[pygame] Rotating an Image about another Point

["Ian Mallett" <geometrian@xxxxxxxxx>]

Hi,

The story so far:
-I looked for this, and Google turned up some stuff which I didn't understand.  
-It seemed to provide code to rotate a point about another, which I already know how to do.  
-pygame.transform.rotate() rotates the image about its center, returning a larger or smaller surface.
-What I need is to rotate the surface about another point.  
-I'm guessing this is impossible with pygame.transform.rotate(), and anyway, this causes more complications.  So, since the rotated surface will be blitted somewhere, the image will appear to rotate around a point if the blitting point moves correctly.  Specifically, I would like to move the blitting point to a location such that, for any rotation, the image appears to rotate around its bottom edge.
-How can one do that?

Thanks,
Ian