how to zoom ?

I use picturebox. How I can zoom in and zoom out when I draw rectangle within the picturebox?

Do a search for the StretchBlt API. Lots of examples here such as http://www.vbforums.com/showthread.p...ght=StretchBlt

I have problem here. Code below work for image or picture in the picturebox. But I not have picture in the picturebox.. It just line draw in the picturebox.. So I cannot see the line.

Code:

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Private Sub picView_MouseDown(Button As Integer, Shift As Integer, X As Single, Y As Single)
    mbDragging = True
    picView.DrawMode = vbInvert
    With mRect
        .Left = X
        .Top = Y
        .Right = X
        .Bottom = Y
    End With
End Sub

Private Sub picView_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
Dim sHexDec$, sTip$

On Error Resume Next

    If Not mbDragging Then
        sHexDec = Hex(picView.Point(X, Y))
        sTip = "R: " & CLng("&H" + Mid(sHexDec, 1, 2)) & Space(5 - Len(CStr(CLng("&H" + Mid(sHexDec, 1, 2))))) & _
              "G: " & CLng("&H" + Mid(sHexDec, 3, 2)) & Space(5 - Len(CStr(CLng("&H" + Mid(sHexDec, 3, 2))))) & _
              "B: " & CLng("&H" + Mid(sHexDec, 5, 2))
        picView.ToolTipText = sTip
        Exit Sub
    End If
    With mRect
        ' erase box
        picView.Line (.Left, .Top)-(.Right, .Bottom), , B
        .Right = X
        .Bottom = Y
        ' draw box
        picView.Line (.Left, .Top)-(X, Y), , B
    End With

End Sub

Private Sub picView_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single)
'===========================================================================================
Dim dblZoom As Double

On Error Resume Next

    mbDragging = False
    ' erase box by redrawing
    picView.Line (mRect.Left, mRect.Top)-(mRect.Right, mRect.Bottom), , B
    picView.DrawMode = vbCopyPen
   
    'show selected in the Picture2
    If IsNumeric(Trim(txtZoom.Text)) Or Trim(txtZoom.Text) = "" Then
        If Trim(txtZoom.Text) = "" Then dblZoom = 1
        dblZoom = CDbl(Trim(txtZoom.Text))
        Picture2.Cls
        Picture2.PaintPicture picView.Picture, _
                              0, _
                              0, _
                              Abs(mRect.Right - mRect.Left) * dblZoom, _
                              Abs(mRect.Bottom - mRect.Top) * dblZoom, _
                              mRect.Left, _
                              mRect.Top, _
                              Abs(mRect.Right - mRect.Left), _
                              Abs(mRect.Bottom - mRect.Top)
    Else
        MsgBox "Invalid zoom value - it must be numeric!"
        txtZoom.SelStart = 0
        txtZoom.SelLength = Len(txtZoom.Text)
        txtZoom.SetFocus
    End If

End Sub

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