[Xy-pic] problem with broken curved double arrows

Ross Moore ross@ics.mq.edu.au
Fri, 24 May 2002 17:24:29 +1000 (EST)


Hi Juergen,


> Hello,
> 
> If I have a curved double arrow that I want to interupt for a label
> (rather than placing the label at its side), the second half of the
> arrow disappears.  This happens in the matrix environment as well as
> in general.  The following example displays this behaviour under
> xy-pic 3.7.

Yes; the problem is within the  xycurve.tex  file, where the starting
parameter is determined, for the edge of the break-object, towards the
target end of a curved arrow or (non-arrow) spline-curve.

It does not happen for all places along the curve, and it doesn't
happen for all arrow-types.

Here's the fix:

%%%%%%%  xycurve.tex ,  line 1495 :   %%%%%%%%%%%%
\xydef@\breakendcontinue@i{%
\splinetrace@{move to end edge, from (\the\X@c,\the\Y@c): val=\the\splineval@ }%
 \ifdim\splineval@<\splinedepth@ \else          %%% <<<---
  \global\advance\splineval@-\splinedepth@\fi   %%% <<<--- insert these 2 lines
 \global\let\splineEndtest=\splineBreakEndtest@
 \global\let\splinetest@=\splineBreakEndtest@
 \gdef\splinerec@{\global\let\splinerec@=\splineErec@\splinedecast@@}%


Simply insert the 2 lines indicated above.
That should initialise \splineval@  so as to correctly record the location
of the edge of the break-object, when it finds it.


Please report any other problems that may arise as a result of this change.
I don't think there will be any; but just in case, please inform me.


Cheers,

	Ross

 
> -- Juergen
> 
> \input xy.tex
> \xyoption{matrix}
> \xyoption{arrow}
> \xyoption{curve}
> \xyoption{dvips}
> \xyoption{ps}
> 
> $$
> \xymatrix{
>   X
> 		\ar@/_4 ex/[rr]|e
> 		\ar@/^4 ex/@{=>}[rr]|f
> &&Y
> }
> $$
> 
> $$
> \xy ;<10 pt,0 pt>:
>   (00,0)*+{A}="A";
>   (10,0)*+{B}="B";
> \ar@/_4 ex/|e "A";"B"
> \ar@/^4 ex/@{=>}|f "A";"B"
> \endxy
> $$
> \bye
> 
> -- 
> Juergen Koslowski               If I don't see you no more on this world
> ITI, TU Braunschweig               I'll meet you on the next one
> koslowj@iti.cs.tu-bs.de               and don't be late!
> http://www.iti.cs.tu-bs.de/~koslowj      Jimi Hendrix (Voodoo Child, SR)
> _______________________________________________
> Xy-pic mailing list
> http://tug.org/mailman/listinfo/xy-pic