Canvas tutorial - Web APIs 编辑

<canvas> is an HTML element which can be used to draw graphics via scripting (usually JavaScript). This can, for instance, be used to draw graphs, combine photos, or create simple (and not so simple) animations. The images on this page show examples of <canvas> implementations which will be created in this tutorial.

This tutorial describes how to use the <canvas> element to draw 2D graphics, starting with the basics. The examples provided should give you some clear ideas about what you can do with canvas, and will provide code snippets that may get you started in building your own content.

First introduced in WebKit by Apple for the OS X Dashboard, <canvas> has since been implemented in browsers. Today, all major browsers support it.

Before you start

Using the <canvas> element is not very difficult, but you do need a basic understanding of HTML and JavaScript. The <canvas> element is not supported in some older browsers, but is supported in recent versions of all major browsers. The default size of the canvas is 300 pixels × 150 pixels (width × height). But custom sizes can be defined using the HTML height and width property. In order to draw graphics on the canvas we use a JavaScript context object, which creates graphics on the fly.

In this tutorial

1. Basic usage
2. Drawing shapes
3. Applying styles and colors
4. Drawing text
5. Using images
6. Transformations
7. Compositing and clipping
8. Basic animations
9. Advanced animations
10. Pixel manipulation
11. Hit regions and accessibility
12. Optimizing the canvas
13. Finale

See also

• Canvas topic page
• HTML5CanvasTutorials

A note to contributors

Due to an unfortunate technical error that occurred the week of June 17, 2013, we lost the history of this tutorial, including attributions to all past contributors to its content. We apologize for this, and hope you'll forgive this unfortunate mishap.

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