[cairo] "retained" surface for cairo

[John Ellson]

Jost Boekemeier wrote:

>Carl,
>
>what do think about a surface that draws "lazy" so
>that cairo could accept huge surfaces which would
>otherwise exceed the X server memory?
>
>Such a surface would apply the transformations on the
>client-side so that when the composite operation is
>requested we can decide what to send to the server and
>what not.
>
>Of course one could do this on a layer above cairo and
>draw only the part of the picture that is necessary,
>but I now think that such a surface would fit better
>into the cairo framework.  I think we could even hide
>the fact that this surface is special and use it
>whenever someone requests a surface that is much
>larger than the physical screen.
>
>The only disadvantage I see is that this surface is
>"software-only" and that it dublicates much of the X
>server's render code.
>
>
>Jost
>  
>

If I'm understanding this right,  could such a "lazy" surface be copied
to one or more real surfaces later, e.g. an X11 surface and then a PNG 
surface,
perhaps through viewport transformations?

If thats the idea, then I think I would find it very useful too.


John Ellson