Conceiving a diagram.

We are now arriving at the central section of this user's guide: the one which describes the basic principle for realizing a diagram. This will be better explained on an example. Let us therefore suppose you want to construct the following diagram. X z y x P k B h g A f C

This diagram contains several items: five vertices A, B, C, P, X, four primary arrows, one secondary arrow and two ternary arrows; one of the arrows is emphasized. All those items are very different in nature, size, orientation, position ...The first basic rule for conceiving a diagram is to ignore completely all those differences and just treat equally all those items; this allows a maximum of flexibility and simplicity. To realize this, the Diagram Macros consider a formal pattern of points, at a 40pt distance from each other, both horizontally and vertically. Then each item of the diagram is centered at one of the points of the pattern, using the picture environment.

Let us for example visualize the pattern of points on which the previous diagram has been constructed.

X z y x P
\begin{picture}(0,0) \multiput(-8000,-8000)(4000,0){5}{\circle*{300}} \multiput(... ...{5}{\circle*{300}} \multiput(-8000,8000)(4000,0){5}{\circle*{300}} \end{picture}
k B h g A f C

The complete pattern needs not be a square nor even a rectangle. It is just compulsory to start all the lines from a same (left) column and leave no hole at all in any line; but lines need not be of equal length. To fill in the holes which could appear inside a line, it suffices to attach empty items at the corresponding points of the pattern. Here is for example the set of items corresponding to the previous diagram.


\begin{picture}(200,200)\thicklines \put(0,0){\line(1,0){200}} \put(0,40){\li... ...slash$\tt\scriptsize smonO\{g\}}} \put(180,20){\makebox(0,0){$C$}} \end{picture}