Added documentation for the half edge.

voronoi/graph/half_edge.py

@@ -4,6 +4,49 @@
 
 class HalfEdge:
     def __init__(self, incident_point, twin=None, origin=None):
+        """
+        Edges are normally treated as undirected and shared between faces. However, for some tasks (such as simplifying
+        or cleaning geometry) it is useful to view faces as each having their own edges.
+        You can think of this as splitting each shared undirected edge along its length into two half edges.
+        (Boundary edges of course will only have one "half-edge".)
+        Each half-edge is directed (it has a start vertex and an end vertex).
+
+        The half-edge properties let you quickly find a half-edge’s source and destination vertex, the next half-edge,
+        get the other half-edge from the same edge, find all half-edges sharing a given point, and other manipulations.
+
+        Examples
+        --------
+        Get the half-edge's source
+
+        >>> edge.origin
+
+        Get the half-edge's destination
+
+        >>> edge.target # or edge.twin.origin
+
+        Get the previous and next half-edge
+
+        >>> edge.prev
+        >>> edge.next
+
+        Get the other half-edge from the same edge
+
+        >>> edge.twin
+
+        Find all half-edges sharing a given point
+
+        >>> edge.origin.connected_edges
+
+        Parameters
+        ----------
+        incident_point: Point
+            The cell point of which this edge is the border
+        twin: HalfEdge
+            The other half-edge from the same edge
+        origin: Breakpoint or Vertex
+            The origin of the half edge. Can be a Breakpoint or a Vertex during construction, and only Vertex when
+            the diagram is finished.
+        """
 
         # Pointer to the origin. Can be breakpoint or vertex.
         self.origin = origin
@@ -25,18 +68,35 @@ def __repr__(self):
         return f"{self.incident_point}/{self.twin.incident_point or '-'}"
 
     def set_next(self, next):
+        """
+        Update the `next`-property for this edge and set the `prev`-property on the `next`-edge to the current edge.
+
+        Parameters
+        ----------
+        next: HalfEdge
+            The next edge
+        """
         if next:
-            next.prev_edge = self
+            next.prev = self
         self.next = next
 
     def get_origin(self, y=None, max_y=None):
         """
-        Get the point of origin.
-
-        :param y: Sweep line (only used when the Voronoi diagram is under construction and we need to calculate
-                  where it currently is)
-        :param max_y: Bounding box top for clipping infinite breakpoints
-        :return: The point of origin, or None
+        Get the coordinates of the edge's origin.
+        During construction of the Voronoi diagram, the origin can be a vertex, which has a fixed location, or a
+        breakpoint, which is a breakpoint between two moving arcs. In the latter case, we need to calculate the
+        position based on the `y`-coordinate of the sweep line.
+
+        Parameters
+        ----------
+        y: Decimal
+            The y-coordinate of the sweep line.
+        max_y:
+            Bounding box top for clipping infinitely highly positioned breakpoints.
+
+        Returns
+        -------
+        origin: Coordinate
         """
         if isinstance(self.origin, Vertex):
             if self.origin.xd is None or self.origin.yd is None:
@@ -50,18 +110,31 @@ def get_origin(self, y=None, max_y=None):
 
     @property
     def twin(self):
+        """
+        Get the other half-edge from the same edge
+
+        Returns
+        -------
+        twin: HalfEdge
+        """
         return self._twin
 
     @twin.setter
     def twin(self, twin):
-
         if twin is not None:
             twin._twin = self
 
         self._twin = twin
 
     @property
     def target(self):
+        """
+        The twin's origin.
+
+        Returns
+        -------
+        vertex: Vertex
+        """
         if self.twin is None:
             return None
         return self.twin.origin

voronoi/visualization/visualizer.py

@@ -49,6 +49,30 @@ def __init__(self, voronoi, canvas_offset=1, figsize=(8, 8)):
         """
         A visualizer for your voronoi diagram.
 
+        Examples
+        --------
+        Quickly plot individual components of the graph.
+
+        >>> vis = Visualizer(voronoi, canvas_offset=1)
+        >>> vis.plot_sites(show_labels=True)
+        >>> vis.plot_edges(show_labels=False)
+        >>> vis.plot_vertices()
+        >>> vis.plot_border_to_site()
+        >>> vis.show()
+
+        Chaining commands
+
+        >>> Visualizer(voronoi, 1).plot_sites().plot_edges().plot_vertices().show()
+
+        Plot all components that are useful to visualize during construction of the diagram
+
+        >>> from voronoi.visualization import Presets
+        >>> Visualizer(voronoi, 1).plot_all(**Presets.construction)
+
+        Plot all components that are useful to visualize when the diagram is constructed
+
+        >>> Visualizer(voronoi, 1).plot_all()
+
         Parameters
         ----------
         voronoi: Voronoi