Delia Graff: Latex Circles with Bezier Curves

How to draw circles of any radius in latex

The four commands below will produce a circle with your chosen radius r (measured in the units determined by the value of the length \unitlength)
The letter k stands for the following value: 0.5522847498 r
(This won't get you a perfect circle, but it's close enough. Thanks to G. Adam Stanislav for the calculations.)
The center of the circle will be at the coordinate (x,y)
Set the length of \unitlength to the desired size, for example to .25in by including the following command in your document: \setlength{\unitlength}{.25in}
Each \cbezier command creates one quadrant of the circle
The \cbezier commands must occur only in either math mode or the picture environment

\cbezier(x-r,y)(x-r,y+k)(x-k,y+r)(x,y+r)
\cbezier(x,y+r)(x+k,y+r)(x+r,y+k)(x+r,y)
\cbezier(x+r,y)(x+r,y-k)(x+k,y-r)(x,y-r)
\cbezier(x,y-r)(x-k,y-r)(x-r,y-k)(x-r,y)

Example 1

Here is an example that I used in a paper: (LaTeX source) (PDF file)

Example 2

Suppose you want to create a circle with a radius of 4.5cm.
- If we set \unitlength to .9cm, then r = 5
- Now calculate the value of k = (5)(0.5522847498) = 2.761423749
Center the circle at (5,5), and the result is:

\setlength{\unitlength}{.9cm}

\cbezier(0,5)(0,7.761423749)(2.238576251,10)(5,10)
\cbezier(5,10)(7.761423749,10)(10,7.761423749)(10,5)
\cbezier(10,5)(10,2.238576251)(7.761423749,0)(5,0)
\cbezier(5,0)(2.238576251,0)(0,2.238576251)(0,5)

To create a circle made from a dotted line rather than a solid line, insert ‘[num]’ directly after each occurrence of ‘\cbezier’, where num represents the number of dots that quadrant of the circle is to contain.

The command \cbezier requires the package bez123.

You can find this pacakge (with its documentation) at any CTAN cite. Or just put the following files in a directory accessible to latex (a directory where other .sty files are stored): bez123.sty multiply.sty

Once you've done that, enable the bezier commands by putting the following in your preamble: \usepackage{bez123}

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Last modified: "Sunday, 01 Jan 06, 13:53"

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