[OpenLayers-Dev] safari bug on window resize

[Paul Spencer]

Devs,

there seems to be a bug in Safari 3 (not sure about 2) with trunk  
where a window resize causes the tiles to disappear.  Zak and I  
tracked this down to the fact that Safari does not trigger an onload  
event on the image when you set the .src of the image and it is not  
different from the current src.

Our fix was this patch:

Index: /ms4w/apps/openlayers/trunk/openlayers/lib/OpenLayers/Tile/ 
Image.js
===================================================================
--- /ms4w/apps/openlayers/trunk/openlayers/lib/OpenLayers/Tile/ 
Image.js	(revision 5069)
+++ /ms4w/apps/openlayers/trunk/openlayers/lib/OpenLayers/Tile/ 
Image.js	(working copy)
@@ -119,6 +119,7 @@
              OpenLayers.Util.modifyAlphaImageDiv(this.imgDiv,
                      null, null, imageSize, this.url);
          } else {
+            this.imgDiv.src = '';
              this.imgDiv.src = this.url;
              OpenLayers.Util.modifyDOMElement(this.imgDiv,
                      null, null, imageSize) ;

By assigning an empty string, this causes Safari to behave properly  
when you assign the real source.

An alternate patch would be to set the imgDiv.src = '' in the clear  
function.

An alternate patch would be to check if the urls are identical (not  
sure if checking == is sufficient or if the isEquivalent function  
should be used) and just show the imgDiv if they are the same:

But all this leads me to question what is happening if we are setting  
the source to the same image?

It appears that a window resize is causing the map to redraw as if  
the zoom level has changed.  This causes all the tiles to get  
cleared.  I don't understand why this is necessary.  There is code in  
setCenter to just move the layer container if the zoom hasn't changed  
and this seems like a reasonable thing, so why is updateSize forcing  
the zoom to change?

I am willing to put together a patch if I can get some feedback on  
what the right solution would be:

1. clear src just before setting it

2. clear src in the clear function when we hide the imgDiv

3. only set the src if the new url is different from the old url,  
otherwise just show the imgDiv again

4. change updateSize in Map to not force a zoom level change

Cheers

Paul

+-----------------------------------------------------------------+
|Paul Spencer                          pspencer at dmsolutions.ca    |
+-----------------------------------------------------------------+
|Chief Technology Officer                                         |
|DM Solutions Group Inc                http://www.dmsolutions.ca/ |
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