Same locations, different labels.

It is not necessary to use the text strings from the .bb file for the labels. Instead, the label can be specified within the TEX or L^ATEX source. This is most convenient, since it means that:

• changes can be made to the labels without the need to make any adjustments to the .eps or .bb files
• the same image can be used many times with different labels
• labels may cross-reference other parts of the document; in a web document the labels could become hyperlinks, as in an ``image-map''

The following example uses this technique as one way to get larger sized mathematics in labels. The actual code used is shown below.

Figure 8: All labels dropped as X_Y-pic styled text boxes.

Figure 9: Coding for the above figure uses various X_Y-pic effects.

\WARMprocessEPS{\exnamei}{eps}{bb2}
\renewcommand{\labeltextstyle}{\large\bfseries\sffamily}
\begin{xy}
 \xyMarkedImport{}
 \xyMarkedPos{1}*+!DR[blue]\txt\labeltextstyle{$F_{\lambda}^*t(m_{\lambda})$}
 \xyMarkedPos{2}*+++!D[blue]\txt\labeltextstyle{$t(m)$}
 \xyMarkedPos{3}*+!U[blue]\txt\labeltextstyle{$m$}
 \xyMarkedPos{4}+/u1ex/*+!DL[F-:red]\txt\labeltextstyle{integral curve of $X$}
 \xyMarkedPos{5}*+!L[blue]\txt\labeltextstyle{$t(m_{\lambda})$}
 \xyMarkedPos{6}*+!UR[blue]\txt\labeltextstyle{$m_{\lambda}=F_{\lambda}(m)$}
 \xyMarkedPos{7}*+!DL[blue]\txt\labeltextstyle{$X(m_{\lambda})$}
\end{xy}

Using \xyMarkedPos allows the most flexibility amongst all the commands available for placing a label. Essentially all that it does is to move the X_Y-pic ``current point'' to the location of the marked point. Now any valid X_Y-pic code can be used to place anything at all at that point.

Commands to allow direct use of X_Y-pic code at the marked points are as follows:

\xyMarkedPos{<num>}<pos>*<object>
\xyShowMark{<pos>*<object>}{<num>}
\xyShowMarkPoints{<pos>*<object>}{<list>}
\xyShowMarksExcept{<pos>*<object>}{<list>}

In the latter three cases, if the {<pos>*<object>} is empty, then a default \markobject is used for each point in the <list>. This is the same for the command \xyShowAllMarkedPoints, as was used in the first example and a later one. All these commands finish with the X_Y-pic \POS-parser command so that further X_Y-pic drawing can be done, if desired. For a single marked point located using \xyShowMark, its number is also placed, using a macro \markobjectlabel. This expands as follows; it can be redefined if desired.

\def\markobjectlabel#1{\POS*\dir{x},
  *+<3pt>!U{\scriptscriptstyle#1}}

Symbolic names.

Although all the examples so far have referred to the marked points by number, they can instead be assigned a symbolic name. Any text string suffices instead of the number within the .bb file. This string can be used instead of the <num> in those macros that require such an argument. Macros wanting a <list> still work since there is an internal counter as well as the symbolic name.