[Xy-pic] an arrow with a tip in the middle

[Ross Moore]

Hi Rafael,

On 31/08/2005, at 11:48 AM, Rafael Villarroel wrote:

> Dear list,
>
> When drawing an \xygraph, I would like to have an arrow with a "tip"
> in the middle.
> If the "direction" is horizontal, I can somewhat fake it, as in the
> "arrow" from A to B.
> But in other directions it just does not work, as in B to C.  Any  
> suggestions?
> TIA
>
> Rafael
>
> \documentclass{article}
> \usepackage[graph]{xy}
>
> \begin{document}
> \xygraph{
>    !~F{[]*+<2.5pt>[o]@{*}}
>    [] !F="A"
>    [rr] !F="B"
>    [ur] !F="C"
>    "A"-|{>}"B"
>    "B"-|{>}"C"
> }

This coding is incorrect for what you want to do.
Use the directional  @{>}  rather than just  {>}
e.g., as follows:

\xygraph{
    !~F{[]*+<2.5pt>[o]@{*}}
    [] !F="A"
    [rr] !F="B"
    [ur] !F="C"
    "A"-|*@{>}"B"
    "B"-|*@{>}"C"
}

If all you want is the dots and arrows, then
you don't need to assign the names "A", "B", "C".
For example:

\xygraph{
    !~F{[]*+<2.5pt>[o]@{*}}
    [](?!F) - [rr]|*@{>}(?!F) - [ur]|*@{>}(?!F)
}


Hope this helps,

     Ross Moore

>
> \end{document}
>
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> http://tug.org/mailman/listinfo/xy-pic
>

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Ross Moore                                         ross at maths.mq.edu.au
Mathematics Department                             office: E7A-419
Macquarie University                               tel: +61 +2 9850 8955
Sydney, Australia  2109                            fax: +61 +2 9850 8114
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