/*
Copyright (C) 2001 by Andrew Zabolotny
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library 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 Library General Public
License along with this library; if not, write to the Free
Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef __RGBPIXEL_H__
#define __RGBPIXEL_H__
#ifdef HAVE_ENDIAN_H
# include <endian.h>
#endif
#ifndef __LITTLE_ENDIAN
# define __LITTLE_ENDIAN 1234
#endif
#ifndef __BIG_ENDIAN
# define __BIG_ENDIAN 4321
#endif
#if !defined __BYTE_ORDER
# if defined _HOST_BIG_ENDIAN || defined __BIG_ENDIAN__ || defined WORDS_BIGENDIAN || defined __sgi__ || defined __sgi || defined __powerpc__ || defined sparc || defined __ppc__ || defined __s390__ || defined __s390x__
# define __BYTE_ORDER __BIG_ENDIAN
# else
# define __BYTE_ORDER __LITTLE_ENDIAN
# endif
#else
# define __BYTE_ORDER __LITTLE_ENDIAN
#endif
// For optimized performance, we sometimes handle all R/G/B values simultaneously
#if __BYTE_ORDER == __BIG_ENDIAN
# define RGB_MASK 0xffffff00
#else
# define RGB_MASK 0x00ffffff
#endif
/**
* An RGB pixel. Besides R,G,B color components this structure also
* contains the Alpha channel component, which is used in images
* (that potentially have an alpha channel).
*/
struct RGBpixel
{
/// The red, green, blue and alpha components
unsigned char red, green, blue, alpha;
/// Constructor (initialize to zero, alpha to 255)
RGBpixel () /* : red(0), green(0), blue(0), alpha(255) {} */
{ *(unsigned *)this = (unsigned)~RGB_MASK; }
/// Copy constructor
RGBpixel (const RGBpixel& p)
/* : red (p.red), green (p.green), blue (p.blue), alpha (p.alpha) {} */
{ *(unsigned *)this = *(unsigned *)&p; }
/// Initialize the pixel with some R/G/B value
RGBpixel (int r, int g, int b) :
red (r), green (g), blue (b), alpha (255) {}
/// Compare with an RGBpixel (including alpha value)
bool operator == (const RGBpixel& p) const
/* { return (p.red == red) && (p.green == green) && (p.blue == blue); } */
{ return *(unsigned *)this == *(unsigned *)&p; }
/// Check if the RGBpixel is not equal to another RGBpixel (including alpha)
bool operator != (const RGBpixel& p) const
{ return !operator == (p); }
/// Compare with another RGBpixel, but don't take alpha into account
bool eq (const RGBpixel& p) const
{ return ((*(unsigned *)this) & RGB_MASK) == ((*(unsigned *)&p) & RGB_MASK); }
/// Get the pixel intensity
int Intensity ()
{ return (red + green + blue) / 3; }
/// Assign given red/green/blue values to this pixel
void Set (const int r, const int g, const int b)
{ red = r; green = g; blue = b; alpha = 255; }
/// Assign given red/green/blue/alpha values to this pixel
void Set (const int r, const int g, const int b, const int a)
{ red = r; green = g; blue = b; alpha = a; }
void Set (const RGBpixel& p)
/* : red (p.red), green (p.green), blue (p.blue), alpha (p.alpha) {} */
{ *(unsigned *)this = *(unsigned *)&p; }
};
// We don't need RGB_MASK anymore
#undef RGB_MASK
/**
* Eye sensivity to different color components, from NTSC grayscale equation.
* The coefficients are multiplied by 100 and rounded towards nearest integer,
* to facilitate integer math. The squared coefficients are also multiplied
* by 100 and rounded to nearest integer (thus 173 == 1.73, 242 == 2.42 etc).
*/
/// Red component sensivity
#define R_COEF 173
/// Green component sensivity
#define G_COEF 242
/// Blue component sensivity
#define B_COEF 107
#endif // RGBPIXEL_H__