HP PCL/PJL reference (PCL 5 Printer Language) - Technical Reference Manual Part II

EN CI, Circle 20-25
CI, Circle
This command draws the circumference of a circle using the specified
radius and chord angle. If you want a filled circle, refer to the WG or
PM commands.
CI radius[,chord angle;]
The CI command includes an automatic pen down. When a CI
command is received, the pen lifts, moves from the center of the
circle (the current pen location) to the starting point on the
circumference, lowers the pen, draws the circle, then returns
with the pen up to the center of the circle. After the circle is drawn,
the previous pen up/down status is restored. To avoid leaving a dot
at the center of the circle, move to and from the circle’s center with
the pen up.
z Radius — Measured from the current pen location. Coordinates
are interpreted in current units: as user-units when scaling is on;
as plotter units when scaling is off.
z Chord Angle — Specifies the chord angle used to draw the arc.
The default is a chord angle of 5°. Refer to the Arc Absolute (AA)
command discussion, earlier in this chapter, for an explanation of
the chord angle.
Each chord of the circle is drawn using the currently defined line
type, width, and attributes. (Refer to Chapter 22, The Line and Fill
Attributes Group, for more information.) Do not use an adaptive
(negative) line type to draw a circle, as the printer attempts to draw
a complete pattern for every chord (72 with the default chord angle).
Always use isotropic scaling in drawings that contain circles, unless
you want your circles to "stretch" with aspect ratio changes of the
drawing (anisotropic scaling may produce an ellipse). For more
information, refer to Chapter 19 for a scaling discussion and for the
Scale (SC) command description.
Parameter Format Functional Range Default
radius current units -2
30
to 2
30
- 1 no default
chord angle clamped real 0.5° to 180° 5°