[OpenLayers-Users] center crosshairs?

[Eric Lemoine]

Hi. You can probably register a moveend listener and re-center the
marker on each map move. Eric

2008/9/9, geoman <csabbey at gmail.com>:
>
> Hello,
>
> I am trying to add a icon that is fixed at the center of a map, to show
> where the center is when people are zooming. I didn't see a way to add an
> icon to a map directly, and it looks like if I put the icon in a marker and
> then add that to a layer on the map then the icon will move with the map.
>
> My solution was to add the icon through the DOM (using Prototype:)
> 				var centerIcon = new Element("img");
> 				centerIcon.src = "img/center5.gif";
> 				centerIcon.id = "mapCenter";				
> 				centerImg.setStyle({
> 					left: ((document.viewport.getWidth() / 2) - (centerImg.getWidth() / 2))
> + 'px',
> 					top: ((document.viewport.getHeight() / 2) - (centerImg.getHeight() /
> 2)) + 'px'
> 				});
> 				$('map_OpenLayers_ViewPort').insert(centerIcon);
>
> Here is the styling I used for this element:
>   img#mapCenter {
>   	position: absolute;
>   	z-index: 10000;
>   }
>
>
> Is there a way to do this using the OpenLayers API? If not, can you offer
> any solutions with a couple major problems I see with the above approach:
> 1. The icon isn't always at the center of the map; it is always close, but
> when I zoom in I can tell it is slightly high and to the left. I'm not sure
> why it is usually dead-center and sometimes off-center.
> 2. Markers under the icon no longer receive mouse events. I tried to set the
> z-index of the icon so it would be under my marker layer, but my
> map_OpenLayers_Container has a z-index of 749 and my marker layer has a
> z-index of 350, and I can't set the z-index both above 749 (so the icon is
> visible over the map tiles) and below 350 (so the markers will receive input
> events).
>
> Thanks in advance,
> Craig
>
>
> --
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> http://www.nabble.com/center-crosshairs--tp19398206p19398206.html
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>
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