Expecting all terminals to be the same [was: Re: x11 point symbols]

[Ethan M. <merritt@u.washington.edu>]

On Monday 27 February 2006 11:40 am, Ga=EBl Varoquaux wrote:
> On Mon, Feb 27, 2006 at 10:05:11AM -0800, Ethan Merritt wrote:
> > Better to have fewer
> > symbols that are mutually distinguishable than to cycle through
> > symbols that are confusingly similar.
>
>     Well, I see your point but I actually think it is annoying to
> have different renders with different terminals. And it does take by
> surprise the newbye.

I understand that new users have unreasonable expectations :-)

The fact remains that there is a huge divide between the essentially
infinite resolution vector-based terminals like postscript, emf, svg,
pdf, and the pixel-based terminals like x11 and png.

The same sort of divide exists with regard to optimal color choice,
where output destined for a physical printer wants different colors
than output destined for display on a screen.

If you truly need to compose a postscript figure accurately, there
is no substitute for using the postscript terminal itself. Trying to
emulate it exactly in x11 is an unreasonable goal, particularly if it
comes at the cost of the legibility of the screen display.=20
We should optimize the x11 settings so that they give the best
appearance on an actual X display.

If I want to end up with an *.eps figure, I preview drafts with
	set term post eps color solid
	set output '| gv:-'
If I want to end up with a *.png figure, I preview drafts with
	set term png
	set output '| display png:-'
and so on.

This is always going to give better control than fiddling with
plot elements in x11 and then hoping they come out the
same on another terminal type. =20

In the run-up to version 4.0 we made an effort to bring terminals
into better agreement for the first 8 or 12 line and point types
(I forget exactly what the upper limit was).  If we missed some
terminals, then certainly let's fix that.  But many terminal types
only *have* 8 linetypes, so I think asking for consistency out to
the 14th or 15th is not realistic.

=2D-=20
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle WA