MakePhoto = function (id) {
    this.id = id;
    var video_element = $("#" + this.id)[0];
    var My = this;
    
        if (navigator.getUserMedia) { // opera应使用opera.getUserMedianow
            navigator.getUserMedia({ video: true }, function (stream) {
                if (window.URL) {
                    video.src = window.URL.createObjectURL(stream);
                } else {
                    video.src = stream;
                }
                video.play();
            }, errocb);
        } else if (navigator.webkitGetUserMedia) {
            navigator.webkitGetUserMedia({ video: true }, function (stream) {
                if (window.URL) {
                    video.src = window.URL.createObjectURL(stream);
                } else {
                    video.src = stream;
                }
                video.play();
            }, errocb);
        } else {
            alert("没有摄像头或不支持");
        }
        function success(stream) {
            video_element.src = stream;
            video_element.play();
        }
        function errocb() {
           
        }
       
        this.PhotoGraph = function (width, height, quality) {
            //生成比例
            var w = width,
                h = height,
                scale = w / h;
            if (width > 0) {
                w = width || w;
                h = w / scale;
            }
            var canvas = document.createElement("canvas"); //动态创建画布对象
            canvas.width = w;
            canvas.height = h;
            var ctx = canvas.getContext("2d");
            ctx.drawImage(video, 0, 0, w, h);
            var base64 = null;
            if (navigator.userAgent.match(/iphone/i)) {
                //修复IOS
                var mpImg = new MegaPixImage(img);
                mpImg.render(canvas, {
                    maxWidth: w,
                    maxHeight: h,
                    quality: quality || 0.8
                });
                base64 = canvas.toDataURL('image/jpeg', quality || 0.8);
            } else if (navigator.userAgent.match(/Android/i)) {
                //修复android
                var encoder = new JPEGEncoder();
                base64 = encoder.encode(ctx.getImageData(0, 0, w, h), quality * 100 || 80);
            } else {
                //其他浏览器
                base64 = canvas.toDataURL('image/jpeg', quality || 0.8);
            }
            // 生成结果
            var result = {
                base64: base64,
                clearBase64: base64.substr(base64.indexOf(',') + 1),
            };
            return result;
        }

 }