mutter/cogl/cogl/cogl-color.c

/*
 * Cogl
 *
 * A Low Level GPU Graphics and Utilities API
 *
 * Copyright (C) 2008,2009 Intel Corporation.
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy,
 * modify, merge, publish, distribute, sublicense, and/or sell copies
 * of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 *
 */

#include "config.h"

#include <string.h>

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

G_DEFINE_BOXED_TYPE (CoglColor,
                     cogl_color,
                     cogl_color_copy,
                     cogl_color_free)

CoglColor *
cogl_color_copy (const CoglColor *color)
{
  if (G_LIKELY (color))
    return g_memdup2 (color, sizeof (CoglColor));

  return NULL;
}

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

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

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

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

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

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

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

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

  g_return_val_if_fail (v1 != NULL, FALSE);
  g_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);
}