This Month in Linebender, January 2025 (#89)

Co-authored-by: Kaur Kuut <strom@nevermore.ee>
Co-authored-by: Thomas Churchman <thomas@kepow.org>

Author: 3 people

content/blog/2025-03-03-tmil-13/emoji_picker.png

@@ -0,0 +1,245 @@
++++
+title = "Linebender in January 2025"
+authors = ["Kaur Kuut", "Daniel McNab", "Tom Churchman", "Raph Levien"]
++++
+
+Linebender is an informal open-source organization working on various projects to advance the state of the art in GUI for [the Rust programming language](https://rust-lang.org).
+
+## Xilem
+
+Xilem is our flagship GUI project, inspired by SwiftUI.
+It lets you build user interfaces declaratively by composing lightweight views together, and will diff them to provide minimal updates to a retained layer.
+
+Xilem saw decent direct progress in January and of course Xilem also benefits from all the progress in the rest of our stack which is detailed in later sections.
+
+- [xilem#420][], [xilem#833][]: Added emoji picker example.
+- [xilem#753][], [xilem#828][]: Added support for transforming widgets with `kurbo::Affine`.
+- [xilem#806][]: Made `Pod` more flexible to allow creating a wider variety of wrapper widgets.
+- [xilem#840][]: Updated to `vello` 0.4.0.
+
+<figure>
+<img style="height: auto" src="emoji_picker.png" alt="A screenshot of a Xilem example app. It shows sixteen different facial expression emoji with a cat face with a wry smile being selected." width="864" height="1121">
+<figcaption>
+Xilem emoji picker example app, showing various emoji options.
+</figcaption>
+</figure>
+
+We also improved documentation, see e.g. [xilem#818][].
+
+## Masonry
+
+Masonry is the widget system used by Xilem.
+It provides a non-opinionated retained widget tree, designed as a base layer for high-level GUI frameworks.
+
+January was quite a busy month for Masonry with lots of significant changes landing, including both new features and improved old ones.
+Most notable are the following highlights:
+
+- [xilem#737][]: Added `zstack` widget for composing widgets on top of each other.
+- [xilem#753][]: Added support for transforming widgets with `kurbo::Affine`.
+- [xilem#808][]: `AppDriver` now takes a reference to `RenderRoot` for more flexibility.
+- [xilem#820][]: Added a basic widget inspector for debugging.
+- [xilem#822][]: Now widget focus is cleared when a user clicks outside of that focused widget.
+- [xilem#823][]: When text of a text area is changed the cursor now gets moved to the end.
+- [xilem#827][]: Refactored `TreeArena`.
+- [xilem#830][]: Improved handling of window focus.
+- [xilem#831][]: Applied `is`/`has` naming convention more consistently across context method names.
+- [xilem#834][]: Fixed crashing in `run_single_update_pass`.
+- [xilem#837][]: Removed a bunch of redundant `Box` usage around `Widget`.
+- [xilem#841][]: Added features to help test `Textbox`.
+- [xilem#848][]: Reorganized modules.
+
+We also improved documentation a lot, see e.g. [xilem#787][], [xilem#809][], [xilem#811][], [xilem#813][], [xilem#815][], [xilem#824][], [xilem#826][], [xilem#829][], [xilem#832][], and [xilem#835][].
+Additionally a bunch of stale code got cleaned up.
+
+## Vello
+
+Vello is our GPU vector renderer.
+It can draw large 2D scenes with high performance, using GPU compute shaders for most of the work.
+
+We released [Vello 0.4.0][] which has a bunch of improvements and fixes from the preceding four months.
+Among the improvements is the change from December that Vello now uses our own [Color][] library.
+Highlights from the additions in January include [image extend modes, alpha, and nearest neighbor sampling][vello#766] and [correct rendering of Apple Color Emoji][vello#792].
+
+<figure>
+<img style="height: auto" src="neighbor.png" alt="A screenshot of a Vello demo app. It shows four different variations of an image extended with nearest neighbor filtering." width="1570" height="1247">
+<figcaption>
+Vello demo, showing image extend modes with nearest neighbor filtering.
+</figcaption>
+</figure>
+
+Of course work didn't stop with this release.
+In preparation for the next release we have already [upgraded Vello to use wgpu 0.24.0][vello#791].
+
+## Kurbo
+
+Kurbo provides data structures and algorithms for curves and vector paths.
+
+- [kurbo#409][]: Added `turn_90` / `rotate_scale` methods to `Vec2`, and fixed the docs of `Vec2::cross`.
+
+## Parley
+
+Parley is a text layout library.
+It handles text layout, mostly at the level of line breaking and resolving glyph positions.
+
+In January, a variety of layout edge cases have been fixed, support for bidirectional text was expanded, and testing of text layout and selection has improved.
+
+- [parley#238][]: Updated to `swash` 0.2.0, which paves the way for future `no_std` support.
+- [parley#239][]: Took another step towards supporting `no_std` by enabling further testing in CI.
+- [parley#241][]: Allows configuring the behavior of alignment for lines that overflow the container width.
+- [parley#244][]: Added screenshots to selection area and cursor positioning tests.
+- [parley#245][]: Enabled detection of the base direction of text layouts (left-to-right or right-to-left).
+- [parley#249][]: Fixed issues related to line breaking around inline boxes, by new Linebender member Wim de With.
+- [parley#254][]: Now adhering to the [CSS white space model][] in stripping leading white space following a new line in white space collapsing mode.
+- [parley#256][]: Corrected the calculation of trailing white space, also by Wim de With.
+
+## Peniko
+
+Peniko provides a set of shared types for concepts that are important for drawing/stroking paths, but excluding the path geometry itself (which can be found in Kurbo).
+It includes types for brush styles (including gradient) and color.
+
+We released [Peniko 0.3.1][] which was a simple maintenance release with tweaked docs and updated dependencies.
+
+## Color
+
+[Color][] provides functionality for representing, converting, parsing, serializing, and manipulating colors in a variety of color spaces.
+It closely follows the [CSS Color Module Level 4][] draft spec.
+
+We released [Color 0.2.2][], soon followed by [Color 0.2.3][], the latter of which added easier methods to convert 8-bit colors from byte streams (for use with GPUs) and to other color representations in [color#135][] and [color#136][].
+This release also saw the addition of the ACES2065-1 color space in [color#124][].
+
+## Velato
+
+- [velato#49][]: Updated to `vello` 0.4.0.
+
+## Vello SVG
+
+We released [Vello SVG 0.6.0][] which most notably includes:
+- [vello_svg#50][]: Added support for raster images to be completely disabled via a feature flag.
+- [vello_svg#53][]: Updated to `vello` 0.4.0.
+
+## Kompari
+
+[Kompari][] is a tool for visual inspection of snapshot tests.
+
+- [kompari#13][]: Interactive review (in HTML).
+- [kompari#14][]: Rework of repository layout.
+- [kompari#16][]: Alternative diff views.
+
+## Resvg
+
+- [resvg#873][]: Added the stylesheet option to the C API.
+- [resvg#878][]: Updated to `svgtypes` 0.15.3.
+
+## SVG Types
+
+We released [SVG Types 0.15.3][] with a few minor fixes.
+This is also the first release under the stewardship of Linebender.
+
+## Tiny Skia
+
+- [tiny-skia#146][]: Added `scale_by` / `scale_to` methods to `Size`.
+
+## SimpleCSS
+
+We released [SimpleCSS 0.2.2][] with `no_std` support, updated docs clarifying Linebender involvement, and to test run the publishing workflow.
+
+## Research and Future Directions
+
+Linebender has an origin story in being a very research oriented group, looking to break new ground.
+While we are focused on shipping code today, we still have an eye on the future and how to be prepared for the new opportunities and technologies that are coming.
+
+While Vello has unmatched rendering speed thanks to its GPU-driven architecture, there are two practical tradeoffs: it can require unpredictable amounts of memory, and it doesn't work on downlevel GPUs with weak or nonexistent support for compute shaders.
+Raph Levien has been exploring a possible hybrid CPU/GPU direction for Vello to address these issues.
+Read the [design doc][Potato design doc], follow the [Zulip thread][Potato zulip thread], or stay tuned for more developments.
+
+## Get Involved
+
+We welcome collaboration on any of our crates.
+This can include improving the documentation, implementing new features, improving our test coverage, or using them within your own code.
+
+We host an hour long office hours meeting each week where we discuss what's going on in our projects.
+See [#office hours in Zulip](https://xi.zulipchat.com/#narrow/channel/359642-office-hours) for details.
+
+* Daniel and Olivier's "office hours" appointments can still be booked by anyone for open-ended discussion of the ecosystem.
+  * [See Daniel's schedule here](https://calendar.google.com/calendar/u/0/appointments/schedules/AcZssZ32eQYJ9DtZ_wJaYNtT36YioETiloZDIdImFpBFRo5-XsqGzpikgkg47LPsiHhpiwiQ1orOwwW2).
+  * [See Olivier's schedule here](https://calendar.google.com/calendar/u/0/appointments/schedules/AcZssZ2t767ZRETD_TkRI_VxK2ZTG0VrO9OZ4l7HvTxefhtJcg85iK0ZN7zWNnAEZtH0Dn7C1GKxrmYM).
+
+[xilem#420]: https://github.com/linebender/xilem/pull/420
+[xilem#737]: https://github.com/linebender/xilem/pull/737
+[xilem#753]: https://github.com/linebender/xilem/pull/753
+[xilem#787]: https://github.com/linebender/xilem/pull/787
+[xilem#806]: https://github.com/linebender/xilem/pull/806
+[xilem#808]: https://github.com/linebender/xilem/pull/808
+[xilem#809]: https://github.com/linebender/xilem/pull/809
+[xilem#811]: https://github.com/linebender/xilem/pull/811
+[xilem#813]: https://github.com/linebender/xilem/pull/813
+[xilem#815]: https://github.com/linebender/xilem/pull/815
+[xilem#818]: https://github.com/linebender/xilem/pull/818
+[xilem#820]: https://github.com/linebender/xilem/pull/820
+[xilem#822]: https://github.com/linebender/xilem/pull/822
+[xilem#823]: https://github.com/linebender/xilem/pull/823
+[xilem#824]: https://github.com/linebender/xilem/pull/824
+[xilem#826]: https://github.com/linebender/xilem/pull/826
+[xilem#827]: https://github.com/linebender/xilem/pull/827
+[xilem#828]: https://github.com/linebender/xilem/pull/828
+[xilem#829]: https://github.com/linebender/xilem/pull/829
+[xilem#830]: https://github.com/linebender/xilem/pull/830
+[xilem#831]: https://github.com/linebender/xilem/pull/831
+[xilem#832]: https://github.com/linebender/xilem/pull/832
+[xilem#833]: https://github.com/linebender/xilem/pull/833
+[xilem#834]: https://github.com/linebender/xilem/pull/834
+[xilem#835]: https://github.com/linebender/xilem/pull/835
+[xilem#837]: https://github.com/linebender/xilem/pull/837
+[xilem#840]: https://github.com/linebender/xilem/pull/840
+[xilem#841]: https://github.com/linebender/xilem/pull/841
+[xilem#848]: https://github.com/linebender/xilem/pull/848
+
+[Vello 0.4.0]: https://github.com/linebender/vello/releases/tag/v0.4.0
+[vello#766]: https://github.com/linebender/vello/pull/766
+[vello#791]: https://github.com/linebender/vello/pull/791
+[vello#792]: https://github.com/linebender/vello/pull/792
+
+[kurbo#409]: https://github.com/linebender/kurbo/pull/409
+
+[parley#238]: https://github.com/linebender/parley/pull/238
+[parley#239]: https://github.com/linebender/parley/pull/239
+[parley#241]: https://github.com/linebender/parley/pull/241
+[parley#244]: https://github.com/linebender/parley/pull/244
+[parley#245]: https://github.com/linebender/parley/pull/245
+[parley#249]: https://github.com/linebender/parley/pull/249
+[parley#254]: https://github.com/linebender/parley/pull/254
+[parley#256]: https://github.com/linebender/parley/pull/256
+[CSS white space model]: https://www.w3.org/TR/CSS2/text.html#white-space-model
+
+[Peniko 0.3.1]: https://github.com/linebender/peniko/releases/tag/v0.3.1
+
+[Color]: https://docs.rs/color/
+[CSS Color Module Level 4]: https://www.w3.org/TR/css-color-4/
+[Color 0.2.2]: https://github.com/linebender/color/releases/tag/v0.2.2
+[Color 0.2.3]: https://github.com/linebender/color/releases/tag/v0.2.3
+[color#124]: https://github.com/linebender/color/pull/124
+[color#135]: https://github.com/linebender/color/pull/135
+[color#136]: https://github.com/linebender/color/pull/136
+
+[velato#49]: https://github.com/linebender/velato/pull/49
+
+[Vello SVG 0.6.0]: https://github.com/linebender/vello_svg/releases/tag/v0.6.0
+[vello_svg#50]: https://github.com/linebender/vello_svg/pull/50
+[vello_svg#53]: https://github.com/linebender/vello_svg/pull/53
+
+[Kompari]: https://github.com/linebender/kompari
+[kompari#13]: https://github.com/linebender/kompari/pull/13
+[kompari#14]: https://github.com/linebender/kompari/pull/14
+[kompari#16]: https://github.com/linebender/kompari/pull/16
+
+[resvg#873]: https://github.com/linebender/resvg/pull/873
+[resvg#878]: https://github.com/linebender/resvg/pull/878
+
+[SVG Types 0.15.3]: https://github.com/linebender/svgtypes/releases/tag/v0.15.3
+
+[tiny-skia#146]: https://github.com/linebender/tiny-skia/pull/146
+
+[SimpleCSS 0.2.2]: https://github.com/linebender/simplecss/releases/tag/v0.2.2
+
+[Potato design doc]: https://docs.google.com/document/d/1gEqf7ehTzd89Djf_VpkL0B_Fb15e0w5fuv_UzyacAPU/edit?usp=sharing
+[Potato zulip thread]: https://xi.zulipchat.com/#narrow/channel/197075-gpu/topic/Potato.20-.20a.20paper.20design.20for.20a.20CPU.2FGPU.20hybrid.20renderer