Symmetry action?

[DeadlyFreeze]

So with the seeming lack of photoshop innovation I was trying to set up an action that would basically mirror one half of my canvas so I could sporadically button spam and have something close to active symmetry in photoshop.

Problem being I'll be damned if I can get it to work right, it will either continually pile up (layer over layer) lines getting darker and darker, or for some reason will move my selection all around shifting everything when I draw.

Seems simple but I'll be damned if I can get it right, suggestions?

[daveneale]

I would have thought you'd have to do a "new layer from merged" (CTRL+ALT+SHIFT+E) 1st, so you have a full layer to start from?. Also, I guess you'd need the canvass to be the same size every time as of the top of my head I can't think of any way to make a marquee tool just choose to select half of the canvass as a rule

[DeadlyFreeze]

Ya the marquee thing seems to be the biggest problem, anyway I've tried requires me to clear half the canvas at some point. For what ever reason won't marquee select the same spot. Thanks for the help though.

[PieterV]

Cool idea, I never tought of making an action for mirroring half the image.
Just tried this... seems to work. You might want to throw in a merging/stamp layers action if you're working on multiple layers.

http://img249.imageshack.us/img249/6262/mirroringaction.jpg