PDF4QT/Pdf4QtLib/sources/pdffont.h

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// Copyright (C) 2019-2021 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
// with the written consent of the copyright owner, 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 PDFFONT_H
#define PDFFONT_H
#include "pdfglobal.h"
#include "pdfencoding.h"
#include "pdfobject.h"
#include <QFont>
#include <QMatrix>
#include <QSharedPointer>
#include <set>
#include <unordered_map>
class QPainterPath;
class QTreeWidgetItem;
namespace pdf
{
class PDFDocument;
class PDFModifiedDocument;
class PDFRenderErrorReporter;
class PDFFontCMap;
using CID = unsigned int;
using GID = unsigned int;
using GlyphIndices = std::array<GID, 256>;
enum class TextRenderingMode
{
Fill = 0,
Stroke = 1,
FillStroke = 2,
Invisible = 3,
FillClip = 4,
StrokeClip = 5,
FillStrokeClip = 6,
Clip = 7
};
/// Item of the text sequence (either single character, or advance)
struct TextSequenceItem
{
inline explicit TextSequenceItem() = default;
inline explicit TextSequenceItem(const QPainterPath* glyph, QChar character, PDFReal advance) : glyph(glyph), character(character), advance(advance) { }
inline explicit TextSequenceItem(PDFReal advance) : character(), advance(advance) { }
inline explicit TextSequenceItem(const QByteArray* characterContentStream, QChar character, PDFReal advance) : characterContentStream(characterContentStream), character(character), advance(advance) { }
inline bool isContentStream() const { return characterContentStream; }
inline bool isCharacter() const { return glyph; }
inline bool isAdvance() const { return advance != 0.0; }
inline bool isNull() const { return !isCharacter() && !isAdvance(); }
const QPainterPath* glyph = nullptr;
const QByteArray* characterContentStream = nullptr;
QChar character;
PDFReal advance = 0;
};
struct TextSequence
{
std::vector<TextSequenceItem> items;
};
constexpr bool isTextRenderingModeFilled(TextRenderingMode mode)
{
switch (mode)
{
case TextRenderingMode::Fill:
case TextRenderingMode::FillClip:
case TextRenderingMode::FillStroke:
case TextRenderingMode::FillStrokeClip:
return true;
default:
return false;
}
}
constexpr bool isTextRenderingModeStroked(TextRenderingMode mode)
{
switch (mode)
{
case TextRenderingMode::Stroke:
case TextRenderingMode::FillStroke:
case TextRenderingMode::StrokeClip:
case TextRenderingMode::FillStrokeClip:
return true;
default:
return false;
}
}
constexpr bool isTextRenderingModeClipped(TextRenderingMode mode)
{
switch (mode)
{
case TextRenderingMode::Clip:
case TextRenderingMode::FillClip:
case TextRenderingMode::StrokeClip:
case TextRenderingMode::FillStrokeClip:
return true;
default:
return false;
}
}
enum class FontType
{
Invalid,
Type0,
Type1,
MMType1,
TrueType,
Type3
};
/// Standard Type1 fonts
enum class StandardFontType
{
Invalid,
TimesRoman,
TimesRomanBold,
TimesRomanItalics,
TimesRomanBoldItalics,
Helvetica,
HelveticaBold,
HelveticaOblique,
HelveticaBoldOblique,
Courier,
CourierBold,
CourierOblique,
CourierBoldOblique,
Symbol,
ZapfDingbats
};
/// Returns builtin encoding for the standard font
static constexpr PDFEncoding::Encoding getEncodingForStandardFont(StandardFontType standardFont)
{
switch (standardFont)
{
case StandardFontType::Symbol:
return PDFEncoding::Encoding::Symbol;
case StandardFontType::ZapfDingbats:
return PDFEncoding::Encoding::ZapfDingbats;
default:
return PDFEncoding::Encoding::Standard;
}
}
struct PDF4QTLIBSHARED_EXPORT FontDescriptor
{
bool isEmbedded() const { return !fontFile.isEmpty() || !fontFile2.isEmpty() || !fontFile3.isEmpty(); }
/// Returns embedded font data, or nullptr, if font is not embedded
const QByteArray* getEmbeddedFontData() const;
QByteArray fontName;
QByteArray fontFamily;
QFont::Stretch fontStretch = QFont::AnyStretch;
PDFReal fontWeight = 400.0;
PDFInteger flags;
QRectF boundingBox;
PDFReal italicAngle = 0.0;
PDFReal ascent = 0.0;
PDFReal descent = 0.0;
PDFReal leading = 0.0;
PDFReal capHeight = 0.0;
PDFReal xHeight = 0.0;
PDFReal stemV = 0.0;
PDFReal stemH = 0.0;
PDFReal avgWidth = 0.0;
PDFReal maxWidth = 0.0;
PDFReal missingWidth = 0.0;
/// Byte array with Type 1 font program (embedded font)
QByteArray fontFile;
/// Byte array with TrueType font program (embedded font)
QByteArray fontFile2;
/// Byte array with font program, whose format is defined by the Subtype array
/// in the font dictionary.
QByteArray fontFile3;
/// Character set
QByteArray charset;
};
class PDFFont;
using PDFFontPointer = QSharedPointer<PDFFont>;
class PDFRealizedFont;
class IRealizedFontImpl;
using PDFRealizedFontPointer = QSharedPointer<PDFRealizedFont>;
struct CharacterInfo
{
GID gid = 0;
QChar character;
};
using CharacterInfos = std::vector<CharacterInfo>;
/// Font, which has fixed pixel size. It is programmed as PIMPL, because we need
/// to remove FreeType types from the interface (so we do not include FreeType in the interface).
class PDF4QTLIBSHARED_EXPORT PDFRealizedFont
{
public:
~PDFRealizedFont();
/// Fills the text sequence by interpreting byte array according font data and
/// produces glyphs for the font.
/// \param byteArray Array of bytes to be interpreted
/// \param textSequence Text sequence to be filled
/// \param reporter Error reporter
void fillTextSequence(const QByteArray& byteArray, TextSequence& textSequence, PDFRenderErrorReporter* reporter);
/// Return true, if we have horizontal writing system
bool isHorizontalWritingSystem() const;
/// Adds information about the font into tree item
void dumpFontToTreeItem(QTreeWidgetItem* item) const;
/// Returns postscript name of the font
QString getPostScriptName() const;
/// Returns character info
CharacterInfos getCharacterInfos() const;
/// Creates new realized font from the standard font. If font can't be created,
/// then exception is thrown.
static PDFRealizedFontPointer createRealizedFont(PDFFontPointer font, PDFReal pixelSize, PDFRenderErrorReporter* reporter);
private:
/// Constructs new realized font
explicit PDFRealizedFont(IRealizedFontImpl* impl) : m_impl(impl) { }
IRealizedFontImpl* m_impl;
};
/// Base class representing font in the PDF file
class PDF4QTLIBSHARED_EXPORT PDFFont
{
public:
explicit PDFFont(FontDescriptor fontDescriptor);
virtual ~PDFFont() = default;
/// Returns the font type
virtual FontType getFontType() const = 0;
/// Returns ToUnicode mapping (or nullptr, if font has no mapping to unicode)
virtual const PDFFontCMap* getToUnicode() const { return nullptr; }
/// Returns cmap for font character encoding
virtual const PDFFontCMap* getCMap() const { return nullptr; }
/// Returns font descriptor
const FontDescriptor* getFontDescriptor() const { return &m_fontDescriptor; }
/// Adds information about the font into tree item
virtual void dumpFontToTreeItem(QTreeWidgetItem* item) const { Q_UNUSED(item); }
/// Creates font from the object. If font can't be created, exception is thrown.
/// \param object Font dictionary
/// \param document Document
static PDFFontPointer createFont(const PDFObject& object, const PDFDocument* document);
/// Tries to read font descriptor from the object
/// \param fontDescriptorObject Font descriptor dictionary
/// \param document Document
static FontDescriptor readFontDescriptor(const PDFObject& fontDescriptorObject, const PDFDocument* document);
protected:
FontDescriptor m_fontDescriptor;
};
/// Simple font, see PDF reference 1.7, chapter 5.5. Simple fonts have encoding table,
/// which maps single-byte character to the glyph in the font.
class PDFSimpleFont : public PDFFont
{
using BaseClass = PDFFont;
public:
explicit PDFSimpleFont(FontDescriptor fontDescriptor,
QByteArray name,
QByteArray baseFont,
PDFInteger firstChar,
PDFInteger lastChar,
std::vector<PDFInteger> widths,
PDFEncoding::Encoding encodingType,
encoding::EncodingTable encoding,
GlyphIndices glyphIndices);
virtual ~PDFSimpleFont() override = default;
PDFEncoding::Encoding getEncodingType() const { return m_encodingType; }
const encoding::EncodingTable* getEncoding() const { return &m_encoding; }
const GlyphIndices* getGlyphIndices() const { return &m_glyphIndices; }
/// Returns the glyph advance (or zero, if glyph advance is invalid)
PDFInteger getGlyphAdvance(size_t index) const;
virtual void dumpFontToTreeItem(QTreeWidgetItem* item) const override;
protected:
QByteArray m_name;
QByteArray m_baseFont;
PDFInteger m_firstChar;
PDFInteger m_lastChar;
std::vector<PDFInteger> m_widths;
PDFEncoding::Encoding m_encodingType;
encoding::EncodingTable m_encoding;
GlyphIndices m_glyphIndices;
};
class PDFType1Font : public PDFSimpleFont
{
using BaseClass = PDFSimpleFont;
public:
explicit PDFType1Font(FontType fontType,
FontDescriptor fontDescriptor,
QByteArray name,
QByteArray baseFont,
PDFInteger firstChar,
PDFInteger lastChar,
std::vector<PDFInteger> widths,
PDFEncoding::Encoding encodingType,
encoding::EncodingTable encoding,
StandardFontType standardFontType,
GlyphIndices glyphIndices);
virtual ~PDFType1Font() override = default;
virtual FontType getFontType() const override;
virtual void dumpFontToTreeItem(QTreeWidgetItem*item) const override;
/// Returns the assigned standard font (or invalid, if font is not standard)
StandardFontType getStandardFontType() const { return m_standardFontType; }
private:
FontType m_fontType;
StandardFontType m_standardFontType; ///< Type of the standard font (or invalid, if it is not a standard font)
};
class PDFTrueTypeFont : public PDFSimpleFont
{
public:
using PDFSimpleFont::PDFSimpleFont;
virtual FontType getFontType() const override;
};
/// Font cache which caches both fonts, and realized fonts. Cache has individual limit
/// for fonts, and realized fonts.
class PDF4QTLIBSHARED_EXPORT PDFFontCache
{
public:
inline explicit PDFFontCache(size_t fontCacheLimit, size_t realizedFontCacheLimit) :
m_fontCacheLimit(fontCacheLimit),
m_realizedFontCacheLimit(realizedFontCacheLimit),
m_document(nullptr)
{
}
/// Sets the document to the cache. Whole cache is cleared,
/// if it is needed.
/// \param document Document to be setted
void setDocument(const PDFModifiedDocument& document);
/// Retrieves font from the cache. If font can't be accessed or created,
/// then exception is thrown.
/// \param fontObject Font object
PDFFontPointer getFont(const PDFObject& fontObject) const;
/// Retrieves realized font from the cache. If realized font can't be accessed or created,
/// then exception is thrown.
/// \param font Font, which should be realized
/// \param size Size of the font (in pixels)
/// \param reporter Error reporter
PDFRealizedFontPointer getRealizedFont(const PDFFontPointer& font, PDFReal size, PDFRenderErrorReporter* reporter) const;
/// Sets or unsets font shrinking (i.e. font can be deleted from the cache). In multithreading environment,
/// font deletion is not thread safe. For this reason, disable font deletion by calling this function.
/// First parameter, \p source determines which object enables cache shrinking (so some objects can
/// enable shrinking, while some objects will disable it). Only if all objects enables cache shrinking,
/// then cache can shrink.
/// \param source Source object
/// \param enabled Enable or disable cache shrinking
void setCacheShrinkEnabled(const void* source, bool enabled);
/// Set font cache limits
void setCacheLimits(int fontCacheLimit, int instancedFontCacheLimit);
/// If shrinking is enabled, then erase font, if cache limit is exceeded.
void shrink();
private:
size_t m_fontCacheLimit;
size_t m_realizedFontCacheLimit;
mutable QMutex m_mutex;
const PDFDocument* m_document;
mutable std::map<PDFObjectReference, PDFFontPointer> m_fontCache;
mutable std::map<std::pair<PDFFontPointer, PDFReal>, PDFRealizedFontPointer> m_realizedFontCache;
mutable std::set<const void*> m_fontCacheShrinkDisabledObjects;
};
/// Performs mapping from CID to GID (even identity mapping, if byte array is empty)
class PDFCIDtoGIDMapper
{
public:
explicit inline PDFCIDtoGIDMapper(QByteArray&& mapping) : m_mapping(qMove(mapping)) { }
/// Maps CID to GID (glyph identifier)
GID map(CID cid) const
{
if (m_mapping.isEmpty())
{
// This means identity mapping
return cid;
}
else if ((2 * cid + 1) < CID(m_mapping.size()))
{
return (GID(m_mapping[2 * cid]) << 8) + GID(m_mapping[2 * cid + 1]);
}
// This should occur only in case of bad (damaged) PDF file - because in this case,
// encoding is missing. Return invalid glyph index.
return 0;
}
/// Maps GID to CID (inverse mapping)
CID unmap(GID gid) const
{
if (m_mapping.isEmpty())
{
// This means identity mapping
return gid;
}
else
{
CID lastCid = CID(m_mapping.size() / 2);
for (CID i = 0; i < lastCid; ++i)
{
if (map(i) == gid)
{
return i;
}
}
}
// This should occur only in case of bad (damaged) PDF file - because in this case,
// encoding is missing. Return invalid character index.
return 0;
}
private:
QByteArray m_mapping;
};
/// Represents a font CMAP (mapping of CIDs)
class PDF4QTLIBSHARED_EXPORT PDFFontCMap
{
public:
explicit PDFFontCMap() = default;
/// Returns true, if mapping is valid
bool isValid() const { return !m_entries.empty(); }
/// Returns true, if vertical writing mode is on
bool isVertical() const { return m_vertical; }
/// Creates mapping from name (name must be one of predefined names)
static PDFFontCMap createFromName(const QByteArray& name);
/// Creates mapping from data (data must be a byte array containing the CMap)
static PDFFontCMap createFromData(const QByteArray& data);
/// Serializes the CMap to the byte array
QByteArray serialize() const;
/// Deserializes the CMap from the byte array
static PDFFontCMap deserialize(const QByteArray& byteArray);
/// Converts byte array to array of CIDs
std::vector<CID> interpret(const QByteArray& byteArray) const;
/// Converts CID to QChar, use only on ToUnicode CMaps
QChar getToUnicode(CID cid) const;
private:
struct Entry
{
constexpr explicit inline Entry() = default;
constexpr explicit inline Entry(unsigned int from, unsigned int to, unsigned int byteCount, CID cid) : from(from), to(to), byteCount(byteCount), cid(cid) { }
unsigned int from = 0;
unsigned int to = 0;
unsigned int byteCount = 0;
CID cid = 0;
// Can merge from other CID entry?
bool canMerge(const Entry& other) const
{
const bool sameBytes = byteCount == other.byteCount;
const bool compatibleRange = (to + 1) == other.from;
const bool compatibleCID = (cid + to + 1) - from == other.cid;
return sameBytes && compatibleRange && compatibleCID;
}
inline constexpr Entry merge(const Entry& other) const
{
return Entry(from, other.to, byteCount, cid);
}
inline constexpr bool operator<(const Entry& other) const
{
return std::tie(byteCount, from) < std::tie(other.byteCount, other.from);
}
};
using Entries = std::vector<Entry>;
explicit PDFFontCMap(Entries&& entries, bool vertical);
/// Optimizes the entries - merges entries, which can be merged. This function
/// requires, that entries are sorted.
static Entries optimize(const Entries& entries);
Entries m_entries;
unsigned int m_maxKeyLength = 0;
bool m_vertical = false;
};
class PDFType3Font : public PDFFont
{
public:
explicit PDFType3Font(FontDescriptor fontDescriptor,
int firstCharacterIndex,
int lastCharacterIndex,
QMatrix fontMatrix,
std::map<int, QByteArray>&& characterContentStreams,
std::vector<double>&& widths,
const PDFObject& resources,
PDFFontCMap toUnicode);
virtual FontType getFontType() const override;
virtual void dumpFontToTreeItem(QTreeWidgetItem*item) const override;
virtual const PDFFontCMap* getToUnicode() const override { return &m_toUnicode; }
/// Returns width of the character. If character doesn't exist, then zero is returned.
double getWidth(int characterIndex) const;
/// Return content stream for the character. If character doesn't exist, then nullptr
/// is returned.
const QByteArray* getContentStream(int characterIndex) const;
const QMatrix& getFontMatrix() const { return m_fontMatrix; }
const PDFObject& getResources() const { return m_resources; }
const std::map<int, QByteArray>& getContentStreams() const { return m_characterContentStreams; }
/// Returns unicode character for given character index. If unicode mapping is not
/// present, empty (null) character is returned.
QChar getUnicode(int characterIndex) const { return m_toUnicode.getToUnicode(characterIndex); }
private:
int m_firstCharacterIndex;
int m_lastCharacterIndex;
QMatrix m_fontMatrix;
std::map<int, QByteArray> m_characterContentStreams;
std::vector<double> m_widths;
PDFObject m_resources;
PDFFontCMap m_toUnicode;
};
/// Composite font (CID-keyed font)
class PDFType0Font : public PDFFont
{
public:
explicit inline PDFType0Font(FontDescriptor fontDescriptor, PDFFontCMap cmap, PDFFontCMap toUnicode, PDFCIDtoGIDMapper mapper, PDFReal defaultAdvance, std::unordered_map<CID, PDFReal> advances) :
PDFFont(qMove(fontDescriptor)),
m_cmap(qMove(cmap)),
m_toUnicode(qMove(toUnicode)),
m_mapper(qMove(mapper)),
m_defaultAdvance(defaultAdvance),
m_advances(qMove(advances))
{
}
virtual ~PDFType0Font() = default;
virtual FontType getFontType() const override { return FontType::Type0; }
virtual const PDFFontCMap* getToUnicode() const override { return &m_toUnicode; }
virtual const PDFFontCMap* getCMap() const override { return &m_cmap; }
const PDFCIDtoGIDMapper* getCIDtoGIDMapper() const { return &m_mapper; }
/// Returns the glyph advance, if it can be obtained, or zero, if it cannot
/// be obtained or error occurs.
/// \param cid CID of the glyph
PDFReal getGlyphAdvance(CID cid) const;
private:
PDFFontCMap m_cmap;
PDFFontCMap m_toUnicode;
PDFCIDtoGIDMapper m_mapper;
PDFReal m_defaultAdvance;
std::unordered_map<CID, PDFReal> m_advances;
};
/// Repository with predefined CMaps
class PDF4QTLIBSHARED_EXPORT PDFFontCMapRepository
{
public:
/// Returns instance of CMAP repository
static PDFFontCMapRepository* getInstance();
/// Adds CMAP to the repository
void add(const QByteArray& key, QByteArray value) { m_cmaps[key] = qMove(value); }
/// Clears the repository
void clear() { m_cmaps.clear(); }
/// Saves the repository content to the file
void saveToFile(const QString& fileName) const;
/// Loads the repository content from the file
bool loadFromFile(const QString& fileName);
private:
explicit PDFFontCMapRepository();
/// Storage for predefined cmaps
std::map<QByteArray, QByteArray> m_cmaps;
};
} // namespace pdf
#endif // PDFFONT_H