Public Class Form1
 
    Private enState As state
 
    Enum state
        none
        setP1
        setP2
    End Enum
 
    Private p1 As Point
    Private p2 As Point
 
    Private img1 As New Bitmap("...")
    Private img2 As New Bitmap("...")
 
    Private Sub Button1_Click(...) Handles Button1.Click
        enState = state.setP1
    End Sub
 
    Private Sub Button2_Click(...) Handles Button2.Click
        enState = state.setP2
    End Sub
 
    Private Sub picTest_MouseUp(...) Handles picTest.MouseUp
        Select Case enState
            Case state.setP1
                p1 = e.Location
                enState = state.none
 
            Case state.setP2
                p2 = e.Location
                enState = state.none
 
        End Select
    End Sub
 
    Private Sub Button3_Click(...) Handles Button3.Click
 
        Dim w As Integer = picTest.ClientSize.Width
        Dim h As Integer = picTest.ClientSize.Height
 
        Dim bmp As New Bitmap(w, h)
 
        ' P2 nach der Verschiebung (P2')
        Dim p3 As New Point(p2.X - p1.X, p2.Y - p1.Y)
 
        Dim alpha As Double
 
        If p3.Y = 0 Then
            ' P2' liegt auf der x-Achse
 
            If p3.X < 0 Then
                alpha = Math.PI
            End If
 
        ElseIf p3.X = 0 Then
            ' P2' liegt auf der y-Achse
 
            If p3.Y < 0 Then
                alpha = 1.5 * Math.PI
            End If
 
            If p3.Y > 0 Then
                alpha = 0.5 * Math.PI
            End If
 
        ElseIf p3.X > 0 Then
            alpha = Math.Atan(p3.Y / p3.X)
 
        ElseIf p3.X < 0 Then
            alpha = Math.PI + Math.Atan(p3.Y / p3.X)
 
        End If
 
        Dim sin_alpha As Double = Math.Sin(alpha)
        Dim cos_alpha As Double = Math.Cos(alpha)
 
        ' Hilfsvariable
        Dim c As Double = -p1.X * cos_alpha - p1.Y * sin_alpha
 
        ' x-Koordinate von P2 nach der Verschiebung und Rotation
        Dim x2 As Double = p2.X * cos_alpha + p2.Y * sin_alpha + c
 
        ' Pixel bestimmen
        For y As Integer = 0 To h - 1
            For x As Integer = 0 To w - 1
 
                Dim xq As Double = x * cos_alpha + y * sin_alpha + c
 
                ' Dim t As Integer = CInt(xq * 255 / x2)
                Dim t As Double = xq / x2
 
                If t < 0 Then
                    t = 0
                End If
 
                ' If t > 255 Then
                '     t = 255
                ' End If
                If t > 1 Then
                    t = 1
                End If
 
                Dim cl1 As Color = img1.GetPixel(x, y)
                Dim cl2 As Color = img2.GetPixel(x, y)
 
                Dim r As Integer = CInt(t * cl1.R + (1 - t) * cl2.R)
                Dim g As Integer = CInt(t * cl1.G + (1 - t) * cl2.G)
                Dim b As Integer = CInt(t * cl1.B + (1 - t) * cl2.B)
 
                ' bmp.SetPixel(x, y, Color.FromArgb(t, t, t))
                bmp.SetPixel(x, y, Color.FromArgb(r, g, b))
            Next
        Next
 
        picTest.Image = bmp
    End Sub
End Class