Screen array starts at 1 index.

def put_abs (self, r, c, ch):
        '''Screen array starts at 1 index.'''

        r = constrain (r, 1, self.rows)
        c = constrain (c, 1, self.cols)
        if isinstance(ch, bytes):
            ch = self._decode(ch)[0]
        else:
            ch = ch[0]
        self.w[r-1][c-1] = ch