This Month in Xilem, March 2024

Daniel McNab, April 4, 2024

Since the last update, there have been three newly released projects from Linebender:

• Velato: A parser and driver for Lottie animation files in applications using Vello
• Vello SVG: Allows displaying (some) SVG documents in Vello applications
• Android Trace: Resilient bindings to NDK Tracing and an integration with tracing

If you have a WebGPU capable browser you can check out the web demo of Velato.

Implementation work for rfcs#1 has started. Masonry is being ported to Vello in masonry#56, with the next step being a move to Winit. This work can be followed in the #masonry stream on Zulip.

We have landed some important improvements to Vello. Euler spiral based stroke expansion (vello#496) enables GPU stroking by default, significantly improving performance in scenes which make heavy use of strokes. Additionally, we now support scenes with more than 64k draw objects (vello#526). We have also been making progress on vello#366, by evaluating different strategies for memory allocation. The first part of this has landed in vello#537, which avoids undefined behaviour in more out-of-memory cases.

Additionally, we have been able to continue taking advantage of improvements in the foundational font crates from Google Fonts. This has enabled support for font fallback in xilem#196. Hinting has been unblocked by vello#544, although the implementation has not yet landed in Xilem.

rfcs#5 has been approved, which will improve the robustness of our continuous integration. Kaur Kuut, the author of the RFC, has also landed these changes in vello#523.

A focus for the next month is preparing for the RustNL conference at the beginning of May. We are hoping to present a compelling demo there.