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Finishing of optimalization

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Jakub Melka
2020-06-06 16:30:06 +02:00
parent 8a97f20ce9
commit 5cb9bdee26
5 changed files with 151 additions and 17 deletions
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46
PdfForQtLib/sources/pdfoptimizer.cpp
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@ -22,6 +22,7 @@
#include "pdfutils.h"
#include "pdfconstants.h"
#include "pdfdocumentbuilder.h"
#include "pdfstreamfilters.h"
namespace pdf
{
@ -502,6 +503,51 @@ bool PDFOptimizer::performShrinkObjectStorage()
bool PDFOptimizer::performRecompressFlateStreams()
{
std::atomic<PDFInteger> bytesSaved = 0;
PDFObjectStorage::PDFObjects objects = m_storage.getObjects();
auto processEntry = [this, &bytesSaved](PDFObjectStorage::Entry& entry)
{
if (entry.object.isStream())
{
const PDFStream* stream = entry.object.getStream();
const PDFDictionary* dictionary = stream->getDictionary();
if (dictionary->hasKey("F"))
{
// External file stream, we do not recompress it
return;
}
PDFStreamFilterStorage::StreamFilters streamFilters = PDFStreamFilterStorage::getStreamFilters(stream, std::bind(QOverload<const PDFObject&>::of(&PDFObjectStorage::getObject), &m_storage, std::placeholders::_1));
if (streamFilters.filterObjects.empty())
{
// No filters
return;
}
const PDFStreamFilter* streamFilter = streamFilters.filterObjects.front();
if (dynamic_cast<const PDFFlateDecodeFilter*>(streamFilter))
{
// Try to recompress. If we end with less data, then we use recompressed stream
QByteArray recompressedData = PDFFlateDecodeFilter::recompress(*stream->getContent());
const PDFInteger currentBytesSaved = stream->getContent()->size() - recompressedData.size();
if (currentBytesSaved > 0)
{
bytesSaved += currentBytesSaved;
PDFDictionary updatedDictionary = *dictionary;
updatedDictionary.setEntry("Length", PDFObject::createInteger(recompressedData.size()));
entry.object = PDFObject::createStream(std::make_shared<PDFStream>(qMove(updatedDictionary), qMove(recompressedData)));
}
}
}
};
PDFExecutionPolicy::execute(PDFExecutionPolicy::Scope::Unknown, objects.begin(), objects.end(), processEntry);
m_storage.setObjects(qMove(objects));
emit optimizationProgress(tr("Bytes saved by recompressing stream: %1").arg(bytesSaved));
return false;
}