MetaFun - Pragma ADE

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1.11 Pens
min_u
enddef ;
The special sequence @# is used to pick up a so called delimited argument :
vardef TryMe@#(expr x) =
% we can now use @#, which is just text
enddef ;
This feature is used in the definition of z as used in z1 or z234:
vardef z@# = (x@#,y@#) enddef ;
Other applications can be found in the label drawing macros where the anchor point is assigned
to the obscure variable @#.
When drawing, three attributes can be applied to it: a dashpattern, a pen and/or a color. You may
consider an arrowhead an attribute, but actually it is just an additional drawing, appended to the
path.
The (predefined) pencircle attribute looks like:
withpen pencircle
where pencircle is a special kind of path, stored in a pen variable. Like any path, you can transform
it. You can scale it equally in all directions:
withpen pencircle scaled 1mm
You can also provide unequal scales, creating an elliptically shaped and rotated pen.
withpen pencircle xscaled 2mm yscaled 4mm rotated 30
In the following graphic, the circle in the center is drawn without any option, which means that
the default pen is used, being a pencircle with a radius of half a base point. The other three circles
are drawn with different pen specifications.
Welcome to MetaPost Pens