[OpenLayers-Dev] Canvas + SelectFeature = Bug (OL 2.11/2.12)
mr at mry4n.net
Wed Jul 11 12:26:46 PDT 2012
Yep. But it will work as expected if you swap the order in
SelectFeature. Of course, needing to do that is not expected.
Not that this might not be a nice feature to have. It could actually be
very useful be able to click features underneath a layer.
On 7/11/2012 3:00 PM, openlayers-dev-request at lists.osgeo.org wrote:
> But the original example also wrong using Canvas: using SVG can not select a
> markers if it is below a square, with Canvas you can, as if there were no
> m1k3ry4n wrote
>> >When I render a layer as a Canvas it no longer respects the layer index.
>> >In my case, the Canvas layer is made up of polygons and a separate layer
>> >above it is made up of points. Any points within polygons cannot be
>> >selected -- only the surrounding polygon gets selected.
>> >I do not have this problem if the polygon layer is rendered as something
>> >other than a Canvas.
>> >This problem is caused by the order of the layers in the array sent to
>> >OpenLayers.Control.SelectFeature. The workaround is ordering the layers
>> >array so that the Canvas layer comes after layers that are above it in
>> >the layer index.
>> >In other words, even though I add layers to the map like this:
>> >map.addLayers([canvas_layer, point_layer])
>> >I have to add layers to the control like this:
>> >map.addControl(new OpenLayers.Control.SelectFeature([point_layer,
>> >To reproduce this problem do the following.
>> >1. Go to:
>> >2. Swap the order of vectors1, vectors2 in lines 62 & 65 so they look
>> >like this:
>> >(line 62) map.addLayers([wmsLayer, vectors2, vectors1]);
>> >(line 65) selectControl = new OpenLayers.Control.SelectFeature(
>> > [vectors2, vectors1],
>> >Changing addLayers puts the markers above the squares. Changing
>> >SelectFeature disallows markers within squares to be selected, even
>> >though they are above the squares. You will only see this problem if you
>> >render the layers as Canvases (i.e. include "?renderer=Canvas" in the
>> >Considering that layer order in SelectFeature has no effect on layers
>> >not rendered as Canvases, this is either a bug or requires some
>> >documentation for SelectFeature.
>> >This was also an issue in OL 2.11, but 2.12 improved the situation. In
>> >2.11 if you turned off the Canvas layer it persisted even though you
>> >could not see the layer! If you panned the map, it would finally go away
>> >and you could click the layers below.
>> >OpenLayers Select Feature on Multiple Layers Example
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Dev