rugo · November 4, 2022 21:12
diff --git a/RenderPDF.html b/RenderPDF.html
 <!DOCTYPE html>
 <html lang="en">
 <head>
  <meta charset="utf-8">
  <title></title>
  <style lang="css">
      #the-canvas {
  border: 1px solid black;
  direction: ltr;
 }
  </style>
 </head>
 <body>

  
    <script src="//mozilla.github.io/pdf.js/build/pdf.js"></script>

    <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>
        // If absolute URL from the remote server is provided, configure the CORS
 // header on that server.
 var url = './cry.pdf';

 // Loaded via <script> tag, create shortcut to access PDF.js exports.
 var pdfjsLib = window['pdfjs-dist/build/pdf'];

 // The workerSrc property shall be specified.
 pdfjsLib.GlobalWorkerOptions.workerSrc = '//mozilla.github.io/pdf.js/build/pdf.worker.js';

 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: 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.
 */
 pdfjsLib.getDocument(url).promise.then(function(pdfDoc_) {
  pdfDoc = pdfDoc_;
  document.getElementById('page_count').textContent = pdfDoc.numPages;

  // Initial/first page rendering
  renderPage(pageNum);
 });

    </script>

 </body>
 </html>
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="utf-8">
	<title></title>
	<style lang="css">
	#the-canvas {
	border: 1px solid black;
	direction: ltr;
	}
	</style>
	</head>
	<body>


	<script src="//mozilla.github.io/pdf.js/build/pdf.js"></script>

	<h1>PDF.js Previous/Next example</h1>

	<div>
	<button id="prev">Previous</button>
	<button id="next">Next</button>

	<span>Page: <span id="page_num"></span> / <span id="page_count"></span></span>
	</div>

	<canvas id="the-canvas"></canvas>

	<script>
	// If absolute URL from the remote server is provided, configure the CORS
	// header on that server.
	var url = './cry.pdf';

	// Loaded via <script> tag, create shortcut to access PDF.js exports.
	var pdfjsLib = window['pdfjs-dist/build/pdf'];

	// The workerSrc property shall be specified.
	pdfjsLib.GlobalWorkerOptions.workerSrc = '//mozilla.github.io/pdf.js/build/pdf.worker.js';

	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: 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.
	*/
	pdfjsLib.getDocument(url).promise.then(function(pdfDoc_) {
	pdfDoc = pdfDoc_;
	document.getElementById('page_count').textContent = pdfDoc.numPages;

	// Initial/first page rendering
	renderPage(pageNum);
	});

	</script>

	</body>
	</html>