Re: performance of goocanvas

[Ed Griffiths <edgrif sanger ac uk>]

Good luck, would love to know how you get on because someday we may migrate to 
goocanvas.....

Ed


On Wed, 20 Nov 2013, 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.
>
> thank you very much,
>
> --daniel
>
> Ed> I think this is a good guess, we had a lot of trouble with foocanvas
> Ed> (the goocanvas predecessor) with this. In the end we were forced to
> Ed> draw certain things ourselves on to the screen in order to get good
> Ed> enough performance.
>
> Ed> If you are moving the scrolled region as you scroll that would do it....
>
> Ed> Ed
>
>
>
> >> I don't think the problem is drawing. I put a "return;" statement at the
> >> top of the GooCanvasPolyline's draw function so it didn't draw anything,
> >> but it was just as slow!
> >>
> >> I think the problem may be that you are sometimes changing items when
> >> the canvas is scrolled, and this causes the canvas to have to
> >> recalculate the bounds of lots of items, which is slow.
> >>
> >> What changes are you making when the canvas is scrolled? Is there a way
> >> to avoid them?
> >>
> >> Damon
> >>
> >>
> >> _______________________________________________
> >> goocanvas-list mailing list
> >> goocanvas-list gnome org
> >> https://mail.gnome.org/mailman/listinfo/goocanvas-list
> >>
>
> Ed> --
> ------------------------------------------------------------------------
> Ed> | Ed Griffiths, Acedb/ZMap development, Informatics Group,               |
> Ed> |  The Morgan Building, Sanger Institute, Wellcome Trust Genome Campus   |
> Ed> |  Hinxton, Cambridge CB10 1HH                                           |
> Ed> |                                                                        |
> Ed> | email: edgrif sanger ac uk  Tel: +44-1223-496844  Fax: +44-1223-494919 |
> ------------------------------------------------------------------------
>
>
> Ed> --
> Ed> The Wellcome Trust Sanger Institute is operated by Genome Research
> Ed> Limited, a charity registered in England with number 1021457 and a
> Ed> company registered in England with number 2742969, whose registered
> Ed> office is 215 Euston Road, London, NW1 2BE.
>
>
> --
> Daniel M. German                  "Much of my work has come
>   John W. Backus ->               from being lazy"
> http://turingmachine.org/
> http://silvernegative.com/
> dmg (at) uvic (dot) ca
> replace (at) with @ and (dot) with .

--
 ------------------------------------------------------------------------
| Ed Griffiths, Acedb/ZMap development, Informatics Group,               |
|  The Morgan Building, Sanger Institute, Wellcome Trust Genome Campus   |
|  Hinxton, Cambridge CB10 1HH                                           |
|                                                                        |
| email: edgrif sanger ac uk  Tel: +44-1223-496844  Fax: +44-1223-494919 |
 ------------------------------------------------------------------------


--
The Wellcome Trust Sanger Institute is operated by Genome Research 
Limited, a charity registered in England with number 1021457 and a 
company registered in England with number 2742969, whose registered 
office is 215 Euston Road, London, NW1 2BE.