[vtkusers] Directed Graph Edges

[David Doria]

On Tue, Feb 23, 2010 at 9:30 AM, Jeff Baumes <jeff.baumes at kitware.com>wrote:

> Arrowheads are possible. Currently the functionality is not exposed in
> vtkGraphLayoutView, but it is possible to create your own actor. Here is the
> python code for doing it:
>
> from vtk import *
>
> # Make a small random graph and graph view.
> source = vtkRandomGraphSource()
> view = vtkGraphLayoutView()
>
> # Do layout manually before handing graph to the view.
> # This allows us to know the positions of edge arrows.
> layout = vtkGraphLayout()
> strategy = vtkSimple2DLayoutStrategy()
> layout.SetInputConnection(source.GetOutputPort())
> layout.SetLayoutStrategy(strategy);
> view.SetLayoutStrategyToPassThrough()
>
> # Add the graph to the view. This will render vertices and edges,
> # but not edge arrows.
> view.AddRepresentationFromInputConnection(layout.GetOutputPort())
>
> # Manually create an actor containing the glyphed arrows.
> graphToPoly = vtkGraphToPolyData()
> graphToPoly.SetInputConnection(layout.GetOutputPort())
> graphToPoly.EdgeGlyphOutputOn()
>
> # Set the position (0: edge start, 1: edge end) where
> # the edge arrows should go.
> graphToPoly.SetEdgeGlyphPosition(0.8)
>
> # Make a simple edge arrow for glyphing.
> arrowSource = vtkGlyphSource2D()
> arrowSource.SetGlyphTypeToEdgeArrow()
> arrowSource.SetScale(0.3)
>
> # Use Glyph3D to repeat the glyph on all edges.
> arrowGlyph = vtkGlyph3D()
> arrowGlyph.SetInputConnection(0, graphToPoly.GetOutputPort(1))
> arrowGlyph.SetInputConnection(1, arrowSource.GetOutputPort())
>
> # Add the edge arrow actor to the view.
> arrowMapper = vtkPolyDataMapper()
> arrowMapper.SetInputConnection(arrowGlyph.GetOutputPort())
> arrowActor = vtkActor()
> arrowActor.SetMapper(arrowMapper)
> view.GetRenderer().AddActor(arrowActor)
>
> # Start interaction.
> view.ResetCamera()
> view.GetInteractor().Start()
>
> Jeff
>
>
I tried to port this to c++:
http://www.vtk.org/Wiki/VTK/Examples/Graphs/VisualizeDirectedGraph

but something didn't translate.

Thoughts?

David
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