Re: Short vectors are not plotted

[sfeam <sf...@us...>]

On Saturday, 11 November 2017 21:58:48 sfeam via gnuplot-beta wrote:
> Very good.
> That allows me to test before/after applying 0005 so that I can evaluate
> the intended change by itself.  Here's what I see.
> 
> 1) Something has gone wrong with the arrowhead direction.
>     Try running arrowstyle.dem.   All the arrows at the page bottom have
>     inverted arrowheads.
> 
> 2) The patch has lost the distinction between "fixed" arrowhead size and
>      the default variable arrowhead size.  Many of the arrows in the
>      arrowstyle demo look strange because their heads are too big.
> 
> 3) Arrowstyle 6 in the demo is supposed to show open unfilled heads.
>     After patch 0005 the arrow shaft extends through the head so it no
>     longer appears unfilled.

[snip]

> I have no clue what is going on with bug (3).  Maybe you can spot the error.
> Otherwise I think this is converging rapidly on a nice improvement.


Found it. 
The old code adjusted the shaft length so that it stopped short of the head.
The adjustment depends on the head style.
The new code always calls (*t->arrow)(sx, sy, ex, ey, NOHEAD)
and then draws the head separately. 
This means that the shaft is never corrected for the head length because
the head style is not known at that point. 

	Ethan