ptrude/: path extrusion, work in progress

ptrude/README

@@ -0,0 +1,24 @@
+File format
+-----------
+
+#r=radius
+	minimum bend radius. Propagates to all subsequent points.
+#delta=distance
+	maximum distance of line from curve. Propagates to all
+	subsequent points.
+#tag=name
+	name point or shape. Gets passed through 2D->2D transform.
+	Affects only the next point.
+x-coord y-coord
+	line endpoint
+
+#r=, #delta=, and #tag= modify the next point, e.g.,
+
+0 0
+#r=2
+#tag=foo
+1 0
+1 1
+
+would set the bend radius at the corner (and the final point) to 2 mm
+and the tag of the corner point to "foo".