Drawing Frequency

[pzl]

Currently redrawing on-demand -- when a module has new things to be drawn, it happens as soon as it's received. This is great for very infrequent updates, there is no need to keep redrawing the screen when nothing changes. But this is not-so-great for quickly updating things.

Should there be a draw loop? Should any module updates be queued for the next draw loop to sweep through?

[pzl]

Note that dispman on the Pi gives:

VCHPRE_ int VCHPOST_ vc_dispmanx_vsync_callback( DISPMANX_DISPLAY_HANDLE_T display, DISPMANX_CALLBACK_FUNC_T cb_func, void *cb_arg );