A mask the model draws arrives approximately right — stopping inside a shoulder, leaking into the hair — and FR-DEV-3's edge controls move the *whole* boundary, so no value of feather or dilation fixes two errors that go opposite ways. What fixes them is a second selection joined to the first, and a layer that held exactly one source had nowhere to put one. The brush the core has had all along was reachable from no control in the application. A layer is now an ordered list of parts. Each names a source and how it joins the mask before it — added to it, or taken out of it — and carries its own edge treatment, because a model's soft coverage and a stroke painted where it stopped short do not want the same feather. Invert and opacity stay on the layer, where the composed shader already reads them. The sidecar grows `[part]` blocks and nothing else. A layer of one part writes exactly the bytes it always did; a mask block with no part blocks after it reads back as one part; and a stroke, a join or a source this build cannot read costs that part rather than the layer. So every sidecar in every library still parses to the edit it always was. On the device the parts fold into the layer's one slice, so eight layers still cost eight channels: union is a `max` blend and subtraction is the erase blend the brush already used. A part is drawn into a scratch texture before it is joined, and that is not incidental — an erase stroke means a hole in *that part*, not a hole in the mask, and drawn straight onto the accumulator it would punch through the subject underneath. A layer of one part skips all of it and takes the path it always took. In the interface: a part list under the selected layer with a chip saying which way each joins, Add and Subtract beside it, a Select/Paint/Erase strip with the brush's size, hardness and flow, and a drag on the photograph that paints. Pressing Paint on a mask that cannot hold a stroke joins a part that can, rather than explaining that a subject is not a brush. A whole stroke is one step in the history. The edge controls now shape the part that is selected rather than the layer, which is the one behaviour change to an existing control: with a correction selected, the feather slider softens the correction and leaves the model's mask alone.
DarkRoom
A cross-platform, non-destructive RAW photo editor for Linux and Android.
Status: 0.9.0, and no longer a spike. A library opens, culls, develops and exports on both platforms, across eight tagged releases. What is not built is written down rather than merely absent — see docs/outstanding.md for the requirements that have no implementation and why, and docs/technical-debt.md for the compromises that were chosen.
Documentation
| Document | Contents |
|---|---|
| CONTRIBUTING.md | How to land a first change without reading the rest |
| requirements.md | What the software must do — 179 numbered requirements |
| architecture.md | How it is built — crates, GPU pipeline, data model, sync |
| technical-debt.md | Compromises taken deliberately, each with the condition that retires it |
| outstanding.md | What is not built, and whether that is a decision or a gap |
| code-health.md | What a contribution costs, per seam, measured |
| traceability.md | Generated: which requirement is claimed by which file |
| faces.md | Face detection and identity — the models, the licence problem, and what S14 measured |
Building
Desktop:
cargo run -p darkroom-desktop
Android (containerised toolchain, see docker/android):
./docker/android/build.sh cargo ndk -t arm64-v8a build --release
Git LFS is required for the model weights, and the toolchain pins itself. CONTRIBUTING.md has the details and the four commands CI will run against what you send.
Current state
Working. A catalog over a local folder, a Nextcloud account, or a folder a
sync client keeps in virtual-files mode — where a placeholder is treated as the
photograph rather than as a one-byte file. A virtualised library grid with a
capture-time timeline, ratings, labels, keywords, collections and a trash that
survives a crash mid-operation. Card ingest. Face detection and identity, with
the index syncing between devices. A develop pipeline of fifteen declared
operations fused into a single compute dispatch, plus the neighbourhood
operations that cannot be — clarity, texture, capture sharpening, noise
reduction, lens correction, spectral film simulation. Crop, straighten, spot
removal, gradient and subject-segmentation masks, named presets, and a
generated panel that no operation in ui/ is allowed to name. Export to JPEG,
PNG and 8- or 16-bit TIFF with resize and output sharpening.
The zero-copy display path works on desktop. The compute pass writes a texture that Slint composites directly, which is what ARCH §6.1 requires; the readback it forbids costs 96% of frame time at 4K, and
cargo run -p dr-gpu --example bench --features readback
still reproduces that measurement. The one exception is the Android develop view, which reads the frame back through the CPU because zero-copy there needs wgpu's Vulkan swapchain, and that tears a portrait window on a tablet whose panel is mounted landscape. It is debt, not a revision of the rule: the reasoning, the on-device measurements that forced it, and the three separate things any one of which would remove it are in technical-debt.md TD-1.
Not built. Plugins, compare and survey culling, focus peaking, burst grouping, AI denoise, tiled and progressive rendering, and most of the Android platform integration beyond running. The performance targets in §4.1 are unverified rather than unmet — the per-commit benchmark suite §8 requires does not exist, so nothing fails a build on a regression. docs/outstanding.md is the list, with the reasoning.
Licence
GPL-3.0-or-later.