Arc parameters

GDDM V3R2 Base Application Programming Reference

Arc parameters

GDDM V3R2 Base Application Programming Reference
SC33-0868-02

This order determines the shape of subsequent arcs. The full parameters give a transformation that maps the unit circle to an ellipse of the required shape:


     x' = Px + Ry
     y' = Sx + Qy

A circle results if P=Q and R=S=0.

If P=a, Q=b, an ellipse results. The axis parallel to the x axis has a length proportional to "a"; the axis parallel to the y axis has a length proportional to "b."

If R and S are nonzero, the ellipse is tilted. Usually, for an ellipse with major and minor axes proportional to "a" and "b", tilted at angle "theta" to the x axis:


     P = a.cos(theta)
     Q = b.cos(theta)
     R = -b.sin(theta)
     S = a.sin(theta)


Fld len	Content	Meaning
1	*Set* X'22'	Arc Parameters order code
	*Push* & *set* X'62'	Arc Parameters order code
1	LEN	Length of following data
*	P	x coordinate of major axis end
*	Q	y coordinate of minor axis end
*	R	x coordinate of minor axis end
*	S	y coordinate of major axis end

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