[OpenLayers-Dev] final animated zooming and panning patches

[Emanuel Schütze]

Now, I think I understand what you mean.
I'm directly testing it in Safari and it seems to be a special  
behavior in this browser because FF doesn't show this effects. It  
really seems that Safari can't remove the old images from DOM. The  
number of loaded objects in status bar rise with each zoom step. The  
DOM in FF is ok.
Do you know a safari plugin to show the DOM tree like firebug for FF?  
It could help for analyse this problem...
Emanuel

Am 29.03.2007 um 20:11 schrieb Paul Spencer:

> Sorry, I'll try to explain more ...  Now using the controls  
> example ... I'm only using the mouse wheel to zoom one step at a  
> time.  By the 3rd step, it is slowing down and by the fifth it  
> causes 100% processor usage for several seconds to complete the one  
> step zoom.
>
> Browser is Safari, hardware is a powerbook g4.
>
> In Firefox, it is much better and rarely shows the really blurry  
> tiles (or briefly enough that I can't get a screencapture of it  
> anyway).
>
> Digging a bit deeper ...
>
> initial load: 4 tiles
> zoom 1: 10 tiles
> zoom 2: 30 tiles
> zoom 3: 44 tiles
> zoom 4: 50 tiles
> zoom 5: 51 tiles
> zoom 6: 60 tiles
>
> Each zoom was a single step zooming in using the mouse wheel.   
> Initially I thought it was keeping all the tiles from a previous  
> zoom level but it actually seems pretty random to me.  Some of the  
> images are definitely from other scales though and I think the  
> blurry image is a symptom of those images being left in the dom  
> tree and being scaled way beyond what they should be.  I haven't  
> looked in the code, but I expect it is a leak of some sort that  
> leaves these tiles in the dom after a smooth zoom.  This theory  
> also explains why performance tails off quickly as I zoom ... more  
> and more images to resize over time.
>
> Cheers
>
> Paul
> <Picture 2.png>
>
> On 29-Mar-07, at 9:49 AM, Emanuel Schütze wrote:
>
>> Hi Paul,
>>
>> I'm not exactly sure what do you mean.
>> If you start the demo; zoom f.e. to level 5 and you drag now the  
>> slider to
>> level 0 you get a new zoomOut tile which show you new informations  
>> arround
>> the last viewport of level 5. This zoomOut tile is 4 times greater  
>> than a
>> standard tile and it contains the max extent. So it comes to some  
>> alleged
>> strange situations if you zoom out from a high level. After  
>> mouseUp the
>> zoomOut tile stay pixelated until the new tiles are loaded. This  
>> is a normal
>> zoom out process. Sure, we could improve it but therefor you have  
>> to load
>> more zoomOut tiles which scales in higher levels - and this could  
>> be evoke
>> new performance problems.
>>
>> To improve your own performance try to make your map smaller. My  
>> demo has a
>> map with 100% width; dependent on your screen resolution there are  
>> many tiles
>> which have to scale. Perhaps there is the bad performance effect  
>> if the tile
>> size over 32768px like in IE? Which browser and hardware do you  
>> use? I can't
>> reproduce these effects on my machines. Try the controls example  
>> [1]. It
>> should works faster.
>>
>> Regards,
>> Emanuel
>>
>> [1]http://dev.openlayers.org/sandbox/emanuel/animatedZooming/ 
>> examples/controls.html
>>
>> On Thursday 29 March 2007 15:10, Paul Spencer wrote:
>>> Hi Emanuel,
>>>
>>> I just tried this out for the first time and its quite good :)  I
>>> have one piece of feedback.  In all browsers (although perhaps  
>>> Safari
>>> is the worst), there is a strange visual effect after it has scaled
>>> the tiles and before the new tiles arrive, some (or all perhaps) of
>>> the tiles change to a very blurry image ... its very pixelated, each
>>> pixel looks like it is about 50 square pixels on my screen.  This
>>> doesn't happen right away, only after I have zoomed in a few times.
>>>
>>> Also, after a few zooms, the whole thing slows down to the point of
>>> being not useful anymore and jacks my processor through the roof ...
>>> at this point, even resizing the window is horribly slow and  
>>> consumes
>>> a lot of processing power.  I've attached a screen grab of the  
>>> blurry
>>> stuff that happens on zoom out.
>>>
>>> It does work great when first opened, though, so hopefully its
>>> fixable :)
>>>
>>> Cheers
>>>
>>> Paul
>
> +-----------------------------------------------------------------+
> |Paul Spencer                          pspencer at dmsolutions.ca    |
> +-----------------------------------------------------------------+
> |Chief Technology Officer                                         |
> |DM Solutions Group Inc                http://www.dmsolutions.ca/ |
> +-----------------------------------------------------------------+
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