[gradsusr] lines in eps output

[Oscar Chimborazo]

Thank you very much for your help Frank.

Oscar

On Wed, Mar 24, 2010 at 11:24 AM, Frank Colby <Frank_Colby at uml.edu> wrote:

>  Oscar,
>
> This is an email I found in my email archive, that might help you with your
> lines.
>
> Frank
>
> **********
>
>
> On Fri, Jul 17, 2009 at 3:17 AM, Dhaval Prajapati <
> dhaval.prajapati at iccsir.org> wrote:
>
>>   Hi,
>>
>> I have prepared  . ps files using grads. Now in the file there are
>> horizontal lines coming for colors
>> How to remove it?
>> is there any command to get batter images?
>> I am attaching one file for sample in both .ps and .jpg format
>>
>
>
>  Try "gxyat" that comes with the opengrads bundle (available from
> http://opengrads.org). Basically, gxyat is a replacement for "printim",
> although it can produce .ps, .pdf and .svg output. More info here:
>
>       http://opengrads.org/wiki/index.php?title=Gxyat
>
>  Some remarks on these "lines":
>
>  1) The "lines" you are referring do not appear if you print your
> postscript file on paper, only on the screen.  These "lines" come from an
> artifact of the grads shading algorithm and the anti-aliasing algorithm used
> by the programs that display postscript on the screen.  However, depending
> on your display program, sometimes you can turn anti-aliasing off and the
> lines go way. However, the fonts do not look as good.
>
>  2) When you convert your postscript to jpg, anti-aliasing is usually
> applied and you get the "lines". Again, depending on your conversion program
> you can turn anti-aliasing off and get rid of the "lines" at the expense of
> jagged fonts.
>
>  3) What "gxyat" does when creating image files (.png in this case) is to
> use anti-aliasing when drawing lines and turn anti-aliasing off when doing
> polygon fills. In the end you get smooth fonts and no "lines". In addition,
> "gxyat" gives you a lot more flexibility with transparency.
>
>  4) If you write .ps/.pdf files with gxyat you will have the same problem
> with the "lines". The reason is that there is no way (that I know of) in
> postscript to turn anti-aliasing on/off for part of a page, it is all or
> nothing.
>
>  BTW, you can use "gxyat" from the grads command line (replacement for
> "printim"):
>
>  ga-> gxyat image.png
>
>  or from the OS command line (replacement for gxpng, gxeps):
>
>  $ gxyat -o image.png image.gmf
>
>  where "image.gmf" is a grads metafile.  The SVG output is very useful to
> import grads output into vector graphics programs such as Adobe Illustrator
> or Inkscape without loosing any resolution (great for posters).
>
>  It would be great if someone could contribute a recipe to the Cookbooks
> illustrating these points.
>
>     Arlindo
>
>
>  --
> Arlindo da Silva
> dasilva at alum.mit.edu
>
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>
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