Canvas API

Added in HTML5, the HTML <canvas> element can be used to draw graphics via scripting in JavaScript. For example, it can be used to draw graphs, make photo compositions, create animations, or even do real-time video processing or rendering.

Mozilla applications gained support for <canvas> starting with Gecko 1.8 (i.e. Firefox 1.5). The element was originally introduced by Apple for the OS X Dashboard and Safari. Internet Explorer supports <canvas> from version 9 onwards; for earlier versions of IE, a page can effectively add support for <canvas> by including a script from Google's Explorer Canvas project. Google Chrome and Opera 9 also support <canvas>.

The <canvas> element is also used by WebGL to draw hardware-accelerated 3D graphics on web pages.

Example

This is just a simple code snippet which uses the CanvasRenderingContext2D.fillRect() method.

HTML

<canvas id="canvas"></canvas>

JavaScript

var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
ctx.fillStyle = 'green';
ctx.fillRect(10, 10, 100, 100);

Edit the code below and see your changes update live in the canvas:

Reference

The interfaces related to the WebGLRenderingContext are referenced under WebGL.

Guides and tutorials

Canvas tutorial
A comprehensive tutorial covering both the basic usage of <canvas> and its advanced features.
Code snippets: Canvas
Some extension developer-oriented code snippets involving <canvas>.
Demo: A basic ray-caster
A demo of ray-tracing animation using canvas.
Drawing DOM objects into a canvas
How to draw DOM content, such as HTML elements, into a canvas.
Manipulating video using canvas
Combining <video> and <canvas> to manipulate video data in real time.

Resources

Generic

Libraries

  • Fabric.js is an open-source canvas library with SVG parsing capabilities.
  • Kinetic.js is an open-source canvas library focused on interactivity for desktop and mobile applications.
  • Paper.js is an open source vector graphics scripting framework that runs on top of the HTML5 Canvas.
  • Origami.js is an open source lightweight canvas library.
  • libCanvas is powerful and lightweight canvas framework.
  • Processing.js is a port of the Processing visualization language.
  • PlayCanvas is an open source game engine.
  • Pixi.js is an open source game engine.
  • PlotKit is a charting and graphing library.
  • Rekapi is an animation key-framing API for Canvas.
  • PhiloGL is a WebGL framework for data visualization, creative coding and game development.
  • JavaScript InfoVis Toolkit creates interactive 2D Canvas data visualizations for the Web.
  • EaselJS is a free/open source library to make it easier to use canvas for games and art
  • Scrawl-canvas is another open-source javascript library for creating and manipulating 2d canvas elements
  • heatmap.js is an open source library to create canvas based heatmaps

Specifications

Specification Status Comment
WHATWG HTML Living Standard
The definition of '<canvas>' in that specification.
Living Standard  

See also