Hi Rob,
This would indeed be a nice feature to have. Looking at the
ModifyFeature control, I think this could be easily accomplished with
minor modifications.
If we look at the ModifyFeature control, it creates a DragFeature
control to allow dragging the vertices around. When you "mouse hover" a
vertex feature, a callback function is triggered because it was defined
here :
https://github.com/openlayers/openlayers/blob/master/lib/OpenLayers/Control/ModifyFeature.js#L267
That's the callbacks for the OpenLayers.Handler.Feature object the
drag control needs to interact with features on the map. The drag
control defines its callbacks method in the featureCallbacks object :
https://github.com/openlayers/openlayers/blob/master/lib/OpenLayers/Control/DragFeature.js#L119
and here's the list of callbacks you can set to a feature handler:
click, clickout, over, out, and dblclick.
https://github.com/openlayers/openlayers/blob/master/lib/OpenLayers/Handler/Feature.js#L30
So, back in the ModifyFeature control, you could add a 'click'
callback function just next to the 'over' one. Instead of coding what
you want it to do directly in the source, just define an abstract
function that needs to be overriden OR you could fire an new vector
layer event : vertexselected (which would need to be added to
OpenLayer.Layer.Vector).
Whoa, sorry for the long reply :) In short, try to create a
delegate method or event we could register to to do whatever we wanted
on vertex selection.
Does that make sense ?
HTH,
Alexandre
On 13-02-26 11:42 AM, Robert Smart wrote:
Hi All,
I'm trying to port some existing functionality into open layers and have
managed to get most of it working. I'm just stuck on a seemingly simple
task.
The current code allows a user to highlight a polygon vertex by
clicking on
it (which changes its colour), so that the user can then press a delete
button to remove the vertex.
Using the modify control I'm able to display the vertices, and even
delete
them if I click on it and then press 'del' on my keyboard, but this is
not a
great solution as there is no visual clue as to what vertex has been
selected.
So is there a way to highlight or change the colour of a single vertex
the
user has clicked on? is there then a way to remove that vertex via
code and
have the polygon redraw on the screen to suit?
I think this would actually be quite useful as a standard feature as
there
are many cases where one might want to select an individual vertex.
Thanks,
Rob
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Alexandre Dubé
Mapgears
www.mapgears.com
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