Re: performance of goocanvas

[Ed Griffiths <edgrif sanger ac uk>]

Damon,

so that's where we got to with the foocanvas....we didn't create a custom item 
but in effect we did have one as we used a group parent and did all our drawing 
within it's space....

Interesting really that every now then a need pops up for a really fast 2D 
canvas that deals with large numbers of lines/boxes etc...not an easy problem to 
crack and have a good interface which is I guess why one doesn't really exist.

Ed



On Thu, 21 Nov 2013, Damon Chaplin wrote:

> On Wed, 2013-11-20 at 22:46 +0900, D M German wrote:
> > Ed, Damon,
> >
> > I really want to thank you both. I was able to find the reason for the
> > performance hit. As you indicated, we were "moving" items to the same
> > location where they were _for the entire document_. I have found some
> > redundancy in some operations during scrolling (and probably in other
> > places too) that I'll remove.
>
> I think your test file created about 330,000 GooCanvasPolyline items,
> which is a bit too much really!
>
> Ideally I think you should use custom canvas items for your stroke
> items, to handle all the segments in one canvas item. You can optimize
> it to calculate the bounds quickly, and you can avoid using object
> properties which are pretty slow. The file will load a lot quicker that
> way.
>
>
> The test file with the handwriting and sketches looks cool! Do you use a
> graphics tablet to do that?
>
> Damon
>
>
> _______________________________________________
> goocanvas-list mailing list
> goocanvas-list gnome org
> https://mail.gnome.org/mailman/listinfo/goocanvas-list

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