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 "filters.h"
18
19void estmateWhite(unsigned char *src, int len, int *wr, int *wb, int *wg){
20
21    int STEP = 4;
22    int RANGE = 256;
23    int *histR = (int *) malloc(256*sizeof(int));
24    int *histG = (int *) malloc(256*sizeof(int));
25    int *histB = (int *) malloc(256*sizeof(int));
26    int i;
27    for (i = 0; i < 255; i++) {
28        histR[i] = histG[i] = histB[i] =0;
29    }
30
31    for (i = 0; i < len; i+=STEP) {
32        histR[(src[RED])]++;
33        histG[(src[GREEN])]++;
34        histB[(src[BLUE])]++;
35    }
36    int min_r = -1, min_g = -1,min_b = -1;
37    int max_r = 0, max_g = 0,max_b = 0;
38    int sum_r = 0,sum_g=0,sum_b=0;
39
40    for (i = 1; i < RANGE-1; i++) {
41        int r = histR[i];
42        int g = histG[i];
43        int b = histB[i];
44        sum_r += r;
45        sum_g += g;
46        sum_b += b;
47
48        if (r>0){
49            if (min_r < 0) min_r = i;
50            max_r = i;
51        }
52        if (g>0){
53            if (min_g < 0) min_g = i;
54            max_g = i;
55        }
56        if (b>0){
57            if (min_b < 0) min_b = i;
58            max_b = i;
59        }
60    }
61
62    int sum15r = 0,sum15g=0,sum15b=0;
63    int count15r = 0,count15g=0,count15b=0;
64    int tmp_r = 0,tmp_g=0,tmp_b=0;
65
66    for (i = RANGE-2; i >0; i--) {
67        int r = histR[i];
68        int g = histG[i];
69        int b = histB[i];
70        tmp_r += r;
71        tmp_g += g;
72        tmp_b += b;
73
74        if ((tmp_r > sum_r/20) && (tmp_r < sum_r/5)) {
75            sum15r += r*i;
76            count15r += r;
77        }
78        if ((tmp_g > sum_g/20) && (tmp_g < sum_g/5)) {
79            sum15g += g*i;
80            count15g += g;
81        }
82        if ((tmp_b > sum_b/20) && (tmp_b < sum_b/5)) {
83            sum15b += b*i;
84            count15b += b;
85        }
86
87    }
88    free(histR);
89    free(histG);
90    free(histB);
91
92    if ((count15r>0) && (count15g>0) && (count15b>0) ){
93        *wr = sum15r/count15r;
94        *wb = sum15g/count15g;
95        *wg = sum15b/count15b;
96    }else {
97        *wg  = *wb = *wr=255;
98    }
99}
100
101void estmateWhiteBox(unsigned char *src, int iw, int ih, int x,int y, int *wr, int *wb, int *wg){
102    int r;
103    int g;
104    int b;
105    int sum;
106    int xp,yp;
107    int bounds = 5;
108    if (x<0) x = bounds;
109    if (y<0) y = bounds;
110    if (x>=(iw-bounds)) x = (iw-bounds-1);
111    if (y>=(ih-bounds)) y = (ih-bounds-1);
112    int startx = x - bounds;
113    int starty = y - bounds;
114    int endx = x + bounds;
115    int endy = y + bounds;
116
117    for(yp= starty;yp<endy;yp++) {
118        for(xp= startx;xp<endx;xp++) {
119            int i = 4*(xp+yp*iw);
120            r += src[RED];
121            g += src[GREEN];
122            b += src[BLUE];
123            sum++;
124        }
125    }
126    *wr = r/sum;
127    *wg = g/sum;
128    *wb = b/sum;
129}
130
131void JNIFUNCF(ImageFilterWBalance, nativeApplyFilter, jobject bitmap, jint width, jint height, int locX,int locY)
132{
133    char* destination = 0;
134    AndroidBitmap_lockPixels(env, bitmap, (void**) &destination);
135    int i;
136    int len = width * height * 4;
137    unsigned char * rgb = (unsigned char * )destination;
138    int wr;
139    int wg;
140    int wb;
141
142    if (locX==-1)
143        estmateWhite(rgb,len,&wr,&wg,&wb);
144    else
145        estmateWhiteBox(rgb, width, height,locX,locY,&wr,&wg,&wb);
146
147    int min = MIN(wr, MIN(wg, wb));
148    int max = MAX(wr, MAX(wg, wb));
149    float avg = (min+max)/2.f;
150    float scaleR =  avg/wr;
151    float scaleG =  avg/wg;
152    float scaleB =  avg/wb;
153
154    for (i = 0; i < len; i+=4)
155    {
156        int r = rgb[RED];
157        int g = rgb[GREEN];
158        int b = rgb[BLUE];
159
160        float Rc =  r*scaleR;
161        float Gc =  g*scaleG;
162        float Bc =  b*scaleB;
163
164        rgb[RED]   = clamp(Rc);
165        rgb[GREEN] = clamp(Gc);
166        rgb[BLUE]  = clamp(Bc);
167    }
168    AndroidBitmap_unlockPixels(env, bitmap);
169}
170