Draw rectangle on a Window DC

[Anand]

Hi

    I need to draw a rectangle when the user selects an area
over a wxPanel containing a wxStaticBitmap. The rectangle shoud change
in size according to the dragging of the mouse.

 How do I write the event processing code so that I dont have many
rectangles overlapping each other, but just one that keeps changing size ?

The code I have right now,

 if event.Dragging():
                  
                    self.endpt = event.GetPosition()
                    w = (self.endpt.x - self.stpt.x) # stpt is stored in earlier 
                                                     # left mouse click.
                    h = (self.endpt.y - self.stpt.y)
                    wdc.DrawRectangle(self.stpt.x, self.stpt.y, w, h)
                    self.SetCursor(wxStockCursor(wxCURSOR_ARROW)) 


This draws a number of rectangles overlapping each other. I am using a
transparent brush and a black pen. I can of course refresh the bitmap 
every time the mouse is dragged but that causes flicker.


Any other functions/approach for this.

Thanks

Anand