Measurements on a VB6 MDI form

Private Sub BitmapViewer1_ImageMouseDown(ByVal Button As Long, ByVal Shift As Long, ByVal x As Long, ByVal Y As Long)
    If mido Or norte Then
        blnMouseDown =
 True 
        'Set start coordinate of the shape to draw
        lngStartX = x
        lngStartY = Y
        'Set end coordinate of the shape to draw
        lngEndX = x
        lngEndY = Y
        'FastRefresh method will fire DoubleBufferPaint event. Here we can
        'redraw the shape
        BitmapViewer1.FastRefresh
    End If
End Sub

Private Sub BitmapViewer1_ImageMouseMove(ByVal Button As Long, ByVal Shift As Long, ByVal x As Long, ByVal Y As Long)
    If blnMouseDown Then
        'Set end coordinate of drawn shape
        lngEndX = x
        lngEndY = Y
        Label1.Caption = "Suelte el boton para marcar el final"
        'FastRefresh method will fire DoubleBufferPaint event. Here we can
        'redraw the shape
        BitmapViewer1.FastRefresh
    End If
End Sub

Private Sub BitmapViewer1_ImageMouseUp(ByVal Button As Long, ByVal Shift As Long, ByVal x As Long, ByVal Y As Long)
    If mido Then
        'Convert start and end coordinates from control coordinate system to bitmap one
        BitmapViewer1.ControlToBitmapCoords lngStartX, lngStartY, lngStartX, lngStartY
        BitmapViewer1.ControlToBitmapCoords lngEndX, lngEndY, lngEndX, lngEndY
        blnMouseDown = False
        BitmapViewer1.Bitmap.Graphics.Pen.ForeColor = lngPenColor
        'Draw line on bitmap
        BitmapViewer1.Bitmap.Graphics.DrawLine lngStartX, lngStartY, lngEndX, lngEndY
        Command1(9).Visible = True
        Command1(9).Enabled = True
        Text1.Enabled = True
        Text1.Visible = True
        Text1.SetFocus
        Label1.Caption = "¿Cual es la dimensión en metros del segmento?"
        'BitmapViewer1.Bitmap.LoadFromFile imagen
        Command1(6).Enabled = False
    End If
    If señalo Then
        'obtengo las coordenadas del centro de la planta en pixeles
        'x,y son independientes del zoom
        BitmapViewer1.ControlToBitmapCoords locaX, locaY, x, Y
        instalax = locaX
        instalay = locaY
        Command1(7).Enabled = False
        Command1(8).Enabled = True
        Label1.Caption = "Ahora traze un segmento de Sur a Norte"
        instala
    End If
    If norte Then
        'Convert start and end coordinates from control coordinate system to bitmap one
        BitmapViewer1.ControlToBitmapCoords lngStartX, lngStartY, lngStartX, lngStartY
        BitmapViewer1.ControlToBitmapCoords lngEndX, lngEndY, lngEndX, lngEndY
        locaX = (lngEndX - lngStartX)
        'debido al manejo de coordenadas del contenedor hay que invertir el signo de Y
        locaY = (lngEndY - lngStartY) * -1
        a = 0
        norte = False
        blnMouseDown = False
        On Error Resume Next
        a = (180 / 3.141596) * Atn(Abs(locaY) / Abs(locaX))
        If locaX > 3 And locaY < -3 And a > 1 And a < 91 Then a = a + 90
        If locaX < -3 And locaY < -3 And a > 1 And a < 91 Then a = a + 180
        If locaX < -3 And locaY > 3 And a > 1 And a < 91 Then a = a + 270
        If a > 88 And a < 92 And locaX < 3 And locaX > -3 And locaY > 3 Then a = 0
        If a > -2 And a < 2 And locaY > -3 And locaX > 3 And locaY < 3 Then a = 90
        If a > 88 And a < 92 And locaX < 3 And locaX > -3 And locaY < -3 Then a = 180
        If a > -2 And a < 2 And locaX < -3 And locaY > -3 And locaY < 3 Then a = 270
        On Error GoTo 0
        'Creas el objeto Bitmap
        Dim objSmallBitmap As New Bitmap
        'Cargas la imagen a sobreponer
        'la ruta en camino, cambiar al integrar al ERA
        objSmallBitmap.LoadFromFile camino + "imagenes\Norte2.jpg"
        'Conviertes al mismo formato de la imagen base
        objSmallBitmap.Data.ConvertTo24bppRgb True
        objSmallBitmap.Transforms.Rotate a, InterpolationModeMediumQuality, &HFFFFFFFF
        objSmallBitmap.DrawOnBitmap BitmapViewer1.Bitmap, (ancho - 50), 1, , , , , , , CombineModeCopy 'CombineModeIfLighter
        BitmapViewer1.FastRefresh
        Command1(8).Enabled = False
        Label1.Caption = ""
    End If
    If BitmapViewer1.MousePointer = MousePointerCrosshair Then BitmapViewer1.MouseMode = MouseModeNone
End Sub

Private Sub BitmapViewer1_DoubleBufferPaint(ByVal hdc As stdole.OLE_HANDLE)
    If mido Or norte Then
        'Attach Graphics to the temporary DC (control's double buffer)
        objGraphics.hdc = hdc
        'Adjust pen and brush
        objGraphics.Brush.PrimaryColor = lngBrushColor
        objGraphics.Pen.ForeColor = lngPenColor
        'Scale pen weight proportionally to zoom
        objGraphics.Pen.Weight = lngPenWeight * BitmapViewer1.Zoom
        'Set clip area
        Dim lngClipTop As Long, lngClipLeft As Long, lngClipRight As Long, lngClipBottom As Long
        BitmapViewer1.BitmapToControlCoords 0, 0, lngClipLeft, lngClipTop
        BitmapViewer1.BitmapToControlCoords BitmapViewer1.Bitmap.Data.Width, BitmapViewer1.Bitmap.Data.Height, lngClipRight, lngClipBottom
        Dim hRgn As Long
        hRgn = CreateRectRgn(lngClipLeft, lngClipTop, lngClipRight, lngClipBottom)
        SelectClipRgn hdc, hRgn
        'Draw line on control
        objGraphics.DrawLine lngStartX, lngStartY, lngEndX, lngEndY
        Debug.Print lngStartX; lngStartY; lngEndX; lngEndY
        DeleteObject hRgn
    End If
End Sub