Added presets and updated examples.

examples/observers.py

@@ -0,0 +1,63 @@
+import os
+
+from voronoi import Polygon, Voronoi, VoronoiObserver, TreeObserver, DebugObserver
+from voronoi.visualization import Presets
+
+# Define some points (a.k.a sites or cell points)
+points = [
+    (2.5, 2.5), (4, 7.5), (7.5, 2.5), (6, 7.5), (4, 4), (3, 3), (6, 3)
+]
+
+# Define a bounding box / polygon
+polygon = Polygon([
+    (2.5, 10), (5, 10), (10, 5), (10, 2.5), (5, 0), (2.5, 0), (0, 2.5), (0, 5)
+])
+
+# Initialize the algorithm
+v = Voronoi(polygon)
+
+# Attach a Voronoi observer that visualizes the Voronoi diagram every step
+v.attach_observer(
+    VoronoiObserver(
+
+        # Settings to pass into the visualizer's plot_all() method.
+        # - By default, the observer uses a set of minimalistic presets that are useful for visualizing during
+        #   construction, clipping and the final result. Have a look at Presets.construction, Presets.clipping and
+        #   Presets.final.
+        # - These settings below will update the default presets used by the observer. For example, by default,
+        #   the arc_labels are not shown, but below we can enable the arc labels. Other parameters can be found in
+        #   the visualizer's plot_all() method.
+        settings=dict(arc_labels=True, site_labels=True),
+
+        # Callback that saves the figure every step
+        # If no callback is provided, it will simply display the figure in a matplotlib window
+        callback=lambda observer, figure: figure.savefig(f"output/voronoi/{observer.n_messages:02d}.png")
+    )
+)
+
+# Attach observer that visualizes the tree every step. This is a binary tree data structure that keeps track of where
+# the arcs and the breakpoints between the arcs are going.
+v.attach_observer(
+    TreeObserver(
+        # Callback that saves the figure every step
+        # If no callback is provided, it will render the figure in a window
+        callback=lambda observer, dot: dot.render(f"output/tree/{observer.n_messages:02d}")
+    )
+)
+
+# Attach a listener that listens to debug messages.
+# If no callback is provided, it will print the messages.
+v.attach_observer(DebugObserver(callback=lambda _: print(_)))
+
+# Create the output directory if it doesn't exist
+if not os.path.exists("output"):
+    os.mkdir("output")
+
+if not os.path.exists("output/tree/"):
+    os.mkdir("output/tree/")
+
+if not os.path.exists("output/voronoi/"):
+    os.mkdir("output/voronoi/")
+
+# Create the Voronoi diagram
+v.create_diagram(points=points)

examples/quickstart.py

@@ -1,5 +1,5 @@
 from typing import List
-from voronoi import Voronoi, Polygon, Visualizer, Point
+from voronoi import Voronoi, Polygon, Visualizer, Point, VoronoiObserver
 from voronoi.graph import HalfEdge, Vertex
 
 # Define some points (a.k.a sites or cell points)
@@ -15,12 +15,18 @@
 # Initialize the algorithm
 v = Voronoi(polygon)
 
+# Optional: visualize the voronoi diagram at every step.
+# You can find more information in the observers.py example file
+# v.attach_observer(
+#     VoronoiObserver()
+# )
+
 # Create the Voronoi diagram
 v.create_diagram(points=points)
 
 # Visualize the Voronoi diagram
 Visualizer(v) \
-    .plot_sites(show_labels=True) \
+    .plot_sites(show_labels=False) \
     .plot_edges(show_labels=False) \
     .plot_vertices() \
     .show()
@@ -33,23 +39,23 @@
 edge, vertex, site = edges[0], vertices[0], sites[0]
 
 # Edge operations
-origin: Vertex = edge.origin              # The vertex in which the edge originates
-target: Vertex = edge.twin.origin         # The twin is the edge that goes in the other direction
-target_alt: Vertex = edge.target          # Same as above, but more convenient
-twin: HalfEdge = edge.twin                # Get the twin of this edge
-next: HalfEdge = edge.next                # Get the next edge
-prev: HalfEdge = edge.twin.next           # Get the previous edge
-prev_alt: HalfEdge = edge.prev            # Same as above, but more convenient
+origin: Vertex = edge.origin               # The vertex in which the edge originates
+target: Vertex = edge.twin.origin          # The twin is the edge that goes in the other direction
+target_alt: Vertex = edge.target           # Same as above, but more convenient
+twin: HalfEdge = edge.twin                 # Get the twin of this edge
+next_edge: HalfEdge = edge.next            # Get the next edge
+prev_edge: HalfEdge = edge.twin.next       # Get the previous edge
+prev_alt: HalfEdge = edge.prev             # Same as above, but more convenient
 
 # Site operations
-size: float = site.area()                 # The area of the cell
-borders: List[HalfEdge] = site.borders()  # A list of all the borders that surround this cell point
-vertices: List[Vertex] = site.vertices()  # A list of all the vertices around this cell point
-site_x: float = site.x                    # X-coordinate of the site
-site_xy: [float, float] = site.xy         # (x, y)-coordinates of the site
+size: float = site.area()                  # The area of the cell
+borders: List[HalfEdge] = site.borders()   # A list of all the borders that surround this cell point
+vertices: List[Vertex] = site.vertices()   # A list of all the vertices around this cell point
+site_x: float = site.x                     # X-coordinate of the site
+site_xy: [float, float] = site.xy          # (x, y)-coordinates of the site
+first_edge: HalfEdge = site.first_edge     # Points to the first edge that is part of the border around the site
 
 # Vertex operations
 connected_edges: List[HalfEdge] = vertex.connected_edges  # A list of all edges that are connected to this vertex
 vertex_x: float = vertex.x                                # x-coordinate of the vertex
 vertex_xy: [float, float] = vertex.xy                     # (x, y)-coordinates of the vertex
-print()

voronoi/graph/half_edge.py

@@ -26,7 +26,7 @@ def __repr__(self):
 
     def set_next(self, next):
         if next:
-            next.prev = self
+            next.prev_edge = self
         self.next = next
 
     def get_origin(self, y=None, max_y=None):

voronoi/observers/voronoi_observer.py

@@ -5,12 +5,12 @@
 from voronoi.observers.observer import Observer
 import matplotlib.pyplot as plt
 
-from voronoi.visualization.visualizer import Visualizer
+from voronoi.visualization.visualizer import Visualizer, Presets
 
 
 class VoronoiObserver(Observer, ABC):
     def __init__(self, visualize_steps=True, visualize_before_clipping=False, visualize_result=True, callback=None,
-                 figsize=(8, 8), canvas_offset=5, settings=None):
+                 figsize=(8, 8), canvas_offset=1, settings=None):
         self.canvas_offset = canvas_offset
         self.figsize = figsize
         self.visualize_steps = visualize_steps
@@ -28,20 +28,20 @@ def update(self, subject: Algorithm, message: Message, **kwargs):
 
         if message == Message.STEP_FINISHED and self.visualize_steps:
             vis = Visualizer(subject, canvas_offset=self.canvas_offset)
-            settings = dict(outgoing_edges=False)
+            settings = Presets.construction
             settings.update(self.settings)
             assert subject.sweep_line == subject.event.yd
             result = vis.plot_all(**settings)
             plt.title(str(subject.event) + "\n")
         elif message == Message.SWEEP_FINISHED and self.visualize_before_clipping:
             vis = Visualizer(subject, canvas_offset=self.canvas_offset)
-            settings = dict(events=False, beach_line=False, outgoing_edges=False)
+            settings = Presets.clipping
             settings.update(self.settings)
             result = vis.plot_all(**settings)
             plt.title("Sweep finished\n")
         elif message == Message.VORONOI_FINISHED and self.visualize_result:
             vis = Visualizer(subject, canvas_offset=self.canvas_offset)
-            settings = dict(events=False, outgoing_edges=False, arcs=False, beach_line=False, sweep_line=False)
+            settings = Presets.final
             settings.update(self.settings)
             result = vis.plot_all(**settings)
             plt.title("Voronoi completed\n")

voronoi/visualization/__init__.py

@@ -1 +1,2 @@
-from voronoi.visualization.visualizer import Visualizer
+from voronoi.visualization.visualizer import Visualizer
+from voronoi.visualization.visualizer import Presets

voronoi/visualization/visualizer.py

@@ -29,6 +29,17 @@ class Colors:
     FIRST_EDGE = "#2ecc71"
 
 
+class Presets:
+    # A minimalistic preset that is useful during construction
+    construction = dict(polygon=True, events=True, beach_line=True, sweep_line=True)
+
+    # A minimalistic preset that is useful during clipping
+    clipping = dict(polygon=True)
+
+    # A minimalistic preset that is useful to show the final result
+    final = dict()
+
+
 class Visualizer:
 
     def __init__(self, voronoi, canvas_offset=1, figsize=(8, 8)):
@@ -52,9 +63,10 @@ def show(self, block=True, **kwargs):
         plt.show(block=block, **kwargs)
         return self
 
-    def plot_all(self, polygon=True, edges=True, vertices=True, sites=True,
-                 outgoing_edges=False, events=True, beach_line=True, arcs=True, border_to_site=False, scale=1,
-                 edge_labels=True, site_labels=True, triangles=False, sweep_line=True, arc_labels=True):
+    def plot_all(self, polygon=False, edges=True, vertices=True, sites=True,
+                 outgoing_edges=False, border_to_site=False, scale=1,
+                 edge_labels=False, site_labels=False, triangles=False, arcs=False, sweep_line=False, events=False,
+                 arc_labels=False, beach_line=False):
 
         self.plot_sweep_line() if sweep_line else False
         self.plot_polygon() if polygon else False
@@ -72,7 +84,8 @@ def plot_polygon(self):
         if hasattr(self.voronoi.bounding_poly, 'radius'):
             # Draw bounding box
             self.canvas.add_patch(
-                patches.Circle((self.voronoi.bounding_poly.xd, self.voronoi.bounding_poly.xd), self.voronoi.bounding_poly.radius,
+                patches.Circle((self.voronoi.bounding_poly.xd, self.voronoi.bounding_poly.xd),
+                               self.voronoi.bounding_poly.radius,
                                fill=False,
                                edgecolor=Colors.BOUNDING_BOX)
             )
@@ -95,8 +108,9 @@ def plot_vertices(self, vertices=None, **kwargs):
 
         return self
 
-    def plot_outgoing_edges(self, vertices=None, scale=1, **kwargs):
+    def plot_outgoing_edges(self, vertices=None, scale=0.5, **kwargs):
         vertices = vertices or self.voronoi.vertices
+        scale = Decimal(str(scale))
 
         for vertex in vertices:
             for edge in vertex.connected_edges:
@@ -116,8 +130,9 @@ def plot_outgoing_edges(self, vertices=None, scale=1, **kwargs):
                 direction = (x_diff / length, y_diff / length)
                 new_end = Coordinate(start.xd + direction[0] * scale, start.yd + direction[1] * scale)
 
-                props = dict(arrowstyle="->", color=Colors.EDGE_DIRECTION, linewidth=1, **kwargs)
-                self.canvas.annotate(text='', xy=(new_end.xd, new_end.yd), xytext=(start.xd, start.yd), arrowprops=props)
+                props = dict(arrowstyle="->", color=Colors.EDGE_DIRECTION, linewidth=3, **kwargs)
+                self.canvas.annotate(text='', xy=(new_end.xd, new_end.yd), xytext=(start.xd, start.yd),
+                                     arrowprops=props)
 
         return self
 
@@ -133,7 +148,7 @@ def plot_sites(self, points=None, show_labels=True, color=Colors.CELL_POINTS, zo
         # Add descriptions
         if show_labels:
             for point in points:
-                self.canvas.text(point.xd, point.yd, s=f"{point} (A={point.area(digits=2)})", zorder=15)
+                self.canvas.text(point.xd, point.yd, s=f"P{point.name if point.name is not None else ''}", zorder=15)
 
         return self