value)

Given an RGB triplet with components in the range 0..1, return the hue in degrees from 0..360 and saturation and value in the range 0..1.

al_color_rgb_to_name

char const *al_color_rgb_to_name(float r, float g, float b)

Given an RGB triplet with components in the range 0..1, find a color name describing it approximately.

al_color_rgb_to_yuv

void al_color_rgb_to_yuv(float red, float green, float blue,
   float *y, float *u, float *v)

al_color_yuv

ALLEGRO_COLOR al_color_yuv(float y, float u, float v)

al_color_yuv_to_rgb

void al_color_yuv_to_rgb(float y, float u, float v,
    float *red, float *green, float *blue)

Last updated: 2009-08-09 08:22:30 UTC