Returns the value of the Sinc function constrained by a window function. Descendant classes override the Window method in order to implement a custom window function.
h(x) = Sinc(x) * Window(x);
Windowed Sinc filters are known for producing high quality resampled images. Ideal resampling corresponds to filtering an image with the ideal low-pass filter (i.e. a Sinc filter). This is computionally expensive, since the Sinc function has infinite extent. Hence a window function is used to constrain the filter.
See topic about Sampling and Rasterization for further information.