如何使用pdf.js和jquery mobile

Question

我的应用程序具有显示pdf收据的功能。收据是动态生成的。我为此目的使用了pdf.js插件。

我要求为pdf页面设置缩放。这里是生成没有缩放因子的pdf文件的工作代码。但是设置缩放系数很困难。

pdfData: function() {

        $("#pdfContainer").empty();
        scale = 3.5; //Set this to whatever you want. This is basically the "zoom" factor for the PDF.
        var pdfBase64 = pdfBase64Res;
        currentPage = 1;
        pages = [];

        // Converts a base64 string into a Uint8Array

        function base64ToUint8Array(base64) {

            var base64New = base64.replace(/\s/g, '');
            var raw = atob(base64New); //This is a native function that decodes a base64-encoded string.
            var uint8Array = new Uint8Array(new ArrayBuffer(raw.length));
            for (var i = 0; i < raw.length; i++) {
                uint8Array[i] = raw.charCodeAt(i);
            }
            return uint8Array;
        }

        function loadPdf(pdfData) {
            PDFJS.disableWorker = true; //Not using web workers. Not disabling results in an error. This line is
            //missing in the example code for rendering a pdf.
            var pdf = PDFJS.getDocument(pdfData);
            pdf.then(renderPdf);
        }



        function renderPdf(pdf) {
            alert("total page numbers :" + pdf.numPages);
            totalPages = pdf.numPages;
            pdf.getPage(currentPage).then(renderPage);


            function renderPage(page) {
                pagesNew = page;
                height = 768;
                viewport = page.getViewport(1);
                scale = height / viewport.height;
                scaledViewport = page.getViewport(scale);

                canvas = document.createElement('canvas');
                //  canvas = document.createElement("<canvas>");
                context = canvas.getContext('2d');
                canvas.height = scaledViewport.height;
                canvas.width = scaledViewport.width;
                // element=document.getElementById("pdfContainer");

                renderContext = {
                    canvasContext: context,
                    viewport: scaledViewport
                };

                pagesNew.render(renderContext).then(function() {
                    if (totalPages == 1) {

                        jQuery("#pdfContainer").append(canvas);

                    } else if (currentPage <= pdf.numPages) {
                        //alert('Current page'+currentPage);
                        pdf.getPage(currentPage).then(renderPage);
                        pages[currentPage] = canvas;
                        console.log(pages[currentPage]);

                        ++currentPage;


                        // alert("before for loop");
                    } else {
                        //alert('in else');

                        //alert("alert(pages.length);"+pages.length);
                        for (var i = 1; i < pages.length; i++) {
                            //alert(i);
                            var element = document.getElementById("pdfContainer");
                            element.appendChild(pages[i]);
                            console.log(element.appendChild(pages[i]));
                        }
                    }
                });

            }
        }
        var pdfData = base64ToUint8Array(pdfBase64);
        loadPdf(pdfData);