But fast OSM renderers exist. Take a look at https://play.google.com/store/apps/details?id=gr.talent.cruiser https://play.google.com/store/apps/details?id=gr.t

But fast OSM renderers exist. Take a look at https://play.google.com/store/apps/details?id=gr.talent.cruiser https://play.google.com/store/apps/details?id=gr.talent.crui... for an example. It's perfectly smooth. The application is closed source but the underlying renderer (VTM) is LGPL3. The renderer, https://github.com/mapsforge/vtm https://github.com/mapsforge/vtm, is basically an OpenGL alternative for the mapsforge offline maps format and maintained by the same guy (the original mapsforge renderer is arguably a bit slow, struggling to hide its slowness behind cached tile bitmaps).