SkIPoint* margin = NULL);
static SkScalar ConvertRadiusToSigma(SkScalar radius);
+
+ /* Helper functions for analytic rectangle blurs */
+
+ /** Look up the intensity of the (one dimnensional) blurred half-plane.
+ @param profile The precomputed 1D blur profile; memory allocated by and managed by
+ ComputeBlurProfile below.
+ @param loc the location to look up; The lookup will clamp invalid inputs, but
+ meaningful data are available between 0 and blurred_width
+ @param blurred_width The width of the final, blurred rectangle
+ @param sharp_width The width of the original, unblurred rectangle.
+ */
+ static uint8_t ProfileLookup(const uint8_t* profile, int loc, int blurred_width, int sharp_width);
+
+ /** Allocate memory for and populate the profile of a 1D blurred halfplane. The caller
+ must free the memory. The amount of memory allocated will be exactly 6*sigma bytes.
+ @param sigma The standard deviation of the gaussian blur kernel
+ @param profile_out The location to store the allocated profile curve
+ */
+
+ static void ComputeBlurProfile(SkScalar sigma, uint8_t** profile_out);
+
+ /** Compute an entire scanline of a blurred step function. This is a 1D helper that
+ will produce both the horizontal and vertical profiles of the blurry rectangle.
+ @param pixels Location to store the resulting pixel data; allocated and managed by caller
+ @param profile Precomputed blur profile computed by ComputeBlurProfile above.
+ @param width Size of the pixels array.
+ @param sigma Standard deviation of the gaussian blur kernel used to compute the profile;
+ this implicitly gives the size of the pixels array.
+ */
+
+ static void ComputeBlurredScanline(uint8_t* pixels, const uint8_t* profile,
+ unsigned int width, SkScalar sigma);
+
+
+
};
#endif