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 "filters.h"
19
20void JNIFUNCF(ImageFilterBwFilter, nativeApplyFilter, jobject bitmap, jint width, jint height, jint rw, jint gw, jint bw)
21{
22    char* destination = 0;
23    AndroidBitmap_lockPixels(env, bitmap, (void**) &destination);
24    unsigned char * rgb = (unsigned char * )destination;
25    float sr = rw;
26    float sg = gw;
27    float sb = bw;
28
29    float min = MIN(sg,sb);
30    min = MIN(sr,min);
31    float max =  MAX(sg,sb);
32    max = MAX(sr,max);
33    float avg = (min+max)/2;
34    sb /= avg;
35    sg /= avg;
36    sr /= avg;
37    int i;
38    int len = width * height * 4;
39
40    for (i = 0; i < len; i+=4)
41    {
42        float r = sr *rgb[RED];
43        float g = sg *rgb[GREEN];
44        float b = sb *rgb[BLUE];
45        min = MIN(g,b);
46        min = MIN(r,min);
47        max = MAX(g,b);
48        max = MAX(r,max);
49        avg =(min+max)/2;
50        rgb[RED]   = CLAMP(avg);
51        rgb[GREEN] = rgb[RED];
52        rgb[BLUE]  = rgb[RED];
53    }
54    AndroidBitmap_unlockPixels(env, bitmap);
55}
56