Openlayers2 ZoomOffset

Question

Hopefully someone can help.

I've created a TMS Layer in OpenLayers which has some local tiles these tiles are OSGB OpenData. I'm trying to get the initial zoom to be level 4 instead of 0. However OpenLayers seems to be ignoring the zoomOffset option.

Here is an example of my layer:

 var newLayer = new OpenLayers.Layer.TMS("Test Layer", "", {
        type:"png",
        getURL:overlay_getTileURL,
        alpha:true,
        setIsBaseLayer:true,
        'buffer':0,
        transitionEffect: 'resize',
        projection:new OpenLayers.Projection(projection),
        displayProjection:new OpenLayers.Projection(displayProjection),
        units:"m",
        resolutions:[400.0, 200.0, 100.0, 50.0],
        maxResolution:"auto",
        maxExtent:new OpenLayers.Bounds(0.0, 0.0, 700000.0, 1300000.0),
        zoomOffset:4
    });

  map.addLayer(newLayer);

Answer 1

I managed to fix this issue by using the Resolution Array and passing the tile offset to the getURL function.