path: root/src/gui/text/qfontengine_ft_p.h

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#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 "qfontengine_p.h"

#ifndef QT_NO_FREETYPE

#include <ft2build.h>
#include FT_FREETYPE_H

#if defined(Q_WS_X11)
#include <private/qt_x11_p.h>
#endif

#include <unistd.h>

#ifndef QT_NO_FONTCONFIG
#include <fontconfig/fontconfig.h>
#endif

#include <qmutex.h>

#include <harfbuzz-shaper.h>

QT_BEGIN_NAMESPACE

class QFontEngineFTRawFont;

/*
 * This struct 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).
 */
struct QFreetypeFace
{
    void computeSize(const QFontDef &fontDef, int *xsize, int *ysize, bool *outline_drawing);
    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);

    // locks the struct for usage. Any read/write operations require locking.
    void lock()
    {
        _lock.lock();
    }
    void unlock()
    {
        _lock.unlock();
    }

    FT_Face face;
    HB_Face hbFace;
#ifndef QT_NO_FONTCONFIG
    FcCharSet *charset;
#endif
    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;

    HB_Error getPointInOutline(HB_Glyph glyph, int flags, hb_uint32 point, HB_Fixed *xpos, HB_Fixed *ypos, hb_uint32 *nPoints);

    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, bool = false);

private:
    friend class QFontEngineFT;
    friend class QScopedPointerDeleter<QFreetypeFace>;
    QFreetypeFace() : _lock(QMutex::Recursive) {}
    ~QFreetypeFace() {}
    QAtomicInt ref;
    QMutex _lock;
    QByteArray fontData;
};

class Q_GUI_EXPORT QFontEngineFT : public QFontEngine
{
public:

    /* we don't cache glyphs that are too large anyway, so we can make this struct rather small */
    struct Glyph {
        ~Glyph();
        short linearAdvance;
        unsigned char width;
        unsigned char height;
        signed char x;
        signed char y;
        signed char advance;
        signed char format;
        uchar *data;
        unsigned int uploadedToServer : 1;
    };

    enum SubpixelAntialiasingType {
        Subpixel_None,
        Subpixel_RGB,
        Subpixel_BGR,
        Subpixel_VRGB,
        Subpixel_VBGR
    };

#if defined(Q_WS_X11) && !defined(QT_NO_XRENDER)
    typedef XGlyphInfo GlyphInfo;
#else
    struct GlyphInfo {
        unsigned short  width;
        unsigned short  height;
        short           x;
        short           y;
        short           xOff;
        short           yOff;
    };
#endif

    struct GlyphAndSubPixelPosition
    {
        GlyphAndSubPixelPosition(glyph_t g, QFixed spp) : glyph(g), subPixelPosition(spp) {}

        bool operator==(const GlyphAndSubPixelPosition &other) const
        {
            return glyph == other.glyph && subPixelPosition == other.subPixelPosition;
        }

        glyph_t glyph;
        QFixed subPixelPosition;
    };

    struct QGlyphSet
    {
        QGlyphSet();
        ~QGlyphSet();
        FT_Matrix transformationMatrix;
        unsigned long id; // server sided id, GlyphSet for X11
        bool outline_drawing;

        void removeGlyphFromCache(glyph_t index, QFixed subPixelPosition);
        void clear();
        inline bool useFastGlyphData(glyph_t index, QFixed subPixelPosition) const {
            return (index < 256 && subPixelPosition == 0);
        }
        inline Glyph *getGlyph(glyph_t index, QFixed subPixelPosition = 0) const
        {
            if (useFastGlyphData(index, subPixelPosition))
                return fast_glyph_data[index];
            return glyph_data.value(GlyphAndSubPixelPosition(index, subPixelPosition));
        }
        void setGlyph(glyph_t index, QFixed spp, Glyph *glyph);

private:
        mutable QHash<GlyphAndSubPixelPosition, Glyph *> glyph_data; // maps from glyph index to glyph data
        mutable Glyph *fast_glyph_data[256]; // for fast lookup of glyphs < 256
        mutable int fast_glyph_count;
    };

    virtual QFontEngine::FaceId faceId() const;
    virtual QFontEngine::Properties properties() const;
    virtual QFixed emSquareSize() const;
    virtual bool supportsSubPixelPositions() const
    {
        return default_hint_style == HintLight ||
               default_hint_style == HintNone;
    }

    virtual bool getSfntTableData(uint tag, uchar *buffer, uint *length) const;
    virtual int synthesized() const;

    virtual QFixed ascent() const;
    virtual QFixed descent() const;
    virtual QFixed leading() const;
    virtual QFixed xHeight() const;
    virtual QFixed averageCharWidth() const;

    virtual qreal maxCharWidth() const;
    virtual qreal minLeftBearing() const;
    virtual qreal minRightBearing() const;
    virtual QFixed lineThickness() const;
    virtual QFixed underlinePosition() const;

    void doKerning(QGlyphLayout *, QTextEngine::ShaperFlags) const;

    inline virtual Type type() const
    { return QFontEngine::Freetype; }
    inline virtual const char *name() const
    { return "freetype"; }

    virtual void getUnscaledGlyph(glyph_t glyph, QPainterPath *path, glyph_metrics_t *metrics);

    virtual bool canRender(const QChar *string, int len);

    virtual void addGlyphsToPath(glyph_t *glyphs, QFixedPoint *positions, int nglyphs,
                         QPainterPath *path, QTextItem::RenderFlags flags);
    virtual void addOutlineToPath(qreal x, qreal y, const QGlyphLayout &glyphs,
                          QPainterPath *path, QTextItem::RenderFlags flags);

    virtual bool stringToCMap(const QChar *str, int len, QGlyphLayout *glyphs, int *nglyphs,
                      QTextEngine::ShaperFlags flags) const;

    virtual glyph_metrics_t boundingBox(const QGlyphLayout &glyphs);
    virtual glyph_metrics_t boundingBox(glyph_t glyph);
    virtual glyph_metrics_t boundingBox(glyph_t glyph, const QTransform &matrix);

    virtual void recalcAdvances(QGlyphLayout *glyphs, QTextEngine::ShaperFlags flags) const;
    virtual QImage alphaMapForGlyph(glyph_t g) { return alphaMapForGlyph(g, 0); }
    virtual QImage alphaMapForGlyph(glyph_t, QFixed);
    virtual QImage alphaRGBMapForGlyph(glyph_t, QFixed subPixelPosition, int margin, const QTransform &t);
    virtual glyph_metrics_t alphaMapBoundingBox(glyph_t glyph,
                                                QFixed subPixelPosition,
                                                const QTransform &matrix,
                                                QFontEngine::GlyphFormat format);
    virtual void removeGlyphFromCache(glyph_t glyph);

    virtual int glyphCount() const;

    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 Glyph *loadGlyph(uint glyph, QFixed subPixelPosition, GlyphFormat format = Format_None, bool fetchMetricsOnly = false) const
    { return loadGlyph(&defaultGlyphSet, glyph, subPixelPosition, format, fetchMetricsOnly); }
    Glyph *loadGlyph(QGlyphSet *set, uint glyph, QFixed subPixelPosition, GlyphFormat = Format_None, bool fetchMetricsOnly = false) const;

    QGlyphSet *defaultGlyphs() { return &defaultGlyphSet; }
    GlyphFormat defaultGlyphFormat() const { return defaultFormat; }

    inline Glyph *cachedGlyph(glyph_t g) const { return defaultGlyphSet.getGlyph(g, 0); }

    QGlyphSet *loadTransformedGlyphSet(const QTransform &matrix);
    QFixed subPixelPositionForX(QFixed x);
    bool loadGlyphs(QGlyphSet *gs, const glyph_t *glyphs, int num_glyphs,
                    const QFixedPoint *positions,
                    GlyphFormat format = Format_Render);

#if defined(Q_WS_QWS) || defined(Q_OS_SYMBIAN)
    virtual void draw(QPaintEngine * /*p*/, qreal /*x*/, qreal /*y*/, const QTextItemInt & /*si*/) {}
#endif

    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);

    virtual HB_Error getPointInOutline(HB_Glyph glyph, int flags, hb_uint32 point, HB_Fixed *xpos, HB_Fixed *ypos, hb_uint32 *nPoints);

    enum HintStyle {
        HintNone,
        HintLight,
        HintMedium,
        HintFull
    };

    void setDefaultHintStyle(HintStyle style);

    virtual QFontEngine *cloneWithSize(qreal pixelSize) const;
    bool initFromFontEngine(const QFontEngineFT *fontEngine);

    HintStyle defaultHintStyle() const { return default_hint_style; }
protected:

    void freeGlyphSets();

    virtual bool uploadGlyphToServer(QGlyphSet *set, uint glyphid, Glyph *g, GlyphInfo *info, int glyphDataSize) const;
    virtual unsigned long allocateServerGlyphSet();
    virtual void freeServerGlyphSet(unsigned long id);

    QFreetypeFace *freetype;
    int default_load_flags;


    HintStyle default_hint_style;

    bool antialias;
    bool transform;
    bool embolden;
    SubpixelAntialiasingType subpixelType;
    int lcdFilterType;
    bool canUploadGlyphsToServer;
    bool embeddedbitmap;

private:
    friend class QFontEngineFTRawFont;

    int loadFlags(QGlyphSet *set, GlyphFormat format, int flags, bool &hsubpixel, int &vfactor) const;

    GlyphFormat defaultFormat;
    FT_Matrix matrix;

    QList<QGlyphSet> transformedGlyphSets;
    mutable QGlyphSet defaultGlyphSet;

    QFontEngine::FaceId face_id;

    int xsize;
    int ysize;

    mutable QFixed lbearing;
    mutable QFixed rbearing;
    QFixed line_thickness;
    QFixed underline_position;

    FT_Size_Metrics metrics;
    mutable bool kerning_pairs_loaded;
};

inline uint qHash(const QFontEngineFT::GlyphAndSubPixelPosition &g)
{
    return (g.glyph << 8)  | (g.subPixelPosition * 10).round().toInt();
}

QT_END_NAMESPACE

#endif // QT_NO_FREETYPE

#endif // QFONTENGINE_FT_P_H