[OpenLayers-Dev] VML rendering in IE is slow with big geometries. Proposed Fix.

[Erik Uzureau]

ps. has someone made a patch for this? sounds like something we
shouldn't let slip through the cracks.


On 10/16/07, Erik Uzureau <erik.uzureau at metacarta.com> wrote:
> On 10/16/07, Christopher Schmidt <crschmidt at metacarta.com> wrote:
> > On Wed, Oct 17, 2007 at 11:58:17AM +1000, Roald de Wit wrote:
> > > The same slowdown most probably applies to the other drawing methods in
> > > this class.
> > >
> > > My question is: what would be the best way to tackle this?
> >
> > Interesting. I'd always followed the type of behavior you're suggsting
> > in Python, but had never known it was needed in JS. (It's always bugged
> > me that we just shoved strings together in Javascript, but it seemed
> > like everyone did it, so I didn't question.)
> >
> > The typical way I do this in Python is to just do the equivilant of:
> >
> > var stringList = [];
> > for (var i = 0; i < 10000; i++) { stringList.push('foo'); }
> > var string = stringList.join("");
> >
> > I think we can even skip the .join("") and use .toString() in JS, but I
> > have no idea how portable that is, and it feels slightly hacky.
> >
> > So, I don't see any need for a stringBuffer object, since it would just
> > be an array (with 'push' replaced with 'append').
> >
> > With these performance numbers in hand, I think that migrating any
> > significant use of string concatanation -- which I think only includes
> > the renderers, and maybe things like getParameterString -- to be array
> > based makes sense, and I'm in support of that path. It probably makes
> > sense to write at least basic tests for the renderer functionality
> > before proceeding with this, to ensure that it doesn't break with the
> > new code in any way that we can be aware of ahead of time.
>
> Wow. Cool trick. Can't see where else in the OL code it would make
> much of a difference other than:
>
> -GeoRSS parseData() -- 197
> - BaseTypes String camelize -- 87
>
> how many times is getParameterString() called?
>
> e
>
>
>
>
>
> > Regards,
> > --
> > Christopher Schmidt
> > MetaCarta
> > _______________________________________________
> > Dev mailing list
> > Dev at openlayers.org
> > http://openlayers.org/mailman/listinfo/dev
> >
>