From: Brian S. Julin <bri@tull.umassp.edu>
  To  : 'ggi-develop@eskimo.com' <ggi-develop@eskimo.com>
  Date: Mon, 17 May 1999 16:45:00 -0400 (EDT)

RE: Some though about raster operation.

On Mon, 17 May 1999, BERNARD Sebastien wrote:
> > No, LibGGI2D is an extension and the reason for extensions is to allow 
> > acceleration of stuff that is beyond the libGGI core.  The core was
> > kept very basic on purpose, so it could be implemented on the widest
> > array of display systems and extensions would have something generic to
> > build on.
> 	[BERNARD Sebastien]  What is the purpose of the libGGI core ? Why
> then 2 blit function are in the core ? I don't understand the underlying
> logic. Could someone explain me which operation goes where and why ?

The "Blit" functions in the core really aren't intended to be "Blits";
it's a bit of a misnomer.  Just a way to CopyBox between two visuals.

The libGGI core implements the very basic primitives of how to initialize
a visual ("How do I draw on X"), determine it's properties ("How many colors
are there in X", "What color is green on X"), draw filled objects,
and put/get data to/from the screen in a fully portable fashion,
that is, using MapColor/Packpixels etc.

> > (There are preliminary plans for better BLT buffer management in the
> > works.)
> 	[BERNARD Sebastien]  Don't know about it. Tell me more.

The list archives from 2-3 months ago have the discussion (under subjects 
like "Lightweight visuals", "sprites", and "buffer cache")  Before 
LibGGI2D really gets BLT done, there needs first to be a way to get
on-card buffers or off-card buffers to BLT from, so "the high
GGI wizards" are handing around a proposed API for this and 
refining it a bit based on their knowlege of LibGGI/KGI guts before 
it gets implemented/brought back to the list.  Once BLTs can really
be hardware accelerated in the truest sense, there will be more incentive
for LibGGI2D developers to complete the BLT code.  But, if you already
have that incentive, contact the coordinator and go to it.

--
Brian