Re: color names and fill colors

From: Mary Haley <haley_at_nyahnyahspammersnyahnyah>
Date: Fri, 26 May 2006 11:06:34 -0600 (MDT)

Hi David,

The distinction between gray87 and gray88 should not be that
noticeable. As a test, can you please go to:

   http://www.ncl.ucar.edu/Document/Graphics/Images/ncolors220-263.gif

Is what you see here for gray 87 and gray 88 the same as what you are
seeing on your screen?

What may be happening is that if the exact color for gray88 is not in
your colormap, then NCL will use the next closest match. In your case,
this may very well be white.

You can try adding gray88 to your color map to make sure it is there:

   i = NhlNewColor(wks,0.875,0.875,0.875)

Of course, if you do this, and you are setting res@gsnSpreadColors to
True, then you may also want to set res@gsnSpreadColorEnd to -2 so
that it doesn't include this new gray color.

--Mary

On Fri, 26 May 2006, David B. Reusch wrote:

> I seem to have run into a step change in the progression of gray colors
> defined in lib/X11/rgb.txt. I would like to use a very light gray for
> mpLandFillColor. "gray87" (rgb=222/222/222) is too dark but everything
> lighter appears to just be white. for example, the next highest, "gray88"
> (rgb=224/224/224) looks to be indistinguishable from white. I don't think
> this is an on-screen rendering problem since going to X11 or to PS produces
> the same result. (trying different PS viewers also had the same result.)
> I've also tried different versions of ncl (a033 on OS 10.4 and a031 on
> Solaris). I think I've tried all tests available to me (different output
> workstations, different versions of ncl, different PS viewers, printing to
> make sure it's not the screen itself) so I'm left wondering if there is
> something in ncl that could explain this behavior? I wouldn't be surprised
> to reach a range of grays that converged on white, that's to be expected, but
> what I'm seeing is a *big* jump. I've also used the default gsdtol and
> gsltod colormaps in the past w/o (obvious) problems, if that's any kind of
> clue.
>
> thanks,
> dave
>
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> Earth & Environmental Systems Institute
> Penn State University
> University Park, PA 16802
>
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Received on Fri May 26 2006 - 11:06:34 MDT

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