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// HSBColor.h
// this file is part of Context Free
// ---------------------
// Copyright (C) 2005-2008 Mark Lentczner - markl@glyphic.com
// Copyright (C) 2005-2008 John Horigan - john@glyphic.com
//
// 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.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// John Horigan can be contacted at john@glyphic.com or at
// John Horigan, 1209 Villa St., Mountain View, CA 94041-1123, USA
//
// Mark Lentczner can be contacted at markl@glyphic.com or at
// Mark Lentczner, 1209 Villa St., Mountain View, CA 94041-1123, USA
//
//
#ifndef __HSBCOLOR_H_
#define __HSBCOLOR_H_
namespace agg {
struct rgba;
};
#define EQUALITY_THRESHOLD 0.00001
#include <math.h>
struct HSBColor
{
enum AssignmentTypes { HueTarget = 1,
SaturationTarget = 2,
BrightnessTarget = 4,
AlphaTarget = 8
};
HSBColor() : h(0), s(0), b(0), a(0), mUseTarget(0) {};
HSBColor(double hue, double sat, double bri, double alpha)
: h(hue), s(sat), b(bri), a(alpha), mUseTarget(0) {};
HSBColor(const agg::rgba&);
void adjustWith(const HSBColor& adj, const HSBColor& target = HSBColor(0,0,0,0));
void getRGBA(agg::rgba& c) const;
bool operator!=(const HSBColor& hsb) const {
return h != hsb.h || s != hsb.s || b != hsb.b || a != hsb.s;
}
double h, s, b, a;
int mUseTarget;
static inline double adjust(const double& base, const double& adjustment,
int useTarget = 0, const double& target = 0.0);
static inline double adjustHue(const double& base, const double& adjustment,
int useTarget = 0, const double& target = 0.0);
static double delta(double to, double from, unsigned int steps = 1);
static double deltaHue(double to, double from, unsigned int steps = 1);
};
inline double
HSBColor::adjust(const double& base, const double& adjustment,
int useTarget, const double& target)
{
if (adjustment == 0.0)
return base;
if (useTarget) {
// If we are really close to the target then don't change, even if
// the adjustment is negative (which way would we go?)
if (adjustment > 0 && fabs(base - target) < EQUALITY_THRESHOLD)
return base;
// Otherwise move away from or toward the target
double edge = base < target ? 0 : 1;
if (adjustment < 0)
return base + ( base - edge) * adjustment;
else
return base + (target - base) * adjustment;
} else {
// Move toward 0 or toward 1
if (adjustment < 0)
return base + base * adjustment;
else
return base + (1 - base) * adjustment;
}
}
inline double
HSBColor::adjustHue(const double& base, const double& adjustment,
int useTarget, const double& target)
{
if (adjustment == 0.0)
return base;
double h;
if (useTarget & HueTarget) {
// decrease or increase toward target. If the target hue does not
// cooperate by being smaller (or larger) than the current hue then
// add/subtract 360 to make it so. This only works if all hues are
// within the interval [0,360).
double t = target;
if (adjustment < 0) {
if (t > base) t -= 360;
h = base + (base - t) * adjustment;
} else {
if (t < base) t += 360;
h = base + (t - base) * adjustment;
}
} else {
h = base + adjustment;
}
// Normalize result to the interval [0,360)
return h < 0.0 ? fmod(h + 360.0, 360.0) : fmod(h, 360.0);
}
#endif
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