Kai KozlovandKirill Bulatov
bcd54d0adf
Closes #50210 Bracket colorization currently runs theme accents through `ensure_minimum_contrast`, which can significantly alter authored palette colors in order to satisfy a single foreground-vs-background target. In practice, that makes rainbow brackets drift away from the theme colors they are supposed to reflect. This PR keeps bracket colorization as a single automatic behavior, but changes how the palette is derived: - preserve authored accent colors when they already work - adjust only the specific accents that are too weak against the editor background - only reorder the palette when adjacent bracket levels are still too similar after that The implementation is staged because bracket colorization has to handle two separate problems: - **Bracket-vs-Background Readability**: is an individual bracket visible against the editor background? - **Adjacent Bracket Separation**: can you still distinguish one nesting level from the next? Those two constraints are also why the implementation cannot simply defer to whatever accent colors the theme provides. Some themes, including the bundled One and Ayu, do not define explicit accents at all, so bracket colorization falls back to Zed's shared default accent palette. That palette was not designed with any particular theme's background in mind, which makes the background contrast check especially important for those cases. That is why the previous `ensure_minimum_contrast(..., 55.0)` path is not enough on its own. It addresses foreground-vs-background readability, but if lightness-only adjustment cannot satisfy that target it escalates to saturation reduction and then black/white fallback. This PR instead keeps the bracket-specific background fix bounded and lightness-only in OKLCH, so the resulting color stays much closer to the authored accent. ### How it works - **Background Contrast Correction**: accents that fall below the APCA floor against the editor background are adjusted by changing OKLCH lightness only, preserving hue and chroma - **Adjacency Correction**: if the resulting palette is still too weak between neighboring nesting levels, the palette is reordered conservatively to improve adjacent separation That ordering matters. Doing the reorder first can easily be undone by the background-fix step. ### Color measurement - background contrast uses APCA, via the existing `apca_contrast` path - adjacent bracket separation uses OKLab Euclidean distance APCA is the right tool for bracket-vs-background readability, but it is not designed to compare two foreground colors against each other. OKLab distance is a better fit for detecting when neighboring bracket levels are perceptually too close. ### Thresholds - background APCA floor: `30` on dark themes, `35` on light themes - adjacent OKLab target: `0.08` on dark themes, `0.10` on light themes - light-theme reorder tolerance band: reorder only triggers below `0.095`, avoiding threshold-artifact reordering on palettes that are visually fine but narrowly miss `0.10` ### Validation - `cargo test -p editor bracket_colorization` - manual comparison on bundled One, Ayu, and Gruvbox theme families Release Notes: - Improved bracket colorization by preserving theme accent colors when possible and applying targeted contrast fixes only when needed. --------- Co-authored-by: Kirill Bulatov <kirill@zed.dev>
Zed
Welcome to Zed, a high-performance, multiplayer code editor from the creators of Atom and Tree-sitter.
Installation
On macOS, Linux, and Windows you can download Zed directly or install Zed via your local package manager (macOS/Linux/Windows).
Other platforms are not yet available:
- Web (tracking discussion)
Developing Zed
Contributing
See CONTRIBUTING.md for ways you can contribute to Zed.
Also... we're hiring! Check out our jobs page for open roles.
Licensing
Zed source code is licensed primarily under GPL-3.0-or-later, with Apache-2.0 components where marked.
License information for third party dependencies must be correctly provided for CI to pass.
We use cargo-about to automatically comply with open source licenses. If CI is failing, check the following:
- Is it showing a
no license specifiederror for a crate you've created? If so, addpublish = falseunder[package]in your crate's Cargo.toml. - Is the error
failed to satisfy license requirementsfor a dependency? If so, first determine what license the project has and whether this system is sufficient to comply with this license's requirements. If you're unsure, ask a lawyer. Once you've verified that this system is acceptable add the license's SPDX identifier to theacceptedarray inscript/licenses/zed-licenses.toml. - Is
cargo-aboutunable to find the license for a dependency? If so, add a clarification field at the end ofscript/licenses/zed-licenses.toml, as specified in the cargo-about book.
Sponsorship
Zed is developed by Zed Industries, Inc., a for-profit company.
If you’d like to financially support the project, you can do so via GitHub Sponsors. Sponsorships go directly to Zed Industries and are used as general company revenue. There are no perks or entitlements associated with sponsorship.