What is HTML Canvas?

http://www.w3schools.com/html/html5_canvas.asp

The HTML <canvas> element is used to draw graphics, on the fly, via JavaScript.

The <canvas> element is only a container for graphics. You must use JavaScript to actually draw the graphics.

Canvas has several methods for drawing paths, boxes, circles, text, and adding images.

---

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

---

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.

Here is an example of a basic, empty canvas:

Example

<canvas id="myCanvas" width="200" height="100" style="border:1px solid #000000;">
</canvas>

Try it Yourself »

---

Draw a Line

Example

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

Example

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

Example

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

Example

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

Example

var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");

// Create gradientvar grd = ctx.createLinearGradient(0,0,200,0);
grd.addColorStop(0,"red");
grd.addColorStop(1,"white");

// Fill with gradientctx.fillStyle = grd;
ctx.fillRect(10,10,150,80);

Try it Yourself »

---

Draw Circular Gradient

Example

var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");

// Create gradientvar grd = ctx.createRadialGradient(75,50,5,90,60,100);
grd.addColorStop(0,"red");
grd.addColorStop(1,"white");

// Fill with gradientctx.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 »