Here's an updated version for test purposes. Mainly to see if the Save Layers option is now working correctly on macs.
As I said in my previous post, this is suffering from a low memory allocation for some reason. I'm not sure what the upper limit is on size right now but if I attempt to load a 4k x 4k template in it refuses to play ball. If you want to get bigger forests the only option right now is to wrap it in an exe maker and allot more memory to the program that way. I'll do this myself in later version if I cannot sort out why the heap is being a git.
On this version I've now put most of the workhorse routines into swingWorkers, which means you need a reasonably up to date version of JVM to run it (version 6 I believe). I would think that most would be ok there though. The swingworkers have allowed me to finally put in a status bar that can relay update messages. I'm still early on in the process though so for now, whenever a process is in operation I've disabled all the controls to stop it being interrupted and throwing up errors. I aim to peel away this disabling in future updates so that button presses will reset the workers or whatever.
So if Paul or anyone with a mac could test this please and let me know if the Save Layers option works now I'd appreciate it. Cheers.