id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,state
235,patch that allows layer opacity to be set,tschaub,,"The following patch allows you to create a partially transparent layer.  You do this by setting an opacity option when constructing the layer.  For example:

{{{
            var shade = new OpenLayers.Layer.WMS(""Shaded Relief"",
                ""http://ims.cr.usgs.gov:80/servlet19/com.esri.wms.Esrimap/USGS_EDC_Elev_NED_3"", 
                {layers: ""HR-NED.IMAGE"", reaspect: ""false"", transparent: 'true'},
                {isBaseLayer: false, opacity: 0.30});

}}}

''Note that if you want the layer to act as an overlay, you have to add the transparent: 'true' parameter to your WMS layer - even though the server has nothing to do with the layer transparency in this case.  The key part here is the opacity: 0.30 option.''

An example of this partially transparent shaded relief in action can be seen here:
[http://dev.geocartic.com/openlayers/examples/layer-opacity.html]


The simple patch to follow creates a partially opaque (or transparent) layer based on the opacity option.

Also, if you want to change the opacity of a layer after it has been added to the map, you could add the following method to the Layer class in Layer.js:


{{{
    /**
     * Sets the opacity for the entire layer (all images)
     * @param {Float} opacity
     */
    setOpacity: function(opacity) {
        for(var i=0; i<this.div.childNodes.length; ++i) {
            var element = this.div.childNodes[i];
            OpenLayers.Util.setOpacity(element, opacity);
        }
    },

}}}

",feature,closed,minor,2.1 Release,general,,fixed,,,