Warning: This function is
currently not documented; only the argument list is
available.
Warning: This function is
EXPERIMENTAL. The behaviour of this function, the
name of this function, and anything else documented about this
function may change without notice in a future release of PHP.
Use this function at your own risk.
Sharpens an image. We convolve the image with a Gaussian operator
of the given radius and standard deviation (sigma). For reasonable
results, the radius should be larger than sigma. Use a radius of
0 and selects a suitable radius for you.
Return Values
Returns TRUE
on success.