levabala_interactjs

JavaScript drag and drop, resizing and multi-touch gestures with inertia and
snapping for modern browsers (and also IE9+).


Features include:

- inertia and snapping
- multiple 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 elements
- being lightweight and standalone (not _yet another_ jQuery plugin)
- not modifying the DOM except to change the cursor (but you can disable
that)

Installation
------------

* Bower: bower install interactjs
* npm: npm install interactjs
* Webjars SBT/Play 2: libraryDependencies ++= Seq("org.webjars.bower" % "interact.js" % "1.2.8")
* Direct download the latest version: http://interactjs.io/#download
* Rails 4 app development (using Rails Asset Pipeline)
* Download the file interact.js (development version) into a new sub-directory: vendor/assets/javascripts/interact
* Add ``//= require interact/interact` in app/assets/javascripts/application.js (above `//= require_tree .`)
* Restart the Rails server
* jsDelivr CDN:
* cdnjs CDN:

Documentation
-------------

Visit http://interactjs.io/docs for the API documentation.

Example
-------

`javascript
var pixelSize = 16;

interact('.rainbow-pixel-canvas')
.origin('self')
.draggable({
snap: {
targets: [ interact.createSnapGrid({
x: pixelSize, y: pixelSize
}) ]
},
// allow multiple drags on the same element
maxPerElement: Infinity
})
// draw colored squares on move
.on('dragmove', 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 http://codepen.io/taye/pen/YPyLxE

License
-------

interact.js is released under the MIT License.

[ijs-twitter]: https://twitter.com/interactjs
[upcoming-changes]: https://github.com/taye/interact.js/blob/master/CHANGELOG.md#upcoming-changes