Re: Offscreenmemory copy

ayachi gherissi wrote:

> Hi (Newbie Question)
>  
> I have created two area with xf86AllocateLinearOffscreenArea
>
> 1) How can I copy the contents of area to screen (if I have to use 
> SubsequentScreenToScreenCopy what src coordinates x, y to use)


ScreenToScreenCopy assumes that the source and destination have the same 
"pitch" -- the distance between scanlines.  When you allocate a linear 
offscreen area, you're usually allocating a space that is not as wide as 
the screen, and "linear" means that the scanlines are packed as tightly 
as possible.  So, ScreenToScreenCopy won't do the job.

However, ScreenToScreenCopy is just setting up the graphics chip to do a 
blit.  You can certainly do the same kind of blit yourself, plus 
whatever setup you need to define the pitch of the source.

> 2) How can I copy one area to another without CPU intervention


Most modern graphics chips can blit between arbitrary offscreen areas.  
You just have to describe the areas (width, height, pitch).  The means 
of doing that depends on the chip.

Anybody know why there were a set of messages from two weeks ago 
(including this one) that are just showing up today?

-- 
Tim Roberts, [email protected]
Providenza & Boekelheide, Inc.