Adding DijkstraGraphGeodesicPath, DirectedGraphToMutableDirectedGraph,

 MutableDirectedGraphToDirectedGraph, TreeToMutableDirectedGraph

src/Cxx/Graphs/DirectedGraphToMutableDirectedGraph.cxx

@@ -31,9 +31,9 @@ int main(int, char*[])
   mdg->SetPoints(points);
 
   std::cout << "MDG: " << std::endl;
-  std::cout << "Type: " << mdg->GetClassName() << std::endl;
-  std::cout << "Vertices: " << mdg->GetNumberOfVertices() << std::endl;
-  std::cout << "Edges: " << mdg->GetNumberOfEdges() << std::endl;
+  std::cout << " Type: " << mdg->GetClassName() << std::endl;
+  std::cout << " Vertices: " << mdg->GetNumberOfVertices() << std::endl;
+  std::cout << " Edges: " << mdg->GetNumberOfEdges() << std::endl;
 
   vtkNew<vtkDirectedGraph> dg;
   if (!dg->CheckedShallowCopy(mdg))
@@ -43,9 +43,9 @@ int main(int, char*[])
   }
 
   std::cout << "DG: " << std::endl;
-  std::cout << "Type: " << dg->GetClassName() << std::endl;
-  std::cout << "Vertices: " << dg->GetNumberOfVertices() << std::endl;
-  std::cout << "Edges: " << dg->GetNumberOfEdges() << std::endl;
+  std::cout << " Type: " << dg->GetClassName() << std::endl;
+  std::cout << " Vertices: " << dg->GetNumberOfVertices() << std::endl;
+  std::cout << " Edges: " << dg->GetNumberOfEdges() << std::endl;
 
   vtkNew<vtkMutableDirectedGraph> mdg2;
 
@@ -56,9 +56,9 @@ int main(int, char*[])
   }
 
   std::cout << "MDG2: " << std::endl;
-  std::cout << "Type: " << mdg2->GetClassName() << std::endl;
-  std::cout << "Vertices: " << mdg2->GetNumberOfVertices() << std::endl;
-  std::cout << "Edges: " << mdg2->GetNumberOfEdges() << std::endl;
+  std::cout << " Type: " << mdg2->GetClassName() << std::endl;
+  std::cout << " Vertices: " << mdg2->GetNumberOfVertices() << std::endl;
+  std::cout << " Edges: " << mdg2->GetNumberOfEdges() << std::endl;
 
   return EXIT_SUCCESS;
 }

src/Cxx/Graphs/MutableDirectedGraphToDirectedGraph.cxx

@@ -31,9 +31,9 @@ int main(int, char*[])
   mdg->SetPoints(points);
 
   std::cout << "MDG: " << std::endl;
-  std::cout << "Type: " << mdg->GetClassName() << std::endl;
-  std::cout << "Vertices: " << mdg->GetNumberOfVertices() << std::endl;
-  std::cout << "Edges: " << mdg->GetNumberOfEdges() << std::endl;
+  std::cout << " Type: " << mdg->GetClassName() << std::endl;
+  std::cout << " Vertices: " << mdg->GetNumberOfVertices() << std::endl;
+  std::cout << " Edges: " << mdg->GetNumberOfEdges() << std::endl;
 
   vtkNew<vtkDirectedGraph> dg;
   if (!dg->CheckedShallowCopy(mdg))
@@ -43,9 +43,9 @@ int main(int, char*[])
   }
 
   std::cout << "DG: " << std::endl;
-  std::cout << "Type: " << dg->GetClassName() << std::endl;
-  std::cout << "Vertices: " << dg->GetNumberOfVertices() << std::endl;
-  std::cout << "Edges: " << dg->GetNumberOfEdges() << std::endl;
+  std::cout << " Type: " << dg->GetClassName() << std::endl;
+  std::cout << " Vertices: " << dg->GetNumberOfVertices() << std::endl;
+  std::cout << " Edges: " << dg->GetNumberOfEdges() << std::endl;
 
   return EXIT_SUCCESS;
 }

src/Cxx/Graphs/TreeToMutableDirectedGraph.cxx

@@ -5,55 +5,63 @@
 
 int main(int, char*[])
 {
+  // vtkTree is a read-only data structure. To construct a tree, create an instance
+  // of vtkMutableDirectedGraph. Add vertices and edges with AddVertex() and AddEdge().
+  // After building the tree, call tree->CheckedShallowCopy(graph) to copy the structure
+  // into a vtkTree.
 
-  // create a graph
+  // Create a graph.
   vtkNew<vtkMutableDirectedGraph> mdg;
 
-  // add 4 vertices to the graph
+  // Add 4 vertices to the graph.
   vtkIdType v1 = mdg->AddVertex();
   vtkIdType v2 = mdg->AddVertex();
   vtkIdType v3 = mdg->AddVertex();
   vtkIdType v4 = mdg->AddVertex();
 
-  // add 3 edges to the graph
+  // Add 3 edges to the graph.
   mdg->AddEdge(v1, v2);
   mdg->AddEdge(v1, v3);
   mdg->AddEdge(v1, v4);
 
-  // create 4 points - one for each vertex
+  // Create 4 points - one for each vertex.
   vtkNew<vtkPoints> points;
   points->InsertNextPoint(0.0, 0.0, 0.0);
   points->InsertNextPoint(1.0, 0.0, 0.0);
   points->InsertNextPoint(0.0, 1.0, 0.0);
   points->InsertNextPoint(0.0, 0.0, 2.0);
 
-  // add the coordinates of the points to the graph
+  // Add the coordinates of the points to the graph.
   mdg->SetPoints(points);
 
   std::cout << "MDG: " << std::endl;
-  std::cout << "Type: " << mdg->GetClassName() << std::endl;
-  std::cout << "Vertices: " << mdg->GetNumberOfVertices() << std::endl;
-  std::cout << "Edges: " << mdg->GetNumberOfEdges() << std::endl;
+  std::cout << " Type: " << mdg->GetClassName() << std::endl;
+  std::cout << " Vertices: " << mdg->GetNumberOfVertices() << std::endl;
+  std::cout << " Edges: " << mdg->GetNumberOfEdges() << std::endl;
 
   vtkNew<vtkTree> tree;
-  tree->CheckedShallowCopy(mdg);
+  if (!tree->CheckedShallowCopy(mdg))
+  {
+    std::cerr << "Could not convert graph to tree!" << std::endl;
+    return EXIT_FAILURE;
+  }
 
   std::cout << "Tree: " << std::endl;
-  std::cout << "Type: " << tree->GetClassName() << std::endl;
-  std::cout << "Vertices: " << tree->GetNumberOfVertices() << std::endl;
-  std::cout << "Edges: " << tree->GetNumberOfEdges() << std::endl;
+  std::cout << " Type: " << tree->GetClassName() << std::endl;
+  std::cout << " Vertices: " << tree->GetNumberOfVertices() << std::endl;
+  std::cout << " Edges: " << tree->GetNumberOfEdges() << std::endl;
 
   vtkNew<vtkMutableDirectedGraph> mdg2;
   if (!mdg2->CheckedShallowCopy(tree))
   {
-    std::cerr << "Could not convert!" << std::endl;
+    std::cerr << "Could not convert tree to mutable directed graph!" << std::endl;
     return EXIT_FAILURE;
   }
 
   std::cout << "MDG2: " << std::endl;
-  std::cout << "Type: " << mdg2->GetClassName() << std::endl;
-  std::cout << "Vertices: " << mdg2->GetNumberOfVertices() << std::endl;
-  std::cout << "Edges: " << mdg2->GetNumberOfEdges() << std::endl;
+  std::cout << " Type: " << mdg2->GetClassName() << std::endl;
+  std::cout << " Vertices: " << mdg2->GetNumberOfVertices() << std::endl;
+  std::cout << " Edges: " << mdg2->GetNumberOfEdges() << std::endl;
 
   return EXIT_SUCCESS;
 }

src/PythonicAPI.md

@@ -246,6 +246,7 @@ This section includes examples of manipulating meshes.
 [ClosedSurface](/PythonicAPI/PolyData/ClosedSurface) | Check if a surface is closed.
 [DeformPointSet](/PythonicAPI/Meshes/DeformPointSet) | Use the vtkDeformPointSet filter to deform a vtkSphereSource with arbitrary polydata.
 [DelaunayMesh](/PythonicAPI/Modelling/DelaunayMesh) | Two-dimensional Delaunay triangulation of a random set of points. Points and edges are shown highlighted with sphere glyphs and tubes.
+[DijkstraGraphGeodesicPath](/PythonicAPI/PolyData/DijkstraGraphGeodesicPath) | Find the shortest path between two points on a mesh.
 [FitToHeightMap](/PythonicAPI/Meshes/FitToHeightMap) | Drape a polydata over an elevation map.
 [PointInterpolator](/PythonicAPI/Meshes/PointInterpolator) | Plot a scalar field of points onto a PolyData surface.
 
@@ -380,6 +381,12 @@ This section includes ?vtkUnstructuredGrid?.
 
 ### Graph Conversions
 
+| Example Name | Description | Image |
+| -------------- | ------------- | ------- |
+[DirectedGraphToMutableDirectedGraph](/PythonicAPI/Graphs/DirectedGraphToMutableDirectedGraph) | vtkDirectedGraph to vtkMutableDirectedGraph.
+[MutableDirectedGraphToDirectedGraph](/PythonicAPI/Graphs/MutableDirectedGraphToDirectedGraph) | vtkMutableDirectedGraph to vtkDirectedGraph.
+[TreeToMutableDirectedGraph](/PythonicAPI/Graphs/TreeToMutableDirectedGraph) | vtkTree to vtkMutableDirectedGraph
+
 ## Data Structures
 
 | Example Name | Description | Image |

src/PythonicAPI/Graphs/DirectedGraphToMutableDirectedGraph.py

+#!/usr/bin/env python3
+
+# noinspection PyUnresolvedReferences
+import vtkmodules.vtkInteractionStyle
+# noinspection PyUnresolvedReferences
+import vtkmodules.vtkRenderingOpenGL2
+from vtkmodules.vtkCommonCore import vtkPoints
+from vtkmodules.vtkCommonDataModel import (
+    vtkDirectedGraph,
+    vtkMutableDirectedGraph
+)
+
+
+def main():
+    # vtkDirectedGraph is a collection of vertices along with a collection of
+    # directed edges n(edges that have a source and target). ShallowCopy() and
+    # DeepCopy() (and CheckedShallowCopy(), CheckedDeepCopy()) accept instances
+    # of vtkTree and vtkMutableDirectedGraph. vtkDirectedGraph is read-only.
+
+    # Create a graph.
+    mdg = vtkMutableDirectedGraph()
+
+    # Add 4 vertices to the graph.
+    v1 = mdg.AddVertex()
+    v2 = mdg.AddVertex()
+    v3 = mdg.AddVertex()
+    v4 = mdg.AddVertex()
+
+    # Add 3 edges to the graph.
+    mdg.AddEdge(v1, v2)
+    mdg.AddEdge(v1, v3)
+    mdg.AddEdge(v1, v4)
+
+    # Create 4 points - one for each vertex.
+    points = vtkPoints()
+    points.InsertNextPoint(0.0, 0.0, 0.0)
+    points.InsertNextPoint(1.0, 0.0, 0.0)
+    points.InsertNextPoint(0.0, 1.0, 0.0)
+    points.InsertNextPoint(0.0, 0.0, 2.0)
+
+    # Add the coordinates of the points to the graph.
+    mdg.SetPoints(points)
+
+    print(
+        f'MDG:\n Type: {mdg.GetClassName()}\n Vertices: {mdg.GetNumberOfVertices()}\n Edges: {mdg.GetNumberOfEdges()}')
+
+    dg = vtkDirectedGraph()
+    if not dg.CheckedShallowCopy(mdg):
+        print('Could not convert mutable directed graph to directed graph!')
+        return
+
+    print(f'DG:\n Type: {dg.GetClassName()}\n Vertices: {dg.GetNumberOfVertices()}\n Edges: {dg.GetNumberOfEdges()}')
+
+    mdg2 = vtkMutableDirectedGraph()
+
+    if not mdg2.CheckedShallowCopy(mdg):
+        print('Could not convert directed graph to mutable directed graph!')
+        return
+
+    print(
+        f'MDG2:\n Type: {mdg2.GetClassName()}\n Vertices: {mdg2.GetNumberOfVertices()}\n Edges: {mdg2.GetNumberOfEdges()}')
+
+
+if __name__ == '__main__':
+    main()

src/PythonicAPI/Graphs/MutableDirectedGraphToDirectedGraph.py

+#!/usr/bin/env python3
+
+# noinspection PyUnresolvedReferences
+import vtkmodules.vtkInteractionStyle
+# noinspection PyUnresolvedReferences
+import vtkmodules.vtkRenderingOpenGL2
+from vtkmodules.vtkCommonCore import vtkPoints
+from vtkmodules.vtkCommonDataModel import (
+    vtkDirectedGraph,
+    vtkMutableDirectedGraph
+)
+
+
+def main():
+    # vtkDirectedGraph is a collection of vertices along with a collection of
+    # directed edges n(edges that have a source and target). ShallowCopy() and
+    # DeepCopy() (and CheckedShallowCopy(), CheckedDeepCopy()) accept instances
+    # of vtkTree and vtkMutableDirectedGraph. vtkDirectedGraph is read-only.
+
+    # Create a graph.
+    mdg = vtkMutableDirectedGraph()
+
+    # Add 4 vertices to the graph.
+    v1 = mdg.AddVertex()
+    v2 = mdg.AddVertex()
+    v3 = mdg.AddVertex()
+    v4 = mdg.AddVertex()
+
+    # Add 3 edges to the graph.
+    mdg.AddEdge(v1, v2)
+    mdg.AddEdge(v1, v3)
+    mdg.AddEdge(v1, v4)
+
+    # Create 4 points - one for each vertex.
+    points = vtkPoints()
+    points.InsertNextPoint(0.0, 0.0, 0.0)
+    points.InsertNextPoint(1.0, 0.0, 0.0)
+    points.InsertNextPoint(0.0, 1.0, 0.0)
+    points.InsertNextPoint(0.0, 0.0, 2.0)
+
+    # Add the coordinates of the points to the graph.
+    mdg.points = points
+
+    print(
+        f'MDG:\n Type: {mdg.GetClassName()}\n Vertices: {mdg.GetNumberOfVertices()}\n Edges: {mdg.GetNumberOfEdges()}')
+
+    dg = vtkDirectedGraph()
+    if not dg.CheckedShallowCopy(mdg):
+        print('Could not convert mutable directed graph to directed graph!')
+        return
+
+    print(f'DG:\n Type: {dg.GetClassName()}\n Vertices: {dg.GetNumberOfVertices()}\n Edges: {dg.GetNumberOfEdges()}')
+
+
+if __name__ == '__main__':
+    main()

src/PythonicAPI/Graphs/TreeToMutableDirectedGraph.py

+#!/usr/bin/env python3
+
+# noinspection PyUnresolvedReferences
+import vtkmodules.vtkInteractionStyle
+# noinspection PyUnresolvedReferences
+import vtkmodules.vtkRenderingOpenGL2
+from vtkmodules.vtkCommonCore import vtkPoints
+from vtkmodules.vtkCommonDataModel import (
+    vtkMutableDirectedGraph, vtkTree
+)
+
+
+def main():
+    # vtkTree is a read-only data structure. To construct a tree, create an
+    # instance of vtkMutableDirectedGraph. Add vertices and edges with
+    # AddVertex() and AddEdge(). After building the tree, call
+    # tree->CheckedShallowCopy(graph) to copy the structure into a vtkTree.
+
+    # Create a graph.
+    mdg = vtkMutableDirectedGraph()
+
+    # Add 4 vertices to the graph.
+    v1 = mdg.AddVertex()
+    v2 = mdg.AddVertex()
+    v3 = mdg.AddVertex()
+    v4 = mdg.AddVertex()
+
+    # Add 3 edges to the graph.
+    mdg.AddEdge(v1, v2)
+    mdg.AddEdge(v1, v3)
+    mdg.AddEdge(v1, v4)
+
+    # Create 4 points - one for each vertex.
+    points = vtkPoints()
+    points.InsertNextPoint(0.0, 0.0, 0.0)
+    points.InsertNextPoint(1.0, 0.0, 0.0)
+    points.InsertNextPoint(0.0, 1.0, 0.0)
+    points.InsertNextPoint(0.0, 0.0, 1.0)
+
+    # Add the coordinates of the points to the graph.
+    mdg.points = points
+
+    print(
+        f'MDG:\n Type: {mdg.GetClassName()}\n Vertices: {mdg.GetNumberOfVertices()}\n Edges: {mdg.GetNumberOfEdges()}')
+
+    tree = vtkTree()
+    if not tree.CheckedShallowCopy(mdg):
+        print('Could not convert graph to tree!')
+        return
+
+    print(
+        f'TREE:\n Type: {tree.GetClassName()}\n Vertices: {tree.GetNumberOfVertices()}\n Edges: {tree.GetNumberOfEdges()}')
+
+    mdg2 = vtkMutableDirectedGraph()
+
+    if not mdg2.CheckedShallowCopy(tree):
+        print('Could not convert tree to mutable directed graph!')
+        return
+
+    print(
+        f'MDG2:\n Type: {mdg2.GetClassName()}\n Vertices: {mdg2.GetNumberOfVertices()}\n Edges: {mdg2.GetNumberOfEdges()}')
+
+
+if __name__ == '__main__':
+    main()

src/PythonicAPI/PolyData/DijkstraGraphGeodesicPath.py

+#!/usr/bin/env python3
+
+# noinspection PyUnresolvedReferences
+import vtkmodules.vtkInteractionStyle
+# noinspection PyUnresolvedReferences
+import vtkmodules.vtkRenderingOpenGL2
+from vtkmodules.vtkCommonColor import vtkNamedColors
+from vtkmodules.vtkFiltersModeling import vtkDijkstraGraphGeodesicPath
+from vtkmodules.vtkFiltersSources import vtkSphereSource
+from vtkmodules.vtkRenderingCore import (
+    vtkActor,
+    vtkPolyDataMapper,
+    vtkRenderer,
+    vtkRenderWindow,
+    vtkRenderWindowInteractor
+)
+
+
+def main():
+    colors = vtkNamedColors()
+
+    # Create a sphere.
+    sphere_source = vtkSphereSource()
+
+    dijkstra = vtkDijkstraGraphGeodesicPath(start_vertex=0, end_vertex=7)
+
+    # Create a mapper and actor.
+    path_mapper = vtkPolyDataMapper()
+    sphere_source >> dijkstra >> path_mapper
+
+    path_actor = vtkActor(mapper=path_mapper)
+    path_actor.property.color = colors.GetColor3d('HotPink')
+    path_actor.property.line_width = 4
+
+    # Create a mapper and actor.
+    mapper = vtkPolyDataMapper()
+    sphere_source >> mapper
+
+    actor = vtkActor(mapper=mapper)
+    actor.property.color = colors.GetColor3d('MistyRose')
+
+    # Create a renderer, render window, and interactor.
+    renderer = vtkRenderer(background=colors.GetColor3d('MidnightBlue'))
+    render_window = vtkRenderWindow(window_name='DijkstraGraphGeodesicPath')
+    render_window.AddRenderer(renderer)
+
+    render_window_interactor = vtkRenderWindowInteractor()
+    render_window_interactor.render_window = render_window
+
+    # Add the actors to the scene.
+    renderer.AddActor(actor)
+    renderer.AddActor(path_actor)
+
+    camera = renderer.active_camera
+    camera.position = (2.9, -1.6, 0.3)
+    camera.focal_point = (0, 0, 0)
+    camera.view_up = (0, 0, 1)
+    camera.distance = 3
+    camera.Zoom(1.5)
+
+    # Render and interact.
+    render_window.Render()
+    render_window_interactor.Start()
+
+
+if __name__ == '__main__':
+    main()