Make a Positioning Method that places non-overlapping speech polygons at the first or last points.
polygon.method(top.bottom.left.right,
offset.cm = 0.1,
padding.cm = 0.05,
custom.colors = NULL)
Character string indicating what side of the plot to label.
Offset from the polygon to the most extreme data point.
Padding inside
the polygon.
Positioning method applied just before draw.polygons
, can set
box.color and text.color for custom colors.