Canvas API

BaselineWidely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

TheCanvas API provides a means for drawing graphics viaJavaScript and theHTML <canvas> element. Among other things, it can be used for animation, game graphics, data visualization, photo manipulation, and real-time video processing.

The Canvas API largely focuses on 2D graphics. TheWebGL API, which also uses the<canvas> element, draws hardware-accelerated 2D and 3D graphics.

Basic example

This simple example draws a green rectangle onto a canvas.

HTML

html

<canvas></canvas>

JavaScript

TheDocument.getElementById() method gets a reference to the HTML<canvas> element. Next, theHTMLCanvasElement.getContext() method gets that element's context—the thing onto which the drawing will be rendered.

The actual drawing is done using theCanvasRenderingContext2D interface. ThefillStyle property makes the rectangle green. ThefillRect() method places its top-left corner at (10, 10), and gives it a size of 150 units wide by 100 tall.

const canvas = document.getElementById("canvas");const ctx = canvas.getContext("2d");ctx.fillStyle = "green";ctx.fillRect(10, 10, 150, 100);

Result

Reference

Note:The interfaces related to theWebGLRenderingContext are referenced under WebGL.

Note:OffscreenCanvas is also available in web workers.

CanvasCaptureMediaStreamTrack is a related interface.

Guides and tutorials

Canvas tutorial: A comprehensive tutorial covering both the basic usage of the Canvas API and its advanced features.
HTML5 Canvas Deep Dive: A hands-on, book-length introduction to the Canvas API and WebGL.
Canvas Handbook: A handy reference for the Canvas API.
Manipulating video using canvas: Combining<video> and<canvas> to manipulate video data in real time.

Libraries

The Canvas API is extremely powerful, but not always simple to use. The libraries listed below can make the creation of canvas-based projects faster and easier.

EaselJS is an open-source canvas library that makes creating games, generative art, and other highly graphical experiences easy.
Fabric.js is an open-source canvas library with SVG parsing capabilities.
heatmap.js is an open-source library for creating canvas-based data heat maps.
JavaScript InfoVis Toolkit creates interactive data visualizations.
Konva.js is a 2D canvas library for desktop and mobile applications.
p5.js has a full set of canvas drawing functionality for artists, designers, educators, and beginners.
Phaser is a fast, free and fun open source framework for Canvas and WebGL powered browser games.
Pts.js is a library for creative coding and visualization in canvas and SVG.
Rekapi is an animation key-framing API for Canvas.
Scrawl-canvas is an open-source JavaScript library for creating and manipulating 2D canvas elements.
TheZIM framework provides conveniences, components, and controls for coding creativity on the canvas — includes accessibility and hundreds of colorful tutorials.
Sprig is a beginner-friendly, open-source, tile-based game development library that uses Canvas.