Re: Snappy GUI response

On Fri, Jul 04, 2003 at 03:24:59PM -0700, Mark Vojkovich wrote:
> 
>   I don't think I'd agree with you there.  I've basically
> been advocating that clients do their own backing store.  It's
> not really a complicated concept, it's just one that doesn't
> seem to be on developer's minds.  There's not alot to understand,
> just one fundamental concept: expose events are expensive.

Right, but very few apps right now even handle expose events. It's all
in the toolkit. (In part this may be because Windows/Mac work
differently so cross-platform toolkits have all had to abstract it.)
There are plenty of people writing sizeable GTK+, Qt, Swing, apps that
couldn't even tell you what an expose event is. Or what backing store
is.

By "app" I mean the executable excluding libs such as the toolkit, by
"app" you may mean everything on the client side of the X server.

GTK does have an idea of 'expose event' on the toolkit level, but most
toolkits don't - GTK just happens to have originated on X by people
used to Motif.

The more common toolkit graphics API doesn't have exposes, instead 
there's a canvas widget that statefully remembers what you've drawn
(pixmap semantics, not window semantics).

Either way, you are usually saying "put a button here" and not dealing
with drawing primitives at all.

Havoc