53 lines
1.8 KiB
C++
53 lines
1.8 KiB
C++
/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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// Native function to extract brightness from image (handed down as ByteBuffer).
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#include "brightness.h"
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#include <math.h>
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#include <string.h>
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#include <jni.h>
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#include <unistd.h>
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#include <android/log.h>
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jfloat
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Java_androidx_media_filterfw_samples_simplecamera_AvgBrightnessFilter_brightnessOperator(
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JNIEnv* env, jclass clazz, jint width, jint height, jobject imageBuffer) {
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if (imageBuffer == 0) {
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return 0.0f;
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}
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float pixelTotals[] = { 0.0f, 0.0f, 0.0f };
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const int numPixels = width * height;
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unsigned char* srcPtr = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer));
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for (int i = 0; i < numPixels; i++) {
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pixelTotals[0] += *(srcPtr + 4 * i);
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pixelTotals[1] += *(srcPtr + 4 * i + 1);
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pixelTotals[2] += *(srcPtr + 4 * i + 2);
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}
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float avgPixels[] = { 0.0f, 0.0f, 0.0f };
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avgPixels[0] = pixelTotals[0] / numPixels;
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avgPixels[1] = pixelTotals[1] / numPixels;
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avgPixels[2] = pixelTotals[2] / numPixels;
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float returnValue = sqrt(0.241f * avgPixels[0] * avgPixels[0] +
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0.691f * avgPixels[1] * avgPixels[1] +
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0.068f * avgPixels[2] * avgPixels[2]);
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return returnValue / 255;
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}
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