flutter_flutter/sky/engine/core/rendering/RenderText.h

/*
 * (C) 1999 Lars Knoll (knoll@kde.org)
 * (C) 2000 Dirk Mueller (mueller@kde.org)
 * Copyright (C) 2004-2009, 2013 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 SKY_ENGINE_CORE_RENDERING_RENDERTEXT_H_
#define SKY_ENGINE_CORE_RENDERING_RENDERTEXT_H_

#include <vector>

#include "sky/engine/core/rendering/RenderObject.h"
#include "sky/engine/platform/LengthFunctions.h"
#include "sky/engine/platform/text/TextPath.h"
#include "sky/engine/wtf/Forward.h"
#include "sky/engine/wtf/PassRefPtr.h"

namespace blink {
class InlineTextBox;
class TextBox;

class RenderText : public RenderObject {
public:
    // FIXME: If the node argument is not a Text node or the string argument is
    // not the content of the Text node, updating text-transform property
    // doesn't re-transform the string.
    RenderText(PassRefPtr<StringImpl>);
#if ENABLE(ASSERT)
    virtual ~RenderText();
#endif

    virtual const char* renderName() const override;

    void extractTextBox(InlineTextBox*);
    void attachTextBox(InlineTextBox*);
    void removeTextBox(InlineTextBox*);

    const String& text() const { return m_text; }
    virtual unsigned textStartOffset() const { return 0; }

    InlineTextBox* createInlineTextBox();
    void dirtyLineBoxes(bool fullLayout);

    void appendAbsoluteTextBoxesForRange(std::vector<TextBox>&, unsigned startOffset = 0, unsigned endOffset = INT_MAX);

    virtual void absoluteQuads(Vector<FloatQuad>&) const override final;
    void absoluteQuadsForRange(Vector<FloatQuad>&, unsigned startOffset = 0, unsigned endOffset = INT_MAX, bool useSelectionHeight = false);

    enum ClippingOption { NoClipping, ClipToEllipsis };
    void absoluteQuads(Vector<FloatQuad>&, ClippingOption = NoClipping) const;

    virtual PositionWithAffinity positionForPoint(const LayoutPoint&) override;

    bool is8Bit() const { return m_text.is8Bit(); }
    const LChar* characters8() const { return m_text.impl()->characters8(); }
    const UChar* characters16() const { return m_text.impl()->characters16(); }
    bool hasEmptyText() const { return m_text.isEmpty(); }
    String substring(unsigned position, unsigned length) const { return m_text.substring(position, length); }
    UChar characterAt(unsigned) const;
    UChar uncheckedCharacterAt(unsigned) const;
    UChar operator[](unsigned i) const { return uncheckedCharacterAt(i); }
    unsigned textLength() const { return m_text.length(); } // non virtual implementation of length()
    void positionLineBox(InlineBox*);

    virtual float width(unsigned from, unsigned len, const Font&, float xPos, TextDirection, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;
    virtual float width(unsigned from, unsigned len, float xPos, TextDirection, bool firstLine = false, HashSet<const SimpleFontData*>* fallbackFonts = 0, GlyphOverflow* = 0) const;

    float minLogicalWidth() const;
    float maxLogicalWidth() const;

    void trimmedPrefWidths(float leadWidth,
        float& firstLineMinWidth, bool& hasBreakableStart,
        float& lastLineMinWidth, bool& hasBreakableEnd,
        bool& hasBreakableChar, bool& hasBreak,
        float& firstLineMaxWidth, float& lastLineMaxWidth,
        float& minWidth, float& maxWidth, bool& stripFrontSpaces,
        TextDirection);

    virtual IntRect linesBoundingBox() const;
    LayoutRect linesVisualOverflowBoundingBox() const;

    FloatPoint firstRunOrigin() const;
    float firstRunX() const;
    float firstRunY() const;

    virtual void setText(PassRefPtr<StringImpl>, bool force = false);
    void setTextWithOffset(PassRefPtr<StringImpl>, unsigned offset, unsigned len, bool force = false);

    virtual bool canBeSelectionLeaf() const override { return true; }
    virtual void setSelectionState(SelectionState s) override final;
    virtual LayoutRect localCaretRect(InlineBox*, int caretOffset, LayoutUnit* extraWidthToEndOfLine = 0) override;

    LayoutUnit marginLeft() const { return minimumValueForLength(style()->marginLeft(), 0); }
    LayoutUnit marginRight() const { return minimumValueForLength(style()->marginRight(), 0); }

    InlineTextBox* firstTextBox() const { return m_firstTextBox; }
    InlineTextBox* lastTextBox() const { return m_lastTextBox; }

    virtual int caretMinOffset() const override;
    virtual int caretMaxOffset() const override;
    unsigned renderedTextLength() const;

    virtual int previousOffset(int current) const override final;
    virtual int previousOffsetForBackwardDeletion(int current) const override final;
    virtual int nextOffset(int current) const override final;

    bool containsReversedText() const { return m_containsReversedText; }

    void checkConsistency() const;

    bool isAllCollapsibleWhitespace() const;

    bool canUseSimpleFontCodePath() const { return m_canUseSimpleFontCodePath; }

    void removeAndDestroyTextBoxes();

protected:
    virtual void willBeDestroyed() override;

    virtual void styleWillChange(StyleDifference, const RenderStyle&) override final { }
    virtual void styleDidChange(StyleDifference, const RenderStyle* oldStyle) override;

    virtual void setTextInternal(PassRefPtr<StringImpl>);
    virtual UChar previousCharacter() const;

    InlineTextBox* createTextBox();

private:
    void computePreferredLogicalWidths(float leadWidth);
    void computePreferredLogicalWidths(float leadWidth, HashSet<const SimpleFontData*>& fallbackFonts, GlyphOverflow&);

    bool computeCanUseSimpleFontCodePath() const;

    // Make length() private so that callers that have a RenderText*
    // will use the more efficient textLength() instead, while
    // callers with a RenderObject* can continue to use length().
    virtual unsigned length() const override final { return textLength(); }

    virtual void paint(PaintInfo&, const LayoutPoint&, Vector<RenderBox*>& layers) override final { ASSERT_NOT_REACHED(); }
    virtual void layout() override final { ASSERT_NOT_REACHED(); }
    virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation&, const LayoutPoint&) override final { ASSERT_NOT_REACHED(); return false; }

    void deleteTextBoxes();
    bool containsOnlyWhitespace(unsigned from, unsigned len) const;
    float widthFromCache(const Font&, int start, int len, float xPos, TextDirection, HashSet<const SimpleFontData*>* fallbackFonts, GlyphOverflow*) const;
    bool isAllASCII() const { return m_isAllASCII; }

    bool isText() const = delete; // This will catch anyone doing an unnecessary check.

    // We put the bitfield first to minimize padding on 64-bit.
    bool m_hasBreakableChar : 1; // Whether or not we can be broken into multiple lines.
    bool m_hasBreak : 1; // Whether or not we have a hard break (e.g., <pre> with '\n').
    bool m_hasTab : 1; // Whether or not we have a variable width tab character (e.g., <pre> with '\t').
    bool m_hasBreakableStart : 1;
    bool m_hasBreakableEnd : 1;
    bool m_hasEndWhiteSpace : 1;
    bool m_linesDirty : 1; // This bit indicates that the text run has already dirtied specific
                           // line boxes, and this hint will enable RenderParagraph::layoutChildren to avoid
                           // just dirtying everything when character data is modified (e.g., appended/inserted
                           // or removed).
    bool m_containsReversedText : 1;
    bool m_isAllASCII : 1;
    bool m_canUseSimpleFontCodePath : 1;
    mutable bool m_knownToHaveNoOverflowAndNoFallbackFonts : 1;

    float m_minWidth;
    float m_maxWidth;
    float m_firstLineMinWidth;
    float m_lastLineLineMinWidth;

    String m_text;

    InlineTextBox* m_firstTextBox;
    InlineTextBox* m_lastTextBox;
};

inline UChar RenderText::uncheckedCharacterAt(unsigned i) const
{
    ASSERT_WITH_SECURITY_IMPLICATION(i < textLength());
    return is8Bit() ? characters8()[i] : characters16()[i];
}

inline UChar RenderText::characterAt(unsigned i) const
{
    if (i >= textLength())
        return 0;

    return uncheckedCharacterAt(i);
}

DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderText, isText());

#if !ENABLE(ASSERT)
inline void RenderText::checkConsistency() const
{
}
#endif

} // namespace blink

#endif  // SKY_ENGINE_CORE_RENDERING_RENDERTEXT_H_