node-canvas/src/color.cc

//
// color.cc
//
// Copyright (c) 2010 LearnBoost <tj@learnboost.com>
//

#include "color.h"

/*
 * Consume whitespace.
 */

#define WHITESPACE \
  while (' ' == *str) ++str;

/*
 * Parse color channel value
 */

#define CHANNEL(NAME) \
   if (*str >= '0' && *str <= '9') { \
     do { \
       NAME *= 10; \
       NAME += *str++ - '0'; \
     } while (*str >= '0' && *str <= '9'); \
   } else { \
     return -1; \
   } \
   while (' ' == *str || ',' == *str) str++;

/*
 * Named colors.
 */

static struct named_color {
  const char *name;
  uint32_t val;
} named_colors[] = {
    {"transparent", 0xffffff00}
  , {"aliceblue", 0xf0f8ffff}
  , {"antiquewhite", 0xfaebd7ff}
  , {"aqua", 0x00ffffff}
  , {"aquamarine", 0x7fffd4ff}
  , {"azure", 0xf0ffffff}
  , {"beige", 0xf5f5dcff}
  , {"bisque", 0xffe4c4ff}
  , {"black", 0x000000ff}
  , {"blanchedalmond", 0xffebcdff}
  , {"blue", 0x0000ffff}
  , {"blueviolet", 0x8a2be2ff}
  , {"brown", 0xa52a2aff}
  , {"burlywood", 0xdeb887ff}
  , {"cadetblue", 0x5f9ea0ff}
  , {"chartreuse", 0x7fff00ff}
  , {"chocolate", 0xd2691eff}
  , {"coral", 0xff7f50ff}
  , {"cornflowerblue", 0x6495edff}
  , {"cornsilk", 0xfff8dcff}
  , {"crimson", 0xdc143cff}
  , {"cyan", 0x00ffffff}
  , {"darkblue", 0x00008bff}
  , {"darkcyan", 0x008b8bff}
  , {"darkgoldenrod", 0xb8860bff}
  , {"darkgray", 0xa9a9a9ff}
  , {"darkgreen", 0x006400ff}
  , {"darkkhaki", 0xbdb76bff}
  , {"darkmagenta", 0x8b008bff}
  , {"darkolivegreen", 0x556b2fff}
  , {"darkorange", 0xff8c00ff}
  , {"darkorchid", 0x9932ccff}
  , {"darkred", 0x8b0000ff}
  , {"darksalmon", 0xe9967aff}
  , {"darkseagreen", 0x8fbc8fff}
  , {"darkslateblue", 0x483d8bff}
  , {"darkslategray", 0x2f4f4fff}
  , {"darkturquoise", 0x00ced1ff}
  , {"darkviolet", 0x9400d3ff}
  , {"deeppink", 0xff1493ff}
  , {"deepskyblue", 0x00bfffff}
  , {"dimgray", 0x696969ff}
  , {"dodgerblue", 0x1e90ffff}
  , {"feldspar", 0xd19275ff}
  , {"firebrick", 0xb22222ff}
  , {"floralwhite", 0xfffaf0ff}
  , {"forestgreen", 0x228b22ff}
  , {"fuchsia", 0xff00ffff}
  , {"gainsboro", 0xdcdcdcff}
  , {"ghostwhite", 0xf8f8ffff}
  , {"gold", 0xffd700ff}
  , {"goldenrod", 0xdaa520ff}
  , {"gray", 0x808080ff}
  , {"green", 0x008000ff}
  , {"greenyellow", 0xadff2fff}
  , {"honeydew", 0xf0fff0ff}
  , {"hotpink", 0xff69b4ff}
  , {"indianred ", 0xcd5c5cff}
  , {"indigo ", 0x4b0082ff}
  , {"ivory", 0xfffff0ff}
  , {"khaki", 0xf0e68cff}
  , {"lavender", 0xe6e6faff}
  , {"lavenderblush", 0xfff0f5ff}
  , {"lawngreen", 0x7cfc00ff}
  , {"lemonchiffon", 0xfffacdff}
  , {"lightblue", 0xadd8e6ff}
  , {"lightcoral", 0xf08080ff}
  , {"lightcyan", 0xe0ffffff}
  , {"lightgoldenrodyellow", 0xfafa}
  , {"lightgrey", 0xd3d3d3ff}
  , {"lightgreen", 0x90ee90ff}
  , {"lightpink", 0xffb6c1ff}
  , {"lightsalmon", 0xffa07aff}
  , {"lightseagreen", 0x20b2aaff}
  , {"lightskyblue", 0x87cefaff}
  , {"lightslateblue", 0x8470ffff}
  , {"lightslategray", 0x778899ff}
  , {"lightsteelblue", 0xb0c4deff}
  , {"lightyellow", 0xffffe0ff}
  , {"lime", 0x00ff00ff}
  , {"limegreen", 0x32cd32ff}
  , {"linen", 0xfaf0e6ff}
  , {"magenta", 0xff00ffff}
  , {"maroon", 0x800000ff}
  , {"mediumaquamarine", 0x66cdaaff}
  , {"mediumblue", 0x0000cdff}
  , {"mediumorchid", 0xba55d3ff}
  , {"mediumpurple", 0x9370d8ff}
  , {"mediumseagreen", 0x3cb371ff}
  , {"mediumslateblue", 0x7b68eeff}
  , {"mediumspringgreen", 0x00fa9af}
  , {"mediumturquoise", 0x48d1ccff}
  , {"mediumvioletred", 0xc71585ff}
  , {"midnightblue", 0x191970ff}
  , {"mintcream", 0xf5fffaff}
  , {"mistyrose", 0xffe4e1ff}
  , {"moccasin", 0xffe4b5ff}
  , {"navajowhite", 0xffdeadff}
  , {"navy", 0x000080ff}
  , {"oldlace", 0xfdf5e6ff}
  , {"olive", 0x808000ff}
  , {"olivedrab", 0x6b8e23ff}
  , {"orange", 0xffa500ff}
  , {"orangered", 0xff4500ff}
  , {"orchid", 0xda70d6ff}
  , {"palegoldenrod", 0xeee8aaff}
  , {"palegreen", 0x98fb98ff}
  , {"paleturquoise", 0xafeeeeff}
  , {"palevioletred", 0xd87093ff}
  , {"papayawhip", 0xffefd5ff}
  , {"peachpuff", 0xffdab9ff}
  , {"peru", 0xcd853fff}
  , {"pink", 0xffc0cbff}
  , {"plum", 0xdda0ddff}
  , {"powderblue", 0xb0e0e6ff}
  , {"purple", 0x800080ff}
  , {"red", 0xff0000ff}
  , {"rosybrown", 0xbc8f8fff}
  , {"royalblue", 0x4169e1ff}
  , {"saddlebrown", 0x8b4513ff}
  , {"salmon", 0xfa8072ff}
  , {"sandybrown", 0xf4a460ff}
  , {"seagreen", 0x2e8b57ff}
  , {"seashell", 0xfff5eeff}
  , {"sienna", 0xa0522dff}
  , {"silver", 0xc0c0c0ff}
  , {"skyblue", 0x87ceebff}
  , {"slateblue", 0x6a5acdff}
  , {"slategray", 0x708090ff}
  , {"snow", 0xfffafaff}
  , {"springgreen", 0x00ff7fff}
  , {"steelblue", 0x4682b4ff}
  , {"tan", 0xd2b48cff}
  , {"teal", 0x008080ff}
  , {"thistle", 0xd8bfd8ff}
  , {"tomato", 0xff6347ff}
  , {"turquoise", 0x40e0d0ff}
  , {"violet", 0xee82eeff}
  , {"violetred", 0xd02090ff}
  , {"wheat", 0xf5deb3ff}
  , {"white", 0xffffffff}
  , {"whitesmoke", 0xf5f5f5ff}
  , {"yellow", 0xffff00ff}
  , {"yellowgreen", 0x9acd32ff}
  , {NULL, NULL}
};

/*
 * Hex digit int val.
 */

static int
h(char c) {
  switch (c) {
    case '0':
    case '1':
    case '2':
    case '3':
    case '4':
    case '5':
    case '6':
    case '7':
    case '8':
    case '9':
      return c - '0';
    case 'a':
    case 'b':
    case 'c':
    case 'd':
    case 'e':
    case 'f':
      return (c - 'a') + 10;
    case 'A':
    case 'B':
    case 'C':
    case 'D':
    case 'E':
    case 'F':
      return (c - 'A') + 10;
  }
  return 0;
}

/*
 * Return rgba_t from rgba.
 */

rgba_t
rgba_create(uint32_t rgba) {
  rgba_t color;
  color.r = rgba >> 24;
  color.g = (rgba & 0x00ff0000) >> 16;
  color.b = (rgba & 0x0000ff00) >> 8;
  color.a = rgba & 0xff;
  return color;
}

/*
 * Return rgba from (r,g,b,a).
 */

inline int32_t
rgba_from_rgba(uint8_t r, uint8_t g, uint8_t b, uint8_t a) {
  return
      r << 24
    | g << 16
    | b << 8
    | a;
}

/*
 * Return rgba from (r,g,b).
 */

int32_t
rgba_from_rgb(uint8_t r, uint8_t g, uint8_t b) {
  return rgba_from_rgba(r, g, b, 0);
}

/*
 * Return rgb from "#RRGGBB".
 */

int32_t
rgba_from_hex6_string(const char *str) {
  return rgba_from_rgb(
      (h(str[0]) << 4) + h(str[1])
    , (h(str[2]) << 4) + h(str[3])
    , (h(str[4]) << 4) + h(str[5])
    );
}

/*
 * Return rgb from "#RGB"
 */

int32_t
rgba_from_hex3_string(const char *str) {
  return rgba_from_rgb(
      (h(str[0]) << 4) + h(str[0])
    , (h(str[1]) << 4) + h(str[1])
    , (h(str[2]) << 4) + h(str[2])
    );
}

/*
 * Return rgb from "rgb()"
 */

int32_t
rgba_from_rgb_string(const char *str) {
  if (str == strnstr(str, "rgb(", 4)) {
    str += 4;
    WHITESPACE;
    uint8_t r = 0, g = 0, b = 0;
    CHANNEL(r);
    CHANNEL(g);
    CHANNEL(b);
    return rgba_from_rgb(r, g, b);
  }
  return -1;
}

/*
 * Return rgb from "rgba()"
 */

int32_t
rgba_from_rgba_string(const char *str) {
  if (str == strnstr(str, "rgba(", 5)) {
    str += 5;
    WHITESPACE;
    uint8_t r = 0, g = 0, b = 0;
    float a = 0;
    CHANNEL(r);
    CHANNEL(g);
    CHANNEL(b);
    // TODO: less strict
    if ('1' == *str) {
      a = 1;
    } else {
      if ('0' == *str) a = 0, ++str;
      if ('.' == *str) {
        ++str;
        float n = .1;
        while (*str >= '0' && *str <= '9') {
          a += (*str++ - '0') * n;
          n *= .1;
        }
      }
    }
    return rgba_from_rgba(r, g, b, a * 255);
  }
  return -1;
}

/*
 * Return rgb from:
 *  
 *  - "#RGB"
 *  - "#RRGGBB"
 *
 */

int32_t
rgba_from_hex_string(const char *str) {
  size_t len = strlen(str);
  if (6 == len) return rgba_from_hex6_string(str);
  if (3 == len) return rgba_from_hex3_string(str);
  return -1;
}

/*
 * Return named color value.
 */

int32_t
rgba_from_name_string(const char *str) {
  int i = 0;
  struct named_color color;
  while ((color = named_colors[i++]).name) {
    if (*str == *color.name && 0 == strcmp(str, color.name))
      return color.val;
  }
  return -1;
}

/*
 * Return rgb from:
 *  
 *  - #RGB
 *  - #RRGGBB
 *  - rgb(r,g,b)
 *  - rgba(r,g,b,a)
 *  - name
 *
 */

int32_t
rgba_from_string(const char *str) {
  if ('#' == str[0]) 
    return rgba_from_hex_string(++str);
  if (str == strnstr(str, "rgba", 4))
    return rgba_from_rgba_string(str);
  if (str == strnstr(str, "rgb", 3))
    return rgba_from_rgb_string(str);
  return rgba_from_name_string(str);
}

/*
 * Inspect the given rgba color.
 */

void
rgba_inspect(int32_t rgba) {
  printf("rgba(%d,%d,%d,%d)\n"
    , rgba >> 24 & 0xFF
    , rgba >> 16 & 0xFF
    , rgba >> 8 & 0xFF
    , rgba & 0xFF
    );
}