The documentation if wrong for PgContextBlitArea*().  One cannot blit to/from any other than a PdOffscreenContext_t with
 that routine.

Attached is code that uses GF to blit to/from PmMemoryContext_t to/from PdOffscreenContext_t.
There are three routines:

blit_init()
blit_deinit()
blit_dc_to_dc()

It does not necessarily perform an accelerated blit, but exposes the capability of the chipset currently in use.