draw-ellipse

Generic Function

Package: common-graphics

Arguments: stream centre semi-major-axis semi-minor-axis semi-major-axis-angle

Draws an ellipse 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.) The ellipse is rotated so that the semi-major-axis makes angle semi-major-axis-angle with the x-axis passing through the center. Angles are measured clockwise.

So, specifying semi-major-axis 200, semi-minor-axis 10, and semi-major-axis-angle 5 produces a long, thin ellipse, 400 pixels wide, with the long axis nearly horizontal, pointing to about 16 minutes after the hour (horizontal would be 15 minutes after the hour), centered at center.

Note: incompatible change in release 6.0: in releases prior to 6.0, when a frame-with-single-child instance was passed to this operator, the operator was actually applied to the child (the result of applying frame-child to the frame-with-single-child instance). In release 6.0, this redirection no longer occurs. If you intend this operator to apply to the frame-child, pass that to this operator rather than the parent. This is a non-backward-compatible-change. See the release notes for more information.

Common Graphics and IDE documentation is described in About Common Graphics and IDE documentation in cgide.htm.

The documentation is described in introduction.htm and the index is in index.htm.

Copyright (c) 1998-2000, Franz Inc. Berkeley, CA., USA. All rights reserved.

Created 2000.10.5.