gimp/libgimpcolor/gimprgb-parse.c

/* LIBGIMP - The GIMP Library
 * Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
 *
 * gimprgb-parse.c
 * Copyright (C) 2004  Sven Neumann <sven@gimp.org>
 *
 * Some of the code in here was inspired and partly copied from pango
 * and librsvg.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include "config.h"

#include <errno.h>
#include <stdlib.h>
#include <string.h>

#include <glib.h>

#include "gimpcolortypes.h"

#include "gimprgb.h"


static gboolean  gimp_rgb_parse_name_internal (GimpRGB     *rgb,
                                               const gchar *name);
static gboolean  gimp_rgb_parse_hex_internal  (GimpRGB     *rgb,
                                               const gchar *hex);
static gboolean  gimp_rgb_parse_css_internal  (GimpRGB     *rgb,
                                               const gchar *css);


/**
 * gimp_rgb_parse_name:
 * @rgb:  a #GimpRGB struct used to return the parsed color
 * @name: a color name (in UTF-8 encoding)
 * @len:  the length of @name, in bytes. or -1 if @name is nul-terminated
 *
 * Attempts to parse a color name. This function accepts RGB hex
 * values or <ulink url="http://www.w3.org/TR/SVG/types.html">SVG 1.0
 * color keywords</ulink>.  The format of an RGB value in hexadecimal
 * notation is a '#' immediately followed by either three or six
 * hexadecimal characters.
 *
 * This funcion does not touch the alpha component of @rgb.
 *
 * Return value: %TRUE if @name was parsed successfully and @rgb has been
 *               set, %FALSE otherwise
 *
 * Since: GIMP 2.2
 **/
gboolean
gimp_rgb_parse_name (GimpRGB     *rgb,
                     const gchar *name,
                     gsize        len)
{
  gchar    *tmp;
  gboolean  result;

  g_return_val_if_fail (rgb != NULL, FALSE);
  g_return_val_if_fail (name != NULL, FALSE);

  if (len < 0)
    len = strlen (name);

  tmp = g_strstrip (g_strndup (name, len));

  result = gimp_rgb_parse_name_internal (rgb, tmp);

  g_free (tmp);

  return result;
}

/**
 * gimp_rgb_parse_hex:
 * @rgb: a #GimpRGB struct used to return the parsed color
 * @hex: a string describing a color in hexadecimal notation
 * @len: the length of @hex, in bytes. or -1 if @hex is nul-terminated
 *
 * Attempts to parse a string describing a color in RGB value in
 * hexadecimal notation (optionally prefixed with a '#'.
 *
 * This funcion does not touch the alpha component of @rgb.
 *
 * Return value: %TRUE if @hex was parsed successfully and @rgb has been
 *               set, %FALSE otherwise
 *
 * Since: GIMP 2.2
 **/
gboolean
gimp_rgb_parse_hex (GimpRGB     *rgb,
                    const gchar *hex,
                    gsize        len)
{
  gchar    *tmp;
  gboolean  result;

  g_return_val_if_fail (rgb != NULL, FALSE);
  g_return_val_if_fail (hex != NULL, FALSE);

  if (len < 0)
    len = strlen (hex);

  tmp = g_strstrip (g_strndup (hex, len));

  result = gimp_rgb_parse_hex_internal (rgb, tmp);

  g_free (tmp);

  return result;
}

/**
 * gimp_rgb_parse_css:
 * @rgb: a #GimpRGB struct used to return the parsed color
 * @css: a string describing a color in CSS notation
 * @len: the length of @hex, in bytes. or -1 if @hex is nul-terminated
 *
 * Attempts to parse a string describing a color in RGB value in
 * CSS notation. This can be either a numerical representation:
 *   <informalexample><programlisting>
 *     rgb (255, 0, 0)
 *     rgb (100%, 0%, 0%)
 *   </programlisting></informalexample>
 * or a hexadecimal notation as parsed by gimp_rgb_parse_hex():
 *   <informalexample><programlisting>
 *     #ff0000
 *   </programlisting></informalexample>
 * or a color name as parsed by  gimp_rgb_parse_name().
 *
 * This funcion does not touch the alpha component of @rgb.
 *
 * Return value: %TRUE if @css was parsed successfully and @rgb has been
 *               set, %FALSE otherwise
 *
 * Since: GIMP 2.2
 **/
gboolean
gimp_rgb_parse_css (GimpRGB     *rgb,
                    const gchar *css,
                    gsize        len)
{
  gchar    *tmp;
  gboolean  result;

  g_return_val_if_fail (rgb != NULL, FALSE);
  g_return_val_if_fail (css != NULL, FALSE);

  if (len < 0)
    len = strlen (css);

  tmp = g_strstrip (g_strndup (css, len));

  result = gimp_rgb_parse_css_internal (rgb, tmp);

  g_free (tmp);

  return result;
}


typedef struct
{
  const gchar  *name;
  const guchar  r;
  const guchar  g;
  const guchar  b;
} ColorEntry;

static gint
gimp_rgb_color_entry_compare (gconstpointer a,
                              gconstpointer b)
{
  const gchar      *name  = a;
  const ColorEntry *entry = b;

  return g_ascii_strcasecmp (name, entry->name);
}

static gboolean
gimp_rgb_parse_name_internal (GimpRGB     *rgb,
                              const gchar *name)
{
  static const ColorEntry colors[] =
  {
    { "aliceblue",             240, 248, 255 },
    { "antiquewhite",          250, 235, 215 },
    { "aqua",                    0, 255, 255 },
    { "aquamarine",            127, 255, 212 },
    { "azure",                 240, 255, 255 },
    { "beige",                 245, 245, 220 },
    { "bisque",                255, 228, 196 },
    { "black",                   0,   0,   0 },
    { "blanchedalmond",        255, 235, 205 },
    { "blue",                    0,   0, 255 },
    { "blueviolet",            138,  43, 226 },
    { "brown",                 165,  42,  42 },
    { "burlywood",             222, 184, 135 },
    { "cadetblue",              95, 158, 160 },
    { "chartreuse",            127, 255,   0 },
    { "chocolate",             210, 105,  30 },
    { "coral",                 255, 127,  80 },
    { "cornflowerblue",        100, 149, 237 },
    { "cornsilk",              255, 248, 220 },
    { "crimson",               220,  20,  60 },
    { "cyan",                    0, 255, 255 },
    { "darkblue",                0,   0, 139 },
    { "darkcyan",                0, 139, 139 },
    { "darkgoldenrod",         184, 132,  11 },
    { "darkgray",              169, 169, 169 },
    { "darkgreen",               0, 100,   0 },
    { "darkgrey",              169, 169, 169 },
    { "darkkhaki",             189, 183, 107 },
    { "darkmagenta",           139,   0, 139 },
    { "darkolivegreen",         85, 107,  47 },
    { "darkorange",            255, 140,   0 },
    { "darkorchid",            153,  50, 204 },
    { "darkred",               139,   0,   0 },
    { "darksalmon",            233, 150, 122 },
    { "darkseagreen",          143, 188, 143 },
    { "darkslateblue",          72,  61, 139 },
    { "darkslategray",          47,  79,  79 },
    { "darkslategrey",          47,  79,  79 },
    { "darkturquoise",           0, 206, 209 },
    { "darkviolet",            148,   0, 211 },
    { "deeppink",              255,  20, 147 },
    { "deepskyblue",             0, 191, 255 },
    { "dimgray",               105, 105, 105 },
    { "dimgrey",               105, 105, 105 },
    { "dodgerblue",             30, 144, 255 },
    { "firebrick",             178,  34,  34 },
    { "floralwhite" ,          255, 255, 240 },
    { "forestgreen",            34, 139,  34 },
    { "fuchsia",               255,   0, 255 },
    { "gainsboro",             220, 220, 220 },
    { "ghostwhite",            248, 248, 255 },
    { "gold",                  255, 215,   0 },
    { "goldenrod",             218, 165,  32 },
    { "gray",                  128, 128, 128 },
    { "green",                   0, 128,   0 },
    { "greenyellow",           173, 255,  47 },
    { "grey",                  128, 128, 128 },
    { "honeydew",              240, 255, 240 },
    { "hotpink",               255, 105, 180 },
    { "indianred",             205,  92,  92 },
    { "indigo",                 75,   0, 130 },
    { "ivory",                 255, 255, 240 },
    { "khaki",                 240, 230, 140 },
    { "lavender",              230, 230, 250 },
    { "lavenderblush",         255, 240, 245 },
    { "lawngreen",             124, 252,   0 },
    { "lemonchiffon",          255, 250, 205 },
    { "lightblue",             173, 216, 230 },
    { "lightcoral",            240, 128, 128 },
    { "lightcyan",             224, 255, 255 },
    { "lightgoldenrodyellow",  250, 250, 210 },
    { "lightgray",             211, 211, 211 },
    { "lightgreen",            144, 238, 144 },
    { "lightgrey",             211, 211, 211 },
    { "lightpink",             255, 182, 193 },
    { "lightsalmon",           255, 160, 122 },
    { "lightseagreen",          32, 178, 170 },
    { "lightskyblue",          135, 206, 250 },
    { "lightslategray",        119, 136, 153 },
    { "lightslategrey",        119, 136, 153 },
    { "lightsteelblue",        176, 196, 222 },
    { "lightyellow",           255, 255, 224 },
    { "lime",                    0, 255,   0 },
    { "limegreen",              50, 205,  50 },
    { "linen",                 250, 240, 230 },
    { "magenta",               255,   0, 255 },
    { "maroon",                128,   0,   0 },
    { "mediumaquamarine",      102, 205, 170 },
    { "mediumblue",              0,   0, 205 },
    { "mediumorchid",          186,  85, 211 },
    { "mediumpurple",          147, 112, 219 },
    { "mediumseagreen",         60, 179, 113 },
    { "mediumslateblue",       123, 104, 238 },
    { "mediumspringgreen",       0, 250, 154 },
    { "mediumturquoise",        72, 209, 204 },
    { "mediumvioletred",       199,  21, 133 },
    { "midnightblue",           25,  25, 112 },
    { "mintcream",             245, 255, 250 },
    { "mistyrose",             255, 228, 225 },
    { "moccasin",              255, 228, 181 },
    { "navajowhite",           255, 222, 173 },
    { "navy",                    0,   0, 128 },
    { "oldlace",               253, 245, 230 },
    { "olive",                 128, 128,   0 },
    { "olivedrab",             107, 142,  35 },
    { "orange",                255, 165,   0 },
    { "orangered",             255,  69,   0 },
    { "orchid",                218, 112, 214 },
    { "palegoldenrod",         238, 232, 170 },
    { "palegreen",             152, 251, 152 },
    { "paleturquoise",         175, 238, 238 },
    { "palevioletred",         219, 112, 147 },
    { "papayawhip",            255, 239, 213 },
    { "peachpuff",             255, 218, 185 },
    { "peru",                  205, 133,  63 },
    { "pink",                  255, 192, 203 },
    { "plum",                  221, 160, 203 },
    { "powderblue",            176, 224, 230 },
    { "purple",                128,   0, 128 },
    { "red",                   255,   0,   0 },
    { "rosybrown",             188, 143, 143 },
    { "royalblue",              65, 105, 225 },
    { "saddlebrown",           139,  69,  19 },
    { "salmon",                250, 128, 114 },
    { "sandybrown",            244, 164,  96 },
    { "seagreen",               46, 139,  87 },
    { "seashell",              255, 245, 238 },
    { "sienna",                160,  82,  45 },
    { "silver",                192, 192, 192 },
    { "skyblue",               135, 206, 235 },
    { "slateblue",             106,  90, 205 },
    { "slategray",             119, 128, 144 },
    { "slategrey",             119, 128, 144 },
    { "snow",                  255, 255, 250 },
    { "springgreen",             0, 255, 127 },
    { "steelblue",              70, 130, 180 },
    { "tan",                   210, 180, 140 },
    { "teal",                    0, 128, 128 },
    { "thistle",               216, 191, 216 },
    { "tomato",                255,  99,  71 },
    { "turquoise",              64, 224, 208 },
    { "violet",                238, 130, 238 },
    { "wheat",                 245, 222, 179 },
    { "white",                 255, 255, 255 },
    { "whitesmoke",            245, 245, 245 },
    { "yellow",                255, 255,   0 },
    { "yellowgreen",           154, 205,  50 }
  };

  ColorEntry *entry = bsearch (name, colors,
                               G_N_ELEMENTS (colors), sizeof (ColorEntry),
                               gimp_rgb_color_entry_compare);

  if (entry)
    {
      gimp_rgb_set_uchar (rgb, entry->r, entry->g, entry->b);

      return TRUE;
    }

  return FALSE;
}


static gboolean
gimp_rgb_parse_hex_component (const gchar *hex,
                              gint         len,
                              gdouble     *value)
{
  gint  i;
  guint c = 0;

  for (i = 0; i < len; i++, hex++)
    {
      if (!*hex || !g_ascii_isxdigit (*hex))
        return FALSE;

      c = (c << 4) | g_ascii_xdigit_value (*hex);
    }

  switch (len)
    {
    case 1: *value = (gdouble) c /    15.0;  break;
    case 2: *value = (gdouble) c /   255.0;  break;
    case 3: *value = (gdouble) c /  4095.0;  break;
    case 4: *value = (gdouble) c / 65535.0;  break;
    default:
      g_return_val_if_reached (FALSE);
    }

  return TRUE;
}

static gboolean
gimp_rgb_parse_hex_internal (GimpRGB     *rgb,
                             const gchar *hex)
{
  gint     i;
  gsize    len;
  gdouble  val[3];

  if (hex[0] == '#')
    hex++;

  len = strlen (hex);
  if (len % 3 || len < 3 || len > 12)
    return FALSE;

  len /= 3;

  for (i = 0; i < 3; i++, hex += len)
    {
      if (! gimp_rgb_parse_hex_component (hex, len, val + i))
        return FALSE;
    }

  gimp_rgb_set (rgb, val[0], val[1], val[2]);

  return TRUE;
}


static gboolean
gimp_rgb_parse_css_internal (GimpRGB     *rgb,
                             const gchar *css)
{
  if (css[0] == '#')
    {
      return gimp_rgb_parse_hex_internal (rgb, css);
    }
  else if (strncmp (css, "rgb(", 4) == 0)
    {
      gchar   *end;
      gint     i;
      gdouble  values[3];

      for (i = 0; i < 3; i++)
        {
          values[i] = g_ascii_strtod (css, &end);

          if (errno == ERANGE)
            return FALSE;

          if (*end == '%')
            values[i] /= 100.0;

          while (*end == ',' || g_ascii_isspace (*end))
            end++;

          css = end;
        }

      if (*css == ')')
        {
          gimp_rgb_set (rgb, values[0], values[1], values[2]);

          return TRUE;
        }
    }
  else
    {
      return gimp_rgb_parse_name_internal (rgb, css);
    }

  return FALSE;
}