WebKit Igalia Periodical #3

The getImageData() canvas method has been optimized to avoid an intermediate memory copy. This made fetching pixel data about ten times faster in the embedded hardware and laptops with integrated GPUs used for testing. The improvement is slated for inclusion in the upcoming 2.46.4 stable release.

The WebKit#31458 PR landed today. This adds a mechanism that leverages the damage information to reduce the amount of painting during composition. The biggest gains of that are expected with WPE used on embedded devices.

Running WebKit layout tests using the multi-threaded Skia-CPU mode (WEBKIT_SKIA_ENABLE_CPU_RENDERING=1, WEBKIT_SKIA_PAINTING_THREADS>0) fired assertions in debug/assert-enabled builds. Recording a DisplayList on the main thread and replaying it on a worker thread exposed a thread-safety issue. The Pattern class was not expecting to be dereferenced from a non-main thread. Pattern now inherits from ThreadSafeRefCounted to fix the problem.

Traditionally, we supported multi-threaded tile rendering using Cairo (which is CPU-only), and also using Skia in CPU rendering mode. Skia with GPU accelerated rendering is driven from the main thread and does not support multi-threading. However, there is a non-negligible amount of CPU work to be performed prior to using the GPU for rendering, where it can be beneficial to parallelize that work across multiple cores.

Preparation is ongoing for threaded GPU rendering, by adding GPU synchronization primitives to NativeImage and ImageBuffer for Skia, and making use of the new GPU synchronization primitives during DisplayList recording (on the main thread) and replays—which will happen in a GPU worker thread, once we have added support for that.

Canvas to PeerConnection streaming was fixed, there was an issue with video orientation tags handling leading to flipped frames on receiving side.

Screen capture support using PipeWire and GStreamer was fixed, DMA-BUFs are now negotiated with PipeWire, enabling zero-copy rendering to video elements. Screen capture streaming to PeerConnection is still an open issue though.

WPEPlatform now supports a Settings API allowing platforms and applications to set options such as fonts or dark mode. This can be tested by launching MiniBrowser and passing an INI-style configuration file with settings:

MiniBrowser --use-wpe-platform-api --config-file=config.ini

WPE-Android got updated to WebKit 2.46.3. Coming from 2.46.0, it includes a fix for DuckDuckGo results link, better text kerning, a better performing Canvas putImageData()operation, improved selection of H.264 encoding parameters, and more.

As usual, the 0.1.2 release at GitHub contains the downloadable .apk packages. The Maven repository has been updated as well.

Producing WPE-Android releases on GitHub has been automated, and version 0.1.2 has already been made this way, the only manual intervention being the approval of the draft created by the CI setup.

GNOME Web Canary builds are working again, now based on the GNOME Flatpak runtime instead of the soon-to-be-deprecated WebKit Flatpak SDK runtime. To install it run:

flatpak --user install \
  https://nightly.gnome.org/repo/appstream/org.gnome.Epiphany.Canary.flatpakref

This version of GNOME Web leverages nightly WebKitGTK builds from the WebKit Git main development branch.

The WebKitGTK Debian 11 bot has been retired. We officially stopped supporting WebKitGTK on Debian 11 on June 12th (one year after the release of Debian 12), however we have been maintaining WebKitGTK on Debian 11 for a longer time than initially expected. Debian 11 Security support reached end-of-life on August 14th, 2024.