image to blob

image to blob

var util = {
	getBlobUrl:function(img){
		if(!this.canvas){
			this.canvas = document.createElement("canvas");
			this.ctx = this.canvas.getContext("2d");
		}
		this.canvas.width = img.width;
		this.canvas.height = img.height;
		this.ctx.drawImage(img, 0, 0);
		
		var base64 = this.canvas.toDataURL();
		base64 = base64.split(',');
		var binary = atob(base64[1]);
		var len = binary.length;
		var buffer = new ArrayBuffer(len);
		var view = new Uint8Array(buffer);
		for (var i = 0; i < len; i++) {
			view[i] = binary.charCodeAt(i);
		}
		var blob = new Blob([view], { 
			type: base64[0].split(':')[1].split(';')[0] 
		});
		return URL.createObjectURL(blob);
	}
};