first commit

helix/models/dxf/graph_node_store.py

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+from helix.helpers.nodequadtree import Bounds, NodeQuadTree
+
+class GraphNodeStore(list):
+
+    def __init__(self):
+        super().__init__()
+        self.variance = 0.2
+        self.first = True
+        self.quadTree = None
+
+    def add_node(self, node):
+        self.append(node)
+        if self.first:
+            self.left = self.right = node.coordinate.x
+            self.top = self.bottom = node.coordinate.y
+            self.first = False
+        else:
+            self.left = min(self.left, node.coordinate.x)
+            self.right = max(self.right, node.coordinate.x)
+            self.bottom = min(self.bottom, node.coordinate.y)
+            self.top = max(self.top, node.coordinate.y)
+
+    def distance_squared(self, node, coordinate):
+        dx = node.coordinate.x - coordinate.x
+        dy = node.coordinate.y - coordinate.y
+        return dx * dx + dy * dy
+
+    def find_coordinate(self, coordinate):
+        # create and populate the quadtree on first request
+        if self.quadTree is None:
+            self.quadTree = NodeQuadTree(1, Bounds(self.left, self.bottom, self.right - self.left, self.top - self.bottom), self.variance)
+            for node in self:
+                self.quadTree.insert(node)
+            del self[:]
+
+        possibilities = self.quadTree.retrieve(coordinate)
+        for node in possibilities:
+            if self.distance_squared(node, coordinate) <= self.variance ** 2:
+                return node
+        else:
+            return None