JavaScript drag and drop, resizing and multi-touch gestures with inertia and snapping for modern browsers (and also IE9+).
Features include:
- **inertia** and **snapping**
- **multi-touch**, simultaneous interactions
- cross browser and device, supporting the **desktop and mobile** versions of
Chrome, Firefox and Opera as well as **Internet Explorer 9+**
- interaction with [**SVG**](http://interactjs.io/#use_in_svg_files) elements
- being **standalone and customizable**
- **not modifying the DOM** except to change the cursor (but you can disable
that)
Installation
------------
* [npm](https://www.npmjs.org/): `npm install interactjs`
* [jsDelivr CDN](https://cdn.jsdelivr.net/npm/interactjs/): ``
* [unpkg CDN](https://unpkg.com/interactjs/): ``
* [Rails 5.1+](https://rubyonrails.org/):
1. `yarn add interactjs`
2. `//= require interactjs/interact`
* [Webjars SBT/Play 2](https://www.webjars.org/): `libraryDependencies ++= Seq("org.webjars.npm" % "interactjs" % version)`
### Typescript definitions
The project is written in Typescript and the npm package includes the type
definitions, but if you need the typings alone, you can install them with:
```
npm install --save-dev @interactjs/types
```
Documentation
-------------
http://interactjs.io/docs
Example
-------
```javascript
var pixelSize = 16;
interact('.rainbow-pixel-canvas')
.origin('self')
.draggable({
modifiers: [
interact.modifiers.snap({
// snap to the corners of a grid
targets: [
interact.snappers.grid({ x: pixelSize, y: pixelSize }),
],
})
],
listeners: {
// draw colored squares on move
move: function (event) {
var context = event.target.getContext('2d'),
// calculate the angle of the drag direction
dragAngle = 180 * Math.atan2(event.dx, event.dy) / Math.PI;
// set color based on drag angle and speed
context.fillStyle = 'hsl(' + dragAngle + ', 86%, '
+ (30 + Math.min(event.speed / 1000, 1) * 50) + '%)';
// draw squares
context.fillRect(event.pageX - pixelSize / 2, event.pageY - pixelSize / 2,
pixelSize, pixelSize);
}
}
})
// clear the canvas on doubletap
.on('doubletap', function (event) {
var context = event.target.getContext('2d');
context.clearRect(0, 0, context.canvas.width, context.canvas.height);
});
function resizeCanvases () {
[].forEach.call(document.querySelectorAll('.rainbow-pixel-canvas'), function (canvas) {
canvas.width = document.body.clientWidth;
canvas.height = window.innerHeight * 0.7;
});
}
// interact.js can also add DOM event listeners
interact(document).on('DOMContentLoaded', resizeCanvases);
interact(window).on('resize', resizeCanvases);
```
See the above code in action at https://codepen.io/taye/pen/tCKAm
License
-------
interact.js is released under the [MIT License](http://taye.mit-license.org).
[ijs-twitter]: https://twitter.com/interactjs
[upcoming-changes]: https://github.com/taye/interact.js/blob/master/CHANGELOG.md#upcoming-changes
