# [Xy-pic] large arrow tips?

Peter Selinger selinger at mathstat.dal.ca
Mon May 15 06:06:53 CEST 2006

Fantastic, thanks! This scaling business of course wreaks havoc with
the layout of my slides (which contain 66 diagrams), but nothing I
cannot fix. They do look much better now. -- Peter

Ross Moore wrote:
>
> Hi Peter,
>
> On 15/05/2006, at 10:53 AM, Peter Selinger wrote:
>
> > Hi,
> >
> > I would appreciate some help with the following problem.
> >
> > When using Xy-pic with SliTeX, the various arrow heads don't scale
> > with the size of the font of the rest of the document. I tried using
> > the \SelectTips command to change their size, but this has no visible
> > effect.
>
> No, that won't help much.
>
> >
> > How can I get larger arrow heads? The below file is a simple example.
> > On a slide show on an LCD projector, the arrow heads will be virtually
> > invisible to the audience, and in particular, the difference between A
> > and B will not be visible from the back of the room.
>
> Make sure the rotation/scaling extension is loaded ...
>
> \usepackage[all,rotate]{xy}
> \xyoption{ps}
> \xyoption{dvips}
>
>
> Then use the [thicker] modifier and/or scale the
> size of the whole diagram; e.g. as follows:
>
> \begin{slide}
>    $> \let\labelstyle\objectstyle > \vcenter{% > \xy*[*3][thicker]\xybox{\tiny > %^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > \xymatrix{ > A \ar@{-}[rr]^<>(.5){\rm id} > \ar@{}[rr]|<>(.5)/.3ex/{\dir2{>}}&&A > \\ > B \ar@{-}[rr]^<>(.5){\rm id} > \ar@{}[rr]|<>(.5)/-.3ex/{\dir2{<}}&&B > \\ > C \ar[r]^{f} & C > }}\endxy > ^^^^^^^ > }% end of \vcenter >$
>    $> \SelectTips{cm}{10} > \xy*[*3][thicker][thicker]\xybox{\tiny\POS*{} \ar > % ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > @{*{\UseTips\dir_{<<}}-*{\UseTips\dir{>}}} > (20,5)*{}}\endxy > ^^^^^^^ >$
>
> \end{slide}
>
>
> Note the \xybox{...} enclosure, which is treated
> as a single <object>, so that the scaling and thickness
> modifiers can be applied consistently.
>
> Also, the use of \tiny is to partially counteract the
> fact that the scaling in PostScript is applied to all
> of the ordinary text and mathematical symbols as well
> as to the Xy-pic parts of the diagram layouts.
>
>
> Alter the <num> scale-factor in   \xy*[*<num>]\xybox{
> to match the text/math-font symbols to the Xy-pic bits,
> according to your own tastes.
>
> >
> > Note that the file below also includes the example from the Xy-pic
> > reference manual, section 10. However, for "family=cm" and
> > "family=eu", I can only change the "size" to 10,11,12, with the
> > changes in the output being almost imperceptible. Any larger size
> > leads to font errors.
>
> Exactly.
> These fonts are only available at the specified sizes.
> But using the PostScript back-end, there is no need
> for fonts at all. Everything is done with vector-graphics,
> which can be scaled arbitrarily.
>
> > For "family=xy", the size is apparently ignored
> > entirely, as I don't get errors, and don't see any change in the
> > output.
> >
> > Is there any way I can, say, double the size of the arrows?
>
> See above.
> The "thickness" parameter is independent of the scaling.
> It alters the appearance of the arrows, making them
> "rounder" as well as thicker in the stem.
>
> By combining thickness and scale-factor you can get
> a significant range of effects.
> The Xy-pic reference manual has a few examples,
> and describes the complete syntax.
>
> >
> > Thanks, -- Peter
> >
>
> Hope this helps,
>
> 	Ross Moore
>
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> Ross Moore                                         ross at maths.mq.edu.au
> Mathematics Department                             office: E7A-419
> Macquarie University                               tel: +61 +2 9850 8955
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