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.
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.
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 |
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:
<canvas id="myCanvas" width="200" height="100" style="border:1px solid #000000;">
</canvas>
Try it Yourself »
After creating the rectangular canvas area, you must add a JavaScript to do the drawing.
Here are some examples:
<script>
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.moveTo(0, 0);
ctx.lineTo(200, 100);
ctx.stroke();
</script>
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<script>
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.beginPath();
ctx.arc(95, 50, 40, 0, 2 * Math.PI);
ctx.stroke();
</script>
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<script>
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.font = "30px Arial";
ctx.fillText("Hello World", 10, 50);
</script>
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<script>
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.font = "30px Arial";
ctx.strokeText("Hello World", 10, 50);
</script>
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<script>
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);
</script>
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<script>
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);
</script>
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<script>
var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
var img = document.getElementById("scream");
ctx.drawImage(img, 10, 10);
</script>
Try it Yourself »
To learn more about <canvas>
, please read our HTML Canvas Tutorial.
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