## Changes Introduced in V3.6

The following describes the most significant changes which occurred in the AST library between versions V3.5 and V3.6:

1. If the Format attribute associated with an axis of a SkyFrameSkyFrame starts with a percent character (“`%`”), then axis values are now formatted and unformatted as a decimal radians value, using the Format syntax of a simple FrameFrame.

2. The PlotPlot class has a new attribute called ClipClip which controls the clipping performed by AST at the plot boundary.

3. The keys used to label components of the PolyMapPolyMap structure when a PolyMap is written out through a ChannelChannel have been changed. The new keys are shorter than the old keys and so can written succesfully to a FitsChanFitsChan. The new PolyMap class always writes new styles keys but can read either old or new style keys. Consequently, PolyMap dumps written by this version of AST cannot be read by older versions of AST.

4. A mimimal cut down subset of the C version of SLALIB is now included with the AST distribution and built as part of building AST. This means that it is no longer necessary to have SLALIB installed separately at your site. The SLALIB code included with AST is distrubuted under the GPL. The default behaviour of the ast_linkast_link script is now to link with this internal slalib subset. However, the “-csla” option can still be used to force linking with an external full C SLALIB library. A new option “-fsla” has been introduced which forces linking with the external full Fortran SLALIB library.