Page 103 Table of Contents Index Page 105
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E


CHAPTER 12. GRAPHICS

Draws either a filled or unfilled rectangle on the sheet sheet that has its sides aligned with the
coordinate axes of the native coordinate system. One corner of the rectangle is at the position
(x1,y1) and the opposite corner is at (x2,y2). The arguments x1, y1, x2, and y1 are real numbers
that are canonicalized in the same way as for make-bounding-rectangle. filled is as for draw-
polygon*.

The current line style (see Chapter 10) affects the drawing of unfilled rectangles in the obvious
way, except that the cap shape has no effect.

=> draw-ellipse sheet center-pt radius-1-dx radius-1-dy radius-2-dx radius-2-dy &key (filled t)
start-angle end-angle ink clipping-region transformation line-style line-thickness line-unit line-
dashes line-cap-shape [Function]
=> draw-ellipse* sheet center-x center-y radius-1-dx radius-1-dy radius-2-dx radius-2-dy &key
(filled t) start-angle end-angle ink clipping-region transformation line-style line-thickness line-
unit line-dashes line-cap-shape [Function]
These functions (structured and spread arguments, respectively) draw an ellipse (when filled is
true, the default) or an elliptical arc (when filled is false) on the sheet sheet. The center of the
ellipse is the point center-pt (or the position (center-x,center-y)).

Two vectors, (radius-1-dx,radius-1-dy) and (radius-2-dx,radius-2-dy) specify the bounding par-
allelogram of the ellipse as explained in Chapter 3. All of the radii are real numbers. If the two
vectors are collinear, the ellipse is not well-defined and the ellipse-not-well-defined error
will be signalled. The special case of an ellipse with its major axes aligned with the coordinate
axes can be obtained by setting both radius-1-dy and radius-2-dx to 0.

start-angle and end-angle are real numbers that specify an arc rather than a complete ellipse.
Angles are measured with respect to the positive x axis. The elliptical arc runs positively
(counter-clockwise) from start-angle to end-angle. The default for start-angle is 0; the default
for end-angle is 2.

In the case of a "filled arc" (that is when filled is true and start-angle or end-angle are supplied
and are not 0 and 2), the figure drawn is the "pie slice" area swept out by a line from the
center of the ellipse to a point on the boundary as the boundary point moves from start-angle
to end-angle.

When drawing unfilled ellipses, the current line style (see Chapter 10) affects the drawing in the
obvious way, except that the joint shape has no effect. Dashed elliptical arcs start "dashing" at
start-angle.

=> draw-circle sheet center-pt radius &key (filled t) start-angle end-angle ink clipping-region
transformation line-style line-thickness line-unit line-dashes line-cap-shape [Function]
=> draw-circle* sheet center-x center-y radius &key (filled t) start-angle end-angle ink clipping-
region transformation line-style line-thickness line-unit line-dashes line-cap-shape [Function]
These functions (structured and spread arguments, respectively) draw a circle (when filled is
true, the default) or a circular arc (when filled is false) on the sheet sheet. The center of the
circle is center-pt or (center-x,center-y) and the radius is radius. These are just special cases of

Page 103 Table of Contents Index Page 105
Chapters
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30
A, B, C, D, E