canvas替换image插件

/** jQuery.imgToCanvas v0.1* Replace a image by a canvas.* ** Usage:* $('#myImage').imgToCanvas(); var $canvas=document.getElementById("myImage"); var $ctx=$canvas.getContext("2d");* Author:* Jiaqi Zhu*/(function( $ ){var methods = {init : function( options ) {return this.each(function(){var $this = $(this),data = $this.data('imgToCanvas');if ( !data ) {var width = $this.width(),height = $this.height(),pos = $this.offset(),$canvas = $("<canvas/>"),canvas = $canvas.get(0),ctx = canvas.getContext("2d");// replace target with canvas$this.after( $canvas );canvas.id = this.id;canvas.className = this.className;canvas.width = width;canvas.height = height;ctx.drawImage( this, 0, 0, width, height );$this.remove();}});},};$.fn.imgToCanvas = function( method ) {if ( methods[method] ) {return methods[method].apply( this, Array.prototype.slice.call( arguments, 1 ));} else if ( typeof method === 'object' || ! method ) {return methods.init.apply( this, arguments );} else {$.error( 'Method ' +  method + ' does not yet exist on jQuery.imgToCanvas' );}};})( jQuery );