Notable changes in version 16:
- horizontally and vertically center canvas and text layer along with fixing text layer alignment in some cases
- set minimum WebView font size to 1px instead of the default 8px to fix text layer alignment issues with tiny fonts
- fix typo causing page rendering cache misses
- add handling for exceptions caused by edge cases with PDF metadata
- add handling for exceptions caused by edge cases with the 'Save as' feature
- replace deprecated APIs
- update pdf.js to 3.1.81
- update Android Gradle plugin to 7.3.1
- update Kotlin Gradle plugin to 1.7.22
A full list of changes from the previous release (version 15) is available through the Git commit log between the releases.
Simple Android PDF viewer based on pdf.js and content providers. The app doesn't require any permissions. The PDF stream is fed into the sandboxed WebView without giving it access to content or files. Content-Security-Policy is used to enforce that the JavaScript and styling properties within the WebView are entirely static content from the apk assets. It reuses the hardened Chromium rendering stack while only exposing a tiny subset of the attack surface compared to actual web content. The PDF rendering code itself is memory safe with dynamic code evaluation disabled, and even if an attacker did gain code execution by exploiting the underlying web rendering engine, they're within the Chromium renderer sandbox with no access to the network (unlike a browser), files, or other content.
This app is available through the Play Store with the app.grapheneos.pdfviewer.play app id. Play Store releases go through review and it usually takes around 1 to 3 days before the Play Store pushes out the update to users. Play Store releases use Play Signing, so we use a separate app id from the releases we publish ourselves to avoid conflicts and to distinguish between them.
Releases of the app signed by GrapheneOS with the app.grapheneos.pdfviewer app id are published in the GrapheneOS app repository and on GitHub. You can use the GrapheneOS app repository client on Android 12 or later for automatic updates.
Releases are initially pushed out through the Beta channel for both the Play Store and our app repository and then get moved to the Stable channel.