qfontengine_ft_p.h

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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef QFONTENGINE_FT_P_H
#define QFONTENGINE_FT_P_H
//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//
 
#include "private/qfontengine_p.h"
 
#ifndef QT_NO_FREETYPE
 
#include <ft2build.h>
#include FT_FREETYPE_H
 
 
#ifndef Q_OS_WIN
#include <unistd.h>
#endif
 
#include <qmutex.h>
 
#include <string.h>
 
QT_BEGIN_NAMESPACE
 
class QFontEngineFTRawFont;
class QFontconfigDatabase;
 
/*
 * This class represents one font file on disk (like Arial.ttf) and is shared between all the font engines
 * that show this font file (at different pixel sizes).
 */
class Q_GUI_EXPORT QFreetypeFace
{
public:
    void computeSize(const QFontDef &fontDef, int *xsize, int *ysize, bool *outline_drawing, QFixed *scalableBitmapScaleFactor);
    QFontEngine::Properties properties() const;
    bool getSfntTable(uint tag, uchar *buffer, uint *length) const;
 
    static QFreetypeFace *getFace(const QFontEngine::FaceId &face_id,
                                  const QByteArray &fontData = QByteArray());
    void release(const QFontEngine::FaceId &face_id);
 
    static int getFaceIndexByStyleName(const QString &faceFileName, const QString &styleName);
 
    // locks the struct for usage. Any read/write operations require locking.
    void lock()
    {
        _lock.lock();
    }
    void unlock()
    {
        _lock.unlock();
    }
 
    FT_Face face;
    int xsize; // 26.6
    int ysize; // 26.6
    FT_Matrix matrix;
    FT_CharMap unicode_map;
    FT_CharMap symbol_map;
 
    enum { cmapCacheSize = 0x200 };
    glyph_t cmapCache[cmapCacheSize];
 
    int fsType() const;
 
    int getPointInOutline(glyph_t glyph, int flags, quint32 point, QFixed *xpos, QFixed *ypos, quint32 *nPoints);
 
    bool isScalableBitmap() const;
 
    static void addGlyphToPath(FT_Face face, FT_GlyphSlot g, const QFixedPoint &point, QPainterPath *path, FT_Fixed x_scale, FT_Fixed y_scale);
    static void addBitmapToPath(FT_GlyphSlot slot, const QFixedPoint &point, QPainterPath *path);
 
private:
    friend class QFontEngineFT;
    friend class QtFreetypeData;
    QFreetypeFace() = default;
    ~QFreetypeFace() {}
    void cleanup();
    QAtomicInt ref;
    QRecursiveMutex _lock;
    QByteArray fontData;
 
    QFontEngine::Holder hbFace;
};
 
class Q_GUI_EXPORT QFontEngineFT : public QFontEngine
{
public:
    struct GlyphInfo {
        int             linearAdvance;
        unsigned short  width;
        unsigned short  height;
        short           x;
        short           y;
        short           xOff;
        short           yOff;
    };
 
    struct GlyphAndSubPixelPosition
    {
        GlyphAndSubPixelPosition(glyph_t g, const QFixedPoint spp) : glyph(g), subPixelPosition(spp) {}
 
        bool operator==(const GlyphAndSubPixelPosition &other) const
        {
            return glyph == other.glyph && subPixelPosition == other.subPixelPosition;
        }
 
        glyph_t glyph;
        QFixedPoint subPixelPosition;
    };
 
    struct QGlyphSet
    {
        QGlyphSet();
        ~QGlyphSet();
        FT_Matrix transformationMatrix;
        bool outline_drawing;
 
        void removeGlyphFromCache(glyph_t index, const QFixedPoint &subPixelPosition);
        void clear();
        inline bool useFastGlyphData(glyph_t index, const QFixedPoint &subPixelPosition) const {
            return (index < 256 && subPixelPosition.x == 0 && subPixelPosition.y == 0);
        }
        inline Glyph *getGlyph(glyph_t index,
                               const QFixedPoint &subPixelPositionX = QFixedPoint()) const;
        void setGlyph(glyph_t index, const QFixedPoint &spp, Glyph *glyph);
 
        inline bool isGlyphMissing(glyph_t index) const { return missing_glyphs.contains(index); }
        inline void setGlyphMissing(glyph_t index) const { missing_glyphs.insert(index); }
private:
        Q_DISABLE_COPY(QGlyphSet);
        mutable QHash<GlyphAndSubPixelPosition, Glyph *> glyph_data; // maps from glyph index to glyph data
        mutable QSet<glyph_t> missing_glyphs;
        mutable Glyph *fast_glyph_data[256]; // for fast lookup of glyphs < 256
        mutable int fast_glyph_count;
    };
 
    QFontEngine::FaceId faceId() const override;
    QFontEngine::Properties properties() const override;
    QFixed emSquareSize() const override;
    bool supportsHorizontalSubPixelPositions() const override
    {
        return default_hint_style == HintLight ||
               default_hint_style == HintNone;
    }
 
    bool supportsVerticalSubPixelPositions() const override
    {
        return supportsHorizontalSubPixelPositions();
    }
 
    bool getSfntTableData(uint tag, uchar *buffer, uint *length) const override;
    int synthesized() const override;
 
    void initializeHeightMetrics() const override;
    QFixed capHeight() const override;
    QFixed xHeight() const override;
    QFixed averageCharWidth() const override;
 
    qreal maxCharWidth() const override;
    QFixed lineThickness() const override;
    QFixed underlinePosition() const override;
 
    glyph_t glyphIndex(uint ucs4) const override;
    void doKerning(QGlyphLayout *, ShaperFlags) const override;
 
    void getUnscaledGlyph(glyph_t glyph, QPainterPath *path, glyph_metrics_t *metrics) override;
 
    bool supportsTransformation(const QTransform &transform) const override;
 
    void addGlyphsToPath(glyph_t *glyphs, QFixedPoint *positions, int nglyphs,
                 QPainterPath *path, QTextItem::RenderFlags flags) override;
    void addOutlineToPath(qreal x, qreal y, const QGlyphLayout &glyphs,
                  QPainterPath *path, QTextItem::RenderFlags flags) override;
 
    bool stringToCMap(const QChar *str, int len, QGlyphLayout *glyphs, int *nglyphs, ShaperFlags flags) const override;
 
    glyph_metrics_t boundingBox(const QGlyphLayout &glyphs) override;
    glyph_metrics_t boundingBox(glyph_t glyph) override;
    glyph_metrics_t boundingBox(glyph_t glyph, const QTransform &matrix) override;
 
    void recalcAdvances(QGlyphLayout *glyphs, ShaperFlags flags) const override;
    QImage alphaMapForGlyph(glyph_t g) override { return alphaMapForGlyph(g, QFixedPoint()); }
    QImage alphaMapForGlyph(glyph_t, const QFixedPoint &) override;
    QImage alphaMapForGlyph(glyph_t glyph, const QFixedPoint &subPixelPosition, const QTransform &t) override;
    QImage alphaRGBMapForGlyph(glyph_t, const QFixedPoint &subPixelPosition, const QTransform &t) override;
    QImage bitmapForGlyph(glyph_t, const QFixedPoint &subPixelPosition, const QTransform &t, const QColor &color) override;
    glyph_metrics_t alphaMapBoundingBox(glyph_t glyph,
                                        const QFixedPoint &subPixelPosition,
                                        const QTransform &matrix,
                                        QFontEngine::GlyphFormat format) override;
    Glyph *glyphData(glyph_t glyph,
                     const QFixedPoint &subPixelPosition,
                     GlyphFormat neededFormat,
                     const QTransform &t) override;
    bool hasInternalCaching() const override { return cacheEnabled; }
    bool expectsGammaCorrectedBlending() const override;
 
    void removeGlyphFromCache(glyph_t glyph) override;
    int glyphMargin(QFontEngine::GlyphFormat /* format */) override { return 0; }
 
    int glyphCount() const override;
 
    enum Scaling {
        Scaled,
        Unscaled
    };
    FT_Face lockFace(Scaling scale = Scaled) const;
    void unlockFace() const;
 
    FT_Face non_locked_face() const;
 
    inline bool drawAntialiased() const { return antialias; }
    inline bool invalid() const { return xsize == 0 && ysize == 0; }
    inline bool isBitmapFont() const { return defaultFormat == Format_Mono; }
    inline bool isScalableBitmap() const { return freetype->isScalableBitmap(); }
 
    inline Glyph *loadGlyph(uint glyph,
                            const QFixedPoint &subPixelPosition,
                            GlyphFormat format = Format_None,
                            bool fetchMetricsOnly = false,
                            bool disableOutlineDrawing = false) const
    { return loadGlyph(cacheEnabled ? &defaultGlyphSet : nullptr, glyph, subPixelPosition, format, fetchMetricsOnly, disableOutlineDrawing); }
    Glyph *loadGlyph(QGlyphSet *set,
                     uint glyph,
                     const QFixedPoint &subPixelPosition,
                     GlyphFormat = Format_None,
                     bool fetchMetricsOnly = false,
                     bool disableOutlineDrawing = false) const;
    Glyph *loadGlyphFor(glyph_t g,
                        const QFixedPoint &subPixelPosition,
                        GlyphFormat format,
                        const QTransform &t,
                        bool fetchBoundingBox = false,
                        bool disableOutlineDrawing = false);
 
    QGlyphSet *loadGlyphSet(const QTransform &matrix);
 
    QFontEngineFT(const QFontDef &fd);
    virtual ~QFontEngineFT();
 
    bool init(FaceId faceId, bool antiaalias, GlyphFormat defaultFormat = Format_None,
              const QByteArray &fontData = QByteArray());
    bool init(FaceId faceId, bool antialias, GlyphFormat format,
              QFreetypeFace *freetypeFace);
 
    int getPointInOutline(glyph_t glyph, int flags, quint32 point, QFixed *xpos, QFixed *ypos, quint32 *nPoints) override;
 
    void setQtDefaultHintStyle(QFont::HintingPreference hintingPreference);
    void setDefaultHintStyle(HintStyle style) override;
 
    QFontEngine *cloneWithSize(qreal pixelSize) const override;
    Qt::HANDLE handle() const override;
    bool initFromFontEngine(const QFontEngineFT *fontEngine);
 
    HintStyle defaultHintStyle() const { return default_hint_style; }
 
    static QFontEngineFT *create(const QFontDef &fontDef, FaceId faceId, const QByteArray &fontData = QByteArray());
    static QFontEngineFT *create(const QByteArray &fontData, qreal pixelSize, QFont::HintingPreference hintingPreference);
 
protected:
 
    QFreetypeFace *freetype;
    mutable int default_load_flags;
    HintStyle default_hint_style;
    bool antialias;
    bool transform;
    bool embolden;
    bool obliquen;
    SubpixelAntialiasingType subpixelType;
    int lcdFilterType;
    bool embeddedbitmap;
    bool cacheEnabled;
    bool forceAutoHint;
    bool stemDarkeningDriver;
 
private:
    friend class QFontEngineFTRawFont;
    friend class QFontconfigDatabase;
    friend class QFreeTypeFontDatabase;
    friend class QFontEngineMultiFontConfig;
 
    int loadFlags(QGlyphSet *set, GlyphFormat format, int flags, bool &hsubpixel, int &vfactor) const;
    bool shouldUseDesignMetrics(ShaperFlags flags) const;
    QFixed scaledBitmapMetrics(QFixed m) const;
    glyph_metrics_t scaledBitmapMetrics(const glyph_metrics_t &m, const QTransform &matrix) const;
 
    GlyphFormat defaultFormat;
    FT_Matrix matrix;
 
    struct TransformedGlyphSets {
        enum { nSets = 10 };
        QGlyphSet *sets[nSets];
 
        QGlyphSet *findSet(const QTransform &matrix, const QFontDef &fontDef);
        TransformedGlyphSets() { std::fill(&sets[0], &sets[nSets], nullptr); }
        ~TransformedGlyphSets() { qDeleteAll(&sets[0], &sets[nSets]); }
    private:
        void moveToFront(int i);
        Q_DISABLE_COPY(TransformedGlyphSets);
    };
    TransformedGlyphSets transformedGlyphSets;
    mutable QGlyphSet defaultGlyphSet;
 
    QFontEngine::FaceId face_id;
 
    int xsize;
    int ysize;
 
    QFixed line_thickness;
    QFixed underline_position;
 
    FT_Size_Metrics metrics;
    mutable bool kerning_pairs_loaded;
    QFixed scalableBitmapScaleFactor;
};
 
 
inline size_t qHash(const QFontEngineFT::GlyphAndSubPixelPosition &g, size_t seed = 0)
{
    return qHashMulti(seed,
                      g.glyph,
                      g.subPixelPosition.x.value(),
                      g.subPixelPosition.y.value());
}
 
inline QFontEngineFT::Glyph *QFontEngineFT::QGlyphSet::getGlyph(glyph_t index,
                                                                const QFixedPoint &subPixelPosition) const
{
    if (useFastGlyphData(index, subPixelPosition))
        return fast_glyph_data[index];
    return glyph_data.value(GlyphAndSubPixelPosition(index, subPixelPosition));
}
 
Q_GUI_EXPORT FT_Library qt_getFreetype();
 
QT_END_NAMESPACE
 
#endif // QT_NO_FREETYPE
 
#endif // QFONTENGINE_FT_P_H