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 rectangle-union
function returns four values: the left , top , right and bottom of the union of the two rectangles specified in the arguments. The values input for the two rectangles are ordered by this function before it uses them.