OPTIONS

  Option      Description               Default
  ------      -----------               -------

  -tick       Whether to draw major       0
              and minor ticks.
              0 = no ticks
              1 = major ticks
              2 = minor ticks

  -parallel   Whether to draw the arrow   true
              parallel to the sequence
              or perpendicular to it.

  -northeast  Whether to draw the         true
              north or east arrowhead
              (depending on orientation)

  -southwest  Whether to draw the         true
              south or west arrowhead
              (depending on orientation)

Set -parallel to false to display a point-like feature such as a polymorphism, or to indicate an important location. If the feature start == end, then the glyph will draw a single arrow at the designated location:

       ^
       |

Otherwise, there will be two arrows at the start and end:

       ^              ^
       |              |