Release 20 · GrapheneOS/PdfViewer
github.com
Notable changes in version 20: improve app compatibility by trying to load data with no MIME type passed improve zoom gesture by scrolling during zooming to keep focus in the same place instead of...

Notable changes in version 20:

  • improve app compatibility by trying to load data with no MIME type passed
  • improve zoom gesture by scrolling during zooming to keep focus in the same place instead of the top left corner
  • simplify zoom gesture by migrating it to using a scale factor
  • hide text layer during scaling to avoid scrollable blank space when zooming out
  • raise minimum Chromium version for the WebView to 119 (will likely be raised much higher in the near future)
  • update pdf.js to 4.8.69
  • replace deprecated pdf.js renderTextLayer API usage with TextLayer
  • remove workaround for pdf.js text layer orientation bug which was fixed
  • set pdf.js isEvalSupported to false as redundant enforcement of our more complete approach of blocking dynamic code execution via Content Security Policy
  • update Android SDK to 35 (Android 15)
  • update target SDK to 35 (Android 15)
  • enable generation of v4 APK signatures
  • update Android build tools to 35.0.0
  • update Kotlin to 2.1.0
  • update Gradle to 8.10.2
  • update Android Gradle plugin to 8.7.2
  • update esbuild to 0.24.0
  • update AndroidX Appcompat library to 1.7.0
  • switch to KTX extension for AndroidX Core

A full list of changes from the previous release (version 19) 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. Each release is initially pushed out through the Beta channel followed by the Stable channel.

Releases of the app signed by GrapheneOS with the app.grapheneos.pdfviewer id are published in the GrapheneOS App Store which provides fully automatic updates. Each release is initially pushed out through the Alpha channel, followed by the Beta channel and then finally the Stable channel. These releases are also bundled as part of GrapheneOS and published on GitHub.

GrapheneOS users must obtain GrapheneOS app updates through our App Store since verified boot metadata is required for out-of-band system app updates on GrapheneOS as part of extending verified boot to them.