I have spent the last few days (weeks?) rewriting psplib into its successor library, libpl. Most importantly, graphics, font and image rendering core is being rewritten from scratch; it’s already significantly better than the older version. Among changes so far:
- Faster bitmap font rendering (swizzled, VRAM-based fonts)
- More accurate image resizing (no more scissoring artifacts, as most apparent in fMSX PSP)
- Support for multiple pixel formats (instead of fixed 16-bit “5551″ format)
Future plans:
- Support for swizzled images, in-place image swizzling
- Completely new GUI system
Simple “upgrading” to libpl from psplib no longer seems possible; therefore, emulators will have to be largely rewritten to use the new library. Once the work is finished, I also hope to have some sample code available, in case anyone wants to write applications based off the library.
If you’re interested in the progress, you can find semi-nightly builds in the libpl directory, under the trunk branch of the svn repository. No promises on the code actually compiling (or doing anything useful, for that matter) 
Many thanks to the ps2dev/psp forum folks for their helpful answers to many of my questions.
Tags: libpl, psplib, work-in-progress