gecko/gfx/thebes/public/gfxUtils.h

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 *   Robert O'Callahan <robert@ocallahan.org>
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#ifndef GFX_UTILS_H
#define GFX_UTILS_H

#include "gfxTypes.h"

class gfxImageSurface;

class THEBES_API gfxUtils {
public:
    static PRBool FuzzyEqual(gfxFloat aV1, gfxFloat aV2) {
        return fabs(aV2 - aV1) < 1e-6;
    }

    /*
     * Premultiply or Unpremultiply aSourceSurface, writing the result
     * to aDestSurface or back into aSourceSurface if aDestSurface is null.
     *
     * If aDestSurface is given, it must have identical format, dimensions, and
     * stride as the source.
     *
     * If the source is not ImageFormatARGB32, no operation is performed.  If
     * aDestSurface is given, the data is copied over.
     */
    static void PremultiplyImageSurface(gfxImageSurface *aSourceSurface,
                                        gfxImageSurface *aDestSurface = nsnull);
    static void UnpremultiplyImageSurface(gfxImageSurface *aSurface,
                                          gfxImageSurface *aDestSurface = nsnull);
};

#endif