1 /* 2 * Copyright (C) 2013 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 // Native function to extract exposure from image (handed down as ByteBuffer). 18 19 #include "exposure.h" 20 21 #include <math.h> 22 #include <string.h> 23 #include <jni.h> 24 #include <unistd.h> 25 #include <android/log.h> 26 27 28 jfloat 29 Java_androidx_media_filterfw_samples_simplecamera_ExposureFilter_overExposureOperator( 30 JNIEnv* env, jclass clazz, jint width, jint height, jobject imageBuffer) { 31 if (imageBuffer == 0) { 32 return 0.0f; 33 } 34 const int numPixels = width * height; 35 unsigned char* srcPtr = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer)); 36 int output = 0; 37 float tempLuminance = 0.0f; 38 39 for (int i = 0; i < numPixels; i++) { 40 tempLuminance = (0.2126f * *(srcPtr + 4 * i) + 41 0.7152f * *(srcPtr + 4 * i + 1) + 42 0.0722f * *(srcPtr + 4 * i + 2)); 43 if (tempLuminance + 5 >= 255) { 44 output++; 45 } 46 } 47 return (static_cast<float>(output)) / numPixels; 48 } 49 50 jfloat 51 Java_androidx_media_filterfw_samples_simplecamera_ExposureFilter_underExposureOperator( 52 JNIEnv* env, jclass clazz, jint width, jint height, jobject imageBuffer) { 53 if (imageBuffer == 0) { 54 return 0.0f; 55 } 56 const int numPixels = width * height; 57 unsigned char* srcPtr = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer)); 58 int output = 0; 59 float tempLuminance = 0.0f; 60 61 for (int i = 0; i < numPixels; i++) { 62 tempLuminance = (0.2126f * *(srcPtr + 4 * i) + 63 0.7152f * *(srcPtr + 4 * i + 1) + 64 0.0722f * *(srcPtr + 4 * i + 2)); 65 if (tempLuminance - 5 <= 0) { 66 output++; 67 } 68 } 69 return (static_cast<float>(output)) / numPixels; 70 } 71