HOCRDocument.h

/*
 * Copyright © 2016-2018 Stefan Kebekus <stefan.kebekus@math.uni-freiburg.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 3 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, see <http://www.gnu.org/licenses/>.
 */


#ifndef HOCRDOCUMENT
#define HOCRDOCUMENT 1


#include "HOCRTextBox.h"
#include "resolution.h"
#include <QPageSize>
#include <QSet>


class HOCRDocument
{
 public:
  HOCRDocument() {clear();};

  explicit HOCRDocument(QIODevice *device) {read(device);};
  
  explicit HOCRDocument(QString fileName) {read(fileName);};

  HOCRDocument(const QImage &image, QStringList languages=QStringList()) {read(image,languages);};  

  void clear();

  bool hasError() const {return !_error.isEmpty();};
  
  QString error() const {return _error; };

  bool hasWarnings() const {return !_warnings.isEmpty();};

  QSet<QString> warnings() const {return _warnings;};

  QSet<QString> system() const {return _OCRSystem;};

  QSet<QString> capabilities() const {return _OCRCapabilities;};
  
  QList<HOCRTextBox> pages() const {return _pages;};
  
  bool isEmpty() const {return _pages.isEmpty();};

    
  bool hasText() const;

  HOCRTextBox takeFirstPage() {
    if (_pages.size() > 0)
      return _pages.takeFirst();
    else
      return HOCRTextBox();
  };
  
  void read(QIODevice *device);

  void read(const QString& fileName);

  void read(const QImage &image, const QStringList& languages=QStringList());
  
  QFont suggestFont() const;
  
  QString toPDF(const QString& fileName, resolution _resolution, const QString& title=QString(), const QPageSize& overridePageSize=QPageSize(), QFont *overrideFont=0) const;
  
  QList<QImage> toImages(QFont *overrideFont=0, QImage::Format format=QImage::Format_Grayscale8) const;
  
  QString toText() const;

  void append(const HOCRDocument &other);

  static QStringList tesseractLanguages();

  static bool areLanguagesSupportedByTesseract(const QStringList& lingos);
  
 private:
  // This is a convenience method that suggests a page size for a given page of
  // the document, taking resolution and overridePageSize into account. The
  // reason for the existence of this method is that the computation is needed
  // in two different places in the method exportToPDF, and I wanted to avoid
  // duplicated code.
  QPageSize findPageSize(int pageNumber, resolution _resolution, const QPageSize &overridePageSize) const;

  // Error
  QString _error;

  // System(s) that generated this file, as specified in a meta tag of the HOCR
  // file
  QSet<QString> _OCRSystem;

  // OCR capabilites used in this file, as specified in a meta tag of the HOCR
  // file
  QSet<QString> _OCRCapabilities;

  // Pages of the document
  QList<HOCRTextBox> _pages;
  
  // Warnings
  QSet<QString> _warnings;
};

#endif