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//------------------------------------------------------------------------
// HSV (Hue, Saturation, Value)
//------------------------------------------------------------------------
//
// Z C++ Lib (C) 2001-2002 Andrew Apted
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program 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 General Public License for more details.
//
//------------------------------------------------------------------------
#ifndef __Z_HSV_H__
#define __Z_HSV_H__
#include "z_types.h"
#include "z_rgb.h"
struct HsvCol
{
/* sealed, value semantics.
*
* h is hue (angle from 0 to 360).
* s is saturation (0 to 255).
* v is value (0 to 255).
*/
int h, s, v;
HsvCol() : h(60), s(255), v(255) { }
// default color is purple !
HsvCol(int _h, int _s, int _v) : h(_h), s(_s), v(_v) { }
HsvCol(const PackCol& rgb);
// conversion from RGB.
PackCol ToRGB() const;
// conversion to RGB.
bool operator== (const HsvCol& other) const;
bool operator!= (const HsvCol& other) const;
// standard equality operators.
int Dist(const HsvCol& other) const;
// compute distance between the two colors. Returns 0 for an exact
// match, and higher values for bigger differences.
/* some useful constants */
static const HsvCol BLACK;
static const HsvCol BLUE;
static const HsvCol CYAN;
static const HsvCol GREEN;
static const HsvCol RED;
static const HsvCol PURPLE;
static const HsvCol YELLOW;
static const HsvCol WHITE;
static const HsvCol D_GREY;
static const HsvCol M_GREY;
static const HsvCol L_GREY;
static const HsvCol ORANGE;
#ifndef NDEBUG
static void TestHSV(const HsvCol& hsv, const char *name);
static void TestCols();
#endif
};
inline bool HsvCol::operator== (const HsvCol& other) const
{
return h == other.h && s == other.s && v == other.v;
}
inline bool HsvCol::operator!= (const HsvCol& other) const
{
return ! operator== (other);
}
inline int HsvCol::Dist(const HsvCol& other) const
{
int dh = int(h) - int(other.h);
int ds = int(s) - int(other.s);
int dv = int(v) - int(other.v);
if (dh > 180)
dh -= 360;
else if (dh < -180)
dh += 360;
/* we give the hue some advantage over saturation/value.
*/
return dh * dh * 2 + ds * ds + dv * dv;
}
#endif /* __Z_HSV_H__ */
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