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/*
dspdfviewer - Dual Screen PDF Viewer for LaTeX-Beamer
Copyright (C) 2012 Danny Edel <mail@danny-edel.de>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef PDFRENDERFACTORY_H
#define PDFRENDERFACTORY_H
#include <QObject>
#include <QMutex>
#include <QCache>
#include <QThread>
#include <QFileSystemWatcher>
#include <QTimer>
#include <qimage.h>
#include "poppler-qt.h"
#include "renderedpage.h"
#include "runtimeconfiguration.h"
#include "pdfcacheoption.h"
#include "pdfdocumentreference.h"
/** Factory for rendered pages
*
* This class is responsible for rendering the PDF to images.
*
* You create a factory using a filename (if the file cannot be opened this will throw),
* then you can simply request renderings by supplying the desired size and page part
* to requestPageRendering.
*
* The class uses the global instance of QThreadPool and renders in paralell, meaning it
* can take advantage of SMP or Multi-Core Systems.
*
* NOTE for updating the external file:
* If you plan on rewriting the displayed file while this application is running,
* you can cache the entire file to memory. This can be done via constructor parameter.
*
* That way, if you create an invalid PDF file (for example you make an error in your latex
* document), it still has a copy of the old file present.
* The tradeoff is that this will cost you additional memory for *the entire PDF file*, which
* can be a lot if you have an image-heavy PDF file.
*
* The class will notify you via signals when it detects a file change. Then it will try to re-read
* the file, and it will notify you if that has succeeded or failed.
*
* If the re-reading failed, you can still get pages from cache, and you can keep rendering new ones
* if you have used the memory cache. However, if you try to render new pages, you will probably
* experience strange behaviour or the program will crash.
*
* If the re-reading went well, the cache will be cleared and new page renders will use the new pdf
* file.
*
*/
class PdfRenderFactory : public QObject
{
Q_OBJECT
private:
PDFDocumentReference documentReference;
QFileSystemWatcher fileWatcher;
QTimer fileWatcherRewatchTimer;
QSet< RenderingIdentifier > currentlyRenderingPages;
QCache< RenderingIdentifier, RenderedPage> renderedPages;
mutable QMutex mutex;
/** This is a little helper for the cache-clear-function to detect
* renderings that have been started before, but finished after
* a cache clearing.
*/
quint64 currentVersion;
int numberOfPages_;
private:
void clearAllCaches();
public:
PdfRenderFactory( const RuntimeConfiguration& );
~PdfRenderFactory() override;
/** Request a page rendering. Defaults to low priority (i.e. background rendering), please set High priority manually
* on the current page.
*/
void requestPageRendering( const RenderingIdentifier& originalIdentifier, QThread::Priority priority = QThread::LowPriority);
int numberOfPages() const;
private slots:
void fileOnDiskChanged(const QString& filename);
void pageThreadFinishedRendering( QSharedPointer<RenderedPage> renderedPage );
signals:
void pageRendered( QSharedPointer<RenderedPage> renderedPage);
void pdfFileChanged();
void pdfFileRereadSuccesfully();
void pdfFileRereadFailed();
public slots:
void rewatchFile();
};
#endif // PDFRENDERFACTORY_H
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