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Diffstat (limited to 'dist/js/pdf-view.js')
-rw-r--r-- | dist/js/pdf-view.js | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/dist/js/pdf-view.js b/dist/js/pdf-view.js new file mode 100644 index 00000000..74e668f3 --- /dev/null +++ b/dist/js/pdf-view.js | |||
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1 | /** This code is under the Apache License Version 2.0, January 2004 | ||
2 | * http://www.apache.org/licenses/, as it is heavily based on | ||
3 | * documentation of pdf.js (which is under Apache License v2.0) | ||
4 | */ | ||
5 | |||
6 | PDFJS.workerSrc = 'dist/js/pdf.worker.min.js'; | ||
7 | |||
8 | var url = 'presentations/investors2017.pdf'; | ||
9 | |||
10 | var pdfDoc = null, | ||
11 | pageNum = 1, | ||
12 | pageRendering = false, | ||
13 | pageNumPending = null, | ||
14 | scale = 1, | ||
15 | canvasLeft = document.getElementById('the-canvas-left'), | ||
16 | canvasRight = document.getElementById('the-canvas-right'); | ||
17 | |||
18 | /** | ||
19 | * Get page info from document, resize canvas accordingly, and render page. | ||
20 | * @param num Page number. | ||
21 | */ | ||
22 | function renderPage(canvas,num) { | ||
23 | pageRendering = true; | ||
24 | // Using promise to fetch the page | ||
25 | pdfDoc.getPage(num).then(function(page) { | ||
26 | var viewport = page.getViewport(scale); | ||
27 | canvas.height = viewport.height; | ||
28 | canvas.width = viewport.width; | ||
29 | |||
30 | // Render PDF page into canvas context | ||
31 | var renderContext = { | ||
32 | canvasContext: canvas.getContext('2d'), | ||
33 | viewport: viewport | ||
34 | }; | ||
35 | var renderTask = page.render(renderContext); | ||
36 | |||
37 | // Wait for rendering to finish | ||
38 | renderTask.promise.then(function() { | ||
39 | pageRendering = false; | ||
40 | if (pageNumPending !== null) { | ||
41 | // New page rendering is pending | ||
42 | renderPage(pageNumPending); | ||
43 | pageNumPending = null; | ||
44 | } | ||
45 | }); | ||
46 | }); | ||
47 | |||
48 | // Update page counters | ||
49 | document.getElementById('page_num').textContent = pageNum; | ||
50 | } | ||
51 | |||
52 | /** | ||
53 | * If another page rendering in progress, waits until the rendering is | ||
54 | * finised. Otherwise, executes rendering immediately. | ||
55 | */ | ||
56 | function queueRenderPage(num) { | ||
57 | if (pageRendering) { | ||
58 | pageNumPending = num; | ||
59 | } else { | ||
60 | renderPage(canvasLeft,num); | ||
61 | renderPage(canvasRight,num+1); | ||
62 | } | ||
63 | } | ||
64 | |||
65 | /** | ||
66 | * Displays previous page. | ||
67 | */ | ||
68 | function onPrevPage() { | ||
69 | if (pageNum <= 1) { | ||
70 | return; | ||
71 | } | ||
72 | pageNum--; | ||
73 | queueRenderPage(pageNum); | ||
74 | } | ||
75 | document.getElementById('canvas-left').addEventListener('click', onPrevPage); | ||
76 | |||
77 | /** | ||
78 | * Displays next page. | ||
79 | */ | ||
80 | function onNextPage() { | ||
81 | if (pageNum >= pdfDoc.numPages - 1) { | ||
82 | return; | ||
83 | } | ||
84 | pageNum++; | ||
85 | queueRenderPage(pageNum); | ||
86 | } | ||
87 | document.getElementById('canvas-right').addEventListener('click', onNextPage); | ||
88 | |||
89 | document.getElementById('canvas-right').style.display = 'block'; | ||
90 | document.getElementById('canvas-left').style.display = 'block'; | ||
91 | |||
92 | /** | ||
93 | * Asynchronously downloads PDF. | ||
94 | */ | ||
95 | PDFJS.getDocument(url).then(function(pdfDoc_) { | ||
96 | pdfDoc = pdfDoc_; | ||
97 | |||
98 | // Initial/first page rendering | ||
99 | renderPage(pageNum); | ||
100 | }); | ||