PDF4QT/Pdf4QtLib/sources/pdfdocumenttextflow.h

112 lines
4.2 KiB
C++

// Copyright (C) 2020 Jakub Melka
//
// This file is part of Pdf4Qt.
//
// Pdf4Qt is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Pdf4Qt 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with Pdf4Qt. If not, see <https://www.gnu.org/licenses/>.
#ifndef PDFDOCUMENTTEXTFLOW_H
#define PDFDOCUMENTTEXTFLOW_H
#include "pdfglobal.h"
#include "pdfexception.h"
namespace pdf
{
class PDFDocument;
/// Text flow extracted from document. Text flow can be created \p PDFDocumentTextFlowFactory.
/// Flow can contain various items, not just text ones. Also, some manipulation functions
/// are available, they can modify text flow by various content.
class Pdf4QtLIBSHARED_EXPORT PDFDocumentTextFlow
{
public:
enum Flag
{
None = 0x0000, ///< No text flag
Text = 0x0001, ///< Ordinary text
PageStart = 0x0002, ///< Page start marker
PageEnd = 0x0004, ///< Page end marker
StructureTitle = 0x0008, ///< Structure tree item title
StructureLanguage = 0x0010, ///< Structure tree item language
StructureAlternativeDescription = 0x0020, ///< Structure tree item alternative description
StructureExpandedForm = 0x0040, ///< Structure tree item expanded form of text
StructureActualText = 0x0080, ///< Structure tree item actual text
StructurePhoneme = 0x0100, ///< Structure tree item phoneme
StructureItemStart = 0x0200, ///< Start of structure tree item
StructureItemEnd = 0x0400, ///< End of structure tree item
};
Q_DECLARE_FLAGS(Flags, Flag)
struct Item
{
Flags flags = None;
PDFInteger pageIndex = 0;
QString text;
};
using Items = std::vector<Item>;
explicit PDFDocumentTextFlow() = default;
explicit PDFDocumentTextFlow(Items&& items) :
m_items(qMove(items))
{
}
const Items& getItems() const { return m_items; }
/// Returns true, if text flow is empty
bool isEmpty() const { return m_items.empty(); }
private:
Items m_items;
};
/// This factory creates text flow for whole document
class Pdf4QtLIBSHARED_EXPORT PDFDocumentTextFlowFactory
{
public:
explicit PDFDocumentTextFlowFactory() = default;
enum class Algorithm
{
Auto, ///< Determine best text layout algorithm automatically
Layout, ///< Use text layout recognition using docstrum algorithm
Content, ///< Use content-stream text layout recognition (usually unreliable), but fast
Structure, ///< Use structure oriented text layout recognition (requires tagged document)
};
/// Performs document text flow analysis using given algorithm. Text flow
/// can be performed only for given subset of pages, if required.
/// \param document Document
/// \param pageIndices Analyzed page indices
/// \param algorithm Algorithm
PDFDocumentTextFlow create(const PDFDocument* document,
const std::vector<PDFInteger>& pageIndices,
Algorithm algorithm);
/// Has some error/warning occured during text layout creation?
bool hasError() const { return !m_errors.isEmpty(); }
/// Returns a list of errors/warnings
const QList<PDFRenderError>& getErrors() const { return m_errors; }
private:
QList<PDFRenderError> m_errors;
};
} // namespace pdf
#endif // PDFDOCUMENTTEXTFLOW_H