[MapProxy] Porting MapProxy to Java

[Peter Borissow]

Hello-
   A colleague of mine recently turned me on to mapproxy and it is Awesome!  MapProxy does exactly what we've been looking for. The cache supports arbitrary zoom levels and bounding boxes and it's lightning fast. We've tried both tilecache and geowebcache, but unfortunately they don't seem to satisfy this requirement.

Now that I'm hooked on mapproxy, I want to port it to Java. I started porting the code a couple days ago and I'm making some good progress. I have ported 23 classes so far. Unfortunately, I'm starting to hit some hurdles and I need your help to see this through. 

I've never worked with Python before so some of my questions might be just Python 101. For example, what is an img_filter? Example in cache.py:

        for img_filter in self.pre_store_filter:
            tile = img_filter(tile)

I can't seem to find the source for img_filter/pre_store_filter anywhere in the code. What is a pre_store_filter and what is it doing to a tile?


BTW, I'd love to give back the java code once I get it ported. Would you guys be cool with that? 

Many Thanks!
Peter