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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_P_H

#define QFONTENGINE_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 <QtGui/private/qtguiglobal_p.h>

#include <QtGui/qfontvariableaxis.h>

#include "QtCore/qatomic.h"

#include <QtCore/qvarlengtharray.h>

#include <QtCore/qhashfunctions.h>

#include "private/qtextengine_p.h"

#include "private/qfont_p.h"

QT_BEGIN_NAMESPACE

class QPainterPath;

class QFontEngineGlyphCache;

struct QGlyphLayout;

// ### this only used in getPointInOutline(), refactor it and then remove these magic numbers

enum HB_Compat_Error {

    Err_Ok                           = 0x0000,

    Err_Not_Covered                  = 0xFFFF,

    Err_Invalid_Argument             = 0x1A66,

    Err_Invalid_SubTable_Format      = 0x157F,

    Err_Invalid_SubTable             = 0x1570

};

typedef void (*qt_destroy_func_t) (void *user_data);

typedef bool (*qt_get_font_table_func_t) (void *user_data, uint tag, uchar *buffer, uint *length);

Q_DECLARE_LOGGING_CATEGORY(lcColrv1)

class Q_GUI_EXPORT QFontEngine

public:

    enum Type {

        Box,

        Multi,

        // MS Windows types

        Win,

        // Apple Mac OS types

        Mac,

        // QWS types

        Freetype,

        QPF1,

        QPF2,

        Proxy,

        DirectWrite,

        TestFontEngine = 0x1000

};

    enum GlyphFormat {

        Format_None,

        Format_Render = Format_None,

        Format_Mono,

        Format_A8,

        Format_A32,

        Format_ARGB

};

    enum ShaperFlag {

        DesignMetrics = 0x0002,

        GlyphIndicesOnly = 0x0004,

        FullStringFallback = 0x008

};

    Q_DECLARE_FLAGS(ShaperFlags, ShaperFlag)

    /* Used with the Freetype font engine. */

    struct Glyph {

        Glyph() = default;

        ~Glyph() { delete [] data; }

        short linearAdvance = 0;

        unsigned short width = 0;

        unsigned short height = 0;

        short x = 0;

        short y = 0;

        short advance = 0;

        signed char format = 0;

        uchar *data = nullptr;

    private:

        Q_DISABLE_COPY(Glyph)

};

    virtual ~QFontEngine();

    inline Type type() const { return m_type; }

    // all of these are in unscaled metrics if the engine supports uncsaled metrics,

    // otherwise in design metrics

    struct Properties {

        QByteArray postscriptName;

        QByteArray copyright;

        QRectF boundingBox;

        QFixed emSquare;

        QFixed ascent;

        QFixed descent;

        QFixed leading;

        QFixed italicAngle;

        QFixed capHeight;

        QFixed lineWidth;

};

    virtual Properties properties() const;

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

    QByteArray getSfntTable(uint tag) const;

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

    struct FaceId {

        FaceId() : index(0), instanceIndex(-1), encoding(0) {}

        QByteArray filename;

        QByteArray uuid;

        int index;

        int instanceIndex;

        int encoding;

        QMap<QFont::Tag, float> variableAxes;

};

    virtual FaceId faceId() const { return FaceId(); }

    enum SynthesizedFlags {

        SynthesizedItalic = 0x1,

        SynthesizedBold = 0x2,

        SynthesizedStretch = 0x4

};

    virtual int synthesized() const { return 0; }

    inline bool supportsSubPixelPositions() const

        return supportsHorizontalSubPixelPositions() || supportsVerticalSubPixelPositions();

    virtual bool supportsHorizontalSubPixelPositions() const { return false; }

    virtual bool supportsVerticalSubPixelPositions() const { return false; }

    virtual QFixedPoint subPixelPositionFor(const QFixedPoint &position) const;

    QFixed subPixelPositionForX(QFixed x) const

        return subPixelPositionFor(QFixedPoint(x, 0)).x;

    bool preferTypoLineMetrics() const;

    bool isColorFont() const { return glyphFormat == Format_ARGB; }

    static bool isIgnorableChar(char32_t ucs4)

        return ucs4 == QChar::LineSeparator

               || ucs4 == QChar::LineFeed

               || ucs4 == QChar::CarriageReturn

               || ucs4 == QChar::ParagraphSeparator

               || (!disableEmojiSegmenter() && (ucs4 & 0xFFF0) == 0xFE00)

               || QChar::category(ucs4) == QChar::Other_Control;

    static int maxCachedGlyphSize();

    virtual QFixed emSquareSize() const;

    /* returns 0 as glyph index for non existent glyphs */

    virtual glyph_t glyphIndex(uint ucs4) const = 0;

    virtual int stringToCMap(const QChar *str, int len, QGlyphLayout *glyphs, int *nglyphs, ShaperFlags flags) const = 0;

    virtual void recalcAdvances(QGlyphLayout *, ShaperFlags) const {}

    virtual void doKerning(QGlyphLayout *, ShaperFlags) const;

    virtual void addGlyphsToPath(glyph_t *glyphs, QFixedPoint *positions, int nglyphs,

                                 QPainterPath *path, QTextItem::RenderFlags flags);

    void getGlyphPositions(const QGlyphLayout &glyphs, const QTransform &matrix, QTextItem::RenderFlags flags,

                           QVarLengthArray<glyph_t> &glyphs_out, QVarLengthArray<QFixedPoint> &positions);

    virtual void addOutlineToPath(qreal, qreal, const QGlyphLayout &, QPainterPath *, QTextItem::RenderFlags flags);

    void addBitmapFontToPath(qreal x, qreal y, const QGlyphLayout &, QPainterPath *, QTextItem::RenderFlags);

/**

     * Create a qimage with the alpha values for the glyph.

     * Returns an image indexed_8 with index values ranging from 0=fully transparent to 255=opaque

*/

    // ### Refactor this into a smaller and more flexible API.

    virtual QImage alphaMapForGlyph(glyph_t);

    virtual QImage alphaMapForGlyph(glyph_t glyph, const QFixedPoint &subPixelPosition);

    virtual QImage alphaMapForGlyph(glyph_t, const QTransform &t);

    virtual QImage alphaMapForGlyph(glyph_t, const QFixedPoint &subPixelPosition, const QTransform &t);

    virtual QImage alphaRGBMapForGlyph(glyph_t, const QFixedPoint &subPixelPosition, const QTransform &t);

    virtual QImage bitmapForGlyph(glyph_t, const QFixedPoint &subPixelPosition, const QTransform &t, const QColor &color = QColor());

    QImage renderedPathForGlyph(glyph_t glyph, const QColor &color);

    qreal effectivePixelSizeSquared(const QTransform &transform) const;

    static bool glyphBoundingBoxExceedsLimit(qreal glyphWidth,

                                             qreal glyphHeight,

                                             qreal effectivePixelSizeSquared);

    bool glyphTransformExceedsLimit(glyph_t glyph, const QTransform &transform);

    virtual Glyph *glyphData(glyph_t glyph, const QFixedPoint &subPixelPosition, GlyphFormat neededFormat, const QTransform &t);

    virtual bool hasInternalCaching() const { return false; }

    virtual glyph_metrics_t alphaMapBoundingBox(glyph_t glyph, const QFixedPoint &/*subPixelPosition*/, const QTransform &matrix, GlyphFormat /*format*/)

        return boundingBox(glyph, matrix);

    virtual void removeGlyphFromCache(glyph_t);

    virtual glyph_metrics_t boundingBox(const QGlyphLayout &glyphs);

    virtual glyph_metrics_t boundingBox(glyph_t glyph) = 0;

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

    glyph_metrics_t tightBoundingBox(const QGlyphLayout &glyphs, QTextItem::RenderFlags flags);

    virtual QFixed ascent() const;

    virtual QFixed capHeight() const = 0;

    virtual QFixed descent() const;

    virtual QFixed leading() const;

    virtual QFixed xHeight() const;

    virtual QFixed averageCharWidth() const;

    virtual QFixed lineThickness() const;

    virtual QFixed underlinePosition() const;

    virtual qreal maxCharWidth() const = 0;

    virtual qreal minLeftBearing() const;

    virtual qreal minRightBearing() const;

    virtual void getGlyphBearings(glyph_t glyph, qreal *leftBearing = nullptr, qreal *rightBearing = nullptr);

    inline bool canRender(uint ucs4) const { return glyphIndex(ucs4) != 0; }

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

    virtual bool supportsTransformation(const QTransform &transform) const;

    virtual int glyphCount() const;

    virtual int glyphMargin(GlyphFormat format) { return format == Format_A32 ? 2 : 0; }

    bool hasHinting() const;

    virtual QFontEngine *cloneWithSize(qreal /*pixelSize*/) const { return nullptr; }

    virtual Qt::HANDLE handle() const;

    virtual QList<QFontVariableAxis> variableAxes() const;

    virtual QString glyphName(glyph_t index) const;

    virtual glyph_t findGlyph(QLatin1StringView name) const;

    void *harfbuzzFont() const;

    void *harfbuzzFace() const;

    bool supportsScript(QChar::Script script) const;

    inline static bool scriptRequiresOpenType(QChar::Script script)

        return ((script >= QChar::Script_Syriac && script <= QChar::Script_Sinhala)

                || script == QChar::Script_Khmer || script == QChar::Script_Nko);

    virtual int getPointInOutline(glyph_t glyph, int flags, quint32 point, QFixed *xpos, QFixed *ypos, quint32 *nPoints);

    void clearGlyphCache(const void *key);

    void setGlyphCache(const void *key, QFontEngineGlyphCache *data);

    QFontEngineGlyphCache *glyphCache(const void *key, GlyphFormat format, const QTransform &transform, const QColor &color = QColor()) const;

    static const uchar *getCMap(const uchar *table, uint tableSize, bool *isSymbolFont, int *cmapSize);

    static quint32 getTrueTypeGlyphIndex(const uchar *cmap, int cmapSize, uint unicode);

    static QByteArray convertToPostscriptFontFamilyName(const QByteArray &fontFamily);

    virtual bool hasUnreliableGlyphOutline() const;

    virtual bool expectsGammaCorrectedBlending(QFontEngine::GlyphFormat format) const;

    static bool disableEmojiSegmenter();

    static constexpr qsizetype maximumEngineCount() { return 256; }

    enum HintStyle {

        HintUnset = -1,

        HintNone,

        HintLight,

        HintMedium,

        HintFull

};

    virtual void setDefaultHintStyle(HintStyle) { }

    enum SubpixelAntialiasingType {

        Subpixel_Unset = -1,

        Subpixel_None,

        Subpixel_RGB,

        Subpixel_BGR,

        Subpixel_VRGB,

        Subpixel_VBGR

};

private:

    const Type m_type;

public:

    QAtomicInt ref;

    QFontDef fontDef;

    class Holder { // replace by std::unique_ptr once available

        void *ptr;

        qt_destroy_func_t destroy_func;

    public:

        Holder() : ptr(nullptr), destroy_func(nullptr) {}

        explicit Holder(void *p, qt_destroy_func_t d) : ptr(p), destroy_func(d) {}

        ~Holder() { if (ptr && destroy_func) destroy_func(ptr); }

        Holder(Holder &&other) noexcept

            : ptr(std::exchange(other.ptr, nullptr)),

              destroy_func(std::exchange(other.destroy_func, nullptr))

        QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_PURE_SWAP(Holder)

        void swap(Holder &other) noexcept

            qSwap(ptr, other.ptr);

            qSwap(destroy_func, other.destroy_func);

        void *get() const noexcept { return ptr; }

        void *release() noexcept {

            void *result = ptr;

            ptr = nullptr;

            destroy_func = nullptr;

            return result;

        void reset() noexcept { Holder().swap(*this); }

        qt_destroy_func_t get_deleter() const noexcept { return destroy_func; }

        bool operator!() const noexcept { return !ptr; }

};

    mutable Holder font_; // \ NOTE: Declared before m_glyphCaches, so font_, face_

    mutable Holder face_; // / are destroyed _after_ m_glyphCaches is destroyed.

    struct FaceData {

        void *user_data;

        qt_get_font_table_func_t get_font_table;

    } faceData;

    uint cache_cost; // amount of mem used in bytes by the font

    uint fsType : 16;

    bool symbol;

    bool isSmoothlyScalable;

    struct KernPair {

        uint left_right;

        QFixed adjust;

        inline bool operator<(const KernPair &other) const

            return left_right < other.left_right;

};

    QList<KernPair> kerning_pairs;

    void loadKerningPairs(QFixed scalingFactor);

    GlyphFormat glyphFormat;

    int m_subPixelPositionCount; // Number of positions within a single pixel for this cache

protected:

    explicit QFontEngine(Type type);

    QFixed firstLeftBearing(const QGlyphLayout &glyphs);

    QFixed lastRightBearing(const QGlyphLayout &glyphs);

    QFixed calculatedCapHeight() const;

    mutable QFixed m_ascent;

    mutable QFixed m_descent;

    mutable QFixed m_leading;

    mutable bool m_heightMetricsQueried;

    virtual void initializeHeightMetrics() const;

    bool processHheaTable() const;

    bool processOS2Table() const;

private:

    struct GlyphCacheEntry {

        GlyphCacheEntry();

        GlyphCacheEntry(const GlyphCacheEntry &);

        ~GlyphCacheEntry();

        GlyphCacheEntry &operator=(const GlyphCacheEntry &);

        QExplicitlySharedDataPointer<QFontEngineGlyphCache> cache;

        bool operator==(const GlyphCacheEntry &other) const { return cache == other.cache; }

};

    typedef std::list<GlyphCacheEntry> GlyphCaches;

    mutable QHash<const void *, GlyphCaches> m_glyphCaches;

private:

    mutable qreal m_minLeftBearing;

    mutable qreal m_minRightBearing;

    mutable int m_hasHinting = -1;

};

Q_DECLARE_TYPEINFO(QFontEngine::KernPair, Q_PRIMITIVE_TYPE);

Q_DECLARE_OPERATORS_FOR_FLAGS(QFontEngine::ShaperFlags)

inline bool operator ==(const QFontEngine::FaceId &f1, const QFontEngine::FaceId &f2)

    return f1.index == f2.index

            && f1.encoding == f2.encoding

            && f1.filename == f2.filename

            && f1.uuid == f2.uuid

            && f1.instanceIndex == f2.instanceIndex

            && f1.variableAxes == f2.variableAxes;

inline size_t qHash(const QFontEngine::FaceId &f, size_t seed = 0)

    noexcept(noexcept(qHash(f.filename)))

    return qHashMulti(seed, f.filename, f.uuid, f.index, f.instanceIndex, f.encoding, f.variableAxes.keys(), f.variableAxes.values());

class QGlyph;

class QFontEngineBox : public QFontEngine

public:

    QFontEngineBox(int size);

    ~QFontEngineBox();

    virtual glyph_t glyphIndex(uint ucs4) const override;

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

    virtual void recalcAdvances(QGlyphLayout *, ShaperFlags) const override;

    void draw(QPaintEngine *p, qreal x, qreal y, const QTextItemInt &si);

    virtual void addOutlineToPath(qreal x, qreal y, const QGlyphLayout &glyphs, QPainterPath *path, QTextItem::RenderFlags flags) override;

    virtual glyph_metrics_t boundingBox(const QGlyphLayout &glyphs) override;

    virtual glyph_metrics_t boundingBox(glyph_t glyph) override;

    virtual QFontEngine *cloneWithSize(qreal pixelSize) const override;

    virtual QFixed emSquareSize() const override { return _size; }

    virtual QFixed ascent() const override;

    virtual QFixed capHeight() const override;

    virtual QFixed descent() const override;

    virtual QFixed leading() const override;

    virtual qreal maxCharWidth() const override;

    virtual qreal minLeftBearing() const override { return 0; }

    virtual qreal minRightBearing() const override { return 0; }

    virtual QImage alphaMapForGlyph(glyph_t) override;

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

    inline int size() const { return _size; }

protected:

    explicit QFontEngineBox(Type type, int size);

private:

    friend class QFontPrivate;

    int _size;

};

class Q_GUI_EXPORT QFontEngineMulti : public QFontEngine

public:

    explicit QFontEngineMulti(QFontEngine *engine, int script, const QStringList &fallbackFamilies = QStringList());

    ~QFontEngineMulti();

    virtual int glyphCount() const override;

    virtual glyph_t glyphIndex(uint ucs4) const override;

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

    virtual glyph_metrics_t boundingBox(const QGlyphLayout &glyphs) override;

    virtual glyph_metrics_t boundingBox(glyph_t glyph) override;

    virtual void recalcAdvances(QGlyphLayout *, ShaperFlags) const override;

    virtual void doKerning(QGlyphLayout *, ShaperFlags) const override;

    virtual void addOutlineToPath(qreal, qreal, const QGlyphLayout &, QPainterPath *, QTextItem::RenderFlags flags) override;

    virtual void getGlyphBearings(glyph_t glyph, qreal *leftBearing = nullptr, qreal *rightBearing = nullptr) override;

    virtual QFixed emSquareSize() const override;

    virtual QFixed ascent() const override;

    virtual QFixed capHeight() const override;

    virtual QFixed descent() const override;

    virtual QFixed leading() const override;

    virtual QFixed xHeight() const override;

    virtual QFixed averageCharWidth() const override;

    virtual QImage alphaMapForGlyph(glyph_t) override;

    virtual QImage alphaMapForGlyph(glyph_t glyph, const QFixedPoint &subPixelPosition) override;

    virtual QImage alphaMapForGlyph(glyph_t, const QTransform &t) override;

    virtual QImage alphaMapForGlyph(glyph_t, const QFixedPoint &subPixelPosition, const QTransform &t) override;

    virtual QImage alphaRGBMapForGlyph(glyph_t, const QFixedPoint &subPixelPosition, const QTransform &t) override;

    virtual QFixed lineThickness() const override;

    virtual QFixed underlinePosition() const override;

    virtual qreal maxCharWidth() const override;

    virtual qreal minLeftBearing() const override;

    virtual qreal minRightBearing() const override;

    virtual QList<QFontVariableAxis> variableAxes() const override;

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

    QString glyphName(glyph_t glyph) const override;

    glyph_t findGlyph(QLatin1StringView name) const override;

    inline int fallbackFamilyCount() const { return m_fallbackFamilies.size(); }

    inline QString fallbackFamilyAt(int at) const { return m_fallbackFamilies.at(at); }

    void setFallbackFamiliesList(const QStringList &fallbackFamilies);

    static uchar highByte(glyph_t glyph); // Used for determining engine

    inline QFontEngine *engine(int at) const

    { Q_ASSERT(at < m_engines.size()); return m_engines.at(at); }

    void ensureEngineAt(int at);

    static QFontEngine *createMultiFontEngine(QFontEngine *fe, int script);

protected:

    virtual void ensureFallbackFamiliesQueried();

    virtual bool shouldLoadFontEngineForCharacter(int at, uint ucs4) const;

    virtual QFontEngine *loadEngine(int at);

private:

    QList<QFontEngine *> m_engines;

    QStringList m_fallbackFamilies;

    const int m_script;

    bool m_fallbackFamiliesQueried;

};

class QTestFontEngine : public QFontEngineBox

public:

    QTestFontEngine(int size);

};

QT_END_NAMESPACE

#endif // QFONTENGINE_P_H