Source/WebCore/platform/graphics/TextRun.h

/*
 * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
 *           (C) 2000 Antti Koivisto (koivisto@kde.org)
 *           (C) 2000 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2003, 2006, 2007, 2011 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#ifndef TextRun_h
#define TextRun_h

#include "TextDirection.h"
#include <wtf/RefCounted.h>
#include <wtf/text/WTFString.h>

namespace WebCore {

class FloatPoint;
class FloatRect;
class Font;
class GraphicsContext;
class GlyphBuffer;
class SimpleFontData;
struct GlyphData;
struct WidthIterator;

class TextRun {
public:
    enum ExpansionBehaviorFlags {
        ForbidTrailingExpansion = 0 << 0,
        AllowTrailingExpansion = 1 << 0,
        ForbidLeadingExpansion = 0 << 1,
        AllowLeadingExpansion = 1 << 1,
    };

    typedef unsigned ExpansionBehavior;

    enum RoundingHackFlags {
        NoRounding = 0,
        RunRounding = 1 << 0,
        WordRounding = 1 << 1,
    };

    typedef unsigned RoundingHacks;

    TextRun(const UChar* c, int len, float xpos = 0, float expansion = 0, ExpansionBehavior expansionBehavior = AllowTrailingExpansion | ForbidLeadingExpansion, TextDirection direction = LTR, bool directionalOverride = false, bool characterScanForCodePath = true, RoundingHacks roundingHacks = RunRounding | WordRounding)
        : m_characters(c)
        , m_charactersLength(len)
        , m_len(len)
        , m_xpos(xpos)
#if ENABLE(SVG)
        , m_horizontalGlyphStretch(1)
#endif
        , m_expansion(expansion)
        , m_expansionBehavior(expansionBehavior)
        , m_allowTabs(false)
        , m_direction(direction)
        , m_directionalOverride(directionalOverride)
        , m_characterScanForCodePath(characterScanForCodePath)
        , m_applyRunRounding((roundingHacks & RunRounding) && s_allowsRoundingHacks)
        , m_applyWordRounding((roundingHacks & WordRounding) && s_allowsRoundingHacks)
        , m_disableSpacing(false)
        , m_tabSize(0)
    {
    }

    TextRun(const String& s, float xpos = 0, float expansion = 0, ExpansionBehavior expansionBehavior = AllowTrailingExpansion | ForbidLeadingExpansion, TextDirection direction = LTR, bool directionalOverride = false, bool characterScanForCodePath = true, RoundingHacks roundingHacks = RunRounding | WordRounding)
        : m_characters(s.characters())
        , m_charactersLength(s.length())
        , m_len(s.length())
        , m_xpos(xpos)
#if ENABLE(SVG)
        , m_horizontalGlyphStretch(1)
#endif
        , m_expansion(expansion)
        , m_expansionBehavior(expansionBehavior)
        , m_allowTabs(false)
        , m_direction(direction)
        , m_directionalOverride(directionalOverride)
        , m_characterScanForCodePath(characterScanForCodePath)
        , m_applyRunRounding((roundingHacks & RunRounding) && s_allowsRoundingHacks)
        , m_applyWordRounding((roundingHacks & WordRounding) && s_allowsRoundingHacks)
        , m_disableSpacing(false)
        , m_tabSize(0)
    {
    }

    UChar operator[](int i) const { ASSERT(i >= 0 && i < m_len); return m_characters[i]; }
    const UChar* data(int i) const { ASSERT(i >= 0 && i < m_len); return &m_characters[i]; }

    const UChar* characters() const { return m_characters; }
    int length() const { return m_len; }
    int charactersLength() const { return m_charactersLength; }

    void setText(const UChar* c, int len) { m_characters = c; m_len = len; }
    void setCharactersLength(int charactersLength) { m_charactersLength = charactersLength; }

#if ENABLE(SVG)
    float horizontalGlyphStretch() const { return m_horizontalGlyphStretch; }
    void setHorizontalGlyphStretch(float scale) { m_horizontalGlyphStretch = scale; }
#endif

    bool allowTabs() const { return m_allowTabs; }
    unsigned tabSize() const { return m_tabSize; }
    void setTabSize(bool, unsigned);

    float xPos() const { return m_xpos; }
    void setXPos(float xPos) { m_xpos = xPos; }
    float expansion() const { return m_expansion; }
    bool allowsLeadingExpansion() const { return m_expansionBehavior & AllowLeadingExpansion; }
    bool allowsTrailingExpansion() const { return m_expansionBehavior & AllowTrailingExpansion; }
    TextDirection direction() const { return static_cast<TextDirection>(m_direction); }
    bool rtl() const { return m_direction == RTL; }
    bool ltr() const { return m_direction == LTR; }
    bool directionalOverride() const { return m_directionalOverride; }
    bool characterScanForCodePath() const { return m_characterScanForCodePath; }
    bool applyRunRounding() const { return m_applyRunRounding; }
    bool applyWordRounding() const { return m_applyWordRounding; }
    bool spacingDisabled() const { return m_disableSpacing; }

    void disableSpacing() { m_disableSpacing = true; }
    void disableRoundingHacks() { m_applyRunRounding = m_applyWordRounding = false; }
    void setDirection(TextDirection direction) { m_direction = direction; }
    void setDirectionalOverride(bool override) { m_directionalOverride = override; }
    void setCharacterScanForCodePath(bool scan) { m_characterScanForCodePath = scan; }

    class RenderingContext : public RefCounted<RenderingContext> {
    public:
        virtual ~RenderingContext() { }

#if ENABLE(SVG_FONTS)
        virtual GlyphData glyphDataForCharacter(const Font&, const TextRun&, WidthIterator&, UChar32 character, bool mirror, int currentCharacter, unsigned& advanceLength) = 0;
        virtual void drawSVGGlyphs(GraphicsContext*, const TextRun&, const SimpleFontData*, const GlyphBuffer&, int from, int to, const FloatPoint&) const = 0;
        virtual float floatWidthUsingSVGFont(const Font&, const TextRun&, int& charsConsumed, String& glyphName) const = 0;
#endif
    };

    RenderingContext* renderingContext() const { return m_renderingContext.get(); }
    void setRenderingContext(PassRefPtr<RenderingContext> context) { m_renderingContext = context; }

    static void setAllowsRoundingHacks(bool);
    static bool allowsRoundingHacks();

private:
    static bool s_allowsRoundingHacks;

    const UChar* m_characters;
    int m_charactersLength; // Marks the end of the m_characters buffer. Default equals to m_len.
    int m_len;

    // m_xpos is the x position relative to the left start of the text line, not relative to the left
    // start of the containing block. In the case of right alignment or center alignment, left start of
    // the text line is not the same as left start of the containing block.
    float m_xpos;  
#if ENABLE(SVG)
    float m_horizontalGlyphStretch;
#endif

    float m_expansion;
    ExpansionBehavior m_expansionBehavior : 2;
    unsigned m_allowTabs : 1;
    unsigned m_direction : 1;
    unsigned m_directionalOverride : 1; // Was this direction set by an override character.
    unsigned m_characterScanForCodePath : 1;
    unsigned m_applyRunRounding : 1;
    unsigned m_applyWordRounding : 1;
    unsigned m_disableSpacing : 1;
    unsigned m_tabSize;
    RefPtr<RenderingContext> m_renderingContext;
};

inline void TextRun::setTabSize(bool allow, unsigned size)
{
    m_allowTabs = allow;
    m_tabSize = size;
}

}

#endif