gimp/libgimpcolor/gimprgb.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 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 "gimprgb.h"


/**
 * SECTION: gimprgb
 * @title: GimpRGB
 * @short_description: Definitions and Functions relating to RGB colors.
 *
 * Definitions and Functions relating to RGB colors.
 **/


/*
 * GIMP_TYPE_RGB
 */

static GimpRGB * gimp_rgb_copy (const GimpRGB *rgb);


G_DEFINE_BOXED_TYPE (GimpRGB, gimp_rgb, gimp_rgb_copy, g_free)

static GimpRGB *
gimp_rgb_copy (const GimpRGB *rgb)
{
  return g_memdup2 (rgb, sizeof (GimpRGB));
}


/*  RGB functions  */

/**
 * gimp_rgb_set:
 * @rgb:   a #GimpRGB struct
 * @red:   the red component
 * @green: the green component
 * @blue:  the blue component
 *
 * 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: the alpha component
 *
 * 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:   the red component
 * @green: the green component
 * @blue:  the blue component
 *
 * 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;
}

/**
 * gimp_rgb_get_uchar:
 * @rgb: a #GimpRGB struct
 * @red: (out) (optional): Location for red component, or %NULL
 * @green: (out) (optional): Location for green component, or %NULL
 * @blue: (out) (optional): Location for blue component, or %NULL
 *
 * Writes the red, green, blue and alpha components of @rgb to the
 * color components @red, @green and @blue.
 */
void
gimp_rgb_get_uchar (const GimpRGB *rgb,
                    guchar        *red,
                    guchar        *green,
                    guchar        *blue)
{
  g_return_if_fail (rgb != NULL);

  if (red)   *red   = ROUND (CLAMP (rgb->r, 0.0, 1.0) * 255.0);
  if (green) *green = ROUND (CLAMP (rgb->g, 0.0, 1.0) * 255.0);
  if (blue)  *blue  = ROUND (CLAMP (rgb->b, 0.0, 1.0) * 255.0);
}

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_multiply (GimpRGB *rgb,
                   gdouble  factor)
{
  g_return_if_fail (rgb != NULL);

  rgb->r *= factor;
  rgb->g *= factor;
  rgb->b *= factor;
}

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;
  else
    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;
  else
    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);
}

/**
 * gimp_rgb_luminance:
 * @rgb: a #GimpRGB struct
 *
 * Returns: the luminous intensity of the range from 0.0 to 1.0.
 *
 * Since: 2.4
 **/
gdouble
gimp_rgb_luminance (const GimpRGB *rgb)
{
  gdouble luminance;

  g_return_val_if_fail (rgb != NULL, 0.0);

  luminance = GIMP_RGB_LUMINANCE (rgb->r, rgb->g, rgb->b);

  return CLAMP (luminance, 0.0, 1.0);
}

/**
 * gimp_rgb_luminance_uchar:
 * @rgb: a #GimpRGB struct
 *
 * Returns: the luminous intensity in the range from 0 to 255.
 *
 * Since: 2.4
 **/
guchar
gimp_rgb_luminance_uchar (const GimpRGB *rgb)
{
  g_return_val_if_fail (rgb != NULL, 0);

  return ROUND (gimp_rgb_luminance (rgb) * 255.0);
}

void
gimp_rgb_composite (GimpRGB              *color1,
                    const GimpRGB        *color2,
                    GimpRGBCompositeMode  mode)
{
  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
        {
          gdouble 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)
        {
          gdouble 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:   the red component
 * @green: the green component
 * @blue:  the blue component
 * @alpha: the alpha component
 *
 * 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:   the red component
 * @green: the green component
 * @blue:  the blue component
 * @alpha: the alpha component
 *
 * Sets the red, green, blue and alpha components of @rgba 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;
}

/**
 * gimp_rgba_get_uchar:
 * @rgba:  a #GimpRGB struct
 * @red: (out) (optional): Location for the red component
 * @green: (out) (optional): Location for the green component
 * @blue: (out) (optional): Location for the blue component
 * @alpha: (out) (optional): Location for the alpha component
 *
 * Gets the 8bit red, green, blue and alpha components of @rgba.
 **/
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_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));
}