HarfBuzzShaperBase.h   [plain text]

/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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#ifndef HarfBuzzShaperBase_h
#define HarfBuzzShaperBase_h

#include "TextRun.h"
#include <wtf/OwnArrayPtr.h>

namespace WebCore {

class Font;

class HarfBuzzShaperBase {
public:
    enum NormalizeMode {
        DoNotNormalizeMirrorChars,
        NormalizeMirrorChars
    };

    HarfBuzzShaperBase(const Font*, const TextRun&);
    virtual ~HarfBuzzShaperBase() { }

protected:
    void setNormalizedBuffer(NormalizeMode = DoNotNormalizeMirrorChars);

    bool isWordEnd(unsigned);
    int determineWordBreakSpacing();
    // setPadding sets a number of pixels to be distributed across the TextRun.
    // WebKit uses this to justify text.
    void setPadding(int);

    // This matches the logic in RenderBlock::findNextLineBreak
    static bool isCodepointSpace(UChar c) { return c == ' ' || c == '\t'; }

    const Font* m_font;
    OwnArrayPtr<UChar> m_normalizedBuffer;
    unsigned m_normalizedBufferLength;
    const TextRun& m_run;

    int m_wordSpacingAdjustment; // delta adjustment (pixels) for each word break.
    float m_padding; // pixels to be distributed over the line at word breaks.
    float m_padPerWordBreak; // pixels to be added to each word break.
    float m_padError; // |m_padPerWordBreak| might have a fractional component.
                      // Since we only add a whole number of padding pixels at
                      // each word break we accumulate error. This is the
                      // number of pixels that we are behind so far.
    int m_letterSpacing; // pixels to be added after each glyph.
};

} // namespace WebCore

#endif // HarfBuzzShaperBase_h