mutter/cogl/cogl-color.c

/*
 * Cogl
 *
 * An object oriented GL/GLES Abstraction/Utility Layer
 *
 * Copyright (C) 2008,2009 Intel Corporation.
 *
 * 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
 * Lesser 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 <http://www.gnu.org/licenses/>.
 *
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <string.h>

#include "cogl-util.h"
#include "cogl-color.h"
#include "cogl-fixed.h"
#include "cogl-color-private.h"

CoglColor *
cogl_color_new (void)
{
  return g_slice_new (CoglColor);
}

CoglColor *
cogl_color_copy (const CoglColor *color)
{
  if (G_LIKELY (color))
    return g_slice_dup (CoglColor, color);

  return NULL;
}

void
cogl_color_free (CoglColor *color)
{
  if (G_LIKELY (color))
    g_slice_free (CoglColor, color);
}

void
cogl_color_init_from_4ub (CoglColor *color,
                          uint8_t red,
                          uint8_t green,
                          uint8_t blue,
                          uint8_t alpha)
{
  _COGL_RETURN_IF_FAIL (color != NULL);

  color->red   = red;
  color->green = green;
  color->blue  = blue;
  color->alpha = alpha;
}

/* XXX: deprecated, use cogl_color_init_from_4ub */
void
cogl_color_set_from_4ub (CoglColor *dest,
                         uint8_t red,
                         uint8_t green,
                         uint8_t blue,
                         uint8_t alpha)
{
  cogl_color_init_from_4ub (dest, red, green, blue, alpha);
}

void
cogl_color_init_from_4f (CoglColor *color,
                         float red,
                         float green,
                         float blue,
                         float alpha)
{
  _COGL_RETURN_IF_FAIL (color != NULL);

  color->red   =  (red * 255);
  color->green =  (green * 255);
  color->blue  =  (blue * 255);
  color->alpha =  (alpha * 255);
}

/* XXX: deprecated, use cogl_color_init_from_4f */
void
cogl_color_set_from_4f (CoglColor *color,
                        float red,
                        float green,
                        float blue,
                        float alpha)
{
  cogl_color_init_from_4f (color, red, green, blue, alpha);
}

void
cogl_color_init_from_4fv (CoglColor *color,
                          const float *color_array)
{
  _COGL_RETURN_IF_FAIL (color != NULL);

  color->red   =  (color_array[0] * 255);
  color->green =  (color_array[1] * 255);
  color->blue  =  (color_array[2] * 255);
  color->alpha =  (color_array[3] * 255);
}

unsigned char
cogl_color_get_red_byte (const CoglColor *color)
{
  return color->red;
}

float
cogl_color_get_red_float (const CoglColor *color)
{
  return (float) color->red / 255.0;
}

float
cogl_color_get_red (const CoglColor *color)
{
  return  ((float) color->red / 255.0);
}

unsigned char
cogl_color_get_green_byte (const CoglColor *color)
{
  return color->green;
}

float
cogl_color_get_green_float (const CoglColor *color)
{
  return (float) color->green / 255.0;
}

float
cogl_color_get_green (const CoglColor *color)
{
  return  ((float) color->green / 255.0);
}

unsigned char
cogl_color_get_blue_byte (const CoglColor *color)
{
  return color->blue;
}

float
cogl_color_get_blue_float (const CoglColor *color)
{
  return (float) color->blue / 255.0;
}

float
cogl_color_get_blue (const CoglColor *color)
{
  return  ((float) color->blue / 255.0);
}

unsigned char
cogl_color_get_alpha_byte (const CoglColor *color)
{
  return color->alpha;
}

float
cogl_color_get_alpha_float (const CoglColor *color)
{
  return (float) color->alpha / 255.0;
}

float
cogl_color_get_alpha (const CoglColor *color)
{
  return  ((float) color->alpha / 255.0);
}

void
cogl_color_set_red_byte (CoglColor     *color,
                         unsigned char  red)
{
  color->red = red;
}

void
cogl_color_set_red_float (CoglColor *color,
                          float      red)
{
  color->red = red * 255.0;
}

void
cogl_color_set_red (CoglColor *color,
                    float      red)
{
  color->red = red * 255.0;
}

void
cogl_color_set_green_byte (CoglColor     *color,
                           unsigned char  green)
{
  color->green = green;
}

void
cogl_color_set_green_float (CoglColor *color,
                            float green)
{
  color->green = green * 255.0;
}

void
cogl_color_set_green (CoglColor *color,
                      float green)
{
  color->green = green * 255.0;
}

void
cogl_color_set_blue_byte (CoglColor *color,
                          unsigned char blue)
{
  color->blue = blue;
}

void
cogl_color_set_blue_float (CoglColor *color,
                           float blue)
{
  color->blue = blue * 255.0;
}

void
cogl_color_set_blue (CoglColor *color,
                     float blue)
{
  color->blue = blue * 255.0;
}

void
cogl_color_set_alpha_byte (CoglColor *color,
                           unsigned char  alpha)
{
  color->alpha = alpha;
}

void
cogl_color_set_alpha_float (CoglColor *color,
                            float alpha)
{
  color->alpha = alpha * 255.0;
}

void
cogl_color_set_alpha (CoglColor *color,
                      float alpha)
{
  color->alpha = alpha * 255.0;
}

void
cogl_color_premultiply (CoglColor *color)
{
  color->red = (color->red * color->alpha + 128) / 255;
  color->green = (color->green * color->alpha + 128) / 255;
  color->blue = (color->blue * color->alpha + 128) / 255;
}

void
cogl_color_unpremultiply (CoglColor *color)
{
  if (color->alpha != 0)
    {
      color->red = (color->red * 255) / color->alpha;
      color->green = (color->green * 255) / color->alpha;
      color->blue = (color->blue * 255) / color->alpha;
    }
}

CoglBool
cogl_color_equal (const void *v1, const void *v2)
{
  const uint32_t *c1 = v1, *c2 = v2;

  _COGL_RETURN_VAL_IF_FAIL (v1 != NULL, FALSE);
  _COGL_RETURN_VAL_IF_FAIL (v2 != NULL, FALSE);

  /* XXX: We don't compare the padding */
  return *c1 == *c2 ? TRUE : FALSE;
}

void
_cogl_color_get_rgba_4ubv (const CoglColor *color,
                           uint8_t *dest)
{
  memcpy (dest, color, 4);
}

void
cogl_color_to_hsl (const CoglColor *color,
                   float           *hue,
                   float           *saturation,
                   float           *luminance)
{
  float red, green, blue;
  float min, max, delta;
  float h, l, s;

  red   = color->red / 255.0;
  green = color->green / 255.0;
  blue  = color->blue / 255.0;

  if (red > green)
    {
      if (red > blue)
	max = red;
      else
	max = blue;

      if (green < blue)
	min = green;
      else
	min = blue;
    }
  else
    {
      if (green > blue)
	max = green;
      else
	max = blue;

      if (red < blue)
	min = red;
      else
	min = blue;
    }

  l = (max + min) / 2;
  s = 0;
  h = 0;

  if (max != min)
    {
      if (l <= 0.5)
	s = (max - min) / (max + min);
      else
	s = (max - min) / (2.0 - max - min);

      delta = max - min;

      if (red == max)
	h = (green - blue) / delta;
      else if (green == max)
	h = 2.0 + (blue - red) / delta;
      else if (blue == max)
	h = 4.0 + (red - green) / delta;

      h *= 60;

      if (h < 0)
	h += 360.0;
    }

  if (hue)
    *hue = h;

  if (luminance)
    *luminance = l;

  if (saturation)
    *saturation = s;
}

void
cogl_color_init_from_hsl (CoglColor *color,
                          float      hue,
                          float      saturation,
                          float      luminance)
{
  float tmp1, tmp2;
  float tmp3[3];
  float clr[3];
  int   i;

  hue /= 360.0;

  if (saturation == 0)
    {
      cogl_color_init_from_4f (color, luminance, luminance, luminance, 1.0f);
      return;
    }

  if (luminance <= 0.5)
    tmp2 = luminance * (1.0 + saturation);
  else
    tmp2 = luminance + saturation - (luminance * saturation);

  tmp1 = 2.0 * luminance - tmp2;

  tmp3[0] = hue + 1.0 / 3.0;
  tmp3[1] = hue;
  tmp3[2] = hue - 1.0 / 3.0;

  for (i = 0; i < 3; i++)
    {
      if (tmp3[i] < 0)
        tmp3[i] += 1.0;

      if (tmp3[i] > 1)
        tmp3[i] -= 1.0;

      if (6.0 * tmp3[i] < 1.0)
        clr[i] = tmp1 + (tmp2 - tmp1) * tmp3[i] * 6.0;
      else if (2.0 * tmp3[i] < 1.0)
        clr[i] = tmp2;
      else if (3.0 * tmp3[i] < 2.0)
        clr[i] = (tmp1 + (tmp2 - tmp1) * ((2.0 / 3.0) - tmp3[i]) * 6.0);
      else
        clr[i] = tmp1;
    }

  cogl_color_init_from_4f (color, clr[0], clr[1], clr[2], 1.0f);
}