fill-ellipse-sector

Arguments: stream center smaj-axis smin-axis smaj-axis-angle start-angle length-angle

Draws the specified filled ellipse sector on stream. An ellipse-sector is an ellipse-arc with the endpoints of the arc connected to the center of the ellipse, like a piece of an elliptical pie.

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. The portion of the ellipse drawn is the sector starting at start-angle (0 is the x axis when the center is the origin) through the length-angle.

Angles are measured in degrees clockwise from the 3 o'clock position (that is, along or parallel to the x axis). The endpoint coordinates may be determined by calling ellipse-start-and-end.

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

Contrast with erase-contents-ellipse-sector which erases the filled ellipse from stream.

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Created 2019.8.20.