[OpenLayers-Users] Get the Tile under mouse cursor?

[Greg Allensworth]

On 10/25/2011 7:00 AM, Doru wrote:
> I'm trying to implement kind of magnifying glass tool for an OL map with
> javascript.
> For this i have to know the ID of each " " tile element from the layer's
> "<div>" element under the current mouse position. Any ideas out there?

I would iterate over the layer's "grid" property to find the tile that 
fits your mouse click. It would go something like this:

// given some click event, get the pixel
// http://openlayers.org/dev/examples/click.html
var pixel = event.xy;

var magnifyMe = null;
for (tilerow in layer.grid) {
    for (tilei in layer.grid[tilerow]) {
       var tile     = layer.grid[tilerow][tilei];
       if (tile.bounds.containsPixel(pixel)) { magnifyMe = tile; break; }
    }
}

// now magnifyMe is a tile object (or else is null)
// see these docs for how to fetch its URL, e.g. imgDiv property

http://dev.openlayers.org/docs/files/OpenLayers/Tile-js.html
http://dev.openlayers.org/docs/files/OpenLayers/Tile/Image-js.html

-- 
Greg Allensworth, Web GIS Developer
BS  A+  Network+  Security+  Linux+  Server+
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