getEnclosingRectangle
This is useful in detecting the enclosing rectangle of a 'pure' barcode.
Return
left,top,width,height enclosing rectangle of all 1 bits, or null if it is all white
This is useful in detecting the enclosing rectangle of a 'pure' barcode.
left,top,width,height enclosing rectangle of all 1 bits, or null if it is all white