[OpenLayers-Trac] Re: [OpenLayers] #3531: add continuous zooming support for tiled layers

OpenLayers trac-20090302 at openlayers.org
Sun Oct 9 05:04:12 EDT 2011

#3531: add continuous zooming support for tiled layers
  Reporter:  erilem      |       Owner:  elemoine    
      Type:  feature     |      Status:  closed      
  Priority:  major       |   Milestone:  2.12 Release
 Component:  Layer.Grid  |     Version:  2.11        
Resolution:  fixed       |    Keywords:              
     State:  Commit      |  

Comment(by erilem):

 Some information about the "client zoom" feature:

 The "client zoom" code is located in the {{{Layer.Grid}}} class, so any
 class extending {{{Layer.Grid}}} can potentially work in "client zoom"

 But some support is actually needed in child classes. The child classes
 that do support "client zoom" currently are: {{{Layer.TMS}}},
 {{{Layer.TileCache}}}, {{{Layer.WMTS}}}, and {{{Layer.XYZ}}}.

 Fortunately making a child class support "client zoom" is pretty
 straightforward. It involves a few changes in the code creating tile URLs,
 to call {{{this.getServerResolution()}}} and {{{this.getServerZoom()}}} in
 place of {{{this.map.getResolution()}}} and {{{this.map.getZoom()}}},
 respectively. See for example
 [https://github.com/openlayers/openlayers/pull/5/files#diff-4 the changes]
 that were applied to {{{Layer.TMS}}}.

 {{{getServerResolution}}} and {{{getServerZoom}}} are functions provided
 by {{{Layer.Grid}}} that return the closest resolution and zoom supported
 by the layer's tile service (based on values provided in

Ticket URL: <http://trac.openlayers.org/ticket/3531#comment:5>
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