https://github.com/hughsk/bezier

n-degree Bezier spline interpolation.
https://github.com/hughsk/bezier

Last synced: 12 days ago
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n-degree Bezier spline interpolation.

• Host: GitHub
• URL: https://github.com/hughsk/bezier
• Owner: hughsk
• License: mit
• Created: 2013-09-30T02:58:28.000Z (about 11 years ago)
• Default Branch: master
• Last Pushed: 2017-01-24T17:55:34.000Z (almost 8 years ago)
• Last Synced: 2024-10-17T16:41:05.138Z (22 days ago)
• Language: JavaScript
• Size: 113 KB
• Stars: 52
• Watchers: 6
• Forks: 6
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# bezier [![experimental](http://hughsk.github.io/stability-badges/dist/experimental.svg)](http://github.com/hughsk/stability-badges) #

n-degree Bezier curve interpolation.

## Usage ##

[![bezier](https://nodei.co/npm/bezier.png?mini=true)](https://nodei.co/npm/bezier)

### `require('bezier')(points, t)` ###

Returns the value at `t` for a bezier curve of `points.length` degrees.

In other words, if you pass it a 3-element array you'll get the results of a

3-degree (quadratic) curve.

``` javascript

var bezier = require('bezier')

bezier([0, 1, 2], 0.5)    // 1

bezier([0, 1, 2, 3], 0.5) // 1.5

```

You can use a curve for each dimension to get the resulting bezier you're

probably familiar with:

``` javascript

var canvas = document.createElement('canvas')

var ctx = canvas.getContext('2d')

var bezier = require('bezier')

var x = [0, 100, 200]

var y = [200, 100, 0]

ctx.beginPath()

ctx.strokeStyle = '#000'

for (var t = 0; t < 1; t += 0.01) {

  ctx.lineTo(bezier(x, t), bezier(y, t))

}

ctx.stroke()

ctx.closePath()

```

### `curve = require('bezier').prepare(pointCount)` ###

Generates a function which takes `pointCount` number of points to draw a

bezier curve. For higher values of `pointCount`, this function is generated on

the fly such that it can run with as little overhead as possible.

It's a small trade-off in flexibility for a small benefit in performance :)

### `curve(points, t)` ###

Given an array of `points` that is `pointCount` long, return the value across

the curve at `t`.

``` javascript

var quadratic = require('bezier').prepare(3)

var cubic = require('bezier').prepare(4)

quadratic([0, 1, 2], 0.5) // 1

cubic([0, 1, 2, 3], 0.5)  // 1.5

// Note that these functions expect

// arrays of the correct length:

quadratic([0, 1, 2, 3], 0.5) // 1

quadratic([0, 1], 0.5)       // NaN

```

## License ##

MIT. See [LICENSE.md](http://github.com/hughsk/bezier/blob/master/LICENSE) for details.