(let (cr1 cr2)
   ;; Ensure that the sheet's clipping region and transformation will be reset:
   (with-drawing-options (sheet :transformation +identity-transformation+
                                :clipping-region +everywhere+)
     (setf (medium-clipping-region sheet) (make-rectangle* 0 0 10 10))
     (setf (medium-transformation sheet) (clim:make-scaling-transformation 2 2))
     (setf cr1 (medium-clipping-region sheet))
     (setf (medium-clipping-region sheet) (make-rectangle* 0 0 10 10))
     (setf (medium-transformation sheet) +identity-transformation+)
     (setf cr2 (medium-clipping-region sheet))
     (values cr1 cr2)))

Major issue: What exactly are "user coordinates"? We need to define all of the coordinate
systems in one place: device, window, stream, etc. | SWM

=> medium-line-style medium [Generic Function]
=> (setf medium-line-style) line-style medium [Generic Function]
Returns (and, with setf, sets) the current line style for the medium medium. This is described
in detail in Chapter 10 and Section 10.3.

=> medium-text-style medium [Generic Function]
=> (setf medium-text-style) text-style medium [Generic Function]
Returns (and, with setf, sets) the current text style for the medium medium of any textual
output that may be displayed on the window. This is described in detail in Chapter 10.

=> medium-default-text-style medium [Generic Function]
=> (setf medium-default-text-style) text-style medium [Generic Function]
Returns (and, with setf, sets) the default text style for output on the medium medium. This is
described in detail in Chapter 10.

=> medium-merged-text-style medium [Generic Function]
Returns the actual text style used in rendering text on the medium medium. It returns the result
of