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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2006 Antoine Cellerier <dionoea -at- videolan -dot- org>
*
* All files in this archive are subject to the GNU General Public License.
* See the file COPYING in the source tree root for full license agreement.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "rgb_hsv.h"
/***********************************************************************
* Colorspace transformations
***********************************************************************
* r, g and b range from 0 to 255
* h ranges from 0 to 3599 (which in fact means 0.0 to 359.9).
* 360 is the same as 0 (it loops)
* s and v range from 0 to 255 (which in fact means 0.00 to 1.00)
***********************************************************************/
void rgb2hsv( int r, int g, int b, int *h, int *s, int *v )
{
int max;
int min;
max = r > g ? r : g;
if( b > max ) max = b;
min = r < g ? r : g;
if( b < min ) min = b;
if( max == 0 )
{
*v = 0;
*h = 0; *s = 0; /* Random since it's black */
return;
}
else if( max == min )
{
*h = 0; /* Random since it's gray */
}
else if( max == r && g >= b )
{
*h = ( 10 * 60 * ( g - b )/( max - min ) );
}
else if( max == r && g < b )
{
*h = ( 10 * ( 60 * ( g - b )/( max - min ) + 360 ));
}
else if( max == g )
{
*h = ( 10 * ( 60 * ( b - r )/( max - min ) + 120 ));
}
else// if( max == b )
{
*h = ( 10 * ( 60 * ( r - g )/( max - min ) + 240 ));
}
/* Just in case ? */
while( *h < 0 ) *h += 3600;
while( *h >= 3600 ) *h-= 3600;
*s = (( max - min )*255)/max;
*v = max;
}
void hsv2rgb( int h, int s, int v, int *r, int *g, int *b )
{
int f, p, q, t;
while( h < 0 ) h += 3600;
while( h >= 3600 ) h-= 3600;
f = h%600;
p = ( v * ( 255 - s ) ) / ( 255 );
q = ( v * ( 600*255 - f*s ) ) / ( 255 * 600 );
t = ( v * ( 600*255 - ( 600 - f ) * s ) ) / ( 255 * 600 );
if( s == 0 ) /* gray */
{
*r = v;
*g = *r;
*b = *r;
return;
}
switch( h/600 )
{
case 0:
*r = v;
*g = t;
*b = p;
break;
case 1:
*r = q;
*g = v;
*b = p;
break;
case 2:
*r = p;
*g = v;
*b = t;
break;
case 3:
*r = p;
*g = q;
*b = v;
break;
case 4:
*r = t;
*g = p;
*b = v;
break;
case 5:
*r = v;
*g = p;
*b = q;
break;
}
}
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