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DocDiff application: LCS algorithm

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This commit is contained in:
Jakub Melka
2021-09-09 18:28:55 +02:00
parent b2a9342047
commit 69c988c756
6 changed files with 303 additions and 26 deletions
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71
Pdf4QtLib/sources/pdfdiff.cpp
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@ -23,6 +23,7 @@
#include "pdfcms.h"
#include "pdfcompiler.h"
#include "pdfconstants.h"
#include "pdfalgorithmlcs.h"
#include <QtConcurrent/QtConcurrent>
@ -34,7 +35,7 @@ PDFDiff::PDFDiff(QObject* parent) :
m_progress(nullptr),
m_leftDocument(nullptr),
m_rightDocument(nullptr),
m_options(Asynchronous),
m_options(Asynchronous | PC_Text | PC_VectorGraphics | PC_Images),
m_epsilon(0.0001),
m_cancelled(false)
{
@ -173,6 +174,7 @@ void PDFDiff::stepProgress()
struct PDFDiffPageContext
{
PDFInteger pageIndex = 0;
std::array<uint8_t, 64> pageHash = { };
PDFPrecompiledPage::GraphicPieceInfos graphicPieces;
};
@ -208,8 +210,11 @@ void PDFDiff::performSteps(const std::vector<PDFInteger>& leftPages, const std::
PDFRenderer renderer(m_leftDocument, &fontCache, cms.data(), &optionalContentActivity, features, pdf::PDFMeshQualitySettings());
renderer.compile(&compiledPage, context.pageIndex);
PDFReal epsilon = calculateEpsilonForPage(m_leftDocument->getCatalog()->getPage(context.pageIndex));
context.graphicPieces = compiledPage.calculateGraphicPieceInfos(epsilon);
auto page = m_leftDocument->getCatalog()->getPage(context.pageIndex);
PDFReal epsilon = calculateEpsilonForPage(page);
context.graphicPieces = compiledPage.calculateGraphicPieceInfos(page->getMediaBox(), epsilon);
finalizeGraphicsPieces(context);
};
PDFExecutionPolicy::execute(PDFExecutionPolicy::Scope::Page, leftPreparedPages.begin(), leftPreparedPages.end(), fillPageContext);
stepProgress();
@ -233,14 +238,33 @@ void PDFDiff::performSteps(const std::vector<PDFInteger>& leftPages, const std::
PDFRenderer renderer(m_rightDocument, &fontCache, cms.data(), &optionalContentActivity, features, pdf::PDFMeshQualitySettings());
renderer.compile(&compiledPage, context.pageIndex);
PDFReal epsilon = calculateEpsilonForPage(m_leftDocument->getCatalog()->getPage(context.pageIndex));
context.graphicPieces = compiledPage.calculateGraphicPieceInfos(epsilon);
const PDFPage* page = m_leftDocument->getCatalog()->getPage(context.pageIndex);
PDFReal epsilon = calculateEpsilonForPage(page);
context.graphicPieces = compiledPage.calculateGraphicPieceInfos(page->getMediaBox(), epsilon);
finalizeGraphicsPieces(context);
};
PDFExecutionPolicy::execute(PDFExecutionPolicy::Scope::Page, rightPreparedPages.begin(), rightPreparedPages.end(), fillPageContext);
stepProgress();
}
// StepMatchPages
if (!m_cancelled)
{
// Match pages
auto comparePages = [](const PDFDiffPageContext& left, const PDFDiffPageContext& right)
{
return left.pageHash == right.pageHash;
};
PDFAlgorithmLongestCommonSubsequence algorithm(leftPreparedPages.cbegin(), leftPreparedPages.cend(),
rightPreparedPages.cbegin(), rightPreparedPages.cend(),
comparePages);
algorithm.perform();
stepProgress();
}
// StepExtractTextLeftDocument
if (!m_cancelled)
{
@ -266,6 +290,43 @@ void PDFDiff::performSteps(const std::vector<PDFInteger>& leftPages, const std::
}
}
void PDFDiff::finalizeGraphicsPieces(PDFDiffPageContext& context)
{
std::sort(context.graphicPieces.begin(), context.graphicPieces.end());
// Compute page hash using active settings
QCryptographicHash hasher(QCryptographicHash::Sha512);
hasher.reset();
for (const PDFPrecompiledPage::GraphicPieceInfo& info : context.graphicPieces)
{
if (info.isText() && !m_options.testFlag(PC_Text))
{
continue;
}
if (info.isVectorGraphics() && !m_options.testFlag(PC_VectorGraphics))
{
continue;
}
if (info.isImage() && !m_options.testFlag(PC_Images))
{
continue;
}
if (info.isShading() && !m_options.testFlag(PC_Mesh))
{
continue;
}
hasher.addData(reinterpret_cast<const char*>(info.hash.data()), int(info.hash.size()));
}
QByteArray hash = hasher.result();
Q_ASSERT(QCryptographicHash::hashLength(QCryptographicHash::Sha512) == 64);
size_t size = qMin<size_t>(hash.length(), context.pageHash.size());
std::copy(hash.data(), hash.data() + size, context.pageHash.data());
}
void PDFDiff::onComparationPerformed()
{
m_cancelled = false;