xiuli.gao
/
newMedia


			
				
					
						
						
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							<html>
<head>
    <title>pdf.js展示1，上一页，下一页</title>
</head>
<h1>PDF.js Previous/Next example</h1>

<div>
    <button id="prev">Previous</button>
    <button id="next">Next</button>
    &nbsp; &nbsp;
    <span>Page: <span id="page_num"></span> / <span id="page_count"></span></span>
</div>

<canvas id="the-canvas"></canvas>
<script src="./pdf.js"></script>
<script src="./pdf.worker.js"></script>
<script>
    var url = 'http://new-media-ca.oss-cn-beijing.aliyuncs.com/upload/ca_signs/2020-09-04/kx-5f52369304d06.pdf';

    var pdfDoc = null,
        pageNum = 1,
        pageRendering = false,
        pageNumPending = null,
        scale = 0.8,
        canvas = document.getElementById('the-canvas'),
        ctx = canvas.getContext('2d');

    /**
     * Get page info from document, resize canvas accordingly, and render page.
     * @param num Page number.
     */
    function renderPage(num) {
        pageRendering = true;
        // Using promise to fetch the page
        pdfDoc.getPage(num).then(function(page) {
            var viewport = page.getViewport(scale);
            canvas.height = viewport.height;
            canvas.width = viewport.width;

            // Render PDF page into canvas context
            var renderContext = {
                canvasContext: ctx,
                viewport: viewport
            };
            var renderTask = page.render(renderContext);

            // Wait for rendering to finish
            renderTask.promise.then(function() {
                pageRendering = false;
                if (pageNumPending !== null) {
                    // New page rendering is pending
                    renderPage(pageNumPending);
                    pageNumPending = null;
                }
            });
        });

        // Update page counters
        document.getElementById('page_num').textContent = num;
    }

    /**
     * If another page rendering in progress, waits until the rendering is
     * finised. Otherwise, executes rendering immediately.
     */
    function queueRenderPage(num) {
        if (pageRendering) {
            pageNumPending = num;
        } else {
            renderPage(num);
        }
    }

    /**
     * Displays previous page.
     */
    function onPrevPage() {
        if (pageNum <= 1) {
            return;
        }
        pageNum--;
        queueRenderPage(pageNum);
    }
    document.getElementById('prev').addEventListener('click', onPrevPage);

    /**
     * Displays next page.
     */
    function onNextPage() {
        if (pageNum >= pdfDoc.numPages) {
            return;
        }
        pageNum++;
        queueRenderPage(pageNum);
    }
    document.getElementById('next').addEventListener('click', onNextPage);

    /**
     * Asynchronously downloads PDF.
     */
    const CMAP_URL = 'https://unpkg.com/pdfjs-dist@2.0.489/cmaps/';
    pdfjsLib.GlobalWorkerOptions.workerSrc ='./pdf.worker.js';//自己的路径
    var loadingTask = pdfjsLib.getDocument({
        data: url,
        cMapUrl: CMAP_URL,
        cMapPacked: true,
    }); 
    loadingTask.promise.then(function(pdfDoc_) {
        pdfDoc = pdfDoc_;
        document.getElementById('page_count').textContent = pdfDoc.numPages;
        // Initial/first page rendering
        renderPage(pageNum);
    });
//     const loadingTask = pdfjsLib.getDocument(/* data here */);
//   loadingTask.promise.then(pdfDocument => {
//     // The document is loaded here...
//   });

</script>
</html>