OpenLayers Client Zoom Example

# Client Zoom

client zoom continuous zooming

This example demonstrates the "client zoom" functionality, where OpenLayers stretches the layer div when the resolution is not supported by that layer's tile service.

The map of this example is configured with 22 resolutions, while the OSM tile server supports the first 19 resolutions only. When the zoom level is 19, 20 or 21 "client zoom" is applied to the OSM layer, i.e. the OSM layer div is stretched as necessary. The map's initial zoom is 18. So if you zoom in using the zoom bar's "+" button you'll effectively trigger "client zoom".

For demonstration purpose the map of this example has `fractionalZoom` set to true. So "client zoom" also applies if you choose arbitrary zoom levels using the slider of the zoom bar, or shift-drag boxes to zoom to arbitrary extents. "client zoom" therefore allows continous zooming for tiled layers.

Enabling "client zoom" on a layer is done by passing `serverResolutions` to the layer constructor. `serverResolutions` is the list of resolutions supported by the tile service. See the clientzoom.js source.