Tile server zoom offset

Describe the idea

Have come across some tile servers hosting smaller regional areas (eg slippy maps for the aerial imagery of city) which are identical format to normal tile servers except the zoom has been changed such that 0 zooms to the extent of the region, not the world. Thus suggest adding the option to add basic arithmetic transformation for the zoom ie an option to add an offset to the zoom eg http://example.com/{z+9}/{x}/{y}.png This is related to how the y value can be inverted for some tile servers for which say JOSM uses {-y} to invert the y coordinates. Would also be nice functionality to add, but could save that for a separate ticket. Has been implemented in GeoWebCache.

Expected behaviour

Ability to use basic transformations to accommodate non-standard tile-map coordinate systems in OsmAnd

Alternatives you've considered

An alternative solution is setting up a MapProxy server to perform the transformations. However adding the ability to offset the zoom in OsmAnd is far simpler and a more elegant solution.

Context

No response

osmandapp / OsmAnd