From 7adab6e80ed0a641f30634ef735bfcc10aa1685d Mon Sep 17 00:00:00 2001
From: Christian Grothoff <christian@grothoff.org>
Date: Wed, 16 Jan 2019 13:08:01 +0100
Subject: fix link for tech.pdf

---
 dist/js/pdf-view-tech.js | 108 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 dist/js/pdf-view-tech.js

(limited to 'dist')

diff --git a/dist/js/pdf-view-tech.js b/dist/js/pdf-view-tech.js
new file mode 100644
index 00000000..9565ed8c
--- /dev/null
+++ b/dist/js/pdf-view-tech.js
@@ -0,0 +1,108 @@
+/** This code is under the Apache License Version 2.0, January 2004
+ * http://www.apache.org/licenses/, as it is heavily based on
+ * documentation of pdf.js (which is under Apache License v2.0)
+ */
+
+PDFJS.workerSrc = '/dist/js/pdf.worker.min.js';
+
+var url = '/presentations/tech.pdf';
+
+var pdfDoc = null,
+    pageNum = 1,
+    pageRendering = false,
+    pageNumPending = null,
+    scale = 1,
+    canvasLeft = document.getElementById('the-canvas-left'),
+    canvasRight = document.getElementById('the-canvas-right');
+
+/**
+ * Get page info from document, resize canvas accordingly, and render page.
+ * @param num Page number.
+ */
+function renderPage(canvas,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: canvas.getContext('2d'),
+        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;
+      }
+    });
+  });
+}
+
+/**
+ * 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(canvasLeft,num);
+    renderPage(canvasRight,num+1);
+  }
+}
+
+/**
+ * Displays previous page.
+ */
+function onPrevPage(event) {
+  event.preventDefault();
+  if (pageNum <= 1) {
+    return;
+  }
+  pageNum--;
+  queueRenderPage(pageNum);
+}
+document.getElementById('canvas-left').addEventListener('click', onPrevPage);
+
+/**
+ * Displays next page.
+ */
+function onNextPage(event) {
+  event.preventDefault();
+  if (pageNum >= pdfDoc.numPages - 1) {
+    return;
+  }
+  pageNum++;
+  queueRenderPage(pageNum);
+}
+document.getElementById('canvas-right').addEventListener('click', onNextPage);
+
+document.getElementById('canvas-left').style.display = 'block';
+document.getElementById('canvas-right').style.display = 'block';
+
+
+function onMouseDown(event) {
+  event.preventDefault();
+}
+
+document.getElementById('canvas-left').addEventListener('mousedown', onMouseDown);
+document.getElementById('canvas-right').addEventListener('mousedown', onMouseDown);
+
+/**
+ * Asynchronously downloads PDF.
+ */
+PDFJS.getDocument(url).then(function(pdfDoc_) {
+  pdfDoc = pdfDoc_;
+
+  // Initial/first page rendering
+  renderPage(canvasLeft,pageNum);
+  renderPage(canvasRight,pageNum + 1);
+});
-- 
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