HTML Canvas Graphics
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 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>
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 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>
HTML SVG Graphics
SVG defines vector-based graphics in XML format.
What is SVG?
- SVG stands for Scalable Vector Graphics
- SVG is used to define graphics for the Web
- SVG is a W3C recommendation
The HTML <svg> Element
The HTML <svg> element is a container for SVG graphics.
SVG has several methods for drawing paths, boxes, circles, text, and graphic images.
Browser Support
The numbers in the table specify the first browser version that fully supports the <svg> element.
| Element | |||||
|---|---|---|---|---|---|
| <svg> | 4.0 | 9.0 | 3.0 | 3.2 | 10.1 |
SVG Circle
Example
<!DOCTYPE html>
<html>
<body>
<svg width=”100″ height=”100″>
<circle cx=”50″ cy=”50″ r=”40″ stroke=”green” stroke-width=”4″ fill=”yellow” />
</svg>
</body>
</html>
SVG Rectangle
Example
<svg width=”400″ height=”100″>
<rect width=”400″ height=”100″ style=”fill:rgb(0,0,255);stroke-width:10;stroke:rgb(0,0,0)” />
</svg>
SVG Rounded Rectangle
Example
<svg width=”400″ height=”180″>
<rect x=”50″ y=”20″ rx=”20″ ry=”20″ width=”150″ height=”150″
style=”fill:red;stroke:black;stroke-width:5;opacity:0.5″ />
</svg>
SVG Star
Example
<svg width=”300″ height=”200″>
<polygon points=”100,10 40,198 190,78 10,78 160,198″
style=”fill:lime;stroke:purple;stroke-width:5;fill-rule:evenodd;” />
</svg>
SVG Logo
SVG
Example
<svg height=”130″ width=”500″>
<defs>
<linearGradient id=”grad1″ x1=”0%” y1=”0%” x2=”100%” y2=”0%”>
<stop offset=”0%” style=”stop-color:rgb(255,255,0);stop-opacity:1″ />
<stop offset=”100%” style=”stop-color:rgb(255,0,0);stop-opacity:1″ />
</linearGradient>
</defs>
<ellipse cx=”100″ cy=”70″ rx=”85″ ry=”55″ fill=”url(#grad1)” />
<text fill=”#ffffff” font-size=”45″ font-family=”Verdana” x=”50″ y=”86″>SVG</text>
Sorry, your browser does not support inline SVG.
</svg>
Differences Between SVG and Canvas
SVG is a language for describing 2D graphics in XML.
Canvas draws 2D graphics, on the fly (with a JavaScript).
SVG is XML based, which means that every element is available within the SVG DOM. You can attach JavaScript event handlers for an element.
In SVG, each drawn shape is remembered as an object. If attributes of an SVG object are changed, the browser can automatically re-render the shape.
Canvas is rendered pixel by pixel. In canvas, once the graphic is drawn, it is forgotten by the browser. If its position should be changed, the entire scene needs to be redrawn, including any objects that might have been covered by the graphic.
Comparison of Canvas and SVG
The table below shows some important differences between Canvas and SVG:
| Canvas | SVG |
|---|---|
| Resolution dependentNo support for event handlersPoor text rendering capabilitiesYou can save the resulting image as .png or .jpgWell suited for graphic-intensive games | Resolution independentSupport for event handlersBest suited for applications with large rendering areas (Google Maps)Slow rendering if complex (anything that uses the DOM a lot will be slow)Not suited for game applications |
SVG Tutorial
To learn more about SVG, please read our SVG Tutorial.