plot issues

[Ben Abbott]

On Jun 5, 2009, at 11:02 AM, Ethan Merritt wrote:

> On Friday 05 June 2009, Ben Abbott wrote:
>
>>>> Petr, what are the benefits of the pdfcairo and pngcairo terminals
>>>> over the pdf and png terminals?
>
> Aside from licensing issues for PDFLib, using cairo to generate the  
> plots
> allows antialiasing, transparency, and UTF-8 support.

Ok, the pdfcairo sounds like it should be our default choice.

>> Are there any license problems with the plain png terminal, or is it
>> just the pdf?
>
> The "plain png" terminal has not been supported for about 8 years now.
> Instead the default is to use libgd, and the newer option is to use
> cairo.  None of these has any licensing issues that I am aware of.

Ok. What syntax is needed to access the libgd version of png?

>> Presently, when the pdf terminal is specified, the print() function
>> checks with gnuplot to determine if the "pdf" terminal is supported.
>> If not, or unknown, print() checks for the presence of ghostscript.  
>> If
>> present, the ps terminal is used to produce a ps-file and then
>> ghostscript is used to convert to pdf.
>
> Going through an intermediate postscript file is non-optimal, because
> PostScript itself does not support transparency or UTF-8 characters.
> At least from the perspective of plot quality, this is probably the
> least satisfactory of several options.
> It would be better to use either pdfcairo or the brand new tikz  
> terminal.
>
> Does Octave have a confguration file or configuration menu that the
> user can find easily?  I suggest to make the production of pdf  
> output a
> user-configurable choice.
> PDF output via (select one)
>   -->  pdf (let gnuplot choose for you)
>   -->  pdfcairo
>   -->  tikz / pdflatex
>   -->  PostScript / ps2pdf


Such a configuration capability is not present in Octave's sources.

However, how do we let gnuplot choose for us (I like this approach) ?

Ben