WebFont.h   [plain text]

/*
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#ifndef WebFont_h
#define WebFont_h

#include "WebCanvas.h"
#include "WebColor.h"
#include "WebCommon.h"

namespace WebKit {

struct WebFontDescription;
struct WebFloatPoint;
struct WebFloatRect;
struct WebPoint;
struct WebRect;
struct WebTextRun;

class WebFont {
public:
    virtual ~WebFont() { }

    WEBKIT_API static WebFont* create(const WebFontDescription&);

    virtual WebFontDescription fontDescription() const = 0;

    virtual int ascent() const = 0;
    virtual int descent() const = 0;
    virtual int height() const = 0;
    virtual int lineSpacing() const = 0;
    virtual float xHeight() const = 0;

    // Draws the text run to the given canvas. The text is positioned at the
    // given left-hand point at the baseline.
    //
    // The text will be clipped to the given clip rect. |canvasIsOpaque| is
    // used to control whether subpixel antialiasing is possible. If there is a
    // possibility the area drawn could be semi-transparent, subpixel
    // antialiasing will be disabled.
    //
    // |from| and |to| allow the caller to specify a subrange of the given text
    // run to draw. If |to| is -1, the entire run will be drawn.
    virtual void drawText(WebCanvas*, const WebTextRun&, const WebFloatPoint& leftBaseline, WebColor,
                          const WebRect& clip, bool canvasIsOpaque,
                          int from = 0, int to = -1) const = 0;

    // Measures the width in pixels of the given text run.
    virtual int calculateWidth(const WebTextRun&) const = 0;

    // Returns the character offset corresponding to the given horizontal pixel
    // position as measured from from the left of the run.
    virtual int offsetForPosition(const WebTextRun&, float position) const = 0;

    // Returns the rectangle representing the selection rect for the subrange
    // |from| -> |to| of the given text run. You can use -1 for |to| to specify
    // the entire run (this will do something similar to calling width()).
    //
    // The rect will be positioned as if the text was drawn at the given
    // |leftBaseline| position. |height| indicates the height of the selection
    // rect you want, typically this will just be the height() of this font.
    //
    // To get the pixel offset of some character (the opposite of
    // offsetForPosition()), pass in a |leftBaseline| = (0, 0), |from| = 0, and
    // |to| = the character you want. The right edge of the resulting selection
    // rect will tell you the right side of the character.
    virtual WebFloatRect selectionRectForText(const WebTextRun&, const WebFloatPoint& leftBaseline,
                                              int height, int from = 0, int to = -1) const = 0;
};

} // namespace WebKit

#endif