hybrid zoom in OpenLayers?

Question

I'm basically putting an OpenLayers application on a DVD that cannot count on Internet connectivity. I've included a base layer on the DVD covering zoom levels 1-9 (due to space limitations). There are various other tiled overlays up to zoom level 17 also included on the DVD.

If I detect Internet connectivity, I augment the local base layers 1-9 with a tile service from levels 10-17. If I don't detect an internet connection, I show a transparent tile for the base layer at zoom levels 10-17 so the user can still explore the overlays at those zoom levels.

Instead of showing a transparent tile when there is no connectivity for the base layer, is there a way to show the last local zoom level (9) of base layer tiles at levels 10-17, but zoomed in? I understand that they will become more pixelated as you zoom in, but I think pixelated reference tiles are better than nothing in this situation. I thought I had read about this at one point while going through the mass of OpenLayers documentation/examples, but now that I need it, I obviously can't find it.

Thanks.

Answer 1

You should take a look at OpenLayer's ClientZoom: http://openlayers.org/dev/examples/clientzoom.html . Looks like it's what you're looking for.