179 lines
3.4 KiB
C
179 lines
3.4 KiB
C
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
|
|
/*
|
|
* e-hsv-utils.c - utilites for manipulating colours in HSV space
|
|
* Copyright (C) 1995-2001 Seth Nickell, Peter Mattis, Spencer Kimball and Josh MacDonald
|
|
*
|
|
* Authors:
|
|
* Seth Nickell <seth@eazel.com>
|
|
*
|
|
* This library is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Library General Public
|
|
* License, version 2, as published by the Free Software Foundation.
|
|
*
|
|
* 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., 59 Temple Place - Suite 330, Boston, MA
|
|
* 02111-1307, USA.
|
|
*/
|
|
|
|
#include <config.h>
|
|
|
|
#include "e-hsv-utils.h"
|
|
|
|
/* tweak_hsv is a really tweaky function. it modifies its first argument, which
|
|
should be the colour you want tweaked. delta_h, delta_s and delta_v specify
|
|
how much you want their respective channels modified (and in what direction).
|
|
if it can't do the specified modification, it does it in the oppositon direction */
|
|
void
|
|
e_hsv_tweak (GdkColor *colour, gdouble delta_h, gdouble delta_s, gdouble delta_v)
|
|
{
|
|
gdouble h, s, v, r, g, b;
|
|
|
|
r = colour->red / 65535.0f;
|
|
g = colour->green / 65535.0f;
|
|
b = colour->blue / 65535.0f;
|
|
|
|
e_rgb_to_hsv (r, g, b, &h, &s, &v);
|
|
|
|
if (h + delta_h < 0) {
|
|
h -= delta_h;
|
|
} else {
|
|
h += delta_h;
|
|
}
|
|
|
|
if (s + delta_s < 0) {
|
|
s -= delta_s;
|
|
} else {
|
|
s += delta_s;
|
|
}
|
|
|
|
if (v + delta_v < 0) {
|
|
v -= delta_v;
|
|
} else {
|
|
v += delta_v;
|
|
}
|
|
|
|
e_hsv_to_rgb (h, s, v, &r, &g, &b);
|
|
|
|
colour->red = r * 65535.0f;
|
|
colour->green = g * 65535.0f;
|
|
colour->blue = b * 65535.0f;
|
|
}
|
|
|
|
/* Copy n' Paste code from the GTK+ colour selector (gtkcolorsel.c) */
|
|
/* Originally lifted, I suspect, from "Foley, van Dam" */
|
|
void
|
|
e_hsv_to_rgb (gdouble h, gdouble s, gdouble v,
|
|
gdouble *r, gdouble *g, gdouble *b)
|
|
{
|
|
gint i;
|
|
gdouble f, w, q, t;
|
|
|
|
if (s == 0.0)
|
|
s = 0.000001;
|
|
|
|
if (h == -1.0)
|
|
{
|
|
*r = v;
|
|
*g = v;
|
|
*b = v;
|
|
}
|
|
else
|
|
{
|
|
if (h == 360.0)
|
|
h = 0.0;
|
|
h = h / 60.0;
|
|
i = (gint) h;
|
|
f = h - i;
|
|
w = v * (1.0 - s);
|
|
q = v * (1.0 - (s * f));
|
|
t = v * (1.0 - (s * (1.0 - f)));
|
|
|
|
switch (i)
|
|
{
|
|
case 0:
|
|
*r = v;
|
|
*g = t;
|
|
*b = w;
|
|
break;
|
|
case 1:
|
|
*r = q;
|
|
*g = v;
|
|
*b = w;
|
|
break;
|
|
case 2:
|
|
*r = w;
|
|
*g = v;
|
|
*b = t;
|
|
break;
|
|
case 3:
|
|
*r = w;
|
|
*g = q;
|
|
*b = v;
|
|
break;
|
|
case 4:
|
|
*r = t;
|
|
*g = w;
|
|
*b = v;
|
|
break;
|
|
case 5:
|
|
*r = v;
|
|
*g = w;
|
|
*b = q;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void
|
|
e_rgb_to_hsv (gdouble r, gdouble g, gdouble b,
|
|
gdouble *h, gdouble *s, gdouble *v)
|
|
{
|
|
double max, min, delta;
|
|
|
|
max = r;
|
|
if (g > max)
|
|
max = g;
|
|
if (b > max)
|
|
max = b;
|
|
|
|
min = r;
|
|
if (g < min)
|
|
min = g;
|
|
if (b < min)
|
|
min = b;
|
|
|
|
*v = max;
|
|
|
|
if (max != 0.0)
|
|
*s = (max - min) / max;
|
|
else
|
|
*s = 0.0;
|
|
|
|
if (*s == 0.0)
|
|
*h = -1.0;
|
|
else
|
|
{
|
|
delta = max - min;
|
|
|
|
if (r == max)
|
|
*h = (g - b) / delta;
|
|
else if (g == max)
|
|
*h = 2.0 + (b - r) / delta;
|
|
else if (b == max)
|
|
*h = 4.0 + (r - g) / delta;
|
|
|
|
*h = *h * 60.0;
|
|
|
|
if (*h < 0.0)
|
|
*h = *h + 360;
|
|
}
|
|
}
|
|
|
|
|