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/*
* 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 brightness from image (handed down as ByteBuffer).
#include "brightness.h"
#include <math.h>
#include <string.h>
#include <jni.h>
#include <unistd.h>
#include <android/log.h>
jfloat
Java_androidx_media_filterfw_samples_simplecamera_AvgBrightnessFilter_brightnessOperator(
JNIEnv* env, jclass clazz, jint width, jint height, jobject imageBuffer) {
if (imageBuffer == 0) {
return 0.0f;
}
float pixelTotals[] = { 0.0f, 0.0f, 0.0f };
const int numPixels = width * height;
unsigned char* srcPtr = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer));
for (int i = 0; i < numPixels; i++) {
pixelTotals[0] += *(srcPtr + 4 * i);
pixelTotals[1] += *(srcPtr + 4 * i + 1);
pixelTotals[2] += *(srcPtr + 4 * i + 2);
}
float avgPixels[] = { 0.0f, 0.0f, 0.0f };
avgPixels[0] = pixelTotals[0] / numPixels;
avgPixels[1] = pixelTotals[1] / numPixels;
avgPixels[2] = pixelTotals[2] / numPixels;
float returnValue = sqrt(0.241f * avgPixels[0] * avgPixels[0] +
0.691f * avgPixels[1] * avgPixels[1] +
0.068f * avgPixels[2] * avgPixels[2]);
return returnValue / 255;
}
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