FR-DEV-10 — Luminance and colour range masks #7

New Issue

2026-09-05T16:09:17Z

dtourolle commented

2026-09-05 16:09:17 +00:00

A mask layer shall support selection by luminance range and by colour range, each a band with soft edges over the image's own values.

Why

Every local adjustment in DarkRoom currently starts from a shape — painted (MaskSource::Brush), drawn (Linear, Radial), or found by a model (Regions, Subject, Category). A range starts from a property, which is what makes a local edit blend without halos and what a luminosity mask has always been.

It is also the only route to skin-tone work, and the prerequisite for composing selections at all — a bright sky is a luminance range that excludes the dark and a colour range that excludes the non-blue.

DarkRoom is ahead of the field at finding a selection. It has nothing for describing one.

Acceptance

Two new MaskSource variants storing band bounds and softness — not pixels — so they diff, sync and merge per field the way the geometry sources already do (FR-NC-9).
Rasterised on the device in the existing mask pass. No CPU raster at any resolution, per the promise mask.rs makes about Stroke.
A range mask renders identically at proxy and at export resolution.
Sidecar round-trip covered by a test.

Lands in

core/dr-pipeline/src/mask.rs, mask.wgsl, ui/dr-ui/src/masks_ui.rs.

Part of the Develop Ergonomics spec (FR-DEV series proposal), 2026-09-05.

A mask layer shall support selection by **luminance range** and by **colour range**, each a band with soft edges over the image's own values. ## Why Every local adjustment in DarkRoom currently starts from a *shape* — painted (`MaskSource::Brush`), drawn (`Linear`, `Radial`), or found by a model (`Regions`, `Subject`, `Category`). A range starts from a *property*, which is what makes a local edit blend without halos and what a luminosity mask has always been. It is also the only route to skin-tone work, and the prerequisite for composing selections at all — a bright sky is a luminance range that excludes the dark **and** a colour range that excludes the non-blue. DarkRoom is ahead of the field at *finding* a selection. It has nothing for *describing* one. ## Acceptance - [ ] Two new `MaskSource` variants storing band bounds and softness — **not pixels** — so they diff, sync and merge per field the way the geometry sources already do (FR-NC-9). - [ ] Rasterised on the device in the existing mask pass. No CPU raster at any resolution, per the promise `mask.rs` makes about `Stroke`. - [ ] A range mask renders identically at proxy and at export resolution. - [ ] Sidecar round-trip covered by a test. ## Lands in `core/dr-pipeline/src/mask.rs`, `mask.wgsl`, `ui/dr-ui/src/masks_ui.rs`. --- Part of the Develop Ergonomics spec (FR-DEV series proposal), 2026-09-05.

dtourolle added the develop masks pipeline size:M labels 2026-09-05 16:09:17 +00:00

dtourolle commented

2026-09-05 16:09:50 +00:00

Blocks #9 — composition without ranges to compose is worth considerably less. Build the ranges first, then do #9 once.
Makes #10 worth doing.

**Blocks** #9 — composition without ranges to compose is worth considerably less. Build the ranges first, then do #9 once. **Makes** #10 worth doing.

dtourolle referenced this issue

2026-09-05 16:09:51 +00:00

FR-DEV-19a — Intersection as a third join #9

dtourolle referenced this issue

2026-09-05 16:09:51 +00:00

FR-DEV-17 — Warn when a crop orphans a mask #10

dtourolle commented

2026-09-11 21:54:20 +00:00

Landed in 68ebf5d. MaskSource::Luminance and MaskSource::Colour store bounds and softness, never pixels, and the band is weighed in mask.wgsl from the demosaiced source. Sidecar round-trip covered by range_masks_keep_their_bands and writing_a_range_mask_twice_is_byte_identical in core/dr-pipeline/tests/mask_sidecar.rs.

Landed in 68ebf5d. MaskSource::Luminance and MaskSource::Colour store bounds and softness, never pixels, and the band is weighed in mask.wgsl from the demosaiced source. Sidecar round-trip covered by range_masks_keep_their_bands and writing_a_range_mask_twice_is_byte_identical in core/dr-pipeline/tests/mask_sidecar.rs.

dtourolle closed this issue

2026-09-11 21:54:20 +00:00

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Reference: dtourolle/DarkRoom#7