code: def _le_diamond(self, annot, p1, p2, lr):
          
          m, im, L, R, w, scol, fcol, opacity = self._le_annot_parms(annot, p1, p2)
          shift = 2.5             # 2*shift*width = length of square edge
          d = shift * max(1, w)
          M = R - (d/2., 0) if lr else L + (d/2., 0)
          r = Rect(M, M) + (-d, -d, d, d)         # the square
      # the square makes line longer by (2*shift - 1)*width
          p = (r.tl + (r.bl - r.tl) * 0.5) * im
          ap = "q\n%s%f %f m\n" % (opacity, p.x, p.y)
          p = (r.tl + (r.tr - r.tl) * 0.5) * im
          ap += "%f %f l\n"   % (p.x, p.y)
          p = (r.tr + (r.br - r.tr) * 0.5) * im
          ap += "%f %f l\n"   % (p.x, p.y)
          p = (r.br + (r.bl - r.br) * 0.5) * im
          ap += "%f %f l\n"   % (p.x, p.y)
          ap += "%g w\n" % w
          ap += scol + fcol + "b\nQ\n"
          return ap
docs: Make stream commands for diamond line end symbol. "lr" denotes left (False) or right point.