Merge pull request #2 from arpastrana/fresh-view-coordinates

Return fresh view coordinates from GraphObject.node_xyz and MeshObject.vertex_xyz

Author: gonzalocasas

CHANGELOG.md

@@ -27,4 +27,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+* `GraphObject.node_xyz` and `MeshObject.vertex_xyz` return fresh view
+  coordinates on every access instead of a mapping cached at first access, so
+  a redraw in a `Plotter.on` animation loop picks up
+  changes to the coordinates of the underlying datastructure.
+
 ### Removed

src/compas_plotters/scene/graphobject.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from compas.colors import Color
+from compas.geometry import transform_points
 from compas.scene import GraphObject as BaseGraphObject
 from matplotlib.collections import LineCollection
 from matplotlib.collections import PatchCollection
@@ -61,6 +62,20 @@ def __init__(
         self.nodetext = nodetext or {}
         self.edgetext = edgetext or {}
 
+    @property
+    def node_xyz(self) -> dict:
+        """Mapping of nodes to their view coordinates."""
+        if self._node_xyz is not None:
+            return self._node_xyz
+        nodes = list(self.graph.nodes())
+        points = self.graph.nodes_attributes("xyz", keys=nodes)
+        points = transform_points(points, self.worldtransformation)
+        return dict(zip(nodes, points))
+
+    @node_xyz.setter
+    def node_xyz(self, node_xyz: dict | None) -> None:
+        self._node_xyz = node_xyz
+
     def _node_radius(self) -> float:
         factor = self.plotter.dpi if self.sizepolicy == "absolute" else max(self.graph.number_of_nodes(), 1)
         return self.nodesize / factor

src/compas_plotters/scene/meshobject.py

@@ -61,18 +61,25 @@ def __init__(
             vertexcolor=vertexcolor,
             **kwargs,
         )
+        self._vertex_xyz = None
         self.vertextext = vertextext or {}
         self.edgetext = edgetext or {}
         self.facetext = facetext or {}
 
     @property
     def vertex_xyz(self) -> dict:
-        """Mapping of vertices to their world coordinates."""
+        """Mapping of vertices to their view coordinates."""
+        if self._vertex_xyz is not None:
+            return self._vertex_xyz
         vertices = list(self.mesh.vertices())
         points = [self.mesh.vertex_coordinates(vertex) for vertex in vertices]
         points = transform_points(points, self.worldtransformation)
         return dict(zip(vertices, points))
 
+    @vertex_xyz.setter
+    def vertex_xyz(self, vertex_xyz: dict | None) -> None:
+        self._vertex_xyz = vertex_xyz
+
     def viewdata(self) -> list[list[float]]:
         return [xyz[:2] for xyz in self.vertex_xyz.values()]
 

tests/test_plotter.py

@@ -181,3 +181,39 @@ def frame(f):
         point.x = f
 
     assert seen == [0, 1, 2]
+
+
+def test_dynamic_on_updates_graph_node_xyz():
+    plotter = Plotter()
+    graph = Graph()
+    a = graph.add_node(x=0, y=0, z=0)
+    b = graph.add_node(x=1, y=0, z=0)
+    graph.add_edge(a, b)
+    obj = plotter.add(graph)
+
+    @plotter.on(interval=0, frames=3)
+    def frame(f):
+        x = graph.node_attribute(b, "x")
+        graph.node_attribute(b, "x", x + f)
+
+    assert obj.node_xyz[b][0] == 4.0
+
+
+def test_mesh_vertex_xyz_is_fresh_and_assignable():
+    plotter = Plotter()
+    mesh = Mesh.from_vertices_and_faces(
+        {0: [0.0, 0.0, 0.0], 1: [1.0, 0.0, 0.0], 2: [1.0, 1.0, 0.0], 3: [0.0, 1.0, 0.0]},
+        [[0, 1, 2, 3]],
+    )
+    obj = plotter.add(mesh)
+
+    @plotter.on(interval=0, frames=3)
+    def frame(f):
+        y = mesh.vertex_attribute(1, "y")
+        mesh.vertex_attribute(1, "y", y + f)
+
+        z = mesh.vertex_attribute(3, "z")
+        mesh.vertex_attribute(3, "z", z + f)
+
+    assert obj.vertex_xyz[1][1] == 3.0
+    assert obj.vertex_xyz[3][2] == 3.0