As so often happens, I set out to do one thing, got sidetracked, and did something else... in this case I was going to add NBT reading/writing support to WorldPorter, but made this instead.
Banners are a Minecraft 1.8 thing. You craft them together with various bits and bobs to put patterns on them. This script lets you set those patterns directly, using a Command Computer. Should be fairly simple to use; you plonk a chest on top of the computer, fill it with banners, create your masterpiece with the script and then "export" it to the banners in the chest.
Worth noting that this is hardly the first banner editor out there - eg Planet Minecraft has a web-based one - but what the heck. It does open up an easy avenue for allowing non-server OPs to fully customise their banners (they can usually only define up to six layers). With any luck it might lead to some more colourful servers?
Edited by Bomb Bloke, 28 March 2018 - 09:50 AM.