| Allegro CL version 8.1Unrevised from 8.0 to 8.1. 8.0 version |

**Arguments: ***
stream center semi-major-axis
semi-minor-axis
semi-major-axis-angle start-angle
length-angle
*

Draws an ellipse arc on *stream*. The ellipse is
defined by the center (a position) and the two half-axes, lengths from
the center to the farthest point on the edge and to the nearest point
on the edge, called the semi-major-axis and the
semi-minor-axis. (Technically, the major axis should be longer than
the minor axis but the two arguments need not have that relationship.)
Because the Windows ellipse drawer can only draw ellipses that are
vertically or horizontally oriented, the
*semi-major-axis-angle* argument must be a multiple
of 90. Other values will signal an error. The argument specifies the
angle between the semi-major-axis and a line parallel to the x-axis
passing through the *center*.

Angles are measured in degrees clockwise from the 3 o'clock
position. The endpoint coordinates may be determined by calling
**ellipse-start-and-end**.

So, the ellipse created when specifying semi-major-axis 200, semi-minor-axis 10, and semi-major-axis-angle 90 is a long, thin ellipse, 400 pixels wide, with the long axis vertical, centered at center. Now, with a start-angle of 0 and a length-angle of 90, all of the ellipse in the lower right quadrant is drawn and no part is drawn in any other quadrant.

*center* should be a position (see **make-position**).
*stream* should be a `cg-stream`

.

See also cg-drawing.htm.

Copyright (c) 1998-2009, Franz Inc. Oakland, CA., USA. All rights reserved.

Documentation for Allegro CL version 8.1. This page was not revised from the 8.0 page.

Created 2009.7.29.

| Allegro CL version 8.1Unrevised from 8.0 to 8.1. 8.0 version |