Re: line corners with terminals for vector graphics

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

On Thursday 02 February 2006 10:44 am, Hans-Bernhard Br=F6ker wrote:
> Ethan Merritt wrote:
> > I understand.  However, if you choose
> > 	set term post rounded
> > then this corner is rendered identically to the others.
> > This is one advantage of choosing the rounded joins and caps.
>
> It's also a rather indirect approach that only fixes the symptom, not
> the problem.  Why should people be restricted to using round joins
> just to get a non-silly display of the graph box?

[shrug]
Different problems may require different solutions.

I took Mojca's question to be along the lines of "what could the
metapost driver do differently?".  So I gave a driver-oriented
answer.  For the very specific case of drawing the plot border,
we could of course have the core code draw 1 + 1/8 of the=20
way around the perimeter, which should give a clean join at
all 4 corners.  That change would not help any other line joins,
however.

We could think about adding a new terminal entry
point term->polyline(), which could handle this case and also
draw nice boundaries around term->filled_polygon() areas.
Or these call sites could also use the method above --
draw a polygon boundary as N + 1/2N segments and let the
driver merge these into a polyline if possible.

On the other hand, even if we did this the joins at
the endpoints of separately drawn vectors would be a problem.
E.g. when 2 or 3 zero-axis lines meet at the origin.
E.g. when different segments of a continuous line plot are
        drawn separately so that they can have different colors.

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