Van Vliet recursive Gaussian filter. \param sigma standard deviation of the Gaussian filter \param order the order of the filter 0,1,2,3 \param

returns: - 0 if outside of [h0, h1] - 0 at h0 - 1 at h1 - linear from h0 to h1

returns: - 0 if outside of [h0, h1] - 1 at h0 - 0 at h1 - linear from h0 to h1

Return a random variable following a Poisson distribution of parameter z. **/

fetch our host APIs from the host struct given us the plugin's set host function must have been already called */

(see comments in Natron code about this feature being buggy)

overriding getRegionOfDefinition is necessary to tell the host that we do not support render scale

CENTRY */

h = (1/16, 1/4, 3/8, 1/4, 1/16) (Murtagh F.: Multiscale transform methods in data analysis)

h = (0.25,0.5,0.25) linear Lagrange interpolation, with mirroring at the edges. could be made edge-aware, maybe? - https://www.darktable.org/wp-conten

/////////////////////////////////////////////////////////////////////////// the entry point for the overlay

/////////////////////////////////////////////////////////////////////////// The main function