The HTML <canvas> element is used to draw graphics on a web page.
The graphic to the left is created with <canvas>. It shows four elements: a red rectangle, a gradient rectangle, a multicolor rectangle, and a multicolor text.
What is HTML Canvas?
The HTML <canvas> element is used to draw graphics, on the fly, via scripting (usually JavaScript).
The <canvas> element is only a container for graphics. You must use a script to actually draw the graphics.
Canvas has several methods for drawing paths, boxes, circles, text, and adding images.
The canvas element is part of HTML5 and allows for dynamic, scriptable rendering of 2D shapes and bitmap images. It is a low level, procedural model that updates a bitmap and does not have a built-in scene graph.
Browser Support
The numbers in the table specify the first browser version that fully supports the <canvas> element.
| Element | |||||
|---|---|---|---|---|---|
| <canvas> | 4.0 | 9.0 | 2.0 | 3.1 | 9.0 |
History
Canvas was initially introduced by Apple for use inside their own Mac OS X WebKit component in 2004 powering applications like Dashboard widgets and the Safari browser.
Later, in 2005 it was adopted in version 1.8 of Gecko browsers, and Opera in 2006, and standardized by the Web Hypertext Application Technology Working Group (WHATWG) on new proposed specifications for next generation web technologies.
Usage
Canvas consists of a drawable region defined in HTML code with height and width attributes. JavaScript code may access the area through a full set of drawing functions similar to those of other common 2D APIs, thus allowing for dynamically generated graphics.
Some anticipated uses of canvas include building graphs, animations, games, and image composition.
Canvas Examples
A canvas is a rectangular area on an HTML page. By default, a canvas has no border and no content.
The markup looks like this:
<canvas id="myCanvas" width="200" height="100"></canvas>
Note: Always specify an id attribute (to be referred to in a script), and a width and height attribute to define the size of the canvas.
To add a border, use the style attribute:
Basic Canvas Example
<canvas id="myCanvas" width="200" height="100" style="border:1px solid #000000;">
</canvas>
Try it Yourself »Drawing with JavaScript
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.fillStyle = "#FF0000";
ctx.fillRect(0,0,150,75);
Try it Yourself »Draw a Line
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.moveTo(0,0);
ctx.lineTo(200,100);
ctx.stroke();
Try it Yourself »Draw a Circle
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.beginPath();
ctx.arc(95,50,40,0,2*Math.PI);
ctx.stroke();
Try it Yourself »Draw a Text
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.font = "30px Arial";
ctx.fillText("Hello World",10,50);
Try it Yourself »Stroke Text
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.font = "30px Arial";
ctx.strokeText("Hello World",10,50);
Try it Yourself »Draw Linear Gradient
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
// Create gradient
var grd = ctx.createLinearGradient(0,0,200,0);
grd.addColorStop(0,"red");
grd.addColorStop(1,"white");
// Fill with gradient
ctx.fillStyle = grd;
ctx.fillRect(10,10,150,80);
Try it Yourself »Draw Circular Gradient
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
// Create gradient
var grd = ctx.createRadialGradient(75,50,5,90,60,100);
grd.addColorStop(0,"red");
grd.addColorStop(1,"white");
// Fill with gradient
ctx.fillStyle = grd;
ctx.fillRect(10,10,150,80);
Try it Yourself »Draw Image
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
var img = document.getElementById("scream");
ctx.drawImage(img,10,10);
Try it Yourself »HTML Canvas Tutorial
To learn all about HTML <canvas>, Visit our full HTML Canvas Tutorial.