`rating_histogram` runs on every star keystroke. On the reference library (24k images, 1,200 of them rated) it cost 6.3 ms best-of-50 by catalog_bench, and up to 10-14 ms when the machine is busy. It was `images LEFT JOIN versions ON ... AND is_default = 1 GROUP BY rating`. The plan: SCAN i USING COVERING INDEX images_folder SEARCH v USING COVERING INDEX versions_judgement (image_id=?) LEFT-JOIN USE TEMP B-TREE FOR GROUP BY A probe of the index per image, then a sort of all 23,500 rows, to put 22,000 of them in slot zero. Now the rated rows are grouped on their own (`rating != 0`: one pass over `versions_judgement`, a sort of 1,200 rows), and slot zero is what is left of the join's row count. That count is three index-only aggregates -- the library size, the default versions, and the images holding one -- so an image with no version is still unrated, and an image with two default versions still counts twice, exactly as the join counted it: SCAN versions USING COVERING INDEX versions_judgement (x3) SCAN images USING COVERING INDEX images_folder `count(DISTINCT image_id)` has its own statement because alone it reads the distinct values off the index order; beside other aggregates SQLite builds a temporary b-tree for it. After: 1.2 ms. The histogram is the same on the reference library ([22364, 663, 19, 47, 115, 374]), and a new test compares it with the old join on a catalog holding every state the schema allows: no version, only a virtual copy, two defaults, ratings below zero and above five.
Documentation
Two audiences, two folders. Most people want the first table and never the second.
Using DarkRoom
| The manual | Every feature, pictured from the application itself — opening a library, rating, labelling and filing, duplicate originals, developing, local masks, repair, film, panoramas, export. The application carries it and opens it from Help and from Settings |
| How it is driven | Every gesture and shortcut, by screen. Generated from the code, so it cannot describe one the application does not have. The same list is the in-app help sheet: Help or F1 in the grid, ? or F1 in develop |
The top-level README says what DarkRoom is, how to get it on each platform, and what is still missing.
Changing DarkRoom
Everything under dev/ is for someone working on the code. Start with
CONTRIBUTING.md, which says how to land a first change
without reading the rest.
The register and the record. What must be built, how it is built, and how far along it is.
| requirements.md | What the software must do — the numbered register, the decisions (D-numbers) and the spikes (S-numbers) |
| architecture.md | How it is built — crates, the GPU pipeline, the data model, sync |
| traceability.md | Generated: which requirement is claimed by which file. Never edited by hand |
| outstanding.md | What is specified and not built, and whether that is a decision or a gap |
| technical-debt.md | Compromises taken deliberately, each with the condition that retires it |
| code-health.md | What a contribution costs, per seam, measured |
Designs, one per subsystem. Each is the specification the code was built to, kept current as the code moved.
| catalog.md | The index, the library view, incremental scan, the job queue |
| storage.md | Storage backends: the seam a folder, a sync client and a Nextcloud account share |
| faces.md | Face detection, identity, clustering and the eye-state models |
| segmentation.md | How the application finds the regions a local mask snaps to |
| mask-editing.md | Painting, erasing and combining masks |
| spot-removal.md | Clone and heal as parameters in the edit graph |
| panorama.md | Alignment, projection, the chunked composite and the border fill |
| inference.md | The neural runtime and model chosen per device, with the measurements |
| display-and-extension.md | The display contract, and why the fused pipeline is already most of a plugin format |
| view-composition.md | A controller for the display layer |
| ui-navigation.md | Finding things in the interface once there are many |
Measurements. Numbers committed so a regression is a diff rather than a recollection.
| benchmarks.md | The per-commit suite: what it covers, what it does not, how to read a failure |
| bench-baseline.json | The committed numbers the suite checks against |
| frame-budget.md | What a frame costs on each device, and the decision those figures settled |
Platforms and distribution.
| distribution.md | Which channels v1 targets and what each one constrains |
| windows.md | The Windows installer, cross-built from the Linux CI |
| android-signing.md | Which key signs the APK, and keeping it |
Archive. Kept as the record of what was asked for, not as plans.
| milestone-v0.1.md | The first milestone, delivered 2026-08-30 and superseded |
| ui-refinement.md | How the interface should look; succeeded by ui-navigation.md |
Conventions
Three files here are generated and must not be edited by hand:
gestures.md, dev/traceability.md and manual/index.html, the page the
packages install, rendered from manual/README.md. All three come from
cargo run -p traceability, the pre-commit hook keeps them in step with the
tree, and CI fails when one is not what the tree generates. The manual's
pictures are recorded by tools/manual and live
in LFS.
A design document links to the requirements it satisfies and to the code
that satisfies them. When the code moves, the link moves with it; a document
that has stopped being true goes to dev/archive/ with a note saying what
replaced it, rather than being deleted.