## Changes Introduced in V3.2

The following describes the most significant changes which have occurred in the AST library between versions V3.1 and V3.2:

1. A new function astPutCardsastPutCards has been added to the FitsChanFitsChan class. This allows multiple concatenated header cards to be stored in a FitsChan in a single call, providing an alternative to the existing astPutCards function.

2. Some signficant changes have been made to the simplification of Mappings which should resultin a greater degree of simplication taking place.Some bugs have also been fixed which could result in an infinite loop being entered when attempting to simplify certain Mappings.

3. The FitsChan class now translates the spectral algorithm codes “-WAV”, “-FRQ” and “-VEL” (specified in early drafts of paper III) to the corresponding “-X2P” form when reading a spectral axis description from a set of FITS header cards.

4. A bug has been fixed in the FitsChan class which could cause keywords associated with alternate axis descriptions to be mis-interpreted.

5. The PlotPlot class now provides facilities for modifying the appearance of sub-strings within text strings such as axis labels, titles, etc, by producing super-scripts, sub-scripts, changing the font colour, size, etc. See attribute EscapeEscape.

6. The default value of the TolTol attribute of the Plot class has been changed from 0.001 to 0.01. This should not usually cause any significant visible change to the plot, but should make the plotting faster. You may need to set a lower value for Tol if you are producing a particularly large plot.

7. The algorithm for finding the default value for the Gap attribute has been changed. This attribute specifies the gap between major axis values in an annotated grid drawn by the Plot class. The change in algorithm may cause the default value to be different to previous versions in cirtain circumstances.

8. Some bugs have been fixed in the Plot class which could cause the system to hang for a long time while drawing certain all-sky grids (notable some of the FITS Quad-cube projections).

9. The SkyAxisSkyAxis class has extended the Format attribute by the addition of the “g” option. this option is similar to the older “l” option in that it results in characters (“h”, “m”, “s”, etc) being used as delimiters between the sexagesimal fields of the celestial position. The difference is that the “g” option includes graphics escape sequences in the returned formatted string which result in the field delimiter characters being drawn as super-scripts when plotted as numerical axis values by a Plot.

10. The Plot class has been extended to include facilities for producing logarithmic axes. See attributes LogPlot, LogTicks, LogGap and LogLabel.

11. New functions astGCap and astGScales have been added to the interface defined by file `grf.h`. The ast_linkast_link command has been modified so that the `-mygrf` switch loads dummy versions of the new grf functions. This means that applications should continue to build without any change. However, the facilities for interpreting escape sequences within strings drawn by the Plot class will not be available unless the new grf functions are implemented. If you choose to implement them, you should modify your linking procedure to use the `-grf` switch in place of the older `-mygrf` switch. See the description of the ast_link command for details of the new switches. Also note that the astGQch function, whilst included in verb+grf.h+ in pervious versions of AST, was not actually called. As of this version of AST, calls are made to the astGQch function, and so any bugs in the implementation of astGQch may cause spurious behaviour when plotting text strings.

12. A new 'static' method called astEscapesastEscapes has been added which is used to control and enquire whether astGetC and astFormatastFormat will strip any graphical escape sequences which may be present out of the returned value.

13. New attribute XmlPrefixXmlPrefix has been added to the XmlChanXmlChan class. It allows XML written by the XmlChan class to include an explicit namespace prefix on each element.

14. New attribute XmlFormatXmlFormat has been added to the XmlChan class. It specifies the format in which AST objects should be written.

15. A new class of MappingMapping, the TranMapTranMap, has been introduced. A TranMap takes its forward transformation from an existing Mapping, and its inverse transformation from another existing Mapping.

16. A bug has been fixed in WcsMapWcsMap which caused error reports to include erroneous axis numbers when referring to missing parameter values.