Sorry sorry sorry sorry. I have not touched Pico in years. Much of the development went into the Android driver, which is basically the idea of Pico in a much more interesting environment. The Android driver has a complete implementation of clipped drawing of text, fonts, polygons, arc, etc. . The missing features are line width and line patters. It supports multiple windows, but not yet a window decoration or desktop. Nevertheless, it is absolutely usable, and most of the non-OpenGL apps compile and run just fine on Android.
I always meant to merge Pico and Android to finally get this idea working, but my job has kept me extremely busy. I'll be happy to help, either in a public forum or by PM: fltk AT matthiasm DOT com , if you feel like investing time into this idea. Starting September, I will have half the work load, and I will hopefully tie all the strings together and implement the original idea of porting FLTK by implementing only three functions (positional event/klick/touch, timer event, and draw a pixel).