HTML5 canvas 绘图 drawImage

• context.drawImage(img,x,y);

• context.drawImage(img,x,y,width,height);

• context.drawImage(img,sx,sy,swidth,sheight,x,y,width,height);

var c=document.getElementById("myCanvas");
var ctx=c.getContext("2d");
var img=document.getElementById("tulip");
ctx.drawImage(img,10,10);

var v=document.getElementById("video1");
var c=document.getElementById("myCanvas");
ctx=c.getContext('2d');
v.addEventListener('play',function() {
　　var i=window.setInterval(function(){
　　　　ctx.drawImage(v,0,0,270,135)
　　}, 20);
}, false);

v.addEventListener('pause',function(){
　　window.clearInterval(i);
}, false);
v.addEventListener('ended',function(){
　　clearInterval(i);
}, false);


http://www.w3school.com.cn/tags/canvas_drawimage.asp