What's the best way to "smudge" an image programmatically?

Question

I'm messing around with image manipulation, mostly using Python. I'm not too worried about performance right now, as I'm just doing this for fun. Thus far, I can load bitmaps, merge them (according to some function), and do some REALLY crude analysis (find the brightest/darkest points, that kind of thing).

I'd like to be able to take an image, generate a set of control points (which I can more or less do now), and then smudge the image, starting at a control point and moving in a particular direction. What I'm not sure of is the process of smudging itself. What's a good algorithm for this?

Answer 1

One method would be to apply a Gaussian blur (or some other type of blur) to each point in the region defined by your control points.

Answer 2

One method would be to create a grid that your control points moves and then use texture mapping techniques to map the image back onto the distorted grid.

Answer 3

Try PythonMagick (ImageMagick library bindings for Python). If you can't find it on your distribution's repositories, get it here: http://www.imagemagick.org/download/python/

It has more effect functions than you can shake a stick at.

Answer 4

I can vouch for a Gaussian Blur mentioned above, it is quite simple to implement and provides a fairly decent blur result.

James