I'm trying to display a PDF within an iFrame, for a PHP, HTML and CSS based web "app" on the iPad. However, when viewing a PDF that's either in an object or in an iFrame, on the iPad, you can't change the page you are viewing. The scrolling just doesn't seem to work.
So my thought is that I need to create a next and prev button that uses javascript to change the currently viewed page. However, I can't seem to find any information on how to achieve this without embedding code in the PDF. This is not an option for the app though, as users will obviously not know how to embed code in the PDF's they upload.
I'd really love any information on how to achieve this solution w/o modifying the PDF's. Also, if there is an alternative to using an object or iFrame that will make this work on the iPad, that would be great too.
Thanks in advance.
This can be done using PDF.js
Their webpage can be found here: http://mozilla.github.io/pdf.js/
I didn't want to use their solution at first, because I heard it will have issues rendering some PDF's. However, so far, it appears to render our PDFs perfectly.
Here is some code I used to implement the process
PDFJS.getDocument('FILE_LOCATION').then(function(pdf) {
state = true;
cur_page = 1;
total_pages = pdf.numPages;
pdf.getPage(cur_page).then(function(page) {
var scale = 1.5;
var viewport = page.getViewport(scale);
// Prepare canvas using PDF page dimensions
var canvas = document.getElementById('the-canvas');
var context = canvas.getContext('2d');
canvas.height = viewport.height;
canvas.width = viewport.width;
// Render PDF page into canvas context
var renderContext = {
canvasContext: context,
viewport: viewport
};
page.render(renderContext);
});
$(".pdf_viewer").on("click", ".prev_page", function(e) {
e.preventDefault();
if( state && cur_page > 1 ) {
--cur_page
pdf.getPage(cur_page).then(function(page) {
var scale = 1.5;
var viewport = page.getViewport(scale);
// Prepare canvas using PDF page dimensions
var canvas = document.getElementById('the-canvas');
var context = canvas.getContext('2d');
canvas.height = viewport.height;
canvas.width = viewport.width;
// Render PDF page into canvas context
var renderContext = {
canvasContext: context,
viewport: viewport
};
page.render(renderContext);
});
}
});
$(".pdf_viewer").on("click", ".next_page", function(e) {
e.preventDefault();
if( state && cur_page < total_pages ) {
++cur_page;
pdf.getPage(cur_page).then(function(page) {
var scale = 1.5;
var viewport = page.getViewport(scale);
// Prepare canvas using PDF page dimensions
var canvas = document.getElementById('the-canvas');
var context = canvas.getContext('2d');
canvas.height = viewport.height;
canvas.width = viewport.width;
// Render PDF page into canvas context
var renderContext = {
canvasContext: context,
viewport: viewport
};
page.render(renderContext);
});
}
});
$(".pdf_viewer").on("click", ".close_window", function(e) {
e.preventDefault();
if( state ) {
state = false;
pdf.destroy();
}
});
EDIT: fixed a typo
Related
I'm trying to pan-zoom with the mouse a <div> that contains a PDF document.
I'm using PDF.js and panzoom libraries (but other working alternatives are welcome)
The snippet below basically does this task, but unfortunately, after the <div> is panzoomed, the PDF is not re-rendered, then its image gets blurry (pan the PDF with the mouse and zoom it with the mouse-wheel):
HTML
<script src="https://mozilla.github.io/pdf.js/build/pdf.js"></script>
<script src="https://cdn.jsdelivr.net/npm/#panzoom/panzoom#4.3.2/dist/panzoom.min.js"></script>
<div id="panzoom-container">
<canvas id="the-canvas"></canvas>
</div>
<style>
#the-canvas {
border: 1px solid black;
direction: ltr;
}
</style>
JAVASCRIPT
// 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 = 'https://mozilla.github.io/pdf.js/build/pdf.worker.js';
var pdfDoc = null,
canvas = document.getElementById('the-canvas'),
ctx = canvas.getContext('2d');
var container = document.getElementById("panzoom-container")
function renderPage(desiredHeight) {
pdfDoc.getPage(1).then(function(page) {
var viewport = page.getViewport({ scale: 1, });
var scale = desiredHeight / viewport.height;
var scaledViewport = page.getViewport({ scale: scale, });
canvas.height = scaledViewport.height;
canvas.width = scaledViewport.width;
// Render PDF page into canvas context
var renderContext = {
canvasContext: ctx,
viewport: scaledViewport
};
page.render(renderContext);
});
}
// Get the PDF
var url = 'https://raw.githubusercontent.com/mozilla/pdf.js/ba2edeae/web/compressed.tracemonkey-pldi-09.pdf';
pdfjsLib.getDocument(url).promise.then(function(pdfDoc_) {
pdfDoc = pdfDoc_;
// Initial/first page rendering
renderPage(250);
});
var panzoom = Panzoom(container, {
setTransform: (container, { scale, x, y }) => {
// here I can re-render the page, but I don't know how
// renderPage(container.getBoundingClientRect().height);
panzoom.setStyle('transform', `scale(${scale}) translate(${x}px, ${y}px)`)
}
})
container.addEventListener('wheel', zoomWithWheel)
function zoomWithWheel(event) {
panzoom.zoomWithWheel(event)
}
https://jsfiddle.net/9rkh7o0e/5/
I think that the procedure is correct, but unfortunately I'm stuck into two issues that must be fixed (then I ask for your help):
I don't know how to re-render correctly the PDF after the panzoom happened.
consecutive renderings have to be queued in order to make this work properly (so that the PDF doesn't blink when panzooming)
How could I fix 1 and 2 ? I could not find any tool for doing that on a PDF, apart the panzoom lib.
Thanks
After some days of attempts, I solved the problem.
The tricky part was to scale down the contained canvas after the container has been scaled, with a transform-origin CSS attribute set:
canvas.style.transform = "scale("+1/panzoom.getScale()+")"
Here is a fiddle of a PDF that can pan-zoomed. Each new render is done after a small delay (here it is set to 250ms) which corresponds to a sort of "wheel stop event".
function zoomWithWheel(event) {
panzoom.zoomWithWheel(event)
clearTimeout(wheelTimeoutHandler);
wheelTimeoutHandler = setTimeout(function() {
canvas.style.transform = "scale("+1/panzoom.getScale()+")"
if (pdfDoc)
renderPage(panzoom.getScale());
}, wheelTimeout)
}
https://jsfiddle.net/7tmk0z42/
I'm implementing some code to to view a PDF file after selecting it from our computer, but I am getting some errors
I have tried with 'pdf.js' but I'm getting some error that 'PDFJS' or 'pdfjsLib' is not defined
function showInCanvas(url) {
'use strict';
var pdfAsArray = convertDataURIToBinary(url);
pdfjsLib.getDocument(pdfAsArray).then(function (pdf) {
pdf.getPage(1).then(function (page) {
var scale = 1.5;
var viewport = page.getViewport(scale);
var canvas = document.getElementById('the-canvas');
var context = canvas.getContext('2d');
canvas.height = viewport.height;
canvas.width = viewport.width;
var renderContext = {
canvasContext: context,
viewport: viewport
};
page.render(renderContext);
});
});
}
The error message that I get is:
Uncaught ReferenceError: pdfjsLib is not defined
Why are you depend on external library to preview pdf file even you could do it using iframe object.you just need to read file from file control and assign file object to iframe.
var file =document.getElementById("filecontrol").files[0];
var url =URL.createObjectURL(file );
$('#iframeid').attr('src',url);
HTML :
<iframe id="iframeid" width="x" height="y"></iframe>
I've managed to display a sample PDF file using mozilla's pdf.js. On the 1st page of the PDF file there is one internal link to page 2 and one external link to google.com.
My next step is getting the links in the sample PDF to work (be clickable) and I'm struggling with this one.
At the moment all I can do is get the links/annotations and print them to the console. Can anyone help me render these links to the annotations div layer?
I've looked through the pdf.js docs but I can't quite find what I'm looking for... I'm just looking to add this clickable links feature to the simple code below.
Here is a code pen of my progress so far: http://codepen.io/laurencemeah/pen/ONrJXj
var pdfFile = 'URL PATH TO PDF FILE';
var pageNum = 1;
PDFJS.getDocument(pdfFile).then(function(pdf) {
pdf.getPage(pageNum).then(function(page) {
var desiredWidth = document.getElementById('pdf-holder').getBoundingClientRect().width;
var viewport = page.getViewport(1);
var scale = desiredWidth / viewport.width;
var scaledViewport = page.getViewport(scale);
var canvas = document.getElementById('pdf-canvas');
var context = canvas.getContext('2d');
canvas.height = scaledViewport.height;
canvas.width = scaledViewport.width;
var renderContext = {
canvasContext: context,
viewport: scaledViewport
};
page.render(renderContext);
page.getAnnotations().then(function(data) {
console.log(data);
// now display them in annotation layer div
});
});
});
#pdf-holder {
width: 100%;
height: auto;
<script src="http://mozilla.github.io/pdf.js/build/pdf.js"></script>
<div id="pdf-holder">
<canvas id="pdf-canvas"></canvas>
<div id="annotation-layer"></div>
</div>
I am making a chrome extension that uses the chrome.tabs.captureVisibleTab method to grab a screencap of the current tab and then displays that in a popup from the chrome extension. If I use the img tag and use the data coming from the chrome function, such as data:image/jpeg;base64,/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAMCAgMCAgMDAwMEAwME…UUUAFFFFABRRRQAUUUUAFFFFABRRRQAUUUUAFFFFABRRRQAUUUUAFFFFABRRRQAUUUUAf/2Q==, the <img> displays pixel perfect, it is crisp and that's what I want. Problem is that I need to make it into a canvas, and when I do that, it becomes blurry.
This is a screencap of the <img> that uses the link data provided by Google to be used as a comparison to the canvas which is below.
This is the blurry canvas.
This is the code that I am using to try to do this, but I can't figure out how to make the canvas crisp like the image.
chrome.runtime.sendMessage({msg: "capture"}, function(response) {
console.log(response.imgSrc);
var img = document.createElement('img');
var _canvas = document.createElement("canvas");
img.src = response.imgSrc;
img.height = 436;
img.width = 800;
document.getElementById('main-canvas').appendChild(img);
draw(response);
});
function draw(response) {
var canvas = document.getElementById('imageCanvas');
canvas.height = window.innerHeight;
canvas.width = window.innerWidth;
//Get a 2d context
var ctx = canvas.getContext('2d');
//use image to paint canvas
var _image = new Image();
_image.onload = function() {
ctx.drawImage(_image, 0, 0, 800, 436);
}
_image.src = response.imgSrc;
document.getElementById('main-canvas').appendChild(canvas);
}
This is what I used to fix my problem: High Resolution Canvas from HTML5Rocks
I'm currently writing a simple Android App due to testing purpose. In it there's a WebView-Element in which a html-File (with javascript (Mozilla PDFJS)) from asset folder should be displayed. From Fragment-Code:
webView.getSettings().setJavaScriptEnabled(true);
webView.getSettings().setDomStorageEnabled(true);
webView.getSettings().setAllowFileAccess(true);
webView.getSettings().setAllowUniversalAccessFromFileURLs(true);
webView.loadDataWithBaseURL("file:///android_asset/", content, "text/html", "utf-8", null);
with content already containing the folowing html:
<script type="text/javascript">
var mypdf = null;
var currentPage = 1;
PDFJS.workerSrc = 'file:///android_asset/pdf.worker.jas';
PDFJS.getDocument('file:///android_asset/pdf.pdf').then(function(pdf) {
mypdf = pdf;
renderPage(currentPage);
});
function renderPage(pageNumber) {
mypdf.getPage(pageNumber).then(function(page) {
var scale = 1;
var viewport = page.getViewport(scale);
var canvas = document.getElementById('viewer');
var context = canvas.getContext('2d');
canvas.height = viewport.height-40;
canvas.width = viewport.width;
var renderContext = {
canvasContext: context,
viewport: viewport
};
page.render(renderContext);
});
}
</script>
....
<body>
<h1>Header</h1>
<canvas id="viewer"></canvas>
</body>
In logcat I receive the following chromium console output and due to that rendering of the requestet pdf-page does not happen (still, the header is displayed normally)
I/chromium﹕ [INFO:CONSOLE(22)] "Uncaught (in promise) TypeError: Cannot read property 'getContext' of null", source: file:///android_asset/ (22)
Line 22 refering to
var context = canvas.getContext('2d');
When I load the exact same file from a remote server (replacing the file:///-links) via webView.loadUrl("http://www.dennissch.de/pdftest/"); everything works fine.
So how come that document.getElementById seems not to work on the local file?
That might be due to the fact that your script tag is declared above the canvas. try to put your tag below the viewer, and it should work
<body>
<h1>Header</h1>
<canvas id="viewer"></canvas>
<script type="text/javascript">
var mypdf = null;
var currentPage = 1;
PDFJS.workerSrc = 'file:///android_asset/pdf.worker.jas';
PDFJS.getDocument('file:///android_asset/pdf.pdf').then(function(pdf) {
mypdf = pdf;
renderPage(currentPage);
});
function renderPage(pageNumber) {
mypdf.getPage(pageNumber).then(function(page) {
var scale = 1;
var viewport = page.getViewport(scale);
var canvas = document.getElementById('viewer');
var context = canvas.getContext('2d');
canvas.height = viewport.height-40;
canvas.width = viewport.width;
var renderContext = {
canvasContext: context,
viewport: viewport
};
page.render(renderContext);
});
}
</script>
</body>
Or at least put the call to renderPage below the viewer in an other script tag