public String getDisplayLine(int row, int offset, int length) {
        StringBuilder sb = new StringBuilder();
        char tmp;
        for (int c = offset; c < offset + length; c++) {

            if (row < numberOfRows && c < numberOfCols) {
                tmp = grid[row][c].getDisplayCharacter();
            } else {
                tmp = NullDisplayChar;
            }

            sb.append(tmp);
        }
        return sb.toString();
    }