Xy-pic User's Guide

3.4 Entry style

As mentioned above, the entries of a diagram are set in math mode in text style. You may change this by redefinining the macro \objectstyle, and the label style by redefining \labelstyle. We can combine this with the above to get "small diagrams," e.g., typing

$\left(
 \def\objectstyle{\scriptstyle}
 \def\labelstyle{\scriptstyle}
 \vcenter{\xymatrix @-1.2pc @ur {
  A \ar[r]^{a}  & B \ar[d]^{b}  \\
  A'\ar[u]^{a'} & B'\ar[l]^{b'} }}
\right)$

in a paragraph will typeset "."

You can even abandon the use of math mode entirely: the command \def \objectstyle {\hbox} will change the format of entries to plain text.

Similarly, all entries are rectangular by default, but it is possible to change this to round by declaring the default modifiers to be applied to all entries that do not override them (cf. section 2.2):

\entrymodifiers={++[o][F-]}
\SelectTips{cm}{}
\xymatrix @-1pc {
 *\txt{start} \ar[r]
 & 0 \ar@(r,u)[]^b \ar[r]_a
 & 1 \ar[r]^b \ar@(r,d)[]_a
 & 2 \ar[r]^b
   \ar `dr_l[l]  `_ur[l]  _a [l]
 &*++[o][F=]{3}
   \ar `ur^l[lll]`^dr[lll]^b [lll]
   \ar `dr_l[ll] `_ur[ll]    [ll] }

will typeset

Notice how we obtain the double ring using the *object form which then has to include all the desired modifiers (and how the use of computer modern tips is nice for diagrams as these).

 

Xy-pic User's Guide