dtourolleandClaude Opus 5
d7b851f622
`Flickable { VerticalLayout { for ... } }` instantiates every row. On the
reference library that is 14,268 row subtrees, which measures at 4.2
seconds before a pixel is drawn — and it was paid again on every action,
because every action reloads the model. Roughly half the wait between
clicking "Identity" and the screen appearing was this.
Slint's compiler has a virtualising path for a `for`; it is what makes
`std-widgets`' `ListView` cheap. It keys on the parent element's base
being *named* `ListView` and exposing the five lengths its layouting code
writes back, and a custom base is explicitly allowed. So `widgets.slint`
grows one, and `std-widgets` stays out of the file that establishes our
style. Measured on the real screen: 200,000 rail rows now render in 62ms.
Three things had to be true together, and each was silent on its own.
**The row height must be constant.** The rail hid a set-aside person with
`height: cond ? 52px : 0px`, a height that reads the model — so the
layout cannot place row N without building rows 0..N, and Slint builds
them all. The filtering moves to Rust, where the toggle was already
reloading anyway.
**The list must not be wrapped.** It carries its own stretch and preferred
size, having no natural height to offer; a Rectangle in between hands the
layout that Rectangle's constraints, which are taken from the list and
are therefore nothing.
**The panel must let it fill.** `Panel` lays its children out with
`alignment: start`, which gives each its preferred height — right for a
column of sliders, wrong for anything that scrolls. Hence `Panel.fill`.
Get any of them wrong and the rail renders empty, with no error and a
model full of people. All three were, in turn, before a headless render
of the real screen showed a blank rail.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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.