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 20 unsigned char clamp(int c) 21 { 22 int N = 255; 23 c &= ~(c >> 31); 24 c -= N; 25 c &= (c >> 31); 26 c += N; 27 return (unsigned char) c; 28 } 29 30 int clampMax(int c,int max) 31 { 32 c &= ~(c >> 31); 33 c -= max; 34 c &= (c >> 31); 35 c += max; 36 return c; 37 } 38 39 void JNIFUNCF(ImageFilterContrast, nativeApplyFilter, jobject bitmap, jint width, jint height, jfloat bright) 40 { 41 char* destination = 0; 42 AndroidBitmap_lockPixels(env, bitmap, (void**) &destination); 43 unsigned char * rgb = (unsigned char * )destination; 44 int i; 45 int len = width * height * 4; 46 float m = (float)pow(2, bright/100.); 47 float c = 127-m*127; 48 49 for (i = 0; i < len; i+=4) { 50 rgb[RED] = clamp((int)(m*rgb[RED]+c)); 51 rgb[GREEN] = clamp((int)(m*rgb[GREEN]+c)); 52 rgb[BLUE] = clamp((int)(m*rgb[BLUE]+c)); 53 } 54 AndroidBitmap_unlockPixels(env, bitmap); 55 } 56 57
