This appendix describes how therion creates the PDF files for atlases. therion defines several TeX macros, and at the end it invokes the TeX command "\dopage " to generate the output page.

The variable used writing the page are

• \mapbox , the box with the map drawing. It has size size_width + 2 * overlap and size_height + 2 * overlap.
• \navbox , the box for the navigation grid. It has size size_width * (1 + 2 * nav_size_x) / nav_factor and size_height * (1 + 2 * nav_size_y) / nav_factor .
• \pointerE \pointerW \pointerN \pointerS , contain the numbers of the pages to the east, west, north and south (or a value 0 if the page is missing);
• \pagenum is the number of the current page;
• \pagename is the map name;
• \pagelabel is the label of the page. It is specified by the layout options "origin" and "origin-label".

Other global variables are:

• \hsize
• \vsize
• \ifpagenumbering

Finally therion uses the macros

• \showpointer#1 , to display one of the cardinal pointers;
• \showpointlist#1 for \pointerU and \pointerD ;
• \processpointeritem#1|#2|#3\endarg , for the formatting. It expands to a hbox with the suitable link: \hbox{\pdfstartlink attr {/Border[0 0 0]} goto name {#3} #2 (#1)\pdfendlink}
• \size[#1] is used to change the font size;
• \rm \it \bf \ss \si are used to change the font style; font;
• insertmap inserts the drawings.

Other variables managed by therion and that can be used are those settable through layout options:

• \explotitle \exploteam \explodate
• \topotitle \topoteam \topodate
• \cartotitle cartoteam \cartodate
• \comment
• \copyright
• \cavelength \cavelengthtitle
• \cavedepth \cavedepthtitle
• \atlastitlepage is a combination of these
• \iflegend \legendtitle \insertlegent e \formattedlegend che combina queste tre;
• \ifnortharrow \northwarrow
• \ifscalebar \scalebar

At ths point we can analize the definition of \dopage contained in the therion source file "tex/therion.tex". The structure, commented on the side, is shown in the figure below in which the vboxes are blue and the hboxes are red.

  \def\dopage{%
    \vbox{%                           +-- global vbox 
      \centerline{\framed{\mapbox}}         +-- center mapbox
      \bigskip                              +-- a space
      \line{%                               +-- "navigation" line
        \vbox to \ht\navbox{                      +-- vbox high as the "navbox"
          \hbox{\size[20]\the\pagelabel                 +-- label
            \ifpagenumbering\space(\the\pagenum)\fi     +-- number
            \space\size[16]\the\pagename}               +-- name
          \ifpagenumbering
            \medskip                                    +-- space
            \hbox{\qquad\qquad                          +-- pointers hbox
              \vtop{%
                \hbox to 0pt{\hss\showpointer\pointerN\hss}
                \hbox to 0pt{\llap{\showpointer\pointerW\hskip0.7em}%
                  \raise1pt\hbox to 0pt{\hss$\updownarrow$\hss}%
                  \raise1pt\hbox to 0pt{\hss$\leftrightarrow$\hss}%
                  \rlap{\hskip0.7em\showpointer\pointerE}}
                  \hbox to 0pt{\hss\showpointer\pointerS\hss}
              }\qquad\qquad
              \vtop{
                \def\arr{$\uparrow$}
                \showpointerlist\pointerU
                \def\arr{$\downarrow$}
                \showpointerlist\pointerD
              }
            }
          \fi
          \vss                                         +-- vertical space
          \ifscalebar\scalebar\fi                      +-- scale-bar
        }\hss                                      +-- horizontal space
        \box\navbox                                +-- navbox
      }
    }
  }