Re: Pixmap performance

[John Cupitt ng-london org uk]

Deekshit Mantampady wrote:
>        I have a small doubt regarding pixmap. I have a pixmap with
resolution of
> 
> 10000x10000 pixels. How fast the image will be rendered ? Assuming I have
a
> scrolled window of size 100x100. How about the scrolled performace(Will it
be
> smooth)..? If this is not the efficient way to display large images, is
there
> any better alternative for the same.

Hi Deekshit, my app displays large images.

http://www.vips.ecs.soton.ac.uk/

I mmap() the image file and then for each expose event render just the 
exposed section from disc to the display. It's quite fast and smooth.

I did my own code, but I think the new gdk-pixbuf library in gtk2 will 
render sections of images. The trick (if there is one) is just to not 
ever deal with the whole thing at once.

http://developer.gnome.org/doc/API/2.0/gdk-pixbuf/index.html

John



========================================================== 
Fabric of Vision 
Dress and Drapery in Painting 

19 June - 8 September 2002 

For information and tickets: 
http://www.nationalgallery.org.uk/exhibitions/fabric/