dtourolle
ec713585a5
Feathering, growing, shrinking, closing and opening are the same number read differently. With the signed distance from the boundary in hand, dilation is the set where d >= -r, erosion where d >= +r, and a feather of any shape is a function of d. So the field is computed once and the controls are arithmetic on it. The **field** is what reaches the GPU, not a finished alpha, and that is the point: growing a mask or changing its falloff then costs a uniform upload and no recomputation, which is what makes them live controls rather than ones that stall on every drag. Only closing and opening rebuild, because after the first threshold the shape has changed and the old distances describe the old one. Exact Euclidean, via Felzenszwalb's separable transform — not a chamfer approximation, which leaves a mask visibly octagonal once grown more than a few pixels. A test asserts the diagonal is √2 rather than 1 or 2. It runs on the CPU, which ARCH §5.4 forbids for masks. The rule is about brush lag — a stroke rasterised per frame — and this is a different operation: once per mask edit, on input the model already produced here, producing a field the GPU then samples for free. What it buys is exact determinism, which matters because masks reach the sidecar as indices and a field that varied by vendor would mean a mask meaning one thing on the desktop and another on the phone. The half-pixel in `signed_distance` is not a detail, and a test caught it. Measuring to the nearest opposite pixel *centre* puts the smallest magnitude at 1 either side, so the boundary is nowhere and **eroding by less than a pixel removes nothing**. A control whose first notch does nothing is a broken control. Half a pixel off each side puts the boundary where it physically is, and eroding by 1 takes exactly the outermost ring. Every falloff curve is 0.5 at the boundary by construction, asserted for all five: changing the curve should change how the transition looks and never where it sits.
DarkRoom
A cross-platform, non-destructive RAW photo editor for Linux and Android.
Status: early. v0.1 is a remote library viewer — see docs/milestone-v0.1.md.
Documentation
| Document | Contents |
|---|---|
| requirements.md | What the software must do — 122 numbered requirements |
| architecture.md | How it is built — crates, GPU pipeline, data model, sync |
| milestone-v0.1.md | The first buildable milestone |
Building
Desktop:
cargo run -p darkroom-desktop
Android (containerised toolchain, see docker/android):
./docker/android/build.sh cargo ndk -t arm64-v8a build --release
Current state
Working: workspace, GPU context and compute pass, adaptive Slint shell, Android cross-compilation of the core crates.
Not yet working: the zero-copy display path. The build currently uploads frames through the CPU, which is exactly what ARCH §6.1 forbids — measured at 96% of frame time at 4K. Replacing it is spike S1, the project's highest priority.
cargo run -p dr-gpu --example bench --features readback
reproduces that measurement.
Licence
GPL-3.0-or-later.