This is expected behavior. Canvas works like a drawing board. Elements drawn to the canvas do not have a DOM representation. Why don't you use in your vector layer's features array to see if your feature was fetched?
Andreas. On Sat, Jun 1, 2013 at 8:34 AM, Ivan Sipka <frka...@gmail.com> wrote: > Hello, > > this is my scenario: a map with one baselayer and one overlay vector layer > with one point feature in it. I want to obtain the feature DOM node via > document.getElementById<https://developer.mozilla.org/en-US/docs/Web/API/document.getElementById>. > Feature gets drawn on screen in both cases. > > If I use canvas renderer the element gets drawn on map but: > > 1) document.getElementById(feature.geometry.id) returns null > 2) DOM tree inspection via chrome debugger shows no elements in canvas > > If I use SVG renderer, I can see it in the DOM tree and > document.getElementById(feature.geometry.id) returns it. > > Example code: > > <!DOCTYPE html> > <html> > <head> > <script src="http://openlayers.org/api/2.12/OpenLayers.js > "></script> > <!--<script src="http://openlayers.org/dev/OpenLayers.js > "></script>--> > <script type="text/javascript"> > > var map,vectors,feature; > > function init() { > var x = 659688.852138; > var y = 5710701.2962197; > > map = new OpenLayers.Map({ > div: "map", > projection: "EPSG:900913", > controls: [ > new OpenLayers.Control.Navigation(), > new OpenLayers.Control.PanZoomBar() > ] > }); > > var renderer = > OpenLayers.Util.getParameters(window.location.href).renderer; > > renderer = typeof(renderer) == 'undefined' ? 'Canvas' : > renderer; > > vectors = new OpenLayers.Layer.Vector('vectors', { > renderers: [renderer] > }); > > feature = new OpenLayers.Feature.Vector(new > OpenLayers.Geometry.Point(x,y)); > > map.addLayers([new OpenLayers.Layer.OSM(),vectors]); > > map.setCenter(new OpenLayers.LonLat(x,y), 18); > vectors.addFeatures(feature); > > var fetched = document.getElementById(feature.geometry.id > ); > > alert('obtaining feature via document.getElementById has > '+ (fetched == null ? 'failed':'suceeded')); > } > </script> > <style> > #map { > width: 600px; > height: 400px; > } > </style> > </head> > <body onload="init();"> > <div id="map"></div> > </body> > </html> > > Default renderer is Canvas if you want to test it you can give the canvas > implementation as a URL parameter like this: > > example.html > example.html?renderer=Canvas > > or > > example.html?renderer=SVG > > Judging by the canvas example<http://openlayers.org/dev/examples/canvas.html> > I'm > doing it right. I tried to alternate OL versions from 2.12 to 2.13dev but > it didn't help. > > Why is this happening? Is there any clever workaround? > > thanks for your time > linski > > _______________________________________________ > Dev mailing list > d...@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/openlayers-dev > > -- Andreas Hocevar OpenGeo - http://opengeo.org/ Expert service straight from the developers.
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