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gimp/libgimpcolor/gimpcolorspace.c

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Import Upstream version 2.10.32
2022-11-23 10:54:48 +08:00
/* 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 3 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, see
* <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <babl/babl.h>
#include <glib-object.h>
#include "libgimpmath/gimpmath.h"
#include "gimpcolortypes.h"
#include "gimpcolorspace.h"
#include "gimprgb.h"
#include "gimphsv.h"
/**
* SECTION: gimpcolorspace
* @title: GimpColorSpace
* @short_description: Utility functions which convert colors between
* different color models.
*
* When programming pixel data manipulation functions you will often
* use algorithms operating on a color model different from the one
* GIMP uses. This file provides utility functions to convert colors
* between different color spaces.
**/
#define GIMP_HSV_UNDEFINED -1.0
#define GIMP_HSL_UNDEFINED -1.0
/*********************************
* color conversion routines *
*********************************/
/* GimpRGB functions */
/**
* gimp_rgb_to_hsv:
* @rgb: A color value in the RGB colorspace
* @hsv: The value converted to the HSV colorspace
*
* Does a conversion from RGB to HSV (Hue, Saturation,
* Value) colorspace.
**/
void
gimp_rgb_to_hsv (const GimpRGB *rgb,
GimpHSV *hsv)
{
gdouble max, min, delta;
g_return_if_fail (rgb != NULL);
g_return_if_fail (hsv != NULL);
max = gimp_rgb_max (rgb);
min = gimp_rgb_min (rgb);
hsv->v = max;
delta = max - min;
if (delta > 0.0001)
{
hsv->s = delta / max;
if (rgb->r == max)
{
hsv->h = (rgb->g - rgb->b) / delta;
if (hsv->h < 0.0)
hsv->h += 6.0;
}
else if (rgb->g == max)
{
hsv->h = 2.0 + (rgb->b - rgb->r) / delta;
}
else
{
hsv->h = 4.0 + (rgb->r - rgb->g) / delta;
}
hsv->h /= 6.0;
}
else
{
hsv->s = 0.0;
hsv->h = 0.0;
}
hsv->a = rgb->a;
}
/**
* gimp_hsv_to_rgb:
* @hsv: A color value in the HSV colorspace
* @rgb: The returned RGB value.
*
* Converts a color value from HSV to RGB colorspace
**/
void
gimp_hsv_to_rgb (const GimpHSV *hsv,
GimpRGB *rgb)
{
gint i;
gdouble f, w, q, t;
gdouble hue;
g_return_if_fail (rgb != NULL);
g_return_if_fail (hsv != NULL);
if (hsv->s == 0.0)
{
rgb->r = hsv->v;
rgb->g = hsv->v;
rgb->b = hsv->v;
}
else
{
hue = hsv->h;
if (hue == 1.0)
hue = 0.0;
hue *= 6.0;
i = (gint) hue;
f = hue - i;
w = hsv->v * (1.0 - hsv->s);
q = hsv->v * (1.0 - (hsv->s * f));
t = hsv->v * (1.0 - (hsv->s * (1.0 - f)));
switch (i)
{
case 0:
rgb->r = hsv->v;
rgb->g = t;
rgb->b = w;
break;
case 1:
rgb->r = q;
rgb->g = hsv->v;
rgb->b = w;
break;
case 2:
rgb->r = w;
rgb->g = hsv->v;
rgb->b = t;
break;
case 3:
rgb->r = w;
rgb->g = q;
rgb->b = hsv->v;
break;
case 4:
rgb->r = t;
rgb->g = w;
rgb->b = hsv->v;
break;
case 5:
rgb->r = hsv->v;
rgb->g = w;
rgb->b = q;
break;
}
}
rgb->a = hsv->a;
}
/**
* gimp_rgb_to_hsl:
* @rgb: A color value in the RGB colorspace
* @hsl: The value converted to HSL
*
* Convert an RGB color value to a HSL (Hue, Saturation, Lightness)
* color value.
**/
void
gimp_rgb_to_hsl (const GimpRGB *rgb,
GimpHSL *hsl)
{
gdouble max, min, delta;
g_return_if_fail (rgb != NULL);
g_return_if_fail (hsl != NULL);
max = gimp_rgb_max (rgb);
min = gimp_rgb_min (rgb);
hsl->l = (max + min) / 2.0;
if (max == min)
{
hsl->s = 0.0;
hsl->h = GIMP_HSL_UNDEFINED;
}
else
{
if (hsl->l <= 0.5)
hsl->s = (max - min) / (max + min);
else
hsl->s = (max - min) / (2.0 - max - min);
delta = max - min;
if (delta == 0.0)
delta = 1.0;
if (rgb->r == max)
{
hsl->h = (rgb->g - rgb->b) / delta;
}
else if (rgb->g == max)
{
hsl->h = 2.0 + (rgb->b - rgb->r) / delta;
}
else
{
hsl->h = 4.0 + (rgb->r - rgb->g) / delta;
}
hsl->h /= 6.0;
if (hsl->h < 0.0)
hsl->h += 1.0;
}
hsl->a = rgb->a;
}
static inline gdouble
gimp_hsl_value (gdouble n1,
gdouble n2,
gdouble hue)
{
gdouble val;
if (hue > 6.0)
hue -= 6.0;
else if (hue < 0.0)
hue += 6.0;
if (hue < 1.0)
val = n1 + (n2 - n1) * hue;
else if (hue < 3.0)
val = n2;
else if (hue < 4.0)
val = n1 + (n2 - n1) * (4.0 - hue);
else
val = n1;
return val;
}
/**
* gimp_hsl_to_rgb:
* @hsl: A color value in the HSL colorspace
* @rgb: The value converted to a value in the RGB colorspace
*
* Convert a HSL color value to an RGB color value.
**/
void
gimp_hsl_to_rgb (const GimpHSL *hsl,
GimpRGB *rgb)
{
g_return_if_fail (hsl != NULL);
g_return_if_fail (rgb != NULL);
if (hsl->s == 0)
{
/* achromatic case */
rgb->r = hsl->l;
rgb->g = hsl->l;
rgb->b = hsl->l;
}
else
{
gdouble m1, m2;
if (hsl->l <= 0.5)
m2 = hsl->l * (1.0 + hsl->s);
else
m2 = hsl->l + hsl->s - hsl->l * hsl->s;
m1 = 2.0 * hsl->l - m2;
rgb->r = gimp_hsl_value (m1, m2, hsl->h * 6.0 + 2.0);
rgb->g = gimp_hsl_value (m1, m2, hsl->h * 6.0);
rgb->b = gimp_hsl_value (m1, m2, hsl->h * 6.0 - 2.0);
}
rgb->a = hsl->a;
}
/**
* gimp_rgb_to_cmyk:
* @rgb: A value in the RGB colorspace
* @pullout: A scaling value (0-1) indicating how much black should be
* pulled out
* @cmyk: The input value naively converted to the CMYK colorspace
*
* Does a naive conversion from RGB to CMYK colorspace. A simple
* formula that doesn't take any color-profiles into account is used.
* The amount of black pullout how can be controlled via the @pullout
* parameter. A @pullout value of 0 makes this a conversion to CMY.
* A value of 1 causes the maximum amount of black to be pulled out.
**/
void
gimp_rgb_to_cmyk (const GimpRGB *rgb,
gdouble pullout,
GimpCMYK *cmyk)
{
gdouble c, m, y, k;
g_return_if_fail (rgb != NULL);
g_return_if_fail (cmyk != NULL);
c = 1.0 - rgb->r;
m = 1.0 - rgb->g;
y = 1.0 - rgb->b;
k = 1.0;
if (c < k) k = c;
if (m < k) k = m;
if (y < k) k = y;
k *= pullout;
if (k < 1.0)
{
cmyk->c = (c - k) / (1.0 - k);
cmyk->m = (m - k) / (1.0 - k);
cmyk->y = (y - k) / (1.0 - k);
}
else
{
cmyk->c = 0.0;
cmyk->m = 0.0;
cmyk->y = 0.0;
}
cmyk->k = k;
cmyk->a = rgb->a;
}
/**
* gimp_cmyk_to_rgb:
* @cmyk: A color value in the CMYK colorspace
* @rgb: The value converted to the RGB colorspace
*
* Does a simple transformation from the CMYK colorspace to the RGB
* colorspace, without taking color profiles into account.
**/
void
gimp_cmyk_to_rgb (const GimpCMYK *cmyk,
GimpRGB *rgb)
{
gdouble c, m, y, k;
g_return_if_fail (cmyk != NULL);
g_return_if_fail (rgb != NULL);
k = cmyk->k;
if (k < 1.0)
{
c = cmyk->c * (1.0 - k) + k;
m = cmyk->m * (1.0 - k) + k;
y = cmyk->y * (1.0 - k) + k;
}
else
{
c = 1.0;
m = 1.0;
y = 1.0;
}
rgb->r = 1.0 - c;
rgb->g = 1.0 - m;
rgb->b = 1.0 - y;
rgb->a = cmyk->a;
}
#define GIMP_RETURN_RGB(x, y, z) { rgb->r = x; rgb->g = y; rgb->b = z; return; }
/****************************************************************************
* Theoretically, hue 0 (pure red) is identical to hue 6 in these transforms.
* Pure red always maps to 6 in this implementation. Therefore UNDEFINED can
* be defined as 0 in situations where only unsigned numbers are desired.
****************************************************************************/
/**
* gimp_rgb_to_hwb:
* @rgb: A color value in the RGB colorspace
* @hue: The hue value of the above color, in the range 0 to 6
* @whiteness: The whiteness value of the above color, in the range 0 to 1
* @blackness: The blackness value of the above color, in the range 0 to 1
*
* Theoretically, hue 0 (pure red) is identical to hue 6 in these transforms.
* Pure red always maps to 6 in this implementation. Therefore UNDEFINED can
* be defined as 0 in situations where only unsigned numbers are desired.
*
* RGB are each on [0, 1]. Whiteness and Blackness are returned in the
* range [0, 1] and H is returned in the range [0, 6]. If W == 1 - B, H is
* undefined.
**/
void
gimp_rgb_to_hwb (const GimpRGB *rgb,
gdouble *hue,
gdouble *whiteness,
gdouble *blackness)
{
/* RGB are each on [0, 1]. W and B are returned on [0, 1] and H is */
/* returned on [0, 6]. Exception: H is returned UNDEFINED if W == 1 - B. */
/* ====================================================================== */
gdouble R = rgb->r, G = rgb->g, B = rgb->b, w, v, b, f;
gint i;
w = gimp_rgb_min (rgb);
v = gimp_rgb_max (rgb);
b = 1.0 - v;
if (v == w)
{
*hue = GIMP_HSV_UNDEFINED;
*whiteness = w;
*blackness = b;
}
else
{
f = (R == w) ? G - B : ((G == w) ? B - R : R - G);
i = (R == w) ? 3.0 : ((G == w) ? 5.0 : 1.0);
*hue = (360.0 / 6.0) * (i - f / (v - w));
*whiteness = w;
*blackness = b;
}
}
/**
* gimp_hwb_to_rgb:
* @hue: A hue value, in the range 0 to 6
* @whiteness: A whiteness value, in the range 0 to 1
* @blackness: A blackness value, in the range 0 to 1
* @rgb: The above color converted to the RGB colorspace
*
* H is defined in the range [0, 6] or UNDEFINED, B and W are both in the
* range [0, 1]. The returned RGB values are all in the range [0, 1].
**/
void
gimp_hwb_to_rgb (gdouble hue,
gdouble whiteness,
gdouble blackness,
GimpRGB *rgb)
{
/* H is given on [0, 6] or UNDEFINED. whiteness and
* blackness are given on [0, 1].
* RGB are each returned on [0, 1].
*/
gdouble h = hue, w = whiteness, b = blackness, v, n, f;
gint i;
h = 6.0 * h/ 360.0;
v = 1.0 - b;
if (h == GIMP_HSV_UNDEFINED)
{
rgb->r = v;
rgb->g = v;
rgb->b = v;
}
else
{
i = floor (h);
f = h - i;
if (i & 1)
f = 1.0 - f; /* if i is odd */
n = w + f * (v - w); /* linear interpolation between w and v */
switch (i)
{
case 6:
case 0: GIMP_RETURN_RGB (v, n, w);
break;
case 1: GIMP_RETURN_RGB (n, v, w);
break;
case 2: GIMP_RETURN_RGB (w, v, n);
break;
case 3: GIMP_RETURN_RGB (w, n, v);
break;
case 4: GIMP_RETURN_RGB (n, w, v);
break;
case 5: GIMP_RETURN_RGB (v, w, n);
break;
}
}
}
/* gint functions */
/**
* gimp_rgb_to_hsv_int:
* @red: The red channel value, returns the Hue channel
* @green: The green channel value, returns the Saturation channel
* @blue: The blue channel value, returns the Value channel
*
* The arguments are pointers to int representing channel values in
* the RGB colorspace, and the values pointed to are all in the range
* [0, 255].
*
* The function changes the arguments to point to the HSV value
* corresponding, with the returned values in the following
* ranges: H [0, 359], S [0, 255], V [0, 255].
**/
void
gimp_rgb_to_hsv_int (gint *red,
gint *green,
gint *blue)
{
gdouble r, g, b;
gdouble h, s, v;
gint min;
gdouble delta;
r = *red;
g = *green;
b = *blue;
if (r > g)
{
v = MAX (r, b);
min = MIN (g, b);
}
else
{
v = MAX (g, b);
min = MIN (r, b);
}
delta = v - min;
if (v == 0.0)
s = 0.0;
else
s = delta / v;
if (s == 0.0)
{
h = 0.0;
}
else
{
if (r == v)
h = 60.0 * (g - b) / delta;
else if (g == v)
h = 120 + 60.0 * (b - r) / delta;
else
h = 240 + 60.0 * (r - g) / delta;
if (h < 0.0)
h += 360.0;
if (h > 360.0)
h -= 360.0;
}
*red = ROUND (h);
*green = ROUND (s * 255.0);
*blue = ROUND (v);
/* avoid the ambiguity of returning different values for the same color */
if (*red == 360)
*red = 0;
}
/**
* gimp_hsv_to_rgb_int:
* @hue: The hue channel, returns the red channel
* @saturation: The saturation channel, returns the green channel
* @value: The value channel, returns the blue channel
*
* The arguments are pointers to int, with the values pointed to in the
* following ranges: H [0, 360], S [0, 255], V [0, 255].
*
* The function changes the arguments to point to the RGB value
* corresponding, with the returned values all in the range [0, 255].
**/
void
gimp_hsv_to_rgb_int (gint *hue,
gint *saturation,
gint *value)
{
gdouble h, s, v, h_temp;
gdouble f, p, q, t;
gint i;
if (*saturation == 0)
{
*hue = *value;
*saturation = *value;
*value = *value;
}
else
{
h = *hue;
s = *saturation / 255.0;
v = *value / 255.0;
if (h == 360)
h_temp = 0;
else
h_temp = h;
h_temp = h_temp / 60.0;
i = floor (h_temp);
f = h_temp - i;
p = v * (1.0 - s);
q = v * (1.0 - (s * f));
t = v * (1.0 - (s * (1.0 - f)));
switch (i)
{
case 0:
*hue = ROUND (v * 255.0);
*saturation = ROUND (t * 255.0);
*value = ROUND (p * 255.0);
break;
case 1:
*hue = ROUND (q * 255.0);
*saturation = ROUND (v * 255.0);
*value = ROUND (p * 255.0);
break;
case 2:
*hue = ROUND (p * 255.0);
*saturation = ROUND (v * 255.0);
*value = ROUND (t * 255.0);
break;
case 3:
*hue = ROUND (p * 255.0);
*saturation = ROUND (q * 255.0);
*value = ROUND (v * 255.0);
break;
case 4:
*hue = ROUND (t * 255.0);
*saturation = ROUND (p * 255.0);
*value = ROUND (v * 255.0);
break;
case 5:
*hue = ROUND (v * 255.0);
*saturation = ROUND (p * 255.0);
*value = ROUND (q * 255.0);
break;
}
}
}
/**
* gimp_rgb_to_hsl_int:
* @red: Red channel, returns Hue channel
* @green: Green channel, returns Lightness channel
* @blue: Blue channel, returns Saturation channel
*
* The arguments are pointers to int representing channel values in the
* RGB colorspace, and the values pointed to are all in the range [0, 255].
*
* The function changes the arguments to point to the corresponding HLS
* value with the values pointed to in the following ranges: H [0, 360],
* L [0, 255], S [0, 255].
**/
void
gimp_rgb_to_hsl_int (gint *red,
gint *green,
gint *blue)
{
gint r, g, b;
gdouble h, s, l;
gint min, max;
gint delta;
r = *red;
g = *green;
b = *blue;
if (r > g)
{
max = MAX (r, b);
min = MIN (g, b);
}
else
{
max = MAX (g, b);
min = MIN (r, b);
}
l = (max + min) / 2.0;
if (max == min)
{
s = 0.0;
h = 0.0;
}
else
{
delta = (max - min);
if (l < 128)
s = 255 * (gdouble) delta / (gdouble) (max + min);
else
s = 255 * (gdouble) delta / (gdouble) (511 - max - min);
if (r == max)
h = (g - b) / (gdouble) delta;
else if (g == max)
h = 2 + (b - r) / (gdouble) delta;
else
h = 4 + (r - g) / (gdouble) delta;
h = h * 42.5;
if (h < 0)
h += 255;
else if (h > 255)
h -= 255;
}
*red = ROUND (h);
*green = ROUND (s);
*blue = ROUND (l);
}
/**
* gimp_rgb_to_l_int:
* @red: Red channel
* @green: Green channel
* @blue: Blue channel
*
* Calculates the lightness value of an RGB triplet with the formula
* L = (max(R, G, B) + min (R, G, B)) / 2
*
* Return value: Luminance value corresponding to the input RGB value
**/
gint
gimp_rgb_to_l_int (gint red,
gint green,
gint blue)
{
gint min, max;
if (red > green)
{
max = MAX (red, blue);
min = MIN (green, blue);
}
else
{
max = MAX (green, blue);
min = MIN (red, blue);
}
return ROUND ((max + min) / 2.0);
}
static inline gint
gimp_hsl_value_int (gdouble n1,
gdouble n2,
gdouble hue)
{
gdouble value;
if (hue > 255)
hue -= 255;
else if (hue < 0)
hue += 255;
if (hue < 42.5)
value = n1 + (n2 - n1) * (hue / 42.5);
else if (hue < 127.5)
value = n2;
else if (hue < 170)
value = n1 + (n2 - n1) * ((170 - hue) / 42.5);
else
value = n1;
return ROUND (value * 255.0);
}
/**
* gimp_hsl_to_rgb_int:
* @hue: Hue channel, returns Red channel
* @saturation: Saturation channel, returns Green channel
* @lightness: Lightness channel, returns Blue channel
*
* The arguments are pointers to int, with the values pointed to in the
* following ranges: H [0, 360], L [0, 255], S [0, 255].
*
* The function changes the arguments to point to the RGB value
* corresponding, with the returned values all in the range [0, 255].
**/
void
gimp_hsl_to_rgb_int (gint *hue,
gint *saturation,
gint *lightness)
{
gdouble h, s, l;
h = *hue;
s = *saturation;
l = *lightness;
if (s == 0)
{
/* achromatic case */
*hue = l;
*lightness = l;
*saturation = l;
}
else
{
gdouble m1, m2;
if (l < 128)
m2 = (l * (255 + s)) / 65025.0;
else
m2 = (l + s - (l * s) / 255.0) / 255.0;
m1 = (l / 127.5) - m2;
/* chromatic case */
*hue = gimp_hsl_value_int (m1, m2, h + 85);
*saturation = gimp_hsl_value_int (m1, m2, h);
*lightness = gimp_hsl_value_int (m1, m2, h - 85);
}
}
/**
* gimp_rgb_to_cmyk_int:
* @red: the red channel; returns the cyan value (0-255)
* @green: the green channel; returns the magenta value (0-255)
* @blue: the blue channel; returns the yellow value (0-255)
* @pullout: the percentage of black to pull out (0-100); returns
* the black value (0-255)
*
* Does a naive conversion from RGB to CMYK colorspace. A simple
* formula that doesn't take any color-profiles into account is used.
* The amount of black pullout how can be controlled via the @pullout
* parameter. A @pullout value of 0 makes this a conversion to CMY.
* A value of 100 causes the maximum amount of black to be pulled out.
**/
void
gimp_rgb_to_cmyk_int (gint *red,
gint *green,
gint *blue,
gint *pullout)
{
gint c, m, y;
c = 255 - *red;
m = 255 - *green;
y = 255 - *blue;
if (*pullout == 0)
{
*red = c;
*green = m;
*blue = y;
}
else
{
gint k = 255;
if (c < k) k = c;
if (m < k) k = m;
if (y < k) k = y;
k = (k * CLAMP (*pullout, 0, 100)) / 100;
*red = ((c - k) << 8) / (256 - k);
*green = ((m - k) << 8) / (256 - k);
*blue = ((y - k) << 8) / (256 - k);
*pullout = k;
}
}
/**
* gimp_cmyk_to_rgb_int:
* @cyan: the cyan channel; returns the red value (0-255)
* @magenta: the magenta channel; returns the green value (0-255)
* @yellow: the yellow channel; returns the blue value (0-255)
* @black: the black channel (0-255); doesn't change
*
* Does a naive conversion from CMYK to RGB colorspace. A simple
* formula that doesn't take any color-profiles into account is used.
**/
void
gimp_cmyk_to_rgb_int (gint *cyan,
gint *magenta,
gint *yellow,
gint *black)
{
gint c, m, y, k;
c = *cyan;
m = *magenta;
y = *yellow;
k = *black;
if (k)
{
c = ((c * (256 - k)) >> 8) + k;
m = ((m * (256 - k)) >> 8) + k;
y = ((y * (256 - k)) >> 8) + k;
}
*cyan = 255 - c;
*magenta = 255 - m;
*yellow = 255 - y;
}
/**
* gimp_rgb_to_hsv4:
* @rgb: RGB triplet, rgb[0] is red channel, rgb[1] is green,
* rgb[2] is blue (0..255)
* @hue: Pointer to hue channel (0..1)
* @saturation: Pointer to saturation channel (0..1)
* @value: Pointer to value channel (0..1)
**/
void
gimp_rgb_to_hsv4 (const guchar *rgb,
gdouble *hue,
gdouble *saturation,
gdouble *value)
{
gdouble red, green, blue;
gdouble h, s, v;
gdouble min, max;
gdouble delta;
red = rgb[0] / 255.0;
green = rgb[1] / 255.0;
blue = rgb[2] / 255.0;
if (red > green)
{
max = MAX (red, blue);
min = MIN (green, blue);
}
else
{
max = MAX (green, blue);
min = MIN (red, blue);
}
v = max;
if (max != 0.0)
s = (max - min) / max;
else
s = 0.0;
if (s == 0.0)
h = 0.0;
else
{
delta = max - min;
if (delta == 0.0)
delta = 1.0;
if (red == max)
h = (green - blue) / delta;
else if (green == max)
h = 2 + (blue - red) / delta;
else
h = 4 + (red - green) / delta;
h /= 6.0;
if (h < 0.0)
h += 1.0;
else if (h > 1.0)
h -= 1.0;
}
*hue = h;
*saturation = s;
*value = v;
}
/**
* gimp_hsv_to_rgb4:
* @rgb: RGB triplet, rgb[0] is red channel, rgb[1] is green,
* rgb[2] is blue (0..255)
* @hue: Hue channel (0..1)
* @saturation: Saturation channel (0..1)
* @value: Value channel (0..1)
**/
void
gimp_hsv_to_rgb4 (guchar *rgb,
gdouble hue,
gdouble saturation,
gdouble value)
{
gdouble h, s, v;
gdouble f, p, q, t;
if (saturation == 0.0)
{
hue = value;
saturation = value;
/*value = value;*/
}
else
{
h = hue * 6.0;
s = saturation;
v = value;
if (h == 6.0)
h = 0.0;
f = h - (gint) h;
p = v * (1.0 - s);
q = v * (1.0 - s * f);
t = v * (1.0 - s * (1.0 - f));
switch ((int) h)
{
case 0:
hue = v;
saturation = t;
value = p;
break;
case 1:
hue = q;
saturation = v;
value = p;
break;
case 2:
hue = p;
saturation = v;
value = t;
break;
case 3:
hue = p;
saturation = q;
value = v;
break;
case 4:
hue = t;
saturation = p;
value = v;
break;
case 5:
hue = v;
saturation = p;
value = q;
break;
}
}
rgb[0] = ROUND (hue * 255.0);
rgb[1] = ROUND (saturation * 255.0);
rgb[2] = ROUND (value * 255.0);
}