Re: GMT4: How to make page background transparent?

Thanks, Brent.  I'll try the ---.  I'm trying the second approach you 
suggest but not getting the result I want.  I'll report back what I find.
J.


On 11/15/13 1:14 PM, Brent Wood wrote:
> 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 <http://www.sdsc.edu/%7Ehellyj>
>
>
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-- 
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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