[fusion-users] Getting zoomscroll to work with baselayers in fusion 1.1 (MapGuide)

[Paul Spencer]

Thanks for digging into this Måns.  I suspect that the difference is  
something to do with the fixed zoom levels in tiled maps vs non-fixed  
in regular maps.

You might want to change your approach here and try something like this:

wheelChange: function(evt, deltaZ) {
     var size    = this.oMapOL.getSize();
     var deltaX  = size.w/2 - evt.xy.x;
     var deltaY  = evt.xy.y - size.h/2;
     if (this.fractionalZoom) {
         var deltaRes = deltaZ > 0 ? 0.5 : 2;  //TODO: use some sort  
of factor here
         var newRes  = this.oMapOL.baseLayer.getResolution()*deltaRes;
     } else {
         var newZoom = this.olMap.getZoom() + deltaZ;
         if (!this.olMap.isValidZoomLevel(newZoom)) {
             return;
         }
         var newRes  =  
this.olMap.baseLayer.getResolutionForZoom(newZoom);
     }
     var zoomPoint = this.oMapOL.getLonLatFromPixel(evt.xy);
     var newCenter = new OpenLayers.LonLat(
                         zoomPoint.lon + deltaX * newRes,
                         zoomPoint.lat + deltaY * newRes );
     var newBounds = new OpenLayers.Bounds(
                         newCenter.lon - size.w*newRes/2,
                         newCenter.lat - size.h*newRes/2,
                         newCenter.lon + size.w*newRes/2,
                         newCenter.lat + size.h*newRes/2);
     this.setExtents(newBounds);
}

Please let me know what you get working and I will incorporate it into  
Fusion.

Cheers

Paul

On 4-Nov-08, at 3:17 AM, Måns Beckman wrote:

> Hi,
>
> Fusion 1.1 is great, but zooming with the scrollwheel doesn’t work. http://trac.osgeo.org/fusion/ticket/59 
>  (like in Zac’s case my map is in a locale coordinate system)
> I have been trying to figure out why, but I’ve had some trouble and  
> some success.
>
> So I started with figuring out that we don’t get the same reply from  
> the server when we use ordinary maps as when we use baselayers maps.  
> Something is happening inside OpenLayers. The same parameters are  
> sent from wheelChange to setExtents, after setExtents something is  
> happening that makes the map stay in the same scale.
>
> But what could be seen was that zooming in using the zoom tool or  
> the navigator worked, so my quick and dirty hack was to copy some  
> code from the navigator widget into wheelChange.
>
> (I know this code is ugly, but it kind of works.)
>
>     wheelChange: function(evt, deltaZ) {
> var deltaRes = deltaZ > 0 ? 0.5 : 2;
> var activeWidget = null;
>         if (this.oActiveWidget) {
>           activeWidget = this.oActiveWidget;
>           this.deactivateWidget(this.oActiveWidget);
>         }
>
>         var center = this.getCurrentCenter();
>         this.zoom(center.x, center.y, deltaRes);
> //Event.stop(e);
>         if (activeWidget) {
>           this.activateWidget(activeWidget);
>         }
> },
>
> This will work, but zooms into the center of the map instead of  
> where the cursor is. I tried to send a different center to the zoom  
> function, like the newCenter calculated in the original wheelChange  
> function, but it still kept zooming into the center of the map, even  
> if I send fixed coordinates like 0,0. This is just strange.
>
> So if anyone can make my code better or find another solution it  
> would be great.
>
> Cheers
> Måns
>
>
> -----------------------------------------------------------
> Måns Beckman
> Man and Machine
> Fabriksgatan 13
> 412 50 Göteborg
> Phone: +46 31 - 762 8182
> Mobile: +46 733 - 38 83 19
>
> _______________________________________________
> fusion-users mailing list
> fusion-users at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/fusion-users


__________________________________________

    Paul Spencer
    Chief Technology Officer
    DM Solutions Group Inc
    http://research.dmsolutions.ca/