Imports System.Math

Public Class Dial

    Public Property value() As Int16
        Get
            Return Nothing
        End Get
        Set(ByVal value As Int16)

            Dim bm_in As New Bitmap(PictureBox1.BackgroundImage)
            Dim wid As Single = bm_in.Width
            Dim hgt As Single = bm_in.Height
            Dim corners As Point() = {New Point(0, 0), New Point(wid, 0), New Point(0, hgt), New Point(wid, hgt)}
            Dim cx As Single = wid / 2
            Dim cy As Single = hgt / 2
            Dim i As Long

            For i = 0 To 3

                corners(i).X -= cx
                corners(i).Y -= cy

            Next i

            Dim theta As Single = Single.Parse(value) * PI / 180.0
            Dim sin_theta As Single = Sin(theta)
            Dim cos_theta As Single = Cos(theta)
            Dim X As Single
            Dim Y As Single

            For i = 0 To 3

                X = corners(i).X
                Y = corners(i).Y

                corners(i).X = X * cos_theta + Y * sin_theta
                corners(i).Y = -X * sin_theta + Y * cos_theta

            Next i

            Dim xmin As Single = corners(0).X
            Dim ymin As Single = corners(0).Y

            For i = 1 To 3

                If xmin > corners(i).X Then xmin = corners(i).X
                If ymin > corners(i).Y Then ymin = corners(i).Y

            Next i

            For i = 0 To 3

                corners(i).X -= xmin
                corners(i).Y -= ymin

            Next i

            Dim bm_out As New Bitmap(CInt(-2 * xmin), CInt(-2 * ymin))
            Dim gr_out As Graphics = Graphics.FromImage(bm_out)
            ReDim Preserve corners(2)

            gr_out.DrawImage(bm_in, corners)

            PictureBox2.Image = bm_out


        End Set
    End Property

End Class
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