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      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 // Native function to extract histogram from image (handed down as ByteBuffer).
     18 
     19 #include "histogram.h"
     20 
     21 #include <string.h>
     22 #include <jni.h>
     23 #include <unistd.h>
     24 #include <android/log.h>
     25 
     26 #include "imgprocutil.h"
     27 
     28 inline void addPixelToHistogram(unsigned char*& pImg, int* pHist, int numBins) {
     29     int R = *(pImg++);
     30     int G = *(pImg++);
     31     int B = *(pImg++);
     32     ++pImg;
     33     int i = getIntensityFast(R, G, B);
     34     int bin = clamp(0, static_cast<int>(static_cast<float>(i * numBins) / 255.0f), numBins - 1);
     35     ++pHist[bin];
     36 }
     37 
     38 void Java_androidx_media_filterpacks_histogram_GrayHistogramFilter_extractHistogram(
     39     JNIEnv* env, jclass clazz, jobject imageBuffer, jobject maskBuffer, jobject histogramBuffer )
     40 {
     41     unsigned char* pImg = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer));
     42     int* pHist = static_cast<int*>(env->GetDirectBufferAddress(histogramBuffer));
     43     int numPixels  = env->GetDirectBufferCapacity(imageBuffer) / 4;  // 4 bytes per pixel
     44     int numBins    = env->GetDirectBufferCapacity(histogramBuffer);
     45 
     46     unsigned char* pMask = NULL;
     47     if(maskBuffer != NULL) {
     48         pMask = static_cast<unsigned char*>(env->GetDirectBufferAddress(maskBuffer));
     49     }
     50 
     51     for(int i = 0; i < numBins; ++i) pHist[i] = 0;
     52 
     53     if(pMask == NULL) {
     54         for( ; numPixels > 0; --numPixels) {
     55             addPixelToHistogram(pImg, pHist, numBins);
     56         }
     57     } else {
     58         for( ; numPixels > 0; --numPixels) {
     59             if(*pMask == 0){
     60                 pMask += 4;
     61                 pImg  += 4;  // Note that otherwise addPixelToHistogram advances pImg by 4
     62                 continue;
     63             }
     64             pMask += 4;
     65             addPixelToHistogram(pImg, pHist, numBins);
     66         }
     67     }
     68 }
     69 
     70 void Java_androidx_media_filterpacks_histogram_ChromaHistogramFilter_extractChromaHistogram(
     71     JNIEnv* env, jclass clazz, jobject imageBuffer, jobject histogramBuffer, jint hBins, jint sBins)
     72 {
     73     unsigned char* pixelIn = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer));
     74     float* histOut = static_cast<float*>(env->GetDirectBufferAddress(histogramBuffer));
     75     int numPixels  = env->GetDirectBufferCapacity(imageBuffer) / 4;  // 4 bytes per pixel
     76 
     77     for (int i = 0; i < hBins * sBins; ++i) histOut[i] = 0.0f;
     78 
     79     int h, s, v;
     80     float hScaler = hBins / 256.0f;
     81     float sScaler = sBins / 256.0f;
     82     for( ; numPixels > 0; --numPixels) {
     83       h = *(pixelIn++);
     84       s = *(pixelIn++);
     85       v = *(pixelIn++);
     86       pixelIn++;
     87 
     88       int index = static_cast<int>(s * sScaler) * hBins + static_cast<int>(h * hScaler);
     89       histOut[index] += 1.0f;
     90     }
     91 }
     92 
     93 void Java_androidx_media_filterpacks_histogram_NewChromaHistogramFilter_extractChromaHistogram(
     94     JNIEnv* env, jclass clazz, jobject imageBuffer, jobject histogramBuffer,
     95     jint hueBins, jint saturationBins, jint valueBins,
     96     jint saturationThreshold, jint valueThreshold) {
     97     unsigned char* pixelIn = static_cast<unsigned char*>(env->GetDirectBufferAddress(imageBuffer));
     98     float* histOut = static_cast<float*>(env->GetDirectBufferAddress(histogramBuffer));
     99     int numPixels  = env->GetDirectBufferCapacity(imageBuffer) / 4;  // 4 bytes per pixel
    100 
    101     // TODO: add check on the size of histOut
    102     for (int i = 0; i < (hueBins * saturationBins + valueBins); ++i) {
    103       histOut[i] = 0.0f;
    104     }
    105 
    106     for( ; numPixels > 0; --numPixels) {
    107       int h = *(pixelIn++);
    108       int s = *(pixelIn++);
    109       int v = *(pixelIn++);
    110 
    111       pixelIn++;
    112       // If a pixel that is either too dark (less than valueThreshold) or colorless
    113       // (less than saturationThreshold), if will be put in a 1-D value histogram instead.
    114 
    115       int index;
    116       if (s > saturationThreshold && v > valueThreshold) {
    117         int sIndex = s * saturationBins / 256;
    118 
    119         // Shifting hue index by 0.5 such that peaks of red, yellow, green, cyan, blue, pink
    120         // will be at the center of some bins.
    121         int hIndex = ((h * hueBins + 128) / 256) % hueBins;
    122         index = sIndex * hueBins + hIndex;
    123       } else {
    124         index =  hueBins * saturationBins + (v * valueBins / 256);
    125       }
    126       histOut[index] += 1.0f;
    127     }
    128 }
    129