纺织机出线口需要保证纺织线相互平行，防止绞线或断线等意外情况，问题是：如何用计算机显示线段，并判断平行与否。-Textile machine outlet to ensure the textile line parallel to each other, to prevent the wire or wire and other unforeseen circumstances, the question is: how to display the line by computer, and whether parallel or not.