Re: [ferret_users] spurious ripples in ps shade plot

[Andy Jacobson <andy.jacobson@xxxxxxxx>]

Hi All,

On Feb 11, 2008, at 10:47 AM, Matthew Hecht wrote:

> Thanks to Ryo Furue, Pierre St-Laurent, Andrew Wittenberg and  
> Jaison. My problem with spurious lines and ripples in a shade plot  
> was not coming from the conversion step done by Fprint (gksm2ps),  
> but from subsequent conversions. I work on a mac, and hadn't quite  
> focussed on the obvious fact that I ordinarily print ps from  
> preview -- which converts to pdf. Turning off anti-aliasing of text  
> and line art (in preview, this is under preferences/pdf) solved my  
> problem.


I use ferret, GMT, and R to make plots on OS X, and my experience is  
that I get these whitish antialiasing artifacts in gridded image  
postscript from both ferret and R, but not GMT.  I suspect that  
ferret and R are calling postscript-writing functions from some  
system library in a manner that triggers this issue, whereas GMT does  
it differently.

Note that turning off antialiasing in general is not a satisfying  
answer, since many programs (not ferret, unfortunately) use real  
postscript fonts that look much better with antialiasing.  Some  
versions of Adobe Reader allow separate control over image and text  
antialiasing, but I also find that Reader almost never displays the  
artifacts.

-Andy

--
Andy Jacobson
andy.jacobson@xxxxxxxx

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