Released clisk 0.4.4 with functionality to support image filters.
(let [filt (com.jhlabs.image.BoxBlurFilter.)] (. filt setRadius 8) (show (image-filter filt cannon)))
The implementation is very general purpose – it basically allows any BufferedImageOp to be used as a filter.
BufferedImageOps operate on
BufferedImages, this poses a slightly interesting problem when applied to clisk image functions (which are arbitrary precision image generators). The solution I chose to handle this is simply to render the clisk image into a BufferedImage to allow the filter to be applied, then convert back to a texture-map so that it can be used in following image functions. Not particularly elegant, but it seems to work OK.
I was happy to stumble across an excellent open source library of Java image filters - Image Filters at JHLabs. So now clisk has a great library of image filters at your disposal, thanks to the power of open source!