Chapter 2 Graphics Tutorial
2-26
Figure 2. 24. Printout of a Circle Made with PMRA
Drawing Complex Curves
PRESCRIBE also provides a second curve-drawing operator for constructing complex
curves that are referred to as Bézier curve segments. The PCRP (Path, Curve to Relative
Position) uses the following format.
PCRP x1, y1, x2, y2, x3, y3;
Figure 2. 25. Bézier Curves
A Bézier curve segment is one that is geometrically defined by a starting point (the cur-
sor’s current position), two control points (x1, y1 and x2, y2), and an ending point (x3,
y3). Coordinates of each of these points are specified as an offset from the cursor’s previ-
ous position.