Applies to: Nevron Diagram for .NET
How to check whether 2 arbitrary shapes intersect/overlap in the Diagram?
In Nevron Diagram for .NET, you may need to know if a shape is intersecting another shape. For example, if you draw a circle (or other) shape, you may need to determine if another shape is intersecting the circle shape.
In order to check whether two arbitrary shapes intersect you can use the Region class. Following are 2 helper methods that can assist you with this:
[C#]
private static Region GetRegion(NShape shape)
{
if (shape is NPrimitiveShape)
{
// This is a primitive shape -> is has only one primitive
NPathPrimitive pathPrimitive = ((NPrimitiveShape)shape).Primitive as NPathPrimitive;
if (pathPrimitive != null)
{
return new Region(pathPrimitive.Path);
}
}
else if (shape is NCompositeShape)
{
// This is a composite shape, so loop through its primitives to create a region
Region region = new Region();
NNodeList pathPrimitives = ((NCompositeShape)shape).Primitives.Children(NFilters.TypeNPathPrimitive);
for (int i = 0, count = pathPrimitives.Count; i < count; i++)
{
NPathPrimitive pathPrimitive = (NPathPrimitive)pathPrimitives[i];
region.Union(pathPrimitive.Path);
}
return region;
}
return null;
}
private static bool Intersects(NShape shape1, NShape shape2, Graphics g)
{
if (shape1 == null || shape2 == null)
return false;
Region region1 = GetRegion(shape1);
if (region1 == null || region1.IsEmpty(g))
return false;
Region region2 = GetRegion(shape2);
if (region2 == null || region2.IsEmpty(g))
return false;
region1.Intersect(region2);
return region1 != null && region1.IsEmpty(g) == false;
}
[VB.NET]
Private Shared Function GetRegion(shape As NShape) As Region
If TypeOf shape Is NPrimitiveShape Then
' This is a primitive shape -> is has only one primitive
Dim pathPrimitive As NPathPrimitive = TryCast(DirectCast(shape, NPrimitiveShape).Primitive, NPathPrimitive)
If pathPrimitive IsNot Nothing Then
Return New Region(pathPrimitive.Path)
End If
ElseIf TypeOf shape Is NCompositeShape Then
' This is a composite shape, so loop through its primitives to create a region
Dim region As New Region()
Dim pathPrimitives As NNodeList = DirectCast(shape, NCompositeShape).Primitives.Children(NFilters.TypeNPathPrimitive)
Dim i As Integer = 0, count As Integer = pathPrimitives.Count
While i < count
Dim pathPrimitive As NPathPrimitive = DirectCast(pathPrimitives(i), NPathPrimitive)
region.Union(pathPrimitive.Path)
i += 1
End While
Return region
End If
Return Nothing
End Function
Private Shared Function Intersects(shape1 As NShape, shape2 As NShape, g As Graphics) As Boolean
If shape1 Is Nothing OrElse shape2 Is Nothing Then
Return False
End If
Dim region1 As Region = GetRegion(shape1)
If region1 Is Nothing OrElse region1.IsEmpty(g) Then
Return False
End If
Dim region2 As Region = GetRegion(shape2)
If region2 Is Nothing OrElse region2.IsEmpty(g) Then
Return False
End If
region1.Intersect(region2)
Return region1 IsNot Nothing AndAlso region1.IsEmpty(g) = False
End Function
Simply call the Intersects method to check whether the two shapes intersect or not.
Article ID: 233, Created On: 1/25/2013, Modified: 1/25/2013