Maintenance script: Initial automated import

2016-02-24T18:14:05Z

Initial automated import

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{{Template:TI-BASIC:Command
|picture=CIRCLE.GIF
|summary=Draws a circle.
|syntax=Circle(''X'',''Y'',''r'')

(83+ and higher only)
Circle(''X'',''Y'',''r'',{''i''})
|location=Press:
# Press [2ND] [PRGM] to enter the DRAW menu
# Press [9] to insert Circle(
|compatibility=TI-83/84/+/SE
|size=1 byte
}}

Circle(''X'',''Y'',''r'') will draw a circle at (''X'',''Y'') with radius ''r''. ''X'' and ''Y'' will be affected by the window settings. The radius will also be affected by the window settings.

:Circle(5,5,5)

= Advanced Uses =

The radius of a circle is affected by the window settings. This means that if the x- and y-increment is two, the radius will be two pixels. However, there is another way to take advantage of this to draw ellipses. If the x- and y-increment are different, then the shape will not be a circle. For instance, with Xmin=0, Xmax=20, Ymin=0, and Ymax=31, Circle(10,10,2) will draw an ellipse, where the width is greater than the height.

= Optimization =

If a complex list such as {''i''} is passed to Circle( as the fourth argument, the "fast circle" routine is used instead, which uses the symmetries of the circle to only do 1/8 of the trig calculations. For example:

:Circle(0,0,5
can be
:Circle(0,0,5,{i

Any list of complex numbers will work as the fourth argument in the same way, but there's no benefit to using any other list.

= Command Timings =

The ordinary Circle( is extremely slow. The fast circle trick discussed above cuts the time down to only about 30% of the "slow Circle(" time! While still not instant, this is faster than any replacement routine that can be written in TI-Basic.

For small radii, replace Circle( with Pt-On( instead.

= Related Commands =

* [[TI-BASIC:Line|Line(]]
* [[TI-BASIC:Pt_On|Pt-On(]][[Category:TI-BASIC]]
[[Category:TIBD]]

TI-BASIC:Circle - Revision history

Maintenance script: Initial automated import