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// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
// Original code is licensed as follows:
/*
* Copyright 2009 ZXing authors
*
* 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.
*/
#include "../barcode.h"
#include "../BC_Binarizer.h"
#include "../BC_LuminanceSource.h"
#include "BC_CommonBitMatrix.h"
#include "BC_CommonBitArray.h"
#include "BC_GlobalHistogramBinarizer.h"
const FX_INT32 LUMINANCE_BITS = 5;
const FX_INT32 LUMINANCE_SHIFT = 8 - LUMINANCE_BITS;
const FX_INT32 LUMINANCE_BUCKETS = 1 << LUMINANCE_BITS;
CBC_GlobalHistogramBinarizer::CBC_GlobalHistogramBinarizer(CBC_LuminanceSource *source): CBC_Binarizer(source)
{
}
CBC_GlobalHistogramBinarizer::~CBC_GlobalHistogramBinarizer()
{
}
CBC_CommonBitArray *CBC_GlobalHistogramBinarizer::GetBlackRow(FX_INT32 y, CBC_CommonBitArray *row, FX_INT32 &e)
{
CBC_LuminanceSource *source = GetLuminanceSource();
FX_INT32 width = source->GetWidth();
CBC_AutoPtr<CBC_CommonBitArray> result(FX_NEW CBC_CommonBitArray(width));
InitArrays(width);
CFX_ByteArray *localLuminances = source->GetRow(y, m_luminance, e);
if (e != BCExceptionNO) {
return result.release();
}
CFX_Int32Array localBuckets;
localBuckets.Copy(m_buckets);
FX_INT32 x;
for (x = 0; x < width; x++) {
FX_INT32 pixel = (*localLuminances)[x] & 0xff;
localBuckets[pixel >> LUMINANCE_SHIFT]++;
}
FX_INT32 blackPoint = EstimateBlackPoint(localBuckets, e);
if (e != BCExceptionNO) {
return result.release();
}
FX_INT32 left = (*localLuminances)[0] & 0xff;
FX_INT32 center = (*localLuminances)[1] & 0xff;
for (x = 1; x < width - 1; x++) {
FX_INT32 right = (*localLuminances)[x + 1] & 0xff;
FX_INT32 luminance = ((center << 2) - left - right) >> 1;
if (luminance < blackPoint) {
result->Set(x);
}
left = center;
center = right;
}
return result.release();
}
CBC_CommonBitMatrix *CBC_GlobalHistogramBinarizer::GetBlackMatrix(FX_INT32 &e)
{
CBC_LuminanceSource *source = GetLuminanceSource();
FX_INT32 width = source->GetWidth();
FX_INT32 height = source->GetHeight();
CBC_CommonBitMatrix *BitMatrixTemp = FX_NEW CBC_CommonBitMatrix();
BitMatrixTemp->Init(width, height);
CBC_AutoPtr<CBC_CommonBitMatrix> matrix(BitMatrixTemp);
InitArrays(width);
CFX_Int32Array localBuckets;
localBuckets.Copy(m_buckets);
FX_INT32 y;
for (y = 1; y < 5; y++) {
FX_INT32 row = height * y / 5;
CFX_ByteArray *localLuminances = source->GetRow(row, m_luminance, e);
BC_EXCEPTION_CHECK_ReturnValue(e, NULL);
FX_INT32 right = (width << 2) / 5;
FX_INT32 x;
for (x = width / 5; x < right; x++) {
FX_INT32 pixel = (*localLuminances)[x] & 0xff;
localBuckets[pixel >> LUMINANCE_SHIFT]++;
}
}
FX_INT32 blackPoint = EstimateBlackPoint(localBuckets, e);
BC_EXCEPTION_CHECK_ReturnValue(e, NULL);
CBC_AutoPtr<CFX_ByteArray> localLuminances(source->GetMatrix());
for (y = 0; y < height; y++) {
FX_INT32 offset = y * width;
for (FX_INT32 x = 0; x < width; x++) {
FX_INT32 pixel = (*localLuminances)[offset + x] & 0xff;
if (pixel < blackPoint) {
matrix->Set(x, y);
}
}
}
return matrix.release();
}
void CBC_GlobalHistogramBinarizer::InitArrays(FX_INT32 luminanceSize)
{
if(m_luminance.GetSize() < luminanceSize) {
m_luminance.SetSize(luminanceSize);
}
if(m_buckets.GetSize() <= 0) {
m_buckets.SetSize(LUMINANCE_BUCKETS);
} else {
FX_INT32 x;
for(x = 0; x < LUMINANCE_BUCKETS; x++) {
m_buckets[x] = 0;
}
}
}
FX_INT32 CBC_GlobalHistogramBinarizer::EstimateBlackPoint(CFX_Int32Array &buckets, FX_INT32 &e)
{
FX_INT32 numBuckets = buckets.GetSize();
FX_INT32 maxBucketCount = 0;
FX_INT32 firstPeak = 0;
FX_INT32 firstPeakSize = 0;
FX_INT32 x;
for (x = 0; x < numBuckets; x++) {
if (buckets[x] > firstPeakSize) {
firstPeak = x;
firstPeakSize = buckets[x];
}
if (buckets[x] > maxBucketCount) {
maxBucketCount = buckets[x];
}
}
FX_INT32 secondPeak = 0;
FX_INT32 secondPeakScore = 0;
for (x = 0; x < numBuckets; x++) {
FX_INT32 distanceToBiggest = x - firstPeak;
FX_INT32 score = buckets[x] * distanceToBiggest * distanceToBiggest;
if (score > secondPeakScore) {
secondPeak = x;
secondPeakScore = score;
}
}
if (firstPeak > secondPeak) {
FX_INT32 temp = firstPeak;
firstPeak = secondPeak;
secondPeak = temp;
}
if (secondPeak - firstPeak <= numBuckets >> 4) {
e = BCExceptionRead;
return 0;
}
FX_INT32 bestValley = secondPeak - 1;
FX_INT32 bestValleyScore = -1;
for (x = secondPeak - 1; x > firstPeak; x--) {
FX_INT32 fromFirst = x - firstPeak;
FX_INT32 score = fromFirst * fromFirst * (secondPeak - x) * (maxBucketCount - buckets[x]);
if (score > bestValleyScore) {
bestValley = x;
bestValleyScore = score;
}
}
return bestValley << LUMINANCE_SHIFT;
}
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