Chapter
10
I
BASIC
Keywords
CIRCLE/Graphics
Statement
Draws an ellipse on the screen with the specified center and
radius.
(x,y)
specify the coordinate
for
the center
of
the circle.
x
is
the
horizontal coordinate and
y
is the vertical coordinate.
Color
indicates the color
of
the ellipse and must be a valid num-
ber in the current color set.
The STEP option tells BASIC that the
(x,y)
coordinates are rela-
tive to the last point referenced.
The possible ranges
for
x,
y,
and
color
depend upon the current
screen mode as defined in Chapter 8, “Displaying Color and
Graphics.
”
Radius
is
the major axis
of
the ellipse.
Start
and
end
are the beginning and ending angles in radians
and must be in the range -6.283186 to 6.283186,
or
-2
*
PI to
2
*
PI, where PI equals 3.141593. If you specify a negative
start
or
end
angle, the ellipse
is
connected
to
the center point with a
line, and the angles are treated
as
if they were positive.
Aspect
is the ratio
of
the x-radius to the y-radius in terms
of
co-
ordinates. If
aspect
is
less than
1,
radius
is the x-radius and is
measured in points in the horizontal direction. If
aspect
is
greater than
1,
radius
is the y-radius and is measured in points
in the vertical direction. If you omit
aspect,
BASIC uses the de-
faults for the current screen mode as defined in Chapter 8. When
you use the default, BASIC draws a circle.
114
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