[sheldonxxxx]

Problem and result

Backport selected upstream fixes for colour processing, RAW previews, export correctness, crop controls, and library behaviour. Adaptations preserve the fork's optional MCP feature, Sony lossless M/S RAW decoder, source freshness, repair compositing, and GPU resource caches.

Type of Change

• Bug fix
• Performance improvement
• Documentation update
• UI/UX improvement

Changes

• Smooth magenta highlight correction, calculate HSL hue in perceptual space, prevent vibrance NaNs, and avoid inactive HSL work and redundant float-upload copies.
• Build export masks from their own image, invalidate stale mask caches, align empty masks, and persist TIFF bit depth and timestamp settings in export presets.
• Use embedded RAW preview fallbacks, retain Nikon lens metadata, and handle closed stdout/stderr without aborting or hanging.
• Filter before RAW/JPEG grouping, respect AI tag limits, save the unrated filter, resize crops from the centre with Ctrl/Cmd, and run custom mask Escape handlers.
• Add regression coverage and strengthen native export checks for unsupported metadata and independently measured ICC differences.

Upstream provenance

Selected changes from these 16 commits; direct patches and fork adaptations are combined in one reviewed commit:

• b4994ed4: fix(settings): allow unrated filter rating to be saved (three-way patch).
• 3c864270: resize crop from center when holding ctrl on a handle (three-way patch).
• d6cda855: perf(gpu): avoid float image copies during upload (three-way patch).
• e99082ad: fix(raw): make magenta highlight correction continuous (three-way patch).
• e8834210: fix(color): compute HSL mixer hue in perceptual space (three-way patch).
• 89020724: prevent NaN in vibrance and skip inactive HSL panel (three-way patch).
• c11c7a5c: fix(exif): read Nikon lens from MakerNote when EXIF has none (three-way patch).
• 476389ad: Persist TIFF bit depth and file timestamp option in export presets (three-way patch).
• f0f1be48: Apply library filters before RAW+JPEG grouping (three-way patch).
• 367145a1: Respect the maximum AI tag count (three-way patch).
• 9671795e: fix(masks): run custom Escape handler instead of storing a wrapper (three-way patch).
• b64adfc6: fix: don't abort or hang when stdout/stderr is a closed pipe (fork adaptation).
• 4e45e620: fix(thumbnails): use rawler embedded preview for non-TIFF raws (fork adaptation).
• 43248097: refactor(thumbnails): share embedded preview fallback with image loader (fork adaptation).
• 078c90a8: Build colour/luminance mask sources from the exported image (fork adaptation).
• cf6813f1: fix stale export cache (fork adaptation).

Testing

The committed patch is identical to the locally validated patch.

• Frontend build, format, typecheck, ESLint and translation checks passed; 133 frontend tests passed.
• npm test --prefix mcp: 147 passed.
• cargo fmt --check and cargo clippy --all-targets --all-features -- -D warnings passed.
• Default Rust suite: 229 passed; MCP Rust suite: 337 passed. Eighteen environment-dependent tests are normally ignored; three selected Metal tests and the real CR3 embedded-preview test were run separately and passed.
• Native RAW engine suite: 80 calls, 10 checks, zero skips. Native delivery suite: 31 calls, 36 checks, zero skips. Native geometry suite: 129 calls, 9 checks, zero skips.
• Independently decoded full-resolution Canon and Sony TIFF exports retained non-replicated 16-bit samples. Metal precision/tile checks retained all 2,055 ramp levels with zero u16 difference.
• Real CLI tests with stdout, stderr, and both closed exited successfully; independent TIFF inspection confirmed 16-bit output and ICC metadata.
• Separate product manager review of README and the Unreleased changelog found no material issues.

Test Configuration:

• OS and architecture: macOS 27.0, arm64.
• GPU / processing backend: Apple M4, Metal.
• Affected entry point: Render/export core, export CLI, MCP, and desktop controls.
• MCP host and native build: Rust 1.98.1 with non-incremental dev/test profiles and debug symbols disabled; native suites used the same MCP binary and source revision.

Cross-platform packaged builds, signing, and interactive desktop acceptance were not run. Native engine and pixel checks do not establish desktop UI acceptance.

Checklist

• Code follows the project's style and affected local checks pass without warnings.
• No unnecessary AI-generated code comments were added.
• README/setup claims match the changes and fork fixes are recorded under Unreleased in CHANGELOG.md.
• Shared files and links contain no credentials, personal paths, or unavailable local evidence.

AI assistance

Prepared with Codex assistance through source review, fork-specific adaptations, regression tests, and native engine/pixel checks. Public documentation was reviewed by a separate product manager.