Intersection -TizzyT

Module Module1
    Public Class Misc
        'Chained comparison function
        Public Shared Function CCOMP(Of T)(ParamArray ByVal item() As T) As Boolean
            Dim Prev As T = Nothing
            For Each I As T In item
                If Prev IsNot Nothing Then If Not I.Equals(Prev) Then Return False
                Prev = I
            Next
            Return True
        End Function
    End Class

    Public Structure XDecimal
        Public Shared Zero As New XDecimal(0D)
        Public Shared NegativeOne As New XDecimal(-1D)

        Private ReadOnly State As States
        Private ReadOnly Value As Decimal

        Public Enum States
            NaN
            Number
            Undefined
        End Enum

        Public Sub New(Value As Decimal)
            State = States.Number
            Me.Value = Value
        End Sub

        Public Sub New(State As States)
            Me.State = State
        End Sub

        Public Overrides Function ToString() As String
            If State = States.Number Then Return Value.ToString
            Return State.ToString
        End Function

        Public Shared Narrowing Operator CType(ByVal Dec As Decimal) As XDecimal
            Return New XDecimal(Dec)
        End Operator

        Public Shared Operator =(XDec1 As XDecimal, XDec2 As XDecimal) As Boolean
            If XDec1.State = XDec2.State Then
                If XDec1.State = States.Number Then Return XDec1.Value = XDec2.Value Else Return False
            End If
            Return False
        End Operator
        Public Shared Operator =(XDec As XDecimal, State As States) As Boolean
            Return XDec.State = State
        End Operator

        Public Shared Operator <>(XDec1 As XDecimal, XDec2 As XDecimal) As Boolean
            If XDec1.State = XDec2.State Then
                If XDec1.State = States.Number Then Return XDec1.Value = XDec2.Value Else Return True
            End If
            Return True
        End Operator
        Public Shared Operator <>(XDec As XDecimal, State As States) As Boolean
            Return XDec.State <> State
        End Operator

        Public Shared Operator *(XDec1 As XDecimal, XDec2 As XDecimal) As XDecimal
            If XDec1.State = States.Number AndAlso XDec2.State = States.Number Then Return New XDecimal(XDec1.Value * XDec2.Value)
            If XDec1.State = States.NaN OrElse XDec2.State = States.NaN Then Return New XDecimal(States.NaN)
            Return New XDecimal(States.Undefined)
        End Operator

        Public Shared Operator /(XDec1 As XDecimal, XDec2 As XDecimal) As XDecimal
            If XDec1.State = States.Number AndAlso XDec2.State = States.Number Then
                If XDec2.Value = 0D Then Return New XDecimal(States.Undefined)
                Return New XDecimal(XDec1.Value / XDec2.Value)
            End If
            If XDec1.State = States.NaN OrElse XDec2.State = States.NaN Then Return New XDecimal(States.NaN)
            Return New XDecimal(States.Undefined)
        End Operator

        Public Shared Operator +(XDec1 As XDecimal, XDec2 As XDecimal) As XDecimal
            If XDec1.State = States.Number AndAlso XDec2.State = States.Number Then Return New XDecimal(XDec1.Value + XDec2.Value)
            If XDec1.State = States.NaN OrElse XDec2.State = States.NaN Then Return New XDecimal(States.NaN)
            Return New XDecimal(States.Undefined)
        End Operator

        Public Shared Operator -(XDec1 As XDecimal, XDec2 As XDecimal) As XDecimal
            If XDec1.State = States.Number AndAlso XDec2.State = States.Number Then Return New XDecimal(XDec1.Value - XDec2.Value)
            If XDec1.State = States.NaN OrElse XDec2.State = States.NaN Then Return New XDecimal(States.NaN)
            Return New XDecimal(States.Undefined)
        End Operator

        Public Shared Operator <(XDec1 As XDecimal, XDec2 As XDecimal) As Boolean
            If XDec1.State = States.Number AndAlso XDec2.State = States.Number Then Return XDec1.Value < XDec2.Value
            Return False
        End Operator

        Public Shared Operator >(XDec1 As XDecimal, XDec2 As XDecimal) As Boolean
            If XDec1.State = States.Number AndAlso XDec2.State = States.Number Then Return XDec1.Value > XDec2.Value
            Return False
        End Operator

        Public Shared Operator >=(XDec1 As XDecimal, XDec2 As XDecimal) As Boolean
            If XDec1.State = States.Number AndAlso XDec2.State = States.Number Then Return XDec1.Value >= XDec2.Value
            Return False
        End Operator

        Public Shared Operator <=(XDec1 As XDecimal, XDec2 As XDecimal) As Boolean
            If XDec1.State = States.Number AndAlso XDec2.State = States.Number Then Return XDec1.Value <= XDec2.Value
            Return False
        End Operator
    End Structure

    Public Structure Point
        Public ReadOnly X As XDecimal
        Public ReadOnly Y As XDecimal
        Public Sub New(ByVal X As XDecimal, ByVal Y As XDecimal)
            Me.X = X
            Me.Y = Y
        End Sub
    End Structure

    Public Structure Line
        Public ReadOnly P1 As Point
        Public ReadOnly P2 As Point
        Public ReadOnly Slope As XDecimal
        Public ReadOnly Yintercept As XDecimal
        Public ReadOnly Xintercept As XDecimal
        Public ReadOnly IsVerticalLine As Boolean
        Public ReadOnly IsHorizontalLine As Boolean
        Public Sub New(ByVal X1 As XDecimal, ByVal Y1 As XDecimal, ByVal X2 As XDecimal, ByVal Y2 As XDecimal)
            P1 = New Point(X1, Y1)
            P2 = New Point(X2, Y2)
            Slope = (P2.Y - P1.Y) / (P2.X - P1.X)
            If Slope = XDecimal.Zero Then
                IsVerticalLine = False
                IsHorizontalLine = True
                Xintercept = XDecimal.States.Undefined
                Yintercept = P1.Y
            ElseIf Slope = XDecimal.States.Undefined Then
                IsVerticalLine = True
                IsHorizontalLine = False
                Yintercept = XDecimal.States.Undefined
                Xintercept = P1.X
            Else
                Yintercept = P1.Y - (P1.X * Slope)
                Xintercept = (Yintercept * XDecimal.NegativeOne) / Slope
            End If
        End Sub
        Public Sub New(ByVal P1 As Point, ByVal P2 As Point)
            Me.P1 = P1
            Me.P2 = P2
            Slope = (P2.Y - P1.Y) / (P2.X - P1.X)
            If Slope = XDecimal.Zero Then
                IsVerticalLine = False
                IsHorizontalLine = True
                Xintercept = XDecimal.States.Undefined
                Yintercept = P1.Y
            ElseIf Slope = XDecimal.States.Undefined Then
                IsVerticalLine = True
                IsHorizontalLine = False
                Yintercept = XDecimal.States.Undefined
                Xintercept = P1.X
            Else
                Yintercept = P1.Y - (P1.X * Slope)
                Xintercept = (Yintercept * XDecimal.NegativeOne) / Slope
            End If
        End Sub

        'Line Intersects Point
        Public Function Intersects(ByVal Point As Point) As Boolean
            If Slope = XDecimal.States.Undefined Then Return Point.X = P1.X
            If Slope = XDecimal.Zero Then Return Point.Y = P1.Y
            If (Point.X * Slope) + Yintercept = Point.Y Then Return True
            Return False
        End Function
        'Line Intersects Line
        Public Function Intersects(ByVal Line As Line) As Boolean
            If Slope = Line.Slope Then Return P1.Y = Line.P1.Y
            If Slope = XDecimal.States.Undefined AndAlso Line.Slope = XDecimal.States.Undefined Then Return P1.X = Line.P1.X
            Return True
        End Function

        Public Shared Function GetSlope(ByVal X1 As XDecimal, ByVal Y1 As XDecimal, ByVal X2 As XDecimal, ByVal Y2 As XDecimal) As XDecimal
            Return (Y2 - Y1) / (X2 - X1)
        End Function
        Public Shared Function GetYintercept(ByVal X1 As XDecimal, ByVal Y1 As XDecimal, ByVal X2 As XDecimal, ByVal Y2 As XDecimal) As XDecimal
            Dim Slope As XDecimal = GetSlope(X1, Y1, X2, Y2)
            Return Y1 - (X1 * Slope)
        End Function
        Public Shared Function GetXintercept(ByVal X1 As XDecimal, ByVal Y1 As XDecimal, ByVal X2 As XDecimal, ByVal Y2 As XDecimal) As XDecimal
            Dim Slope As XDecimal = GetSlope(X1, Y1, X2, Y2)
            Dim Yintercept As XDecimal = Y1 - (X1 * Slope)
            Return (Yintercept * -1) / Slope
        End Function
    End Structure

    Public Structure LineSegment
        Public ReadOnly P1 As Point
        Public ReadOnly P2 As Point
        Public ReadOnly Slope As XDecimal
        Public ReadOnly Yintercept As XDecimal
        Public ReadOnly Xintercept As XDecimal
        Public ReadOnly IsVerticalLineSegment As Boolean
        Public ReadOnly IsHorizontalLineSegment As Boolean
        Public Sub New(ByVal X1 As XDecimal, ByVal Y1 As XDecimal, ByVal X2 As XDecimal, ByVal Y2 As XDecimal)
            P1 = New Point(X1, Y1)
            P2 = New Point(X2, Y2)
            Slope = (P2.Y - P1.Y) / (P2.X - P1.X)
            If Slope = XDecimal.Zero Then
                IsVerticalLineSegment = False
                IsHorizontalLineSegment = True
                Xintercept = XDecimal.States.Undefined
                If (P1.X <= XDecimal.Zero AndAlso P2.X >= XDecimal.Zero) _
                    OrElse (P2.X <= XDecimal.Zero AndAlso P1.X >= XDecimal.Zero) _
                    Then Yintercept = P1.Y Else Yintercept = XDecimal.States.Undefined
            ElseIf Slope = XDecimal.States.Undefined Then
                IsVerticalLineSegment = True
                IsHorizontalLineSegment = False
                Yintercept = XDecimal.States.Undefined
                If (P1.Y >= XDecimal.Zero AndAlso P2.Y <= XDecimal.Zero) _
                    OrElse (P2.Y <= XDecimal.Zero AndAlso P1.Y >= XDecimal.Zero) _
                    Then Xintercept = P1.X _
                    Else Xintercept = XDecimal.States.Undefined
            Else
                If (P1.X <= XDecimal.Zero AndAlso P2.X >= XDecimal.Zero) _
                    OrElse (P2.X <= XDecimal.Zero AndAlso P1.X >= XDecimal.Zero) _
                    Then Yintercept = P1.Y - (P1.X * Slope) _
                    Else Yintercept = XDecimal.States.Undefined
                If (P1.Y >= XDecimal.Zero AndAlso P2.Y <= XDecimal.Zero) _
                    OrElse (P2.Y <= XDecimal.Zero AndAlso P1.Y >= XDecimal.Zero) _
                    Then Xintercept = (Yintercept * XDecimal.NegativeOne) / Slope _
                    Else Xintercept = XDecimal.States.Undefined
            End If
        End Sub
        Public Sub New(ByVal P1 As Point, ByVal P2 As Point)
            Me.P1 = P1
            Me.P2 = P2
            Slope = (P2.Y - P1.Y) / (P2.X - P1.X)
            If Slope = XDecimal.Zero Then
                IsVerticalLineSegment = False
                IsHorizontalLineSegment = True
                Xintercept = XDecimal.States.Undefined
                If (P1.X <= XDecimal.Zero AndAlso P2.X >= XDecimal.Zero) _
                    OrElse (P2.X <= XDecimal.Zero AndAlso P1.X >= XDecimal.Zero) _
                    Then Yintercept = P1.Y Else Yintercept = XDecimal.States.Undefined
            ElseIf Slope = XDecimal.States.Undefined Then
                IsVerticalLineSegment = True
                IsHorizontalLineSegment = False
                Yintercept = XDecimal.States.Undefined
                If (P1.Y >= XDecimal.Zero AndAlso P2.Y <= XDecimal.Zero) _
                    OrElse (P2.Y <= XDecimal.Zero AndAlso P1.Y >= XDecimal.Zero) _
                    Then Xintercept = P1.X _
                    Else Xintercept = XDecimal.States.Undefined
            Else
                If (P1.X <= XDecimal.Zero AndAlso P2.X >= XDecimal.Zero) _
                    OrElse (P2.X <= XDecimal.Zero AndAlso P1.X >= XDecimal.Zero) _
                    Then Yintercept = P1.Y - (P1.X * Slope) _
                    Else Yintercept = XDecimal.States.Undefined
                If (P1.Y >= XDecimal.Zero AndAlso P2.Y <= XDecimal.Zero) _
                    OrElse (P2.Y <= XDecimal.Zero AndAlso P1.Y >= XDecimal.Zero) _
                    Then Xintercept = (Yintercept * XDecimal.NegativeOne) / Slope _
                    Else Xintercept = XDecimal.States.Undefined
            End If
        End Sub
        'LineSegment Intersects Point
        Public Function Intersects(ByVal Point As Point) As Boolean
            If (Point.X >= P1.X AndAlso Point.X <= P2.X) _
                OrElse (Point.X >= P2.X AndAlso Point.X <= P1.X) _
                Then Return (Point.X * Slope) + Yintercept = Point.Y
            Return False
        End Function
        'LineSegment Intersects Line
        Public Function Intersects(ByVal Line As Line) As Boolean
            If Slope = XDecimal.States.Undefined Then
                If Line.Slope = XDecimal.States.Undefined Then Return P1.X = Line.P1.X
                Return Intersects(New Point(P1.X, (P1.X * Line.Slope) + Line.Yintercept))
            ElseIf Slope = Line.Slope Then
                Return Line.Intersects(New Point(P1.X, P1.Y))
            Else
                Dim X1 As XDecimal = (Line.Slope * P1.X) + Line.Yintercept
                Dim X2 As XDecimal = (Line.Slope * P2.X) + Line.Yintercept
                If X1 <= P1.X Then Return X2 >= P2.X Else If X1 >= P1.X Then Return X2 <= P2.X
            End If
            Return False
        End Function
        'LineSegment Intersects LineSegment
        Public Function Intersects(ByVal LineSegment As LineSegment) As Boolean
            If Slope = XDecimal.States.Undefined Then
                If LineSegment.Slope = XDecimal.States.Undefined Then
                    If P1.X = LineSegment.P1.X Then
                        If (P1.Y >= LineSegment.P1.Y AndAlso P2.Y <= LineSegment.P1.Y) _
                            OrElse (P1.Y <= LineSegment.P1.Y AndAlso P2.Y >= LineSegment.P1.Y) _
                            Then Return True
                    End If
                    Return False
                Else
                    Dim L As New Line(LineSegment.P1, LineSegment.P2)
                    Return LineSegment.Intersects(New Point(P1.X, (P1.X * L.Slope) + L.Yintercept))
                End If
            Else
                If LineSegment.Slope = XDecimal.States.Undefined Then
                    Dim L As New Line(P1, P2)
                    Return Intersects(New Point(LineSegment.P1.X, (LineSegment.P1.X * L.Slope) + L.Yintercept))
                Else
                    Dim L1 As New Line(P1, P2)
                    Dim L2 As New Line(LineSegment.P1, LineSegment.P2)
                    Dim X As XDecimal = (L2.Yintercept - L1.Yintercept) / (L1.Slope - L2.Slope)
                    If (X >= L1.P1.X AndAlso X <= L1.P2.X) OrElse (X <= L1.P1.X AndAlso X >= L1.P2.X) Then Return True
                End If
            End If
            Return False
        End Function

        Public Shared Function GetSlope(ByVal X1 As XDecimal, ByVal Y1 As XDecimal, ByVal X2 As XDecimal, ByVal Y2 As XDecimal) As XDecimal
            Return (Y2 - Y1) / (X2 - X1)
        End Function
    End Structure

    Private Structure Circle
        Public X As XDecimal
        Public Y As XDecimal
        Public Radius As XDecimal

        Public Sub New(ByVal X As XDecimal, ByVal Y As XDecimal, ByVal Radius As XDecimal)
            Me.X = X
            Me.Y = Y
            Me.Radius = Radius
        End Sub

        Public Function ContainsPoint(ByVal Point As Point) As Boolean
            Dim _X As XDecimal = Point.X - X
            _X *= _X
            Dim _Y As XDecimal = Point.Y - Y
            _Y *= _Y
            If _X + _Y <= Radius * Radius Then Return True
            Return False
        End Function

        Public Function Intersects(ByVal Line As Line) As Boolean

        End Function

        Public Function Intersects(ByVal LineSegment As LineSegment) As Boolean

        End Function

        Public Function Intersects(ByVal Circle As Circle) As Boolean
            Dim _X As XDecimal = Circle.X - X
            _X *= _X
            Dim _Y As XDecimal = Circle.Y - Y
            _Y *= _Y
            If _X + _Y <= (Radius * Radius) + (Circle.Radius * Circle.Radius) Then Return True
            Return False
        End Function
    End Structure
End Module