Efficient wxOGL redraws

[Ben]

Hi all,

I hope one or other of the experts here can give me some advice...

In my wxPython (oh how I love it) app under Win32, I am wanting to use
little wxOGL wxShapes as slider bars, for defining start and stop
positions.  The idea is very simple - the user clicks on the bar,
drags it to the required position, and releases it.  The trick is that
the bar must have a fixed Y position.  That is, when the user drags
the bar, it only moves horizontally.


Now I've managed to get it working after a fashion, but it's VERY
inefficient.  My event handler includes the following:

def OnMovePre(self,dc,x,y,oldX,oldY,display):
		if y == oldY:
			return true			
		return false

def OnDragLeft(self,draw,x,y,keys, attachment):
		shape = self.GetShape()
		canvas = shape.GetCanvas() 
		dc = wxClientDC(canvas)
        	canvas.PrepareDC(dc) 
		self.GetShape().Erase(dc)
		self.GetShape().SetX(x)	
		self.GetShape().SetY(18)
		self.canvas.Redraw(dc)

Doing this causes horrid flicker, and steals lots of CPU cycles.

Can anyone think of a more elegant way of doing this using wxOGL?  I
could probably use GDI primitives, but I don't fancy all the schlep of
doing hit testing etc.

Thanks & regards,

Ben