So, you wanna make your own background? You'll have to use a special image to create it called the Threepatch.
The idea comes from the Ninepatch that's available for Android - based upon a special 1px border around the image, you can make an image automatically be sized and stretched to allow for any size of content to fit inside.
I tried to duplicate the functionality of this Ninepatch within the ACoS Message Generator. Sadly, I couldn't find the sourcecode for these Ninepatches, and it was much too confusing to replicate. So, instead, I went with a simpler approach: the Threepatch.
The Threepatch functions essentially the same way: it'll resize your background to the exact width it needs to in order to fit your content. Here's what it looks like:
Note, this is just a simple example. But notice the black 2px line that's at the very bottom of the image - the lower pixel of that is what makes this a Threepatch.
What that line does is tell the tool where it's allowed to stretch. It'll keep the left and right sides on a 1:1 pixel ratio, and then stretching the middle to fit the content.
Note that this isn't like a Ninepatch - there's only an extra pixel row along the bottom. That was a choice made to ease the coding of this tool. If you've used (or even heard) of the Ninepatch before, take special note of that.
Note that the area you want to indicate as stretchable has to be marked
BLACK - #000000. If you make it
any other color, it won't recognize it.
Something else about this tool is that it will only fit the content
within the stretched area. This is what allows you to create customized graphics on either side. As well, it's the height of this Threepatch that defines the height of the resulting message image... minus the bottom pixel row, of course.
Once you've created your Threepatch, it has to be saved with a special extension: ".3.png". This is how the tool identifies your Threepatches. It also has to be stored in the "backs" subfolder, which would be in the same folder as the tool and the "faces" folder.
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