% Copyright 2007 TeX Users Group.
% You may freely use, modify and/or distribute this file.
\nopagenumbers

% -------------------------------------------------------------------------
% How to output displayed math so that an accurate bounding box is created.
% -------------------------------------------------------------------------

% Problem: to make an EPS file using DVIPSONE of displayed math such that
%          the bounding box accurately reflects the area actually used.

% DVIPSONE normally puts a %%BoundingBox: ... comment in the PostScript file
% based on the information passed to it by TeX (you can override this using 
% -*P=... command line argument to force a paper-size derived bounding box).

% Normally TeX sets `width' and `height' in the DVI file based on page size.
% You can avoid this by using \shipout{...} directly rather than letting TeX's
% normal page \output{...} processing occur.  

% But displayed math is center in a box that has the current line width.
% You can work around this problem by not using display math ($$...$$),
% instead using ordinary math ($...$), but then large operators and
% spacing will correspond to \textstyle, not \displaystyle rules.

% This in turn can be avoided by explicitly adding \displaystyle to the math
% to be typeset.  This is somewhat awkward if you have to do it every time.
% You can simplify life by defining \everymath to do this automatically for
% you. See below. 

% \shipout\hbox{$r=\sqrt{x^2+y^2}$} %% OK, but textstyle, not displaystyle

% \shipout\hbox{$\displaystyle r=\sqrt{x^2+y^2}$} %% OK, but awkward

% Consider the idea from 19.4 excerise in TeX book:

% \def\leftdisplay#1$${\leftline{$\displaystyle{#1}$}$$}
% \everydisplay{\leftdisplay}

% \shipout\vbox{\noindent$$x=\sqrt{x^2+y^2}$$}

% But it is better to make $...$ automatically use displaystyle:

\def\forcedisplay#1${\displaystyle{#1}$}
\everymath{\forcedisplay}

% Then you can simply use the following, for example:

\shipout\hbox{$z=\sqrt{x^2\over y^2}$}

% Now the bounding box created by TeX is accurate.  Check it out in DVIWindo!

\end

% Here are some more ideas from Donald Arseneau:

% In LaTeX check out [fleqn]

% Can also force equation left using:

% $$\hskip0pt ... \hskip\displaywidth minus1fil\eqno ... $$

% $$\hskip0pt ... \hskip\displaywidth minus1fil$$