Gnuplot: linetype Version 5.0 patchlevel 3

Question

I am using gnuplot 5.9 patchlevel 3 and I wanted to use different lt thus I wanted to reproduce the following this tutorial from gnuplot 5.0 patchlevel 1.

In particular if I copy it and launch it both from term and as .eps I couldn't see dashed lines, here the output

In particular I do not understand the following line:

You will only see dashed lines if your current terminal setting permits it

What does it mean? How I can 'force' gnuplot to print the different dashed lines in .eps, .png or via screen?

I found this guide but its refer to a 4.2.5 version of gnuplot, even if I use:

set termoption dashed or set terminal x11 dashed

I can't see the dashed lines...Those are the terminals I can use in gnuplot 5.0 patchlevel 3 from help term:

canvas            cgm               context           corel
dumb              dxf               eepic             emf
emtex             epslatex          fig               hpgl
latex             mf                mp                pcl5
pop               postscript        pslatex           pstex
pstricks          push              qms               svg
tek40xx           tek410x           texdraw           tgif
tkcanvas          tpic              vttek             x11
xlib              xterm

I red also this answer but gnuplot 5.0 doesn't support pngcairo (???) as a test, in fact, I just try:

set term pngcairo dashed

And I receive the answer:

Terminal type set to 'unknown' ^ unknown or ambiguous terminal type; type just 'set terminal' for a list

Thus I tried to install pngciaro following this page using homebrew which I found not so useful unfortunately due to the fact that the question about gnuplot 5.0 does not have an answer and because I receive some warning that could be connected with the installation of the pngcairo.

Answer 1

I am using gnuplot 5.9 patchlevel 3

Surely you mean 5.0.3? The image you attached shows dashed lines so what's your question? Then I tried this example script you link to with the eps terminal and it works fine as well on 5.0.3.

Gnuplot renders output using different "terminals", some of the more terminals do not support support dashed lines and this includes the default PNG terminal png, the png terminal from the cairo library, pngcairo, does however support dashed lines. Terminals must be integrated into your Gnuplot build at compile-time, so options must be flagged to enable certain terminals. If Gnuplot was not built with the cairo library then the pngcairo or epscairo terminals will not be available and you will receive that message

unknown or ambiguous terminal type; type just 'set terminal' for a list

when attempting to set you plot to one of those terminals. When you do set term it just displays the terminals which your build was compiled with.

Gnuplot 5 does support pngcairo, it just has to be built with it. Are you on OSX and have homebrew installed? Just install it with cairo support using

brew install gnuplot --with-cairo