Re: GMT4: How to make page background transparent?

Hi John,


In your cpt file, what have you defined for the B, F & N colours? 

(last 3 lines?)

These are the values for the colurs GMT will use for Background, Foreground & NaN pixels, or use the parameters COLOR_BACKGROUND, COLOR_FOREGROUND, and COLOR_NAN specified in the .gmtdefaults4 file or on the command line.

I can't find it in the docs right now, but I seem to recall that setting these to - - - instead of an RGB triplet will cause them to be transparent.

Also note that you can set your palette "white" to RGB 254 254 254, which is very close, then use imagemagick to convert 255 255 255 to transparent - then convert (if necessary) 254 254 254 to 255 255 255. This will convert your white background to transparent, but not your white "image" (which is not quite white) will br unaffected. Then you can change your near white to white...

HTH,

  Brent Wood




________________________________
 From: John Helly <[email protected]>
To: [email protected] 
Sent: Saturday, November 16, 2013 9:32 AM
Subject: [GMT-HELP] GMT4: How to make page background transparent?
 

Hi.
I've looked around but can't find a solution.

I'm using grdimage followed by psbasemap to produce a map. I've created 
a custom colormap and its high-end is white (255/255/255).

I would like to print the white in the map at high elevation but have 
the page background transparent.  Currently the code produces a white 
background outside of the map frame as well as in the interior of the map.

I don't seem to be able to find the right parameter(s) to do this with 
so maybe it's not possible?

J.
-- 
John Helly, University of California, San Diego / San Diego 
Supercomputer Center / Scripps Institution of Oceanography / 760 840 
8660 mobile / stonesteps (Skype) / stonesteps7 (iChat) / 
http://www.sdsc.edu/~hellyj


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