The Curve Structure (IM: XG)

Inside Macintosh: QuickDraw GX Graphics /

Chapter 2 - Geometric Shapes / Geometric Shapes Reference

The Curve Structure
You use the gxCurve structure to specify the geometry of a curve shape.
The gxCurve structure is defined as follows:
struct gxCurve {
   struct gxPoint first;
   struct gxPoint control;
   struct gxPoint last;
};
Field Description

first
The coordinate position where the curve begins.
control
The coordinate position of the off-curve control point, which QuickDraw GX uses to determine the tangents of the curve.
last
The coordinate position where the curve ends.
The curve defined by these three points is a quadratic Bézier curve.
Because the geometric points that define a curve are ordered, curves have direction. The direction of a curve can affect how QuickDraw GX draws the curve shape, particularly when the curve shape has stylistic variations.
For more information about curves and curve shapes, see "Curve Shapes" on page 2-18.