




ordered-rectangle-union 
left-1
 
top-1
 
right-1
 
bottom-1
                        
left-2
 
top-2
 
right-2
 
bottom-2
                        => 
left
, 
top
, 
right
, 
bottom
A real number.
A real number.
A real number.
A real number.
A real number.
A real number.
A real number.
A real number.
The 
ordered-rectangle-union
 function returns four values: the 
left
, 
top
, 
right
 and 
bottom
 of the union of the two rectangles specified in the arguments. The caller guarantees that each input rectangle is ordered, that is, the left values must be smaller or equal to the right values, and the top values must be greater than or equal to the bottom ones.