This change adds a lot of flexibility to working with tile
layers: Sources where the server projection or tile grid do not
matter can now be constructed without specifying a projection or
tile grid.
The tileUrlFunction/imageUrlFunction now also creates updated
URLs when the params of the layer change, so things like
mergeNewParams in ol2 will be possible.
A nice side effect of this whole change is that there is no more
duplicated code between tiled and single image WMS layers.
While I was at it, I also fixed a WMS 1.1.1 axis order issue
and incorrect STYLES params (STYLES=& instead of STYLES&).
Previously, the TiledWMS source generated a resolutions array
derived from the world extent in meters, to match the default
Web Mercator resolutions of the map. This wouldn't work for
projections with distance units different than meters. It is
better to commit to a default resolutions array where zoom level
0 is the validity extent of the projection (not the Web Mercator
world extent!) at a 256 pixel tile size.
* The Map's private createProjection_ method is now a public
method of the Projection. It is also used by TiledWMSSource
to calculate the appropriate projection from the user
configuration.
* ol.Projection.addProjection now adds the transformation for
the source == target case. This makes it easy for the user
to create custom projection maps without including proj4js and
without adding a custom transformation, as long as the
userProjection equals the projection.
* The TiledWMSSource now uses the same default resolutions as
the map (i.e. the OSM resolutions)
* The modulo calculation for wrapping extents now works for all
grid configurations, by not calculating the number of columns
based on an assumption about the way the zoom levels relate to
resolutions.
* The wms-custom-proj example now shows how to properly
configure a custom resolution, i.e. by using the validity
extent of the projection as its extent.
Setting the extent on a tile source now only means that tiles
won't be drawn outside that extent. Now the only way to specify
the origin of the tile grid is to provide a custom tileGrid. By
default, the grid origin is the top left corner of the
projection's extent.
The WMS used in the example does not send CORS headers (I think
not many WMS services do). It seems that the WebGL renderer
needs script access to the image data, so the example only works
with the DOM renderer in Firefox.
This ensures that maps with WMS layers with different extents
do not scale the tiles differently for each layer when the
default tileGrid is used. Note that it is always possible to
configure WMS sources with a custom tileGrid.
