[OpenLayers-Dev] OpenLayers performance

[Christopher Schmidt]

On Mon, Apr 07, 2008 at 05:34:41PM +0200, Tomas Novotny wrote:
> I'm after few months of using OpenLayers (OL). I've built some 
> application on OL and appreciated it's architecture for good extensibility.
> But when things come to performance of such common task as panning 
> (moving a map with mouse), I am really dissatisfied.

Patches welcome.

> The way the panning is implemented is everything but not 
> browser-friendly. There is coord2pixel and pixel2coord processing on 
> several places in those moveTo() and setCenter() methods on every mouse 
> move and it is only part of the problem. A tried to prune OL for tests 
> to just moving map div with one empty layer and things were still the 
> same. You can feel lags as you are moving map from side to side, up and 
> down. When you try to compare it with ie. GoogleMaps you can really feel 
> the difference.

I'll state for the record that I don't feel any difference -- if
anything, I typically feel like GMaps is slower than OpenLayers.
However, there are a number of patches in trac which have been stated by
their authors to be 'faster' or 'improve performance', which are
currently marked for further investigation in OpenLayers 2.7.

> I haven't seen any OL example with better feeling so I think it's a 
> matter of source architecture, not bug.

The architecture of OpenLayers is not designed to be slow. If you are
finding that it is slow, there is no reason that a refactoring of that
aspect of the code would not be appreciated so long as it did not
regress in behavior in some important way.

> What I'm trying to say? I found out that OL are good for building robust 
> applications where wide functionality is the goal, not the performance. 
> If I'm not right and making something wrong please tell me.

I don't think that OpenLayers tries to be slow in any way. If you feel
there are obvious deficiencies in the way that OpenLayers does things,
and see a better way, please feel free to offer them up as comments to
the community. 

Regards,
-- 
Christopher Schmidt
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