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Invert - Mapping inversion flag   

Description:
This attribute controls which one of a Mapping's two possible coordinate transformations is considered the "forward" transformation (the other being the "inverse" transformation). If the attribute value is zero (the default), the Mapping's behaviour will be the same as when it was first created. However, if it is non-zero, its two transformations will be inter-changed, so that the Mapping displays the inverse of its original behaviour.

Inverting the boolean sense of the Invert attribute will cause the values of a Mapping's Nin and Nout attributes to be interchanged. The values of its TranForward and TranInverse attributes will also be interchanged. This operation may be performed with the AST_INVERT routine.

Type:
Integer (boolean).

Class Applicability:
Mapping
All Mappings have this attribute.
UnitMap
The value of the Invert attribute has no effect on the behaviour of a UnitMap.
FrameSet
Inverting the boolean sense of the Invert attribute for a FrameSet will cause its base and current Frames (and its Base and Current attributes) to be interchanged. This, in turn, may affect other properties and attributes of the FrameSet (such as Nin, Nout, Naxes, TranForward, TranInverse, etc.). The Invert attribute of a FrameSet is not itself affected by selecting a new base or current Frame.



next up previous
Next: Invisible - Draw graphics using invisible ink?
Up: AST Attribute Descriptions
Previous: IntraFlag - IntraMap identification string

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 210
R.F. Warren-Smith & D.S. Berry
30th April 2003
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2003 Central Laboratory of the Research Councils