UniscribeHelperTextRun.h   [plain text]

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#ifndef UniscribeHelperTextRun_h
#define UniscribeHelperTextRun_h

#include "UniscribeHelper.h"

namespace WebCore {

class Font;
class TextRun;

// Wrapper around the Uniscribe helper that automatically sets it up with the
// WebKit types we supply.
class UniscribeHelperTextRun : public UniscribeHelper {
public:
    // Regular constructor used for WebCore text run processing.
    UniscribeHelperTextRun(const TextRun&, const Font&);

    // Constructor with the same interface as the gfx::UniscribeState. Using
    // this constructor will not give you font fallback, but it will provide
    // the ability to load fonts that may not be in the OS cache
    // ("TryToPreloadFont") if the caller does not have a TextRun/Font.
    UniscribeHelperTextRun(const wchar_t* input,
                           int inputLength,
                           bool isRtl,
                           HFONT hfont,
                           SCRIPT_CACHE*,
                           SCRIPT_FONTPROPERTIES*);

protected:
    virtual void tryToPreloadFont(HFONT);

private:
    // This function retrieves the Windows font data (HFONT, etc) for the next
    // WebKit font in the list. If the font data corresponding to font_index_
    // has been obtained before, returns the values stored in our internal
    // vectors (hfonts_, etc).  Otherwise, it gets next SimpleFontData from
    // WebKit and adds them to in hfonts_ and friends so that font data can be
    // returned quickly next time they're requested.
    virtual bool nextWinFontData(HFONT*, SCRIPT_CACHE**, SCRIPT_FONTPROPERTIES**, int* ascent);
    virtual void resetFontIndex();

    // Reference to WebKit::Font that contains all the information about fonts
    // we can use to render this input run of text.  It is used in
    // NextWinFontData to retrieve Windows font data for a series of
    // non-primary fonts.
    //
    // This pointer can be NULL for no font fallback handling.
    const Font* m_font;

    // It's rare that many fonts are listed in stylesheets.
    // Four would be large enough in most cases.
    const static size_t kNumberOfFonts = 4;

    // These vectors are used to store Windows font data for non-primary fonts.
    Vector<HFONT, kNumberOfFonts> m_hfonts;
    Vector<SCRIPT_CACHE*, kNumberOfFonts> m_scriptCaches;
    Vector<SCRIPT_FONTPROPERTIES*, kNumberOfFonts> m_fontProperties;
    Vector<int, kNumberOfFonts> m_ascents;

    // Index of the fallback font we're currently using for NextWinFontData.
    int m_fontIndex;
};

}  // namespace WebCore

#endif  // UniscribeHelperTextRun_h