Home > Tutorials > Html Tutorials

Html5 canvas usage example

Source: Internet
Author: User
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

Comments: This is the first article. There is no technical content, so I will not explain it ..
The Code is as follows:
<! Doctype html>
<Html>
<Head>
<Meta charset = "UTF-8">
<Title> HTML5 example </title>
<Style type = "text/css">
# Container {border: 1px solid # ccc; width: 800px; height: 600px; position: relative ;}
Canvas {position: absolute; top: 0px; left: 0px; z-index: 1 ;}
</Style>
</Head>
<Body>
<Select id = "tools">
<Option value = "pen"> pencil </option>
<Option value = "line"> straight line </option>
<Option value = "rect"> rectangle </option>
<Option value = "circle"> circle </option>
<Option value = "ellipse"> elliptic </option>
</Select>
<Div id = "container">
<Canvas id = "canvas" width = "800" height = "600"> </canvas>
<Canvas id = "canvas_temp" style = "z-index: 2;" width = "800" height = "600"> </canvas>
</Div>
<Script type = "text/javascript">
Var canvas = document. getElementById ('canvas ');
Var context = canvas. getContext ('2d ');

Var _ canvas = document. getElementById ('canvas _ temp ');
Var _ context = _ canvas. getContext ('2d ');
Var tools = document. getElementById ('tool ');

Tools. onchange = function (e ){
Tool [this. value] ();
};
Var tool = {
Pen: function (){
This. reset ();
_ Canvas. onmousedown = function (e ){
_ Context. moveTo (e. layerX, e. layerY );
_ Canvas. onmousemove = function (e ){
_ Context. lineTo (e. layerX, e. layerY );
_ Context. stroke ();
};
_ Canvas. onmouseup = function (e ){
_ Canvas. onmousemove = null;
_ Canvas. onmouseup = null;
Tool. updata ();
};
};
},
Line: function (){
This. reset ();
_ Canvas. onmousedown = function (e ){
Var _ e = e;
_ Canvas. onmousemove = function (e ){
_ Context. clearRect (0, 0, canvas. width, canvas. height );
_ Context. beginPath ();
_ Context. moveTo (_ e. layerX, _ e. layerY );
_ Context. lineTo (e. layerX, e. layerY );
_ Context. stroke ();
_ Context. closePath ();
};
_ Canvas. onmouseup = function (e ){
_ Canvas. onmousemove = null;
_ Canvas. onmouseup = null;
Tool. updata ();
};
}
},
Rect: function (){
This. reset ();
_ Canvas. onmousedown = function (e ){
Var _ e = e;
_ Context. strokeStyle = "#000 ";
_ Canvas. onmousemove = function (e ){
_ Context. clearRect (0, 0, canvas. width, canvas. height );
_ Context. strokeRect (_ e. layerX, _ e. layerY, e. layerX-_ e. layerX, e. layerY-_ e. layerY );
};
_ Canvas. onmouseup = function (e ){
_ Canvas. onmousemove = null;
_ Canvas. onmouseup = null;
Tool. updata ();
};
}
},
Circle: function (){
This. reset ();
_ Canvas. onmousedown = function (e ){
Var _ e = e;
_ Canvas. onmousemove = function (e ){
_ Context. clearRect (0, 0, canvas. width, canvas. height );
_ Context. beginPath ();
_ Context. arc (_ e. layerX, _ e. layerY, e. layerX-_ e. layerX, 0, Math. PI * 2, true );
_ Context. stroke ();
_ Context. closePath ();
};
_ Canvas. onmouseup = function (e ){
_ Canvas. onmousemove = null;
_ Canvas. onmouseup = null;
Tool. updata ();
};
}
},
Ellipse: function (){
This. reset ();
_ Canvas. onmousedown = function (e ){
Var _ e = e;
_ Canvas. onmousemove = function (e ){
Var st = 0;
_ Context. clearRect (0, 0, canvas. width, canvas. height );
_ Context. beginPath ();
_ Context. moveTo (_ e. layerX + (e. layerX-_ e. layerX) * Math. cos (st), _ e. layerY + (e. layerX-_ e. layerX) * Math. sin (st ));
St + = 1/180 * Math. PI;
For (var I = 0; I <360; I ++ ){
_ Context. lineTo (_ e. layerX + (e. layerX-_ e. layerX) * Math. cos (st), _ e. layerY + (e. layerY-_ e. layerY) * Math. sin (st ));
St + = 1/180 * Math. PI;
}
_ Context. stroke ();
_ Context. closePath ();
};
_ Canvas. onmouseup = function (e ){
_ Canvas. onmousemove = null;
_ Canvas. onmouseup = null;
Tool. updata ();
};
}
},
Reset: function (){
_ Canvas. onmousedown = null;
_ Canvas. onmouseup = null;
_ Canvas. onmousemove = null;
},
Updata: function (){
Context. drawImage (_ canvas, 0, 0 );
_ Context. clearRect (0, 0, canvas. width, canvas. height );
}
};
Tool ['pen '] ();
</Script>
</Body>
</Html>

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
html5 canvas clock html5 canvas examples html5 canvas 3d tutorial html5 canvas print html5 canvas chart tutorial html5 canvas text editor html5 canvas animation tutorial
Related Article
What is the META tag in HTML? Introduction to META Tag proper...
An article that allows you to read basic HTML rules and Web p...
How does HTML set the background color? HTML background color...
HTML5 new label--nav label Introduction
What are the canvases and SVG in HTML5? What is the differenc...
How do I use the HTML5 feature of the Rel property in the?

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

What's Trending
Top 10 Tags
datastax versions naming convention zookeeper client class definition md5 microsoft sql server 2005 data structures exception handling error handling
Top 10 Keywords
microsoft download center down wordpress address url site address url wordpress address url windows installer 4 0 download 302 not found web address url definition site address url wordpress db2 integer mac os installation step by step pdf abbreviation for return

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More