rotation and offset on labels

[jodygarnett]

report:

rotation is not in geostyler offset is actually available in geostyler and sld, however geoserver seems to use different unit (and different direction)

Checking:

Symbology Encoding 1.1 The Rotation of a PointPlacement gives the clockwise rotation of the label in degrees from the normal direction for a font (left-to-right for Latin-derived human languages at least). Rotation is formally defined in Subclause 11.3.2.

GeoTools data structure:

• https://docs.geotools.org/latest/javadocs/org/geotools/styling/TextSymbolizer.html
• https://docs.geotools.org/latest/javadocs/org/opengis/style/PointPlacement.html

[jodygarnett]

We would need to double check if rotation is implemented, but the SE 1.1 standard, and geotools data structure support the idea.

[jodygarnett]

And rotation is documented in the user manual, https://docs.geoserver.org/latest/en/user/styling/sld/reference/labeling.html#rotation

[volaya]

Rotation for labels is supported already. There is even a test style to test it.

@jodygarnett Maybe it would be a good idea to have the library add a comment with the version that has produced the sld, since it looks like we are getting some false issues for using older versions...