[VB6 - API] - selection of an item\image graphic effect

[joaquim]

i'm build 1 code for show\select 1 item\object in an image.
for now i can show the item\object in that color selection, but i only need the selection in line way and show the item\object.

Private Sub SelectionImage(Source As PictureBox, Destination As PictureBox, SelectionColor As Long)
    Dim x As Long, y As Long
    Dim blnFirstPixel As Boolean
    Dim lngBackColor As Long
    lngBackColor = GetPixel(Source.hdc, 0, 0)
    blnFirstPixel = False
    For y = 0 To Source.ScaleHeight - 1
        For x = 0 To Source.ScaleWidth - 1
            If GetPixel(Source.hdc, x, y) <> lngBackColor And blnFirstPixel = False Then
                blnFirstPixel = True
                SetPixel Destination.hdc, x, y, SelectionColor
            ElseIf GetPixel(Source.hdc, x, y) <> lngBackColor And blnFirstPixel = True Then
                SetPixel Destination.hdc, x, y, SelectionColor
                blnFirstPixel = False
            ElseIf GetPixel(Source.hdc, x, y) = lngBackColor And blnFirstPixel = False Then
                SetPixel Destination.hdc, x, y, GetPixel(Source.hdc, x, y)
            Else
                SetPixel Destination.hdc, x, y, GetPixel(Source.hdc, x, y)
            End If
        Next x
    Next y
    Destination.Refresh
End Sub

i have the blnFirstPixel for try do the line, but isn't correct
can anyone advice me?
see the image in selection of rectangule(from black to green). i want do the same in these sub selections of itens(what is in image). thanks