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/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
* e-hsv-utils.c - utilites for manipulating colors 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, 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 color 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 *color,
gdouble delta_h,
gdouble delta_s,
gdouble delta_v)
{
gdouble h, s, v, r, g, b;
r = color->red / 65535.0f;
g = color->green / 65535.0f;
b = color->blue / 65535.0f;
gtk_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;
}
gtk_hsv_to_rgb (h, s, v, &r, &g, &b);
color->red = r * 65535.0f;
color->green = g * 65535.0f;
color->blue = b * 65535.0f;
}
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