Re: Proposal: Saving graphs from Qt and wxt terminals

[<pl...@pi...>]

On 10/25/14 00:19, Ethan A Merritt wrote:
> On Friday, 24 October, 2014 15:17:01 Daniel J Sebald wrote:
>
>  >
>
>  > One thing to be careful of is the fact that saving to PDF (which is
>
>  > certainly welcome in my opinion because the first word of PDF means
>
>  > "portable") in the Qt terminal isn't using the PDF terminal.  There are
>
>  > no colors in the PDF output via Qt
>
> Weird. I get a perfectly normal full-color PDF.
>
>> Do we want as setup in which the interactive  terminals use the
>
>> PDF terminal, or a setup in which the interactive  terminals use their
>
>> own custom PDF output?

Worth noting here that this is a different thing to reproducing what is 
on the screen in a file. The pdf case is drifting into a pdf replot via 
pdf term or a pseudo pdf term. This is the logical way to produce a pdf 
but is differing from reproducing what is on the screen.  It does fulfil 
Philipp's  ease of use objective but may not produce the same thing. As 
per the other terminal output differences.

This will presumably be subject to the usual font size and placement and 
line style irregularities.

This should be clearly documented otherwise users will not understand 
why, when they save the output, it looks different.

>
> I have been thinking that it would be nice to have build options for
>
> two flavors of gnuplot.
>
> gnuplot+Qt
>
> no dependence on cairo or wxt
>
> svg pdf png output via the Qt libraries
>
> default terminal is qt
>
> gnuplot+wxt
>
> no dependence on Qt libraries
>
> pdf png output via cairo (can it do svg?)
>
> default terminal is wxt
>
> Either of these options could also do away with dependence on libgd,
>
> so long as people can live without gif/jpeg output.

Almost the only argument for lossy jpeg is the compression ratio. 
However, on images with few colours and large blocks png comes pretty 
close and does not have ringing and edge distortions. I never use jpeg 
for graphs.

OTOH, gif has a substantial advantage for graphs which typically have a 
very low colour count and compresses block graphics very well and is 
lossless.

I don't use it much myself but it would not be hard to image web-based 
or embedded applications where producing a very compact version of a 
graph may be needed.

I use gnuplot actually running on an embedded system and retained just 
the SVG terminal because I needed to rescale the image and interactive 
mouse  for accurate readout in a scientific context. Size and bandwidth 
was not a key criterion on this very specific application. If the usage 
did not require these features I would have used gif.

Peter.


>
> Given that it looks like wxt3 is causing problems for people who are
>
> building on bleeding edge linux systems (or building on OSX),
>
> the qt-only build option could become important.
>
> Ethan
>
>