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