qtextengine_p.h

奇趣公司比较新的qt/emd版本

    unsigned short charShape         :1;
    unsigned short digitSubstitute   :1;
    unsigned short inhibitLigate     :1;
    unsigned short fDisplayZWG        :1;
    unsigned short arabicNumContext  :1;
    unsigned short gcpClusters       :1;
    unsigned short reserved          :1;
    unsigned short engineReserved    :2;
};
Q_DECLARE_TYPEINFO(QScriptAnalysis, Q_PRIMITIVE_TYPE);

inline bool operator == (const QScriptAnalysis &sa1, const QScriptAnalysis &sa2)
{
    return
        sa1.script == sa2.script &&
        sa1.bidiLevel == sa2.bidiLevel;
        // ###
//             && override == other.override;
}

#endif

struct QGlyphLayout
{
    inline QGlyphLayout()
        : glyph(0), justificationType(0), nKashidas(0), space_18d6(0)
        {}

    // highest value means highest priority for justification. Justification is done by first inserting kashidas
    // starting with the highest priority positions, then stretching spaces, afterwards extending inter char
    // spacing, and last spacing between arabic words.
    // NoJustification is for example set for arabic where no Kashida can be inserted or for diacritics.
    enum Justification {
        NoJustification= 0,   // Justification can't be applied after this glyph
        Arabic_Space   = 1,   // This glyph represents a space inside arabic text
        Character      = 2,   // Inter-character justification point follows this glyph
        Space          = 4,   // This glyph represents a blank outside an Arabic run
        Arabic_Normal  = 7,   // Normal Middle-Of-Word glyph that connects to the right (begin)
        Arabic_Waw     = 8,    // Next character is final form of Waw/Ain/Qaf/Fa
        Arabic_BaRa    = 9,   // Next two chars are Ba + Ra/Ya/AlefMaksura
        Arabic_Alef    = 10,  // Next character is final form of Alef/Tah/Lam/Kaf/Gaf
        Arabic_HaaDal  = 11,  // Next character is final form of Haa/Dal/Taa Marbutah
        Arabic_Seen    = 12,  // Initial or Medial form Of Seen/Sad
        Arabic_Kashida = 13   // Kashida(U+640) in middle of word
    };

    glyph_t glyph;
    struct Attributes {
        unsigned short justification   :4;  // Justification class
        unsigned short clusterStart    :1;  // First glyph of representation of cluster
        unsigned short mark            :1;  // needs to be positioned around base char
        unsigned short zeroWidth       :1;  // ZWJ, ZWNJ etc, with no width
        unsigned short dontPrint       :1;
        unsigned short combiningClass  :8;
    };
    Attributes attributes;
    QFixedPoint advance;
    QFixedPoint offset;

    enum JustificationType {
        JustifyNone,
        JustifySpace,
        JustifyKashida
    };
    uint justificationType :2;
    uint nKashidas : 6; // more do not make sense...
    uint space_18d6 : 24;
};
Q_DECLARE_TYPEINFO(QGlyphLayout, Q_PRIMITIVE_TYPE);

inline bool qIsControlChar(ushort uc)
{
    return uc >= 0x200b && uc <= 0x206f
        && (uc <= 0x200f /* ZW Space, ZWNJ, ZWJ, LRM and RLM */
            || (uc >= 0x2028 && uc <= 0x202f /* LS, PS, LRE, RLE, PDF, LRO, RLO, NNBSP */)
            || uc >= 0x206a /* ISS, ASS, IAFS, AFS, NADS, NODS */);
}


struct QCharAttributes {
    enum LineBreakType {
        NoBreak,
        SoftHyphen,
        Break,
        ForcedBreak
    };
    uchar lineBreakType  :2;
    uchar whiteSpace     :1;     // A unicode whitespace character, except NBSP, ZWNBSP
    uchar charStop       :1;     // Valid cursor position (for left/right arrow)
};
Q_DECLARE_TYPEINFO(QCharAttributes, Q_PRIMITIVE_TYPE);

struct QScriptItem
{
    inline QScriptItem() : position(0), isSpace(false), isTab(false),
                           isObject(false),
                           num_glyphs(0), descent(-1), ascent(-1), width(-1),
                           glyph_data_offset(0) {}

    int position;
    QScriptAnalysis analysis;
    unsigned short isSpace  : 1;
    unsigned short isTab    : 1;
    unsigned short isObject : 1;
    int num_glyphs;
    QFixed descent;
    QFixed ascent;
    QFixed width;
    int glyph_data_offset;
    QFixed height() const { return ascent + descent; }
};


Q_DECLARE_TYPEINFO(QScriptItem, Q_MOVABLE_TYPE);

typedef QVector<QScriptItem> QScriptItemArray;

struct QScriptLine
{
    QScriptLine()
        : from(0), length(0),
        justified(0), gridfitted(0),
        hasTrailingSpaces(0) {}
    QFixed descent;
    QFixed ascent;
    QFixed x;
    QFixed y;
    QFixed width;
    QFixed textWidth;
    int from;
    signed int length : 29;
    mutable uint justified : 1;
    mutable uint gridfitted : 1;
    uint hasTrailingSpaces : 1;
    QFixed height() const { return ascent + descent + 1; }
    void setDefaultHeight(QTextEngine *eng);
    void operator+=(const QScriptLine &other);
};
Q_DECLARE_TYPEINFO(QScriptLine, Q_PRIMITIVE_TYPE);


inline void QScriptLine::operator+=(const QScriptLine &other)
{
    descent = qMax(descent, other.descent);
    ascent = qMax(ascent, other.ascent);
    textWidth += other.textWidth;
    length += other.length;
}

typedef QVector<QScriptLine> QScriptLineArray;

class QFontPrivate;
class QTextFormatCollection;

class Q_GUI_EXPORT QTextEngine {
public:
    struct LayoutData {
        LayoutData(const QString &str, void **stack_memory, int mem_size);
        LayoutData();
        ~LayoutData();
        mutable QScriptItemArray items;
        int allocated;
        int available_glyphs;
        void **memory;
        unsigned short *logClustersPtr;
        QGlyphLayout *glyphPtr;
        int num_glyphs;
        mutable int used;
        uint hasBidi : 1;
        uint inLayout : 1;
        uint memory_on_stack : 1;
        bool haveCharAttributes;
        QString string;
        void reallocate(int totalGlyphs);
    };

    QTextEngine(LayoutData *data);
    QTextEngine();
    QTextEngine(const QString &str, const QFont &f);
    ~QTextEngine();

    enum Mode {
        WidthOnly = 0x07
    };

    // keep in sync with QAbstractFontEngine::TextShapingFlag!!
    enum ShaperFlag {
        RightToLeft = 0x0001,
        DesignMetrics = 0x0002,
        GlyphIndicesOnly = 0x0004
    };
    Q_DECLARE_FLAGS(ShaperFlags, ShaperFlag)

    void invalidate();

    void validate() const;
    void itemize() const;

    static void bidiReorder(int numRuns, const quint8 *levels, int *visualOrder);

    const QCharAttributes *attributes() const;

    void shape(int item) const;

    void justify(const QScriptLine &si);

    QFixed width(int charFrom, int numChars) const;
    glyph_metrics_t boundingBox(int from,  int len) const;
    glyph_metrics_t tightBoundingBox(int from,  int len) const;

    int length(int item) const {
        const QScriptItem &si = layoutData->items[item];
        int from = si.position;
        item++;
        return (item < layoutData->items.size() ? layoutData->items[item].position : layoutData->string.length()) - from;
    }
    int length(const QScriptItem *si) const {
        int end;
        if (si + 1 < layoutData->items.constData()+ layoutData->items.size())
            end = (si+1)->position;
        else
            end = layoutData->string.length();
        return end - si->position;
    }

    QFontEngine *fontEngine(const QScriptItem &si, QFixed *ascent = 0, QFixed *descent = 0) const;
    QFont font(const QScriptItem &si) const;
    inline QFont font() const { return fnt; }

    inline unsigned short *logClusters(const QScriptItem *si) const
        { return layoutData->logClustersPtr+si->position; }
    inline QGlyphLayout *glyphs(const QScriptItem *si) const
        { return layoutData->glyphPtr + si->glyph_data_offset; }

    inline void ensureSpace(int nGlyphs) const {
        if (layoutData->num_glyphs - layoutData->used < nGlyphs)
            layoutData->reallocate((((layoutData->used + nGlyphs)*3/2 + 15) >> 4) << 4);
    }

    void freeMemory();

    int findItem(int strPos) const;
    inline QTextFormatCollection *formats() const {
#ifdef QT_BUILD_COMPAT_LIB
        return 0; // Compat should never reference this symbol
#else
        return block.docHandle()->formatCollection();
#endif
    }
    QTextCharFormat format(const QScriptItem *si) const;
    inline QAbstractTextDocumentLayout *docLayout() const {
#ifdef QT_BUILD_COMPAT_LIB
        return 0; // Compat should never reference this symbol
#else
        return block.docHandle()->document()->documentLayout();
#endif
    }
    int formatIndex(const QScriptItem *si) const;

    QFixed nextTab(const QScriptItem *si, QFixed x) const;

    mutable QScriptLineArray lines;

    QString text;
    QFont fnt;
    QTextBlock block;

    QTextOption option;

    QFixed minWidth;
    QFixed maxWidth;
    QPointF position;
    uint ignoreBidi : 1;
    uint cacheGlyphs : 1;
    uint stackEngine : 1;
    uint forceJustification : 1;

    int *underlinePositions;

    mutable LayoutData *layoutData;

    inline bool hasFormats() const { return (block.docHandle() || specialData); }

    struct SpecialData {
        int preeditPosition;
        QString preeditText;
        QList<QTextLayout::FormatRange> addFormats;
        QVector<int> addFormatIndices;
        QVector<int> resolvedFormatIndices;
    };
    SpecialData *specialData;

    bool atWordSeparator(int position) const;
    void indexAdditionalFormats();

    QString elidedText(Qt::TextElideMode mode, const QFixed &width, int flags = 0) const;

private:
    void setBoundary(int strPos) const;
    void addRequiredBoundaries() const;
    void shapeText(int item) const;
    void splitItem(int item, int pos) const;

    void resolveAdditionalFormats() const;
};

class QStackTextEngine : public QTextEngine {
public:
    enum { MemSize = 256*40/sizeof(void *) };
    QStackTextEngine(const QString &string, const QFont &f);
    LayoutData _layoutData;
    void *_memory[MemSize];
};


Q_DECLARE_OPERATORS_FOR_FLAGS(QTextEngine::ShaperFlags)


#endif // QTEXTENGINE_P_H