5b3d3c7dd9
Note that the textContent is returned in "chunks" from the API, through the use of `ReadableStream`s, and on the main-thread we're (normally) using just one temporary canvas in order to measure the size of the textLayer `span`s; see the [`#layout`](5b4c2fe1a8/src/display/text_layer.js (L396-L428)) method. *Order of events, for parallel textLayer rendering:* 1. Call [`render`](5b4c2fe1a8/src/display/text_layer.js (L155-L177)) of the textLayer for page A. 2. Immediately call `render` of the textLayer for page B. 3. The first text-chunk for pageA arrives, and it's parsed/layout which means updating the cached [fontSize/fontFamily](5b4c2fe1a8/src/display/text_layer.js (L409-L413)) for the textLayer of page A. 4. The first text-chunk for pageB arrives, which means updating the cached fontSize/fontFamily *for the textLayer of page B* since this data is unique to each `TextLayer`-instance. 5. The second text-chunk for pageA arrives, and we don't update the canvas-font since the cached fontSize/fontFamily still apply from step 3 above. Where this potentially breaks down is between the last steps, since we're using just one temporary canvas for all measurements but have *individual* fontSize/fontFamily caches for each textLayer. Hence it's possible that the canvas-font has actually changed, despite the cached values suggesting otherwise, and to address this we instead cache the fontSize/fontFamily globally through a new (static) helper method. *Note:* Includes a basic unit-test, using dummy text-content, which fails on `master` and passes with this patch. Finally, pun intended, ensure that temporary textLayer-data is cleared *before* the `render`-promise resolves to avoid any intermittent problems in the unit-tests.
PDF.js 
PDF.js is a Portable Document Format (PDF) viewer that is built with HTML5.
PDF.js is community-driven and supported by Mozilla. Our goal is to create a general-purpose, web standards-based platform for parsing and rendering PDFs.
Contributing
PDF.js is an open source project and always looking for more contributors. To get involved, visit:
- Issue Reporting Guide
- Code Contribution Guide
- Frequently Asked Questions
- Good Beginner Bugs
- Projects
Feel free to stop by our Matrix room for questions or guidance.
Getting Started
Online demo
Please note that the "Modern browsers" version assumes native support for the latest JavaScript features; please also see this wiki page.
-
Modern browsers: https://mozilla.github.io/pdf.js/web/viewer.html
-
Older browsers: https://mozilla.github.io/pdf.js/legacy/web/viewer.html
Browser Extensions
Firefox
PDF.js is built into version 19+ of Firefox.
Chrome
- The official extension for Chrome can be installed from the Chrome Web Store. This extension is maintained by @Rob--W.
- Build Your Own - Get the code as explained below and issue
npx gulp chromium. Then open Chrome, go toTools > Extensionand load the (unpackaged) extension from the directorybuild/chromium.
Getting the Code
To get a local copy of the current code, clone it using git:
$ git clone https://github.com/mozilla/pdf.js.git
$ cd pdf.js
Next, install Node.js via the official package or via nvm. If everything worked out, install all dependencies for PDF.js:
$ npm install
Note
On MacOS M1/M2 you may see some
node-gyp-related errors when runningnpm install. This is because one of our dependencies,"canvas", does not provide pre-built binaries for this platform and insteadnpmwill try to build it from source. Please make sure to first install the necessary native dependencies usingbrew: https://github.com/Automattic/node-canvas#compiling.
Finally, you need to start a local web server as some browsers do not allow opening
PDF files using a file:// URL. Run:
$ npx gulp server
and then you can open:
Please keep in mind that this assumes the latest version of Mozilla Firefox; refer to Building PDF.js for non-development usage of the PDF.js library.
It is also possible to view all test PDF files on the right side by opening:
Building PDF.js
In order to bundle all src/ files into two production scripts and build the generic
viewer, run:
$ npx gulp generic
If you need to support older browsers, run:
$ npx gulp generic-legacy
This will generate pdf.js and pdf.worker.js in the build/generic/build/ directory (respectively build/generic-legacy/build/).
Both scripts are needed but only pdf.js needs to be included since pdf.worker.js will
be loaded by pdf.js. The PDF.js files are large and should be minified for production.
Using PDF.js in a web application
To use PDF.js in a web application you can choose to use a pre-built version of the library
or to build it from source. We supply pre-built versions for usage with NPM and Bower under
the pdfjs-dist name. For more information and examples please refer to the
wiki page on this subject.
Including via a CDN
PDF.js is hosted on several free CDNs:
- https://www.jsdelivr.com/package/npm/pdfjs-dist
- https://cdnjs.com/libraries/pdf.js
- https://unpkg.com/pdfjs-dist/
Learning
You can play with the PDF.js API directly from your browser using the live demos below:
More examples can be found in the examples folder. Some of them are using the pdfjs-dist package, which can be built and installed in this repo directory via npx gulp dist-install command.
For an introduction to the PDF.js code, check out the presentation by our contributor Julian Viereck:
More learning resources can be found at:
The API documentation can be found at:
Questions
Check out our FAQs and get answers to common questions:
Talk to us on Matrix:
File an issue: