Re: Event loop

[rsmith xs4all nl]

On 13 Nov, Havoc Pennington wrote:
> Nils Rennebarth <nils ipe uni-stuttgart de> writes:
> > In my application I have to save a 1MB image to a file using .png which
> > takes a lot of time on that oldish P166. What would you suggest to use
> > for saving the image "in the background"?
>
> libpng may support progressive saving. If it does, an idle handler is
> easy to support; just feed some fixed small chunk of data into the
> saver on every idle.

Looking at the manual page for libpng(3), it seems you don't have to write
the whole picture at once, you can write a couple of rows at a time. So you
can stick it in an idle or timeout functions. 

BTW, don't try to read the png header file, it's horrible, especially the
macro declaration of functions. :-(

> If it doesn't, you are pretty much forced to use
> a thread or process unless you write your own PNG encoder. I'll stay
> out of the "threads vs. processes" debate. ;-)

Right on. Let everybody use what suits themselves and don't flame others
for doing otherwise. :-) Although I wonder if the issue isn't becoming moot
with the ever increasing speed and memory available.

Roland
-- 
Roland Smith                        "When life hands you a lemon,
r s m i t h @ x s 4 a l l . n l      make lemonade."
http://www.xs4all.nl/~rsmith/