Hey Alexandre,
Note that simply merging the existing code is not enough, you'll need to fix the architecture. IMO it needs to be based on the DC driver interface, but this will also require some changes to that interface.
I presume with this you mean the way we hooked the dibengine into the x11drv?
What we did (it's been a while, but if my memory serves) is modify x11drv's /graphics/x11drv/graphics.c so that the gdi calls were routed to the dibengine if the dibsection (or whatever) it's rendering to is in appmod. There is a very good reason for this:
If we just always used the dibengine no matter what, we would sometimes 'lose' on the whole coerce thing - what if the dibsection (or whatever) is in gdimod, we'd then have to do a whole copy of it back to sync things up, which is just silly when we could use x11's renderer (the image is already over there)...
Cheers
David