Re: Scaling and offset parameters in MIDAS PLOT commands

[Claus Tappert <claus1@sole.pd.astro.it>]

Dear Rein,

> In summary,  for the plot commands I intend to have:
>    scales:  positive numbers refer to world coord/mm
>                  negative numbers refer to mm sizes
>    offsets: positive numbers refer to screen coordinates
>                  negative numbers refer to mm offsets
> 
> The implementation would however not be quite backwards
> compatible.  If you feel this would cause a major problem for
> you or if you can think of a better solution please let me know.

I'm afraid this would indeed cause some problems as one would have
to re-write every single batch which uses plot/axes commands and alike.
Possible, but very annoying and time-consuming. Would the usage of a
special character be more difficult to implement (like the '@' in the
image commands to distinguish pixel and world coordinates)? Maybe an 's'
for screen coordinate? This would not be as confusing and inconsistent as
using negative values for the screen coordinates, and it preserves the
backwards compatibility.

Saluti,
Claus. 

------------------------------------------------------------------------
Claus Tappert, Dipartimento di Astronomia dell'Universita di Padova,
Vicolo dell'Osservatorio 5, I-35122 Padova, Italy
Tel.: preliminarily ++39-049-829-3478, Fax: ++39-049-875-9840
email: ctappert@pd.astro.it
WWW: still http://www.astro.ruhr-uni-bochum.de/cta/
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