1 /* 2 * Copyright (C) 2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <math.h> 18 #include <stdlib.h> /* For abs */ 19 #include "filters.h" 20 21 double fastevalPoly(double *poly,int n, double x){ 22 23 double f =x; 24 double sum = poly[0]+poly[1]*f; 25 int i; 26 for (i = 2; i < n; i++) { 27 f*=x; 28 sum += poly[i]*f; 29 } 30 return sum; 31 } 32 33 void rgb2hsv( unsigned char *rgb,int rgbOff,unsigned short *hsv,int hsvOff) 34 { 35 int iMin,iMax,chroma; 36 int ABITS = 4; 37 int HSCALE = 256; 38 39 int k1=255 << ABITS; 40 int k2=HSCALE << ABITS; 41 42 int ri = rgb[rgbOff+0]; 43 int gi = rgb[rgbOff+1]; 44 int bi = rgb[rgbOff+2]; 45 short rv,rs,rh; 46 47 if (ri > gi) { 48 iMax = MAX (ri, bi); 49 iMin = MIN (gi, bi); 50 } else { 51 iMax = MAX (gi, bi); 52 iMin = MIN (ri, bi); 53 } 54 55 chroma = iMax - iMin; 56 // set value 57 rv = (short)( iMax << ABITS); 58 59 // set saturation 60 if (rv == 0) 61 rs = 0; 62 else 63 rs = (short)((k1*chroma)/iMax); 64 65 // set hue 66 if (rs == 0) 67 rh = 0; 68 else { 69 if ( ri == iMax ) { 70 rh = (short)( (k2*(6*chroma+gi - bi))/(6*chroma)); 71 if (rh >= k2) rh -= k2; 72 } else if (gi == iMax) 73 rh = (short)( (k2*(2*chroma+bi - ri ))/(6*chroma)); 74 else // (bi == iMax ) 75 rh = (short)( (k2*(4*chroma+ri - gi ))/(6*chroma)); 76 } 77 hsv[hsvOff+0] = rv; 78 hsv[hsvOff+1] = rs; 79 hsv[hsvOff+2] = rh; 80 } 81 82 void hsv2rgb(unsigned short *hsv,int hsvOff, unsigned char *rgb,int rgbOff) 83 { 84 int ABITS = 4; 85 int HSCALE = 256; 86 int m; 87 int H,X,ih,is,iv; 88 int k1=255<<ABITS; 89 int k2=HSCALE<<ABITS; 90 int k3=1<<(ABITS-1); 91 int rr=0; 92 int rg=0; 93 int rb=0; 94 short cv = hsv[hsvOff+0]; 95 short cs = hsv[hsvOff+1]; 96 short ch = hsv[hsvOff+2]; 97 98 // set chroma and min component value m 99 //chroma = ( cv * cs )/k1; 100 //m = cv - chroma; 101 m = ((int)cv*(k1 - (int)cs ))/k1; 102 103 // chroma == 0 <-> cs == 0 --> m=cv 104 if (cs == 0) { 105 rb = ( rg = ( rr =( cv >> ABITS) )); 106 } else { 107 ih=(int)ch; 108 is=(int)cs; 109 iv=(int)cv; 110 111 H = (6*ih)/k2; 112 X = ((iv*is)/k2)*(k2- abs(6*ih- 2*(H>>1)*k2 - k2)) ; 113 114 // removing additional bits --> unit8 115 X=( (X+iv*(k1 - is ))/k1 + k3 ) >> ABITS; 116 m=m >> ABITS; 117 118 // ( chroma + m ) --> cv ; 119 cv=(short) (cv >> ABITS); 120 switch (H) { 121 case 0: 122 rr = cv; 123 rg = X; 124 rb = m; 125 break; 126 case 1: 127 rr = X; 128 rg = cv; 129 rb = m; 130 break; 131 case 2: 132 rr = m; 133 rg = cv; 134 rb = X; 135 break; 136 case 3: 137 rr = m; 138 rg = X; 139 rb = cv; 140 break; 141 case 4: 142 rr = X; 143 rg = m; 144 rb = cv; 145 break; 146 case 5: 147 rr = cv; 148 rg = m ; 149 rb = X; 150 break; 151 } 152 } 153 rgb[rgbOff+0] = rr; 154 rgb[rgbOff+1] = rg; 155 rgb[rgbOff+2] = rb; 156 } 157 158
