Re: Re[4]: arrowheads too long in PostScript terminal

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

On Tuesday 21 October 2003 13:42, Alan G Isaac wrote:

> A picture is worth a thousand words.  How can the sript
> below be considered to produce desirable output for these
> script commands?
> ##############################################################
> set term post eps color solid butt
> set output 'c:\temp3.eps'
> set xrange [0:4]
> set yrange [0:5]
> set style arrow 1 front head size 0.2,15 nofilled lt -1
> set style arrow 2 front nohead lt -1
> set style arrow 3 front nohead lw 5 lt -1
> set style arrow 4 front head size 0.2,15 nofilled lw 5 lt -1
> set arrow from  1,1 to 3,1 as 1
> set arrow from  1,2 to 3,2 as 2
> set arrow from  1,3 to 3,3 as 3
> set arrow from  1,4 to 3,4 as 4
> plot '-' with points ps 1 pt 7 lt 1
> 3 1
> 3 2
> 3 3
> e
> ##############################################################

If you change that first line to=20
   'set term post eps color solid round'
then it looks just fine to me.
The ugliness comes from requesting butt ends.

Nonetheless, let me suggest a couple of possible code modifications.
Please consider whether these would address your concerns.

1) The tail of a filled-head arrow could be drawn to reach only to
the back of the head, not all the way to the tip. This would make=20
your sample arrow 4 much less ugly

2) There could be an offset parameter, expressed in screen coordinates
I suppose, applied to the tip positioning of arrows.  The arrow would be
shortened by shifting the nominal "to" position back along the direction =
of
the arrow by this amount.  This would allow you to use fat arrows (thick
lines) for emphasis without obscuring the feature being pointed to.

I think both of these could be implemented fairly easily in the
device-independent code, and so would apply to all terminal types.


--=20
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center Box 357742
University of Washington, Seattle, WA 98195