Over two years ago, TSG developed OpenAnnotate “view only” mode optimized for high speed viewing. This year we have made even more updates to continue to improve viewing performance. This post will compare and offer a video showing off different PDF viewing options.
The Comparison Candidates
For our viewing comparison we chose Internet Explorer 11 and Chrome, our most common client browsers. For each of the viewers below, we tested separately in each browser.
- Browser Default
- Chromium Viewer for Chrome
- Adobe Reader integration for Internet Explorer 11
- PDFJS
- OpenAnnotate in View Only Mode
For some quick background, the different viewing options work differently
- Browsers
- Chrome – Downloads the PDF, then display it using Google’s PDFium
- InternetExplorer – No Out-of-the-Box PDF viewing. Integrates with Adobe Reader if installed on the PC to download the PDF, then display it in Adobe Reader lite within InternetExplorer.
- PDFJS
- Downloads the PDF into the browser, then uses Javascript to parse and display the PDF in an HTML5 canvas.
- OpenAnnotate in View only mode
- Renders the PDFs pages to a png image server-side, then displays the document view in the browser using HTML5 and canvases. Here only the png and PDF metadata needs to be downloaded to the browser, rather than the entire PDF.
Testing Approach
For our large document testing, we looked at both a large number of pages, as well as large file sizes. Numbers of pages ranged from 100 at the low end, to over 10,000 at the high end, with file sizes ranging from 10 mb to 100 mb.
Our main target for the large document tests was initial load time for viewing the first page. Browsers’ viewers and PDFJS struggle with larger files due to the need to download the entire document into the browser. This initial download time bottleneck is also typically very sensitive to poor network conditions as waiting for a document to load has an outsized impact on a user’s perception of a tool’s performance. See our work with helping clients understand performance perceptions.
We also tested how smooth navigation of a document was once it was loaded. We performed separate tests for page scrolling, and “jump to page” navigation for when user clicks a bookmark. See video of a sample test run below.
Testing Results
- 10,000 page documents – OpenAnnnotate “view only” is about 2 to 3 times faster than the typical viewing options Browser Default and PDFJS. OpenAnnotate achieves the performance because it avoids loading the entire document into the browser at once. By loading only the pages in view, the document, and particularly the first page, is shown to the user quicker.
- 1000+ Documents – OpenAnnotate “view only” is about 5 times faster for 1000+ page documents that are greater than 20 mb.
- New OpenAnnotate is an improvement over the current OpenAnnotate for across the board when talking about documents for larger 100 pages
- For up 1000 page documents, the new version of OpenAnnotate can deliver sub-second view times users are used to seeing for smaller documents.
What’s Next?
Next on the roadmap for OpenAnnotate, we will be looking to add these same performance improvements to Annotation mode as well. We’re excited to see how that will help OpenAnnotate’s performance to compare other tools like Brava!, ARender and Snowbound’s performance for large documents.
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