gimp/libgimpcolor/gimprgb.c

686 lines
19 KiB
C

/* LIBGIMP - The GIMP Library
* Copyright (C) 1995-1997 Peter Mattis and Spencer Kimball
*
* 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 <stdlib.h>
#include <string.h>
#include <glib.h>
#include "libgimpmath/gimpmath.h"
#include "gimpcolortypes.h"
#include "gimprgb.h"
static gboolean gimp_rgb_parse (GimpRGB *rgb,
const gchar *name);
/* RGB functions */
/**
* gimp_rgb_set:
* @rgb: a #GimpRGB struct
* @red:
* @green:
* @blue:
*
* Sets the red, green and blue components of @rgb and leaves the
* alpha component unchanged. The color values should be between 0.0
* and 1.0 but there is no check to enforce this and the values are
* set exactly as they are passed in.
**/
void
gimp_rgb_set (GimpRGB *rgb,
gdouble r,
gdouble g,
gdouble b)
{
g_return_if_fail (rgb != NULL);
rgb->r = r;
rgb->g = g;
rgb->b = b;
}
/**
* gimp_rgb_set_alpha:
* @rgb: a #GimpRGB struct
* @alpha:
*
* Sets the alpha component of @rgb and leaves the RGB components unchanged.
**/
void
gimp_rgb_set_alpha (GimpRGB *rgb,
gdouble a)
{
g_return_if_fail (rgb != NULL);
rgb->a = a;
}
/**
* gimp_rgb_set_uchar:
* @rgb: a #GimpRGB struct
* @red:
* @green:
* @blue:
*
* Sets the red, green and blue components of @rgb from 8bit values
* (0 to 255) and leaves the alpha component unchanged.
**/
void
gimp_rgb_set_uchar (GimpRGB *rgb,
guchar r,
guchar g,
guchar b)
{
g_return_if_fail (rgb != NULL);
rgb->r = (gdouble) r / 255.0;
rgb->g = (gdouble) g / 255.0;
rgb->b = (gdouble) b / 255.0;
}
void
gimp_rgb_get_uchar (const GimpRGB *rgb,
guchar *r,
guchar *g,
guchar *b)
{
g_return_if_fail (rgb != NULL);
if (r) *r = ROUND (CLAMP (rgb->r, 0.0, 1.0) * 255.0);
if (g) *g = ROUND (CLAMP (rgb->g, 0.0, 1.0) * 255.0);
if (b) *b = ROUND (CLAMP (rgb->b, 0.0, 1.0) * 255.0);
}
/**
* 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 (rgb, tmp);
g_free (tmp);
return result;
}
void
gimp_rgb_add (GimpRGB *rgb1,
const GimpRGB *rgb2)
{
g_return_if_fail (rgb1 != NULL);
g_return_if_fail (rgb2 != NULL);
rgb1->r += rgb2->r;
rgb1->g += rgb2->g;
rgb1->b += rgb2->b;
}
void
gimp_rgb_subtract (GimpRGB *rgb1,
const GimpRGB *rgb2)
{
g_return_if_fail (rgb1 != NULL);
g_return_if_fail (rgb2 != NULL);
rgb1->r -= rgb2->r;
rgb1->g -= rgb2->g;
rgb1->b -= rgb2->b;
}
void
gimp_rgb_multiply (GimpRGB *rgb,
gdouble factor)
{
g_return_if_fail (rgb != NULL);
rgb->r *= factor;
rgb->g *= factor;
rgb->b *= factor;
}
gdouble
gimp_rgb_distance (const GimpRGB *rgb1,
const GimpRGB *rgb2)
{
g_return_val_if_fail (rgb1 != NULL, 0.0);
g_return_val_if_fail (rgb2 != NULL, 0.0);
return (fabs (rgb1->r - rgb2->r) +
fabs (rgb1->g - rgb2->g) +
fabs (rgb1->b - rgb2->b));
}
gdouble
gimp_rgb_max (const GimpRGB *rgb)
{
g_return_val_if_fail (rgb != NULL, 0.0);
if (rgb->r > rgb->g)
return (rgb->r > rgb->b) ? rgb->r : rgb->b;
return (rgb->g > rgb->b) ? rgb->g : rgb->b;
}
gdouble
gimp_rgb_min (const GimpRGB *rgb)
{
g_return_val_if_fail (rgb != NULL, 0.0);
if (rgb->r < rgb->g)
return (rgb->r < rgb->b) ? rgb->r : rgb->b;
return (rgb->g < rgb->b) ? rgb->g : rgb->b;
}
void
gimp_rgb_clamp (GimpRGB *rgb)
{
g_return_if_fail (rgb != NULL);
rgb->r = CLAMP (rgb->r, 0.0, 1.0);
rgb->g = CLAMP (rgb->g, 0.0, 1.0);
rgb->b = CLAMP (rgb->b, 0.0, 1.0);
rgb->a = CLAMP (rgb->a, 0.0, 1.0);
}
void
gimp_rgb_gamma (GimpRGB *rgb,
gdouble gamma)
{
gdouble ig;
g_return_if_fail (rgb != NULL);
if (gamma != 0.0)
ig = 1.0 / gamma;
else
ig = 0.0;
rgb->r = pow (rgb->r, ig);
rgb->g = pow (rgb->g, ig);
rgb->b = pow (rgb->b, ig);
}
gdouble
gimp_rgb_intensity (const GimpRGB *rgb)
{
gdouble intensity;
g_return_val_if_fail (rgb != NULL, 0.0);
intensity = GIMP_RGB_INTENSITY (rgb->r, rgb->g, rgb->b);
return CLAMP (intensity, 0.0, 1.0);
}
guchar
gimp_rgb_intensity_uchar (const GimpRGB *rgb)
{
g_return_val_if_fail (rgb != NULL, 0);
return ROUND (gimp_rgb_intensity (rgb) * 255.0);
}
void
gimp_rgb_composite (GimpRGB *color1,
const GimpRGB *color2,
GimpRGBCompositeMode mode)
{
gdouble factor;
g_return_if_fail (color1 != NULL);
g_return_if_fail (color2 != NULL);
switch (mode)
{
case GIMP_RGB_COMPOSITE_NONE:
break;
case GIMP_RGB_COMPOSITE_NORMAL:
/* put color2 on top of color1 */
if (color2->a == 1.0)
{
*color1 = *color2;
}
else
{
factor = color1->a * (1.0 - color2->a);
color1->r = color1->r * factor + color2->r * color2->a;
color1->g = color1->g * factor + color2->g * color2->a;
color1->b = color1->b * factor + color2->b * color2->a;
color1->a = factor + color2->a;
}
break;
case GIMP_RGB_COMPOSITE_BEHIND:
/* put color2 below color1 */
if (color1->a < 1.0)
{
factor = color2->a * (1.0 - color1->a);
color1->r = color2->r * factor + color1->r * color1->a;
color1->g = color2->g * factor + color1->g * color1->a;
color1->b = color2->b * factor + color1->b * color1->a;
color1->a = factor + color1->a;
}
break;
}
}
/* RGBA functions */
/**
* gimp_rgba_set:
* @rgba: a #GimpRGB struct
* @red:
* @green:
* @blue:
* @alpha:
*
* Sets the red, green, blue and alpha components of @rgb. The values
* should be between 0.0 and 1.0 but there is no check to enforce this
* and the values are set exactly as they are passed in.
**/
void
gimp_rgba_set (GimpRGB *rgba,
gdouble r,
gdouble g,
gdouble b,
gdouble a)
{
g_return_if_fail (rgba != NULL);
rgba->r = r;
rgba->g = g;
rgba->b = b;
rgba->a = a;
}
/**
* gimp_rgba_set_uchar:
* @rgba: a #GimpRGB struct
* @red:
* @green:
* @blue:
* @alpha:
*
* Sets the red, green, blue and alpha components of @rgb from 8bit
* values (0 to 255).
**/
void
gimp_rgba_set_uchar (GimpRGB *rgba,
guchar r,
guchar g,
guchar b,
guchar a)
{
g_return_if_fail (rgba != NULL);
rgba->r = (gdouble) r / 255.0;
rgba->g = (gdouble) g / 255.0;
rgba->b = (gdouble) b / 255.0;
rgba->a = (gdouble) a / 255.0;
}
void
gimp_rgba_get_uchar (const GimpRGB *rgba,
guchar *r,
guchar *g,
guchar *b,
guchar *a)
{
g_return_if_fail (rgba != NULL);
if (r) *r = ROUND (CLAMP (rgba->r, 0.0, 1.0) * 255.0);
if (g) *g = ROUND (CLAMP (rgba->g, 0.0, 1.0) * 255.0);
if (b) *b = ROUND (CLAMP (rgba->b, 0.0, 1.0) * 255.0);
if (a) *a = ROUND (CLAMP (rgba->a, 0.0, 1.0) * 255.0);
}
void
gimp_rgba_add (GimpRGB *rgba1,
const GimpRGB *rgba2)
{
g_return_if_fail (rgba1 != NULL);
g_return_if_fail (rgba2 != NULL);
rgba1->r += rgba2->r;
rgba1->g += rgba2->g;
rgba1->b += rgba2->b;
rgba1->a += rgba2->a;
}
void
gimp_rgba_subtract (GimpRGB *rgba1,
const GimpRGB *rgba2)
{
g_return_if_fail (rgba1 != NULL);
g_return_if_fail (rgba2 != NULL);
rgba1->r -= rgba2->r;
rgba1->g -= rgba2->g;
rgba1->b -= rgba2->b;
rgba1->a -= rgba2->a;
}
void
gimp_rgba_multiply (GimpRGB *rgba,
gdouble factor)
{
g_return_if_fail (rgba != NULL);
rgba->r *= factor;
rgba->g *= factor;
rgba->b *= factor;
rgba->a *= factor;
}
gdouble
gimp_rgba_distance (const GimpRGB *rgba1,
const GimpRGB *rgba2)
{
g_return_val_if_fail (rgba1 != NULL, 0.0);
g_return_val_if_fail (rgba2 != NULL, 0.0);
return (fabs (rgba1->r - rgba2->r) + fabs (rgba1->g - rgba2->g) +
fabs (rgba1->b - rgba2->b) + fabs (rgba1->a - rgba2->a));
}
/* private functions */
static gboolean
gimp_rgb_parse_hex (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;
}
typedef struct
{
const gchar *name;
guchar r;
guchar g;
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 (GimpRGB *rgb,
const gchar *name)
{
if (name[0] == '#')
{
gint i;
gsize len;
gdouble val[3];
len = strlen (++name);
if (len % 3 || len < 3 || len > 12)
return FALSE;
len /= 3;
for (i = 0; i < 3; i++, name += len)
{
if (! gimp_rgb_parse_hex (name, len, val + i))
return FALSE;
}
gimp_rgb_set (rgb, val[0], val[1], val[2]);
return TRUE;
}
else
{
const static 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;
}