mfpic-doc.pdf.

4.11 PARAMETERS. 61
\axisheadlen
This dimension stores the length of the arrowhead drawn by the \axes, \xaxis and \yaxis
macros, and by the macros \axis and \doaxes when applied to the parameters x and y. The initial
value is 5pt.
\sideheadlen
This dimension stores the length of the arrowhead drawn by the \axis and \doaxes macros
when applied to l, b, r or t. The initial value is 0pt (that is, the default is not to put arrowheads on
border axes).
\headshape{〈ratio〉}{〈tension〉}{〈filled〉}
This establishes the shape of the Arrowhead drawn by the \arrow... and \axes macros. It
also establishes the shape of Leftharpoon and Rightharpoon. The value of 〈ratio〉 is the ratio of
the width of the arrowhead to its length; 〈tension〉 is the tension of the Bézier curves; and 〈filled〉 is a
METAFONT boolean value indicating whether the arrowheads are to be filled (if true) or open. The
initial values are 1, 1, and false, respectively. Setting 〈tension〉 to the literal keyword ‘infinity’
will make the sides of the arrowheads straight lines. The harpoon heads are arranged to be exactly
half of the full arrowhead. The 〈ratio〉, 〈tension〉 and 〈filled〉 values are stored by METAFONT.
After \headshape is used, the symbols Arrowhead, Leftharpoon, and Rightharpoon take
on the new shape if used in one of the \plot... commands.
\dashlen, \dashspace
These dimensions store, respectively, the length of dashes and the length of spaces between
dashes, for lines drawn by the \dashed macro. The \dashed macro may adjust the dashes and the
spaces between by as much as 1/n of their value, where n is the number of spaces appearing in the
curve, in order not to have partial dashes at the ends. The initial values are both 4pt. The dashes will
actually be longer (and the spaces shorter) by the thickness of the pen used when they are drawn.
\dashlineset, \dotlineset
These macros provide shorthands for certain settings of the \dashlen and \dashspace dimensions.
The macro \dashlineset sets both values to 4pt, while \dotlineset sets \dashlen to
1pt and \dashspace to 2pt. They are kept mainly for backward compatibility.
\hashlen
This dimension stores the length of the axis hash marks drawn by the \xmarks and \ymarks
macros. The initial value is 4pt.
\shadespace
This dimension establishes the spacing between dots drawn by the \shade macro. The initial
value is 1pt.
\darkershade, \lightershade
These macros both multiply the \shadespace dimension by constant factors, 5/6 = .833333
and 6/5 = 1.2 respectively, to provide convenient standard settings for several levels of shading.
Under METAFONT it is possible that using one of these macros can have no visible effect. See the
discussion of the \shade macro in subsection 4.5.2.