Option Explicit

Private Declare Function SetPixel Lib "gdi32" (ByVal hDC As Long, ByVal x As Long, ByVal y As Long, ByVal Color As Long) As Long


Private Sub Drawline(X1 As Single, Y1 As Single, X2 As Single, Y2 As Single)
   'Temporary variables for loop count
   Dim A As Single
   Dim B As Single
   ' Temporary variable, for swapping
   Dim temp As Single
   ' X2 must be greater than X1
   If X1 > X2 Then
      temp = X1
      X1 = X2
      X2 = temp
   End If
   ' Y2 must be greater than Y1
   If Y1 > Y2 Then
      temp = Y1
      Y1 = Y2
      Y2 = temp
   End If
   'Two deltas for computing the Slope
   Dim DeltaX As Single
   Dim DeltaY As Single
   'The slope itself, used for determining the line direction
   Dim Slope As Single
   'Two variables, for drawing the line
   'Note: it's easy to change the code, so you'll get a matrix of pixels
   Dim CurrX As Single
   Dim CurrY As Single
   DeltaX = X2 - X1
   DeltaY = Y2 - Y1
   'Allready fixed, but a good habbit to make deltas value absolute
   DeltaX = Abs(DeltaX)
   DeltaY = Abs(DeltaY)
   'Two boolean variables for determining the line type
   Dim isVertical As Boolean
   Dim isHorizonal As Boolean
   'Checks if the line is vertical or horizonal, or both, in this case see next quote
   If DeltaY = 0 Then isHorizonal = True
   If DeltaX = 0 Then isVertical = True
   'In case that that the pixels are in the same place, draw one pixel
   If isVertical And isHorizonal Then
      'You may replace the setpixel command with any pixel drawing procedure, It won't affect the outcome
      SetPixel picMain.hDC, X1, X2, RGB(255, 0, 0)
      Exit Sub
   End If
   'In case that the pixel is not horizonal and not vertical, draw using slope
   If Not isVertical And Not isHorizonal Then
      'These three features are built to give the best slopes
check:
      If DeltaY > DeltaX Then
         Slope = DeltaY / DeltaX
         CurrY = Y1
         For CurrX = X1 To X2
            'Draws the pixels that build the line
            SetPixel picMain.hDC, CurrX, CurrY, RGB(255, 0, 0)
            CurrY = CurrY + Slope
         Next CurrX
         Exit Sub
      End If
      If DeltaX > DeltaY Then
         Slope = DeltaX / DeltaY
         CurrX = X1
         For CurrY = Y1 To Y2
            'Draws the pixels that build the line
            SetPixel picMain.hDC, CurrX, CurrY, RGB(255, 0, 0)
            CurrX = CurrX + Slope
         Next CurrY
         Exit Sub
      End If
      'This one in case DeltaX = DeltaY, changing one of the deltas, and going back to to check
      If DeltaX = DeltaY Then
         DeltaX = DeltaX + 1
         GoTo check
      End If
   End If
   'In case that the line is vertical, always use the same X, and with Y ahead
   If isVertical Then
      CurrX = X1
      For CurrY = Y1 To Y2
         SetPixel picMain.hDC, CurrX, CurrY, RGB(255, 0, 0)
      Next CurrY
   End If
   'In case that the line is horizonal, always use the same Y, and with X ahead
   If isHorizonal Then
      CurrY = Y1
      For CurrX = X1 To X2
         SetPixel picMain.hDC, CurrX, CurrY, RGB(255, 0, 0)
      Next CurrX
   End If
End Sub

Private Sub cmdDraw_Click()
   Drawline InputBox("X1"), InputBox("Y1"), InputBox("X2"), InputBox("Y1")
   picMain.Refresh
End Sub

Private Sub picMain_MouseMove(Button As Integer, Shift As Integer, x As Single, y As Single)
   lblX = x
   lblY = y
End Sub




scalemode

1pouce = 1440 twips
1cm = 567 twips


Private Sub mnuFileOpen_Click()
    OpenDocument 'Call OpenDocument function
End Sub