Issue #3272: AI masks are enlarged along the photo's edges, no outline under a raised Exposure

An Object / Describe mask is stored as a model's logit grid (288² over the whole photo,
~20 px cells on a 24 MP export) and was enlarged by bilinear sampling alone, so its edge
spilled 1–2 px onto the background; raising the mask's Exposure turned that strip into a
bright outline in previews and exports (CPU and GPU: the GPU renderer evaluates these
shapes with the same CPU `shape_alpha`).

`sample_seg` now guided-filters the sampled logits by the photo's log luminance where the
grid is coarser than the output: the fast (subsampled) guided filter, a window of 1.5 grid
cells, so a preview and an export put the edge in the same place. Filtering logits, not
coverage, lets the confident side win (the spill goes to ≈ 0, not to a mean of ≈ 0.1).
Pixels whose window is all inside or all outside, and edges the photo has no contrast
across, keep the plain sample exactly. Refine Edges still runs afterwards on the combined
mask and finds the edges in place: no second halo, no tightening.

One implementation: `guided_cross` (Refine Edges, Auto Mask) and the new
`guided_cross_fast` share `guided_coeffs`; the subsampled form uses
`local::guided_fast_step` and a box `resize`, like `local::guided_fast`. `guided_cross`'s
output is unchanged.

Existing AI masks become 1–2 px tighter at a subject's edges, on every process; their
inside, outside and contrast-less edges are unchanged. This lands in place under the
bug-fix rule of docs/process-versions.md (output that is in neither the photo nor the
edit), noted there.

Cost per AI selection (M2 Pro, 12 cores; one shape_alpha, before → after):
24 MP 25.7 → 48.2 ms, heap peak 96.5 → 108.8 MB; 60 MP 64.1 → 109.9 ms, 239.9 → 256.7 MB;
2.7 MP preview 3.1 → 10.6 ms, 11.2 → 26.5 MB.

Tests (a dark disc on a light background, its mask on a 32² grid): ≈ 0 one and two px
outside and ≈ 1 inside, all around (1 px outside was 0.66), bit-identical away from the
edge; with Refine Edges 50 / 100 (was 0.29 outside) and the edge within 1 px of the
unrefined one; the same edge position at 256, 512 and 1024 px; a Prompt mask's window
matches the whole render.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/ai-masks.md

@@ -27,6 +27,16 @@ In the Masking panel (M):
   the people out of a sky mask; − ▸ Object then clicks remove one object.
 - **Edge** (per selection, −100…100): below 0 a crisper border, above 0 a feathered one (up to 2 %
   of the long edge, so previews and exports match).
+- **Edges follow the photo** (issue #3272): the model's grid (288² over the whole photo) has
+  ~20 px cells on a 24 MP export, so a plain enlargement put the mask's edge up to a cell off the
+  subject's and a raised Exposure drew a bright outline around it. Where the grid is coarser than
+  the output, the mask's logits are guided-filtered by the photo's log luminance (the fast guided
+  filter, a window of 1.5 grid cells, so a preview and an export put the edge in the same place):
+  near the edge the selection follows the photo's tones, ≈ 0 a pixel or two outside a subject that
+  stands out from its background and ≈ 1 inside. Pixels whose surroundings are all in or all out,
+  and edges the photo has no contrast across, keep the plain enlargement. Refine Edges then works
+  on the combined mask and finds these edges in place. Cost on an M2 Pro, per AI selection: +22 ms
+  and +12 MB at 24 MP, +46 ms and +17 MB at 60 MP, +7.5 ms on a 2.7 MP preview.
 - **Detail:** about a second after the last click (or right after a description), the photo
   around the selection is analyzed again, zoomed in, from a sharper source (~5 s on an M4 Pro,
   in the background); the result is kept as a high-resolution patch (at most 4 per selection),

docs/gaps.md

@@ -1,6 +1,6 @@
 # Gaps: where LightCraft falls short of Lightroom
 
-> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-10-24 · **Change:** minor (gap 30: the Info panel shows the selected photos' shared metadata and marks mixed fields; gap 28: ⌘⌥⇧C / ⌘⌥⇧V copy and paste metadata; gap 13: before a Lightroom catalog import the app asks merge or new library, #2672; gap 28: F8 shows / hides the right panel; import review album hierarchy, #2362; gap 20: Minolta MRW decodes; gap 10: 551 models verified; gap 15: Print Page Options — page numbers, page info, crop marks; gap 28: `\` shows / hides the Filter Bar in the grids; gap 21: Indonesian interface shipped, every message but What's New; gap 27: the Windows x64 installer verified on Windows 11; the Settings → Apps uninstall confirmation remains; gap 28: ⌘L Enable Filters switches the filter off and on; gap 15: Japanese photo and postcard paper sizes in the Print page setup and PDF)
+> **Last reviewed:** 2026-10-11 · **Last updated:** 2026-10-29 · **Change:** minor (gap 5: AI mask edges follow the photo's, no outline under a raised Exposure, #3272; gap 30: the Info panel shows the selected photos' shared metadata and marks mixed fields; gap 28: ⌘⌥⇧C / ⌘⌥⇧V copy and paste metadata; gap 13: before a Lightroom catalog import the app asks merge or new library, #2672; gap 28: F8 shows / hides the right panel; import review album hierarchy, #2362; gap 20: Minolta MRW decodes; gap 10: 551 models verified; gap 15: Print Page Options — page numbers, page info, crop marks; gap 28: `\` shows / hides the Filter Bar in the grids; gap 21: Indonesian interface shipped, every message but What's New; gap 27: the Windows x64 installer verified on Windows 11; the Settings → Apps uninstall confirmation remains; gap 28: ⌘L Enable Filters switches the filter off and on; gap 15: Japanese photo and postcard paper sizes in the Print page setup and PDF)
 
 Every known shortfall, one entry each, ranked by user impact (how many Lightroom users hit it, and
 how hard it blocks them), then by effort. **Agents pick work from the top** (the first entry nobody is
@@ -84,6 +84,7 @@ Beta-blocking gaps (B) total **~230–430 h**; with the stability and platform w
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-29 | minor | Gap 5: Object / Describe masks are enlarged along the photo's edges, so a raised Exposure no longer outlines the subject (#3272); the gap (heuristic Subject / Sky / People, no model mirror) and its hours are unchanged |
 | 2026-10-24 | minor | Gap 28: ⌘⌥⇧C / ⌘⌥⇧V (Ctrl+Alt+Shift+C / V on Windows and Linux) copy and paste metadata; no key leaves the entry; hours unchanged |
 | 2026-10-24 | minor | Gap 30 shrinks: the Info panel's Show Metadata For (Target Photo / Selected Photos, `view.infoSelectedPhotos`) shows the selected photos' shared values and marks fields that differ as Mixed; the All Metadata dialog remains; 1–3 h (was 4–8) |
 | 2026-10-23 | minor | Gap 13: before a Lightroom catalog import the app asks whether it merges into the open library or goes into a new one (opt-out in Settings, #2672); hours unchanged |

docs/parity-checklist.md

@@ -1,6 +1,6 @@
 # Lightroom parity checklist
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-25 · **Change:** minor (LR-BEHAV-TITLEBAR: a double-click follows the system setting, and a panel over the bar keeps the window still; KEYC-METADATA, LRC-LIB-KEYWORDS: ⌥0 / ⌥⇧0 go to the next / previous keyword set; LRC-DEV-HISTOGRAM-DRAG: the histogram's five tonal zones — hover for the value, drag to adjust the Basic control the press locked, double-click to reset; LR-VIEW-HISTOGRAM note updated; MENU-BAR: on macOS a menu item that yields its key to a focused text field or to shortcut recording really lets it go; LR-MERGE-HDR / LR-MERGE-PANO: Lanczos-3 warps; LR-IMP-LOCAL: browsing from the sidebar records the folder; LR-VIEW-ZOOM: only a full-size drag within 20 ms clears a slow-drag verdict; LR-IMP-ADD-DIALOG: hierarchical import album destination reconciled with main, #2362; KEY-SLIDER-NUDGE: vertical wheel nudges need a click or drag in the row; leaving it disarms them; LR-EDIT-OPTICS-PROFILE: Fujifilm nine-knot lens tables read at the plain radius; LR-VIEW-ZOOM: only a full-size drag within 20 ms clears a slow-drag verdict; LRC-LIB-LIBFOLDERS, LR-BEHAV-BG-TASKS: Synchronize Folder's scan shows its folder listing and stops it on ✕; LRC-LIB-LIBFOLDERS: Synchronize Folder says a folder is up to date; LR-LIB-STACK: filmstrip stack badge click; LRC-LIB-REFVIEW / CATALOG-SWITCH: Escape preserves edits; catalog-local pins; deleted and malformed references refused; LRC-LIB-COMPARE: the Info panel labels the active photo while culling, #2398; KEYC-RATING: `\` shows / hides the Filter Bar in the grids; LR-VIEW-PHOTOGRID: the grid reads only the photos an import batch or an edit touched, not the whole list; earlier: LRC-PRINT-PAGE: Print Page Options; LR-META-XMP: fewer false unimported-XMP warnings; KEYC-METADATA: ⌘K / Ctrl+K Add Keywords; LRC-DEV-HISTOGRAM-DRAG: the histogram's five tonal zones — hover for the value, drag to adjust the Basic control the press locked, double-click to reset; LR-VIEW-HISTOGRAM note updated; MENU-BAR: on macOS a menu item that yields its key to a focused text field or to shortcut recording really lets it go; LR-MERGE-HDR / LR-MERGE-PANO: Lanczos-3 warps; LR-IMP-LOCAL: browsing from the sidebar records the folder; LR-VIEW-ZOOM: only a full-size drag within 20 ms clears a slow-drag verdict; LR-IMP-ADD-DIALOG: hierarchical import album destination reconciled with main, #2362; KEY-SLIDER-NUDGE: vertical wheel nudges need a click or drag in the row; leaving it disarms them; LR-EDIT-OPTICS-PROFILE: Fujifilm nine-knot lens tables read at the plain radius; LR-VIEW-ZOOM: only a full-size drag within 20 ms clears a slow-drag verdict; LRC-LIB-LIBFOLDERS, LR-BEHAV-BG-TASKS: Synchronize Folder's scan shows its folder listing and stops it on ✕; LRC-LIB-LIBFOLDERS: Synchronize Folder says a folder is up to date; LR-LIB-STACK: filmstrip stack badge click; LRC-LIB-REFVIEW / CATALOG-SWITCH: Escape preserves edits; catalog-local pins; deleted and malformed references refused; LRC-LIB-COMPARE: the Info panel labels the active photo while culling, #2398; KEYC-RATING: `\` shows / hides the Filter Bar in the grids; LR-VIEW-PHOTOGRID: the grid reads only the photos an import batch or an edit touched, not the whole list; earlier: LRC-PRINT-PAGE: Print Page Options; LR-META-XMP: fewer false unimported-XMP warnings) · **Target:** Adobe Lightroom Classic 15.5 / Lightroom 9.6
+> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-29 · **Change:** minor (LR-MASK-OBJECTS: AI mask edges follow the photo's when enlarged, no outline under a raised Exposure, #3272; LR-BEHAV-TITLEBAR: a double-click follows the system setting, and a panel over the bar keeps the window still; KEYC-METADATA, LRC-LIB-KEYWORDS: ⌥0 / ⌥⇧0 go to the next / previous keyword set; LRC-DEV-HISTOGRAM-DRAG: the histogram's five tonal zones — hover for the value, drag to adjust the Basic control the press locked, double-click to reset; LR-VIEW-HISTOGRAM note updated; MENU-BAR: on macOS a menu item that yields its key to a focused text field or to shortcut recording really lets it go; LR-MERGE-HDR / LR-MERGE-PANO: Lanczos-3 warps; LR-IMP-LOCAL: browsing from the sidebar records the folder; LR-VIEW-ZOOM: only a full-size drag within 20 ms clears a slow-drag verdict; LR-IMP-ADD-DIALOG: hierarchical import album destination reconciled with main, #2362; KEY-SLIDER-NUDGE: vertical wheel nudges need a click or drag in the row; leaving it disarms them; LR-EDIT-OPTICS-PROFILE: Fujifilm nine-knot lens tables read at the plain radius; LR-VIEW-ZOOM: only a full-size drag within 20 ms clears a slow-drag verdict; LRC-LIB-LIBFOLDERS, LR-BEHAV-BG-TASKS: Synchronize Folder's scan shows its folder listing and stops it on ✕; LRC-LIB-LIBFOLDERS: Synchronize Folder says a folder is up to date; LR-LIB-STACK: filmstrip stack badge click; LRC-LIB-REFVIEW / CATALOG-SWITCH: Escape preserves edits; catalog-local pins; deleted and malformed references refused; LRC-LIB-COMPARE: the Info panel labels the active photo while culling, #2398; KEYC-RATING: `\` shows / hides the Filter Bar in the grids; LR-VIEW-PHOTOGRID: the grid reads only the photos an import batch or an edit touched, not the whole list; earlier: LRC-PRINT-PAGE: Print Page Options; LR-META-XMP: fewer false unimported-XMP warnings; KEYC-METADATA: ⌘K / Ctrl+K Add Keywords; LRC-DEV-HISTOGRAM-DRAG: the histogram's five tonal zones — hover for the value, drag to adjust the Basic control the press locked, double-click to reset; LR-VIEW-HISTOGRAM note updated; MENU-BAR: on macOS a menu item that yields its key to a focused text field or to shortcut recording really lets it go; LR-MERGE-HDR / LR-MERGE-PANO: Lanczos-3 warps; LR-IMP-LOCAL: browsing from the sidebar records the folder; LR-VIEW-ZOOM: only a full-size drag within 20 ms clears a slow-drag verdict; LR-IMP-ADD-DIALOG: hierarchical import album destination reconciled with main, #2362; KEY-SLIDER-NUDGE: vertical wheel nudges need a click or drag in the row; leaving it disarms them; LR-EDIT-OPTICS-PROFILE: Fujifilm nine-knot lens tables read at the plain radius; LR-VIEW-ZOOM: only a full-size drag within 20 ms clears a slow-drag verdict; LRC-LIB-LIBFOLDERS, LR-BEHAV-BG-TASKS: Synchronize Folder's scan shows its folder listing and stops it on ✕; LRC-LIB-LIBFOLDERS: Synchronize Folder says a folder is up to date; LR-LIB-STACK: filmstrip stack badge click; LRC-LIB-REFVIEW / CATALOG-SWITCH: Escape preserves edits; catalog-local pins; deleted and malformed references refused; LRC-LIB-COMPARE: the Info panel labels the active photo while culling, #2398; KEYC-RATING: `\` shows / hides the Filter Bar in the grids; LR-VIEW-PHOTOGRID: the grid reads only the photos an import batch or an edit touched, not the whole list; earlier: LRC-PRINT-PAGE: Print Page Options; LR-META-XMP: fewer false unimported-XMP warnings) · **Target:** Adobe Lightroom Classic 15.5 / Lightroom 9.6
 
 The measured, row-by-row checklist: one row per Lightroom feature, menu item and shortcut, what we
 have and what is missing. It answers *does the feature exist?* (feature breadth). Whether it is good
@@ -293,7 +293,7 @@ differences and missing bindings are in [ui-parity.md](ui-parity.md#shortcuts).
 | LR-MASK-SUBJECT | Select subject | P2 | 🟡 | `cmd:mask.add` (`subject`), `crates/pipeline/src/masks.rs` | saliency heuristic, no segmentation model; a photo that carries person mattes (DNG semantic masks: iPhone ProRAW portrait / skin / hair / teeth / glasses mattes) uses them instead (synthetic files only: no corpus file carries person mattes) |
 | LR-MASK-SKY | Select sky | P2 | 🟡 | `cmd:mask.add` (`sky`), `crates/pipeline/src/masks.rs` (`Mattes`), `crates/raw/src/semantic.rs` | heuristic; a photo that carries a sky matte (DNG semantic mask, e.g. iPhone ProRAW) uses it instead, through orientation / crop / lens corrections, preview = export (checked on one CC0 iPhone 12 Pro ProRAW and synthetic files) |
 | LR-MASK-BACKGROUND | Select background | P2 | 🟡 | `cmd:mask.add` (`background`) | inverse of the subject mask (heuristic, or the photo's person mattes) |
-| LR-MASK-OBJECTS | Object selection | P2 | 🟡 | `cmd:mask.add` (`object`, `prompt`), `cmd:mask.objectPoint`, `cmd:mask.refineDetail`, `cmd:segment.prepare`, `cmd:segment.model.status`, `cmd:segment.model.download`, `cmd:segment.model.cancel`, `cmd:app.openSamModelFolder`, `crates/segment`, `crates/engine/src/segment.rs` | SAM 3 in pure Rust (candle; Metal on macOS, CPU elsewhere): Object tile → click to include, ⌥-click to leave out; Describe tile → a text prompt selects every instance ("sky", "the red car"); both also as Add/Subtract/Intersect components; + / − under the selected mask; comma lists (`car, road`); a zoomed-in detail pass for 5–10× finer edges on small objects; per-selection Edge (hard ↔ soft). The model runs on its own worker thread (the UI never waits; panics become errors; a job that fails on the Mac's GPU runs again on the CPU, which then serves the rest of the session, #1974), is unloaded after 10 min idle, and is optional: the segmentation is stored with the mask (288² logits), so renders and exports never need it. Weights are never bundled (SAM License): without them the app offers a consented background download (mirrors, resume, timeouts, SHA-256) — **but no default download location is configured yet** (users set `LIGHTCRAFT_SAM3_MIRRORS` or install by hand: the dialog names the three files, opens the configured model folder with the host opener, preserves setup on an open error, and links docs/ai-masks.md). Not verified against Lightroom's Select Object; no brush/box object mode; the first click on a photo waits for its analysis (~4 s on an M4 Pro, much longer on CPU) |
+| LR-MASK-OBJECTS | Object selection | P2 | 🟡 | `cmd:mask.add` (`object`, `prompt`), `cmd:mask.objectPoint`, `cmd:mask.refineDetail`, `cmd:segment.prepare`, `cmd:segment.model.status`, `cmd:segment.model.download`, `cmd:segment.model.cancel`, `cmd:app.openSamModelFolder`, `crates/segment`, `crates/engine/src/segment.rs` | SAM 3 in pure Rust (candle; Metal on macOS, CPU elsewhere): Object tile → click to include, ⌥-click to leave out; Describe tile → a text prompt selects every instance ("sky", "the red car"); both also as Add/Subtract/Intersect components; + / − under the selected mask; comma lists (`car, road`); a zoomed-in detail pass for 5–10× finer edges on small objects; per-selection Edge (hard ↔ soft); the stored grid is enlarged along the photo's edges (a guided filter of its logits by log luminance, so no outline spills onto the background under a raised Exposure, #3272). The model runs on its own worker thread (the UI never waits; panics become errors; a job that fails on the Mac's GPU runs again on the CPU, which then serves the rest of the session, #1974), is unloaded after 10 min idle, and is optional: the segmentation is stored with the mask (288² logits), so renders and exports never need it. Weights are never bundled (SAM License): without them the app offers a consented background download (mirrors, resume, timeouts, SHA-256) — **but no default download location is configured yet** (users set `LIGHTCRAFT_SAM3_MIRRORS` or install by hand: the dialog names the three files, opens the configured model folder with the host opener, preserves setup on an open error, and links docs/ai-masks.md). Not verified against Lightroom's Select Object; no brush/box object mode; the first click on a photo waits for its analysis (~4 s on an M4 Pro, much longer on CPU) |
 | LR-MASK-PEOPLE | People parts | P2 | ⬜ | | shape exists (no UI): uses the photo's person / skin / hair / teeth / glasses mattes when it carries them (DNG semantic masks), else the subject heuristic |
 | LR-MASK-LANDSCAPE | Landscape classes | P2 | ⬜ | | shape exists, evaluates empty |
 | LR-MASK-BRUSH | Brush mask | P0 | 🟡 | `cmd:tool.brush`, `cmd:mask.brushStroke` (`autoMask`), `crates/pipeline/src/masks.rs`, `crates/ui-egui/src/brush_live.rs` | size/feather/flow/density/erase; Create New Mask starts a separate brush in paint mode; the stroke shows while the button is held with the committed stroke's dab spacing, feather and flow, so fast strokes have no gaps (#517); coverage builds up by passes, not hold time (holding the brush still adds nothing, live or committed, #518); Auto Mask: dabs weighted by similarity to the colour under the dab centre, refined by a guided filter on luminance (CPU + GPU); ⇧-click draws a straight stroke from where the last stroke ended (`connect`), tapering size, feather and flow from that stroke's values when they changed; no A/B brushes; pen pressure (Brush ▸ Pen Pressure, on by default; `pressure` per point in `mask.brushStroke`) scales each dab's size (a tenth to all of it) and flow, live and committed alike, where winit reports a pen force (Windows; not macOS / Linux tablets yet); no tilt |
@@ -959,3 +959,4 @@ Latin stays upright. Advanced Japanese composition remains open. Regression cove
 | 2026-10-23 | patch | LR-BEHAV-ACCESS: the name field of New Album, New Smart Album, Rename and the other one-field dialogs takes the keyboard focus once when the dialog opens instead of every frame, so Tab and Shift+Tab reach the check box, Cancel and OK; status unchanged (🟡) |
 | 2026-10-22 | minor | LR-CROP-AUTO: Auto straighten turns by at most 10° and only on at least 3 agreeing lines, and says when it finds nothing to level by; measured on 68 photos straightened by hand and 300 left as shot, unwanted turns of more than 1° fell from 79 to 19 of the 300. Downgraded ✅ → 🟡: it still leaves most tilted photos alone |
 | 2026-10-23 | patch | LRC-LIB-FILTERBAR: showing an album (`library.source`) while the filter holds an album drops the filter's album, as showing a library folder already dropped its folder filter; before, the old album stayed in the filter unseen (the filter bar has no album chip) and narrowed the next source such as All Photos; the row's note says so; status unchanged (✅) |
+| 2026-10-29 | minor | LR-MASK-OBJECTS: an Object / Describe selection's stored grid is enlarged along the photo's edges (fast guided filter of its logits by log luminance, a 1.5-cell window), so a raised Exposure no longer draws an outline around the subject (#3272); existing AI masks are 1–2 px tighter at edges; status unchanged (🟡) |

docs/process-versions.md

@@ -27,6 +27,13 @@ Blacks at 0) is the identity up to white: the SDR shoulder no longer pulls 1.0 d
 255 to 254, issue #1945). It landed in place as a bug fix, since the tone map promised identity at
 neutral settings; edited curves keep the shoulder and their V1 look.
 
+**AI mask edges** (Object and Describe selections stored as a model's grid) follow the photo's edges
+when they are enlarged to the output (issue #3272): the plain enlargement spilled 1–2 px onto the
+background, which a raised Exposure turned into a bright outline around the subject in previews and
+exports. Existing AI masks become 1–2 px tighter at a subject's edges, on every process; their
+inside, their outside and edges without contrast in the photo are unchanged. It landed in place as
+a bug fix: the outline is output that isn't in the photo nor in the edit, not a look anyone chose.
+
 ## Adding a process
 
 1. Add a variant to `Process` (`V2`), append it to `Process::ALL` (oldest first), give it its number in