Bezier.coffee

A lightweight library for generating n-dimensional bezier curves with an arbitrary number of control points. Curves are defined parametrically. BezierPath enables a curve to be exported as an SVG path.

Usage

Two Dimensions

To generate a simple 2D bezier curve with two control points (with JavaScript):

Define the control points:

var start = new Point(0, 0),
    end   = new Point(1, 1),
    cont1 = new Point(0.5, 0),
    cont2 = new Point(0.5, 1);

Define the curve:

var curve = new BezierCurve(start, cont1, cont2, end);

Evaluate for specific t values:

curve.evaluate(0).coords();    // => 0,0
curve.evaluate(0.25).coords(); // => 0.3671875,0.0859375
curve.evaluate(1).coords();    // => 1,1

Sample curve to generate SVG:

var path = new BezierPath(curve);
path.sample(); // => M0,0 L...

Reduce sample interval (default is 20 samples):

path.sample(100); // => M0,0 L...

Generate a 'debug' path between the control points:

path.control(); // => M0,0 L...

Three Dimensions

Now a 3D example of a bezier curve, this time with three control points (with CoffeeScript):

points = [
	new Point 0,   0,   0  
	new Point 0.5, 0.5, 1  
	new Point 1,   0,   0.5
	new Point 1,   0.5, 0  
	new Point 1,   1,   1  
]

curve = new BezierCurve points...
path  = new BezierPath curve

path.sample 50 # => M0,0,0 L...
path.control() # => M0,0,0 L...

Results in the following (green path is the control curve):

(Drawn with SVG3d)

Higher Dimensions

Just supply more data values:

origin = new Point 0, 0, 0, 0