Enable gesture (swipe) input (on Fairphone 2) without Google Keyboard

I have Fairphone 2 running Fairphone Open OS, and I'm making a quixotic effort to avoid installing non-free (as in freedom) software on it and to optimize privacy. I want swipe input, but I don't want to install Google Keyboard, (LatimeImeGoogle.apk) By default, the OS has AOSP keyboard. I've also installed the wonderfully code-friendly AnySoftKeyboard (which also has awesome themes) and Hacker's Keyboard from F-Droid, but though they are useful to me, they don't have swipe input. I've read [this post](http://forum.xda-developers.com/nexus-4/general/guide-how-to-enable-googles-gesture-t2012628/post34605586#post34605586) which makes me think I have to get the source and compile the keyboard. I don't know how to do this at the moment, but I'm prepared to learn. I tried just replacing the library (by cheating and taking the correct library from the Google apk) mentioned in the post, and nothing changed (if I delete the library the keyboard stops working completely, so clearly I am making a system change by replacing it - it just doesn't do what I want). I would like any of the following, in order of preference 1. a nice code-friendly FOSS keyboard with gesture input 2. a simple* way to enable gesture input for AOSP 3. confirmation that I do, in fact, need to build AOSP myself to do what I want 4. any other relevant advice(!) Obviously, I have root :) *I have an Ubuntu system to play with on my laptop if it helps...