MetaFun - Pragma ADE

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Now, what happens when we want to place labels in other positions? In the worst case, given
that we place the labels manually, we end up in vague arguments in favour for one or the other
placement.
upper left
left
top
lower left bottom
upper right
right
lower right
Although any automatic mechanism will be sub--optimal, we can give it a try to write a macro that
deals with arbitrary locations. This macro will accept three arguments and return a picture.
thefreelabel("some string or picture",a position,the origin)
Our testcase is just a simple for loop that places a series of labels. The freedotlabel macro is
derived from thefreelabel.
pickup pencircle scaled 1mm ;
path p ; p := fullcircle scaled 3cm ;
draw p withcolor .625yellow ;
for i=0 step .5 until 7.5 :
freedotlabel ("text" , point i of p, center p) ;
endfor ;
As a first step we will simply place the labels without any correction. We also visualize the bounding
box.
vardef thefreelabel (expr str, loc, ori) =
save s ; picture s ; s := thelabel(str,loc) ;
draw boundingbox s withpen pencircle scaled .5pt ;
s
enddef ;
To make our lives more easy, we also define a macro that draws the dot as well as a macro that
draws the label.
vardef freedotlabel (expr str, loc, ori) =
drawdot loc ; draw thefreelabel(str,loc,ori) ;
enddef ;
vardef freelabel (expr str, loc, ori) =
draw thefreelabel(str,loc,ori) ;
enddef ;
Now we get:
A few applications Free labels