blob: 222f738a3a1dd6eba96e895db16c8c40cfa675b8 [file] [log] [blame]
/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// Native function to extract contrast ratio from image (handed down as ByteBuffer).
#include "contrast.h"
#include <math.h>
#include <string.h>
#include <jni.h>
#include <unistd.h>
#include <android/log.h>
jfloat
Java_androidx_media_filterfw_samples_simplecamera_ContrastRatioFilter_contrastOperator(
JNIEnv* env, jclass clazz, jint width, jint height, jobject imageBuffer) {
if (imageBuffer == 0) {
return 0.0f;
}
float total = 0;
const int numPixels = width * height;
unsigned char* srcPtr = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer));
float* lumArray = new float[numPixels];
for (int i = 0; i < numPixels; i++) {
lumArray[i] = (0.2126f * *(srcPtr + 4 * i) + 0.7152f *
*(srcPtr + 4 * i + 1) + 0.0722f * *(srcPtr + 4 * i + 2)) / 255;
total += lumArray[i];
}
const float avg = total / numPixels;
float sum = 0;
for (int i = 0; i < numPixels; i++) {
sum += (lumArray[i] - avg) * (lumArray[i] - avg);
}
delete[] lumArray;
return ((float) sqrt(sum / numPixels));
}