[2.3.5] External layout algorithms: All VertexSizes passed in are (0,0)

[ValentinMarinov]

To reproduce:

1. Create a custom layout algorithm by inheriting from IExternalLayout<TVertex, TEdge>
2. Make sure NeedVertexSizes returns true (otherwise VertexSizes will be null)
3. Put a breakpoint on Compute(...) and inspect the elements in VertexSizes (all are zero-sized)

Bug cause (assumption):

public Dictionary<TVertex, Size> GetVertexSizes()
{
    //measure if needed and get all vertex sizes            
    Measure(new USize(double.PositiveInfinity, double.PositiveInfinity));
    var vertexSizes = new Dictionary<TVertex, Size>(_vertexlist.Count(a => ((IGraphXVertex)a.Value.Vertex).SkipProcessing != ProcessingOptionEnum.Exclude));
    //go through the vertex presenters and get the actual layoutpositions
    foreach (var vc in VertexList.Where(vc => ((IGraphXVertex)vc.Value.Vertex).SkipProcessing != ProcessingOptionEnum.Exclude))
    {
        vertexSizes[vc.Key] = new Size(vc.Value.ActualWidth, vc.Value.ActualHeight);
    }
    return vertexSizes;
}

Note: ActualWidth and ActualHeight (If I am right) are determined in the Arrange/Render step
and vc.Value.DesiredSize.Width and vc.Value.DesiredSize.Height should be used instead.

Workaround:

public class MyExternalAlgorithm: IExternalLayout<DataVertex, DataEdge>, ILayoutEdgeRouting<DataEdge>
{
    private MyGraph Graph { get; set; }

    private void WorkaroundForZeroVertexSizes()
    {
        var vertexControls = GraphArea.GetAllVertexControls();
        foreach (var vertexControl in vertexControls)
        {
            var vertex = vertexControl.Vertex as DataVertex;
            VertexSizes[vertex] = new GraphX.Measure.Size()
            {
                Width = vertexControl.DesiredSize.Width,
                Height = vertexControl.DesiredSize.Height
            };
        }
    }

    public void Compute(CancellationToken cancellationToken)
    {
        WorkaroundForZeroVertexSizes();
        // Now VertexSizes should be properly assigned
    }

    public IDictionary<DataVertex, GraphX.Measure.Point> VertexPositions { get; set; }
    public IDictionary<DataVertex, GraphX.Measure.Size> VertexSizes { get; set; }

    public bool NeedVertexSizes
    {
        get { return true; }
    }
    public bool SupportsObjectFreeze
    {
        get { return false; }
    }

    public MyExternalAlgorithm(MyGraph graph)
    {
        Graph = graph;
    }
}

[panthernet]

Thanks! Fixed.