HannWindow.txt
number width,height;
number twoPi = 2*Pi();
// obtain selected image and get its size:
Image img=getFrontImage()
getSize(img,width,height)
// produce Hann window:
Image Hann:=ExprSize(width,height,0.5*(1-cos(twoPi*icol/iwidth))*0.5*(1-cos(twoPi*irow/height)))
showimage(Hann)