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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <math.h>
#include "filters.h"
double fastevalPoly(double *poly,int n, double x){
double f =x;
double sum = poly[0]+poly[1]*f;
int i;
for (i = 2; i < n; i++) {
f*=x;
sum += poly[i]*f;
}
return sum;
}
void rgb2hsv( unsigned char *rgb,int rgbOff,unsigned short *hsv,int hsvOff)
{
int iMin,iMax,chroma;
int ABITS = 4;
int HSCALE = 256;
int k1=255 << ABITS;
int k2=HSCALE << ABITS;
int ri = rgb[rgbOff+0];
int gi = rgb[rgbOff+1];
int bi = rgb[rgbOff+2];
short rv,rs,rh;
if (ri > gi) {
iMax = MAX (ri, bi);
iMin = MIN (gi, bi);
} else {
iMax = MAX (gi, bi);
iMin = MIN (ri, bi);
}
chroma = iMax - iMin;
// set value
rv = (short)( iMax << ABITS);
// set saturation
if (rv == 0)
rs = 0;
else
rs = (short)((k1*chroma)/iMax);
// set hue
if (rs == 0)
rh = 0;
else {
if ( ri == iMax ) {
rh = (short)( (k2*(6*chroma+gi - bi))/(6*chroma));
if (rh >= k2) rh -= k2;
} else if (gi == iMax)
rh = (short)( (k2*(2*chroma+bi - ri ))/(6*chroma));
else // (bi == iMax )
rh = (short)( (k2*(4*chroma+ri - gi ))/(6*chroma));
}
hsv[hsvOff+0] = rv;
hsv[hsvOff+1] = rs;
hsv[hsvOff+2] = rh;
}
void hsv2rgb(unsigned short *hsv,int hsvOff, unsigned char *rgb,int rgbOff)
{
int ABITS = 4;
int HSCALE = 256;
int m;
int H,X,ih,is,iv;
int k1=255<<ABITS;
int k2=HSCALE<<ABITS;
int k3=1<<(ABITS-1);
int rr=0;
int rg=0;
int rb=0;
short cv = hsv[hsvOff+0];
short cs = hsv[hsvOff+1];
short ch = hsv[hsvOff+2];
// set chroma and min component value m
//chroma = ( cv * cs )/k1;
//m = cv - chroma;
m = ((int)cv*(k1 - (int)cs ))/k1;
// chroma == 0 <-> cs == 0 --> m=cv
if (cs == 0) {
rb = ( rg = ( rr =( cv >> ABITS) ));
} else {
ih=(int)ch;
is=(int)cs;
iv=(int)cv;
H = (6*ih)/k2;
X = ((iv*is)/k2)*(k2- abs(6*ih- 2*(H>>1)*k2 - k2)) ;
// removing additional bits --> unit8
X=( (X+iv*(k1 - is ))/k1 + k3 ) >> ABITS;
m=m >> ABITS;
// ( chroma + m ) --> cv ;
cv=(short) (cv >> ABITS);
switch (H) {
case 0:
rr = cv;
rg = X;
rb = m;
break;
case 1:
rr = X;
rg = cv;
rb = m;
break;
case 2:
rr = m;
rg = cv;
rb = X;
break;
case 3:
rr = m;
rg = X;
rb = cv;
break;
case 4:
rr = X;
rg = m;
rb = cv;
break;
case 5:
rr = cv;
rg = m ;
rb = X;
break;
}
}
rgb[rgbOff+0] = rr;
rgb[rgbOff+1] = rg;
rgb[rgbOff+2] = rb;
}
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