Add missing parts of ConvexHullIncremental

The algorithm parts to clean up the four parts of the convex hull were
not implemented yet. Also added draw function for completed algorithm.

algorithm.py

@@ -191,7 +191,7 @@ class NearestNeighborsSweep(Algorithm):
                     self._result["points"][0], self._result["points"][1] \
                 ).draw(canvas, width, height, max_x, max_y, "#FF0000")
 
-class ConvexHull(Algorithm):
+class ConvexHullIncremental(Algorithm):
 
     """This algorithm calculates the convex hull for a set of points"""
 
@@ -220,7 +220,11 @@ class ConvexHull(Algorithm):
 
         self._result["success"] = False
         self._sss = {"max": None, \
-                     "min": None}
+                     "min": None, \
+                     "lt": [], \
+                     "lb": [], \
+                     "rt": [], \
+                     "rb": []}
         # Populate event structure
         self._es = copy.deepcopy(self._input)
         # Sort the input elements
@@ -236,66 +240,150 @@ class ConvexHull(Algorithm):
             event = self._es.pop(0)
             if self._sss["min"] is None or self._sss["max"] is None:
                 self._sss["min"] = event
+                self._result["lb"].append(event)
                 self._sss["max"] = event
+                self._result["lt"].append(event)
             elif event.get_y() < self._sss["min"].get_y():
-                self._result["rb"].append(linesegment.LineSegment(self._sss["min"], event))
+                self._result["lb"].append(event)
                 self._sss["min"] = event
             elif event.get_y() > self._sss["max"].get_y():
-                self._result["rt"].append(linesegment.LineSegment(self._sss["max"], event))
+                self._result["lt"].append(event)
                 self._sss["max"] = event
 
             super().step()
             if len(self._es) == 0:
                 self._sss["min"] = None
                 self._sss["max"] = None
-                self._es = copy.deepcopy(self._input).reverse()
+                self._es = copy.deepcopy(self._input)
+                self._num_steps["sort"] = point.sort_set(self._es)
                 self._section = "sweep-right-to-left"
 
         elif self._section == "sweep-right-to-left":
-            event = self._es.pop(0)
+            event = self._es.pop(-1)
             if self._sss["min"] is None or self._sss["max"] is None:
                 self._sss["min"] = event
+                self._result["rb"].append(event)
                 self._sss["max"] = event
+                self._result["rt"].append(event)
             elif event.get_y() < self._sss["min"].get_y():
-                self._result["rb"].append(linesegment.LineSegment(self._sss["min"], event))
+                self._result["rb"].append(event)
                 self._sss["min"] = event
             elif event.get_y() > self._sss["max"].get_y():
-                self._result["rt"].append(linesegment.LineSegment(self._sss["max"], event))
+                self._result["rt"].append(event)
                 self._sss["max"] = event
 
             super().step()
             if len(self._es) == 0:
+                self._es = copy.deepcopy(self._result["lt"])
                 self._section = "sweep-left-to-top"
 
         elif self._section == "sweep-left-to-top":
             event = self._es.pop(0)
+            self._sss["lt"].append(event)
+            start_idx = len(self._sss["lt"]) - 1
+            for i in range(start_idx, 0, -1):
+                if len(self._es) > 0:
+                    slope_a = linesegment.LineSegment( \
+                        self._sss["lt"][i-1], self._sss["lt"][i]).get_slope()
+                    slope_b = linesegment.LineSegment(self._sss["lt"][i], self._es[0]).get_slope()
+                    super().step()
+                    if slope_a < slope_b:
+                        del self._sss["lt"][i]
+                    else:
+                        break
+                else:
+                    break
             if len(self._es) == 0:
+                self._result["lt"] = copy.deepcopy(self._sss["lt"])
+                self._es = copy.deepcopy(self._result["lb"])
                 self._section = "sweep-left-to-bottom"
 
         elif self._section == "sweep-left-to-bottom":
             event = self._es.pop(0)
+            self._sss["lb"].append(event)
+            start_idx = len(self._sss["lb"]) - 1
+            for i in range(start_idx, 0, -1):
+                if len(self._es) > 0:
+                    slope_a = linesegment.LineSegment( \
+                        self._sss["lb"][i-1], self._sss["lb"][i]).get_slope()
+                    slope_b = linesegment.LineSegment(self._sss["lb"][i], self._es[0]).get_slope()
+                    super().step()
+                    if slope_a > slope_b:
+                        del self._sss["lb"][i]
+                    else:
+                        break
+                else:
+                    break
             if len(self._es) == 0:
+                self._result["lb"] = copy.deepcopy(self._sss["lb"])
+                self._es = copy.deepcopy(self._result["rt"])
                 self._section = "sweep-right-to-top"
 
         elif self._section == "sweep-right-to-top":
             event = self._es.pop(0)
+            self._sss["rt"].append(event)
+            start_idx = len(self._sss["rt"]) - 1
+            for i in range(start_idx, 0, -1):
+                if len(self._es) > 0:
+                    slope_a = linesegment.LineSegment( \
+                        self._sss["rt"][i-1], self._sss["rt"][i]).get_slope()
+                    slope_b = linesegment.LineSegment(self._sss["rt"][i], self._es[0]).get_slope()
+                    super().step()
+                    if slope_a > slope_b:
+                        del self._sss["rt"][i]
+                    else:
+                        break
+                else:
+                    break
             if len(self._es) == 0:
+                self._result["rt"] = copy.deepcopy(self._sss["rt"])
+                self._es = copy.deepcopy(self._result["rb"])
                 self._section = "sweep-right-to-bottom"
 
         elif self._section == "sweep-right-to-bottom":
             event = self._es.pop(0)
+            self._sss["rb"].append(event)
+            start_idx = len(self._sss["rb"]) - 1
+            for i in range(start_idx, 0, -1):
+                if len(self._es) > 0:
+                    slope_a = linesegment.LineSegment( \
+                        self._sss["rb"][i-1], self._sss["rb"][i]).get_slope()
+                    slope_b = linesegment.LineSegment(self._sss["rb"][i], self._es[0]).get_slope()
+                    super().step()
+                    if slope_a < slope_b:
+                        del self._sss["rb"][i]
+                    else:
+                        break
+                else:
+                    break
             if len(self._es) == 0:
+                self._result["rb"] = copy.deepcopy(self._sss["rb"])
                 self._section = "report-hull"
+
         elif self._section == "report-hull":
-            for line in self._result["lb"]:
-                self._result["hull"].append(line)
-            for line in self._result["rb"].reverse():
-                self._result["hull"].append(line)
-            for line in self._result["rt"]:
-                self._result["hull"].append(line)
-            for line in self._result["lt"].reverse():
-                self._result["hull"].append(line)
+            for i in range(len(self._result["lb"]) - 1):
+                self._result["hull"].append(self._result["lb"][i])
+            for i in range(len(self._result["rb"]) - 1, 0, -1):
+                self._result["hull"].append(self._result["rb"][i])
+            for i in range(len(self._result["rt"]) - 1):
+                self._result["hull"].append(self._result["rt"][i])
+            for i in range(len(self._result["lt"]) - 1, 0, -1):
+                self._result["hull"].append(self._result["lt"][i])
             self._result["success"] = True
             self._running = False
-
-
+    def draw(self, canvas, width, height, max_x, max_y):
+        if self._running:
+            pass
+        else:
+            for i in range(len(self._result["hull"]) - 1):
+                linesegment.LineSegment( \
+                    self._result["hull"][i], self._result["hull"][i+1]) \
+                    .draw(canvas, width, height, max_x, max_y, "#FF0000")
+            linesegment.LineSegment( \
+                self._result["hull"][-1], self._result["hull"][0]) \
+                .draw(canvas, width, height, max_x, max_y, "#FF0000")
+            for pnt in self._input:
+                if pnt in self._result["hull"]:
+                    pnt.draw(canvas, width, height, max_x, max_y, "#000000")
+                else:
+                    pnt.draw(canvas, width, height, max_x, max_y, "#777777")