plot issues

[Benjamin Lindner]

Ben Abbott wrote:
> 
> On Jun 5, 2009, at 4:08 PM, Ethan Merritt wrote:
> 
>> On Friday 05 June 2009 11:12:52 Benjamin Lindner wrote:
>>> 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.
>>>
>>> This may be a sutpid question, but what should a vector-based graphics
>>> description support antialiasing for?
>>
>> Ben asked about both pdfcairo and pngcairo.
>> The anti-aliasing is an issue for png, not for pdf.
>> Conversely, the transparency support is an issue for pdf but not for png.
>>
>>> pdfcairo might be superior if you require transparency and UTF-8,
>>> granted, but the quality of the generated output is disappointing
>>> compared to pdf via postscript.
>>> I do a lot of image plots and found that the resulting file sizes with
>>> the pdfcairo terminal are 4-8 times larger than a ps->pdf output. Also
>>> you don't have good control over font selection, which is IMO a
>>> knock-out criteria when doing high-quality plots for e.g. latex 
>>> inclusion.
>>
>> All I can say is that I have had the opposite experience.
>> Maybe that's because I work in a UTF environment and need support
>> for CJK character sets.  PostScript is basically hopeless for those.
>> There are some very fragile workarounds, but they are so installation-
>> specific that it doesn't work to build scripts or work flow around them.
>>
>> For latex inclusion, ps2pdf or direct PDF generation should be exactly
>> the same, and subject to the same limitations of whatever converted
>> Computer Modern fonts you are using.  If that is a primary concern,
>> then using one of the latex-based terminals directly is a better bet.
>>
>>     Ethan
> 
> It doesn't appear to me that there is one solution that is preferred 
> over the other in all cases.
> 
> I'll propose the following, and encourage all to comment.
> 
> -----------
> 1) if "pdfcairo" is present => use "set term pdfcairo ..."
> 2) if "pdf" is present => use "set term pdf ..."
> 3) if neither => use "set term postscript ..." and then convert using 
> ghostscript
> -----------
>

Sounds very reasonable to me.

> Although I'm a big LaTeX user, I elevated pdfcairo over pdf for the 
> transparency feature.
> 
> Similarly for png
> 
> -----------
> 1) if "pngcairo" is present => use "set term pngcairo ..."
> 2) if "png" is present => use "set term png ..."
> 3) if neither => use "set term postscript eps ..." and then convert 
> using ghostscript
> -----------
> 

same as above

> For LaTeX, I will soon be adding support for the Lua/TikZ terminal. Its 
> rendering is a bit slow, but produces excellent results for both latex 
> and pdflatex.
> 
> The solutions above will only work well for gnuplot 4.3+. Prior to that 
> the variable GPVAL_TERMINALS does not exist, and octave has no manner to 
> check for the existence of specific terminals.

For windows platform this is OK, since a working console application is 
only possible with 4.3+
Also interactive zooming with piped gnuplot works only with 4.3+

benjamin