Re: [ferret_users] white contour and PostScript error

["William S. Kessler" <William.S.Kessler@xxxxxxxx>]

Hi Ryo -

Ah yes, the dreaded "white contour" bug. Thanks, Ryo, for figuring  
this out.

I have used a workaround, which is to choose an unused color and  
define it as nearly white:

ppl color,6,99,99,99   ! replace magenta with near-white

This avoids the problem, and in addition allows making thick white  
lines (contour/col=18 ....), and also to plot white lines using  
colors 6,12,18.

Billy

On Mar 6, 2008, at 3:07 PM, Ryo Furue wrote:

> Hi Ferreters,
>
> We sometimes see an error like this
>
>   ERROR: /typecheck in --aload--
>   Operand stack:
>   . . . . . . .
>
> for a PostScript file generated with gksm2ps from a Ferret metafile,
> when we use white contours.
>
> I've identified part of the cause.  In the PostScript file, the
> white contours are assigned color 0, which isn't defined in the
> color table "ct".  So, when color 0 is used, as in
>
>   0 o
>
> error occurs.  ("o" is a function that changes the color, it seems.)
>
> A workaround is to edit the PostScript file and manually define
> color 0, as
>
>   ct 0 [1.000000 1.000000 1.000000] put
>
> Since I don't know the metafile "language", I don't know whether this
> problem is due to the conversion by gksm2ps or it is already there in
> the metafile.
>
> Hope this helps,
> Ryo