\simple_arrow

Description 

A useful operator to define arrows associated to folds is available. A simple arrow is a circle arc arrow. Two different syntaxes can be used whether two vertices or one vertex and a fold line to cross are provided. An arrow is drawn proportionally to the length between points but always remains to a defined circle arc length (default is $60^\circ$). The type of each arrow head and the side of the arrow can be specified (default value is right). Indeed, the arrow is always defined from a source vertex, which defines the arrow beginning. Along the arrow direction, the arc can be drawn to the left or to the right, depending of the drawing situation.
This operator should only appear within a step block.

Usage

  \simple_arrow(a, c, unfold, valley, left, 100);
  \simple_arrow(a, [b, d], none, mountain, right);

Formal structure

  \simple_arrow(SRC_VERTEX, DST_VERTEX, SRC_ARROW, DST_ARROW, SIDE, ARC);
  \simple_arrow(SRC_VERTEX, EDGE, SRC_ARROW, DST_ARROW, SIDE, ARC);

Parameters

  SRC_VERTEX
  Description    : Indicates the name of the beginning vertex arrow. 
  Type           : Symbol, vertex identifier.
  Allowed values : Any vertex identifier previously defined.

  DST_VERTEX
  Description    : Indicates the name of the end vertex arrow. 
  Type           : Symbol, vertex identifier.
  Allowed values : Any vertex identifier previously defined.

  EDGE
  Description    : Indicates the fold line. 
                   DST_VERTEX is computed as the symmetric of
                   SRC_VERTEX through this edge.
  Type           : Edge, couple of vertex identifiers
  Allowed values : Any couple of vertex identifiers already 
                   defined in a previous step.

  SRC_ARROW
  Description    : Indicates the type of arrow head at the origin.
  Type           : Arrow head type.
  Allowed values : One value in {valley, mountain, unfold, none}.

  DST_ARROW
  Description    : Indicates the type of arrow head at the end.
  Type           : Arrow head type.
  Allowed values : One value in {valley, mountain, unfold, none}.

  SIDE (optional)
  Description    : Indicates the orientation side of the arrow.
  Type           : Side type.
  Allowed values : One value in {left, right}.
  Default value  : right.

  ARC (optional)
  Description    : Indicates the circle arc length in degrees.
  Type           : Integer.
  Allowed values : Any positive non null integer value.
  Default value  : 60.