is pixel an outline pixel

Code:

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Public Shared Function isOutLine(ByVal xPos As Integer, ByVal Ypos As Integer, ByVal image As Bitmap, ByVal bias As Integer) As Boolean

        Dim result As Boolean = False
        Dim change As Byte = 0
        If xPos > 0 And xPos < image.Width - 1 And Ypos > 0 And Ypos < image.Height - 1 Then
            Dim color1, color2, color3, color4, color5, color6, color7, color8, color9 As Color
            color1 = image.GetPixel(xPos - 1, Ypos - 1)
            color2 = image.GetPixel(xPos, Ypos - 1)
            color3 = image.GetPixel(xPos + 1, Ypos - 1)
            color7 = image.GetPixel(xPos - 1, Ypos + 1)
            color8 = image.GetPixel(xPos, Ypos + 1)
            color9 = image.GetPixel(xPos + 1, Ypos + 1)
            color4 = image.GetPixel(xPos - 1, Ypos)
            color6 = image.GetPixel(xPos + 1, Ypos)
            color5 = image.GetPixel(xPos, Ypos)

            If (CType(color5.R, Integer) > CType(color4.R, Integer) - bias) And (CType(color5.R, Integer) < CType(color4.R, Integer) + bias) Then
                change += 1

            End If
            If (CType(color5.G, Integer) > CType(color4.G, Integer) - bias) And (CType(color5.G, Integer) < CType(color4.G, Integer) + bias) Then
                change += 1

            End If
            If (CType(color5.B, Integer) > CType(color4.B, Integer) - bias) And (CType(color5.B, Integer) < CType(color4.B, Integer) + bias) Then
                change += 1

            End If
            If (CType(color5.R, Integer) > CType(color8.R, Integer) - bias) And (CType(color5.R, Integer) < CType(color8.R, Integer) + bias) Then
                change += 1

            End If
            If (CType(color5.G, Integer) > CType(color8.G, Integer) - bias) And (CType(color5.G, Integer) < CType(color8.G, Integer) + bias) Then
                change += 1

            End If
            If (CType(color5.B, Integer) > CType(color8.B, Integer) - bias) And (CType(color5.B, Integer) < CType(color8.B, Integer) + bias) Then
                change += 1

            End If
        End If

        'Dim sumR, sumG, sumB As Integer

        'sumR = (CType(color1.R, Integer) + CType(color2.R, Integer) + CType(color3.R, Integer))
        'sumR -= (CType(color7.R, Integer) + CType(color8.R, Integer) + CType(color9.R, Integer))
        ''sumG = (CType(color7.R, Integer) + CType(color8.R, Integer) + CType(color9.R, Integer))
        ''sumG -= (CType(color1.G, Integer) + CType(color2.G, Integer) + CType(color3.G, Integer))
        ''sumB = (CType(color1.B, Integer) + CType(color2.B, Integer) + CType(color3.B, Integer))
        ''sumB -= (CType(color7.B, Integer) + CType(color8.B, Integer) + CType(color9.B, Integer))
        'sumR = Abs(sumR)
        ''sumG = Abs(sumG)
        ''sumB = Abs(sumB)
        ''Dim sumR2, sumG2, sumB2 As Integer
        ''sumR2 = (CType(color1.R, Integer) + CType(color4.R, Integer) + CType(color7.R, Integer))
        ''sumG2 = (CType(color1.G, Integer) + CType(color4.G, Integer) + CType(color7.G, Integer))
        ''sumB2 = (CType(color1.B, Integer) + CType(color4.B, Integer) + CType(color7.B, Integer))
        ''sumR2 -= (CType(color3.R, Integer) + CType(color6.R, Integer) + CType(color9.R, Integer))
        ''sumG2 -= (CType(color3.G, Integer) + CType(color6.G, Integer) + CType(color9.G, Integer))
        ''sumB2 -= (CType(color3.B, Integer) + CType(color6.B, Integer) + CType(color9.B, Integer))
        ''sumR2 = Abs(sumR2)
        ''sumG2 = Abs(sumG2)
        ''sumB2 = Abs(sumB2)

        ''sumR2 = color1.R + color4.R + color7.R
        ''sumG2 = color1.G + color4.G + color7.G
        ''sumB2 = color1.B + color4.B + color7.B
        ''sumR2 -= color3.R + color6.R + color9.R
        ''sumG2 -= color3.G + color6.G + color9.G
        ''sumB2 -= color3.B + color6.B + color9.B
        If change = 6 Then
            result = True
        End If
        Return result
    End Function

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Is this a working code snippet? What does it do, and is that what it's supposed to do?

Quote:

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Originally Posted by .paul.

Is this a working code snippet? What does it do, and is that what it's supposed to do?

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the method checks a specific pixel at the (x,y) position of a bitmap, and checks if said pixel is a part of an outline (contour) of
an object.