It also adds the value of originX, which specifies the x-coordinate of the left-most point in the graph.
它还将添加originx的值，该值将指定图形最左侧点的x坐标。
2
But the quadratic curve can be used only in condition when each X-coordinate of the points sequence mapping to only one Y-coordinate, so it can't be used in fitting closing curve.
但二次多项式只能拟合x坐标与Y坐标之间成函数关系的点序列，无法拟合闭合曲线。
3
The paper introduces the thinking and steps of drawing the curvilinear, at the same time presents in detail the program of protracting x-coordinate and the skills of ruler labelling.