Let the fill show the model an open void: mirror depth 0 means no ring and nothing known beyond the band

core/dr-pano/src/fill.rs

@@ -89,12 +89,19 @@ pub struct Params {
     pub coarse: usize,
     /// The fine passes' band width.
     pub band: usize,
-    /// How deep into the picture the mirrored context reaches. A plain
+    /// How deep into the picture the mirrored context reaches, or **zero
-    /// reflection of a deep hole pulls in whatever is that far from the
+    /// for no mirrored context at all**: the void is then shown to the
-    /// edge — a ridge, a peak — and the model, told that is what lies
+    /// model as it is — reaching the picture's edge with nothing beyond,
-    /// beyond, paints it upside down. Folding the reflection within this
+    /// and, beyond the band being filled, still unknown. That is what the
-    /// band keeps the ring looking like the edge it continues (sky beside
+    /// shipped model was trained on (a fine-tune of MI-GAN on voids cut
-    /// sky, grass beside grass) and nothing further away.
+    /// from photographs the way a cylindrical merge cuts them, see
+    /// `docs/panorama.md` §14); a ring would give it a fold to continue.
+    ///
+    /// Non-zero is the stock model's crutch: a plain reflection of a deep
+    /// hole pulls in whatever is that far from the edge — a ridge, a peak —
+    /// and the model, told that is what lies beyond, paints it upside down.
+    /// Folding the reflection within this band keeps the ring looking like
+    /// the edge it continues and nothing further away.
     pub mirror_depth: usize,
     /// How far inside the real edge the fill also regenerates, the two
     /// blended by distance. A hard cut between real pixels and invented
@@ -108,9 +115,9 @@ pub struct Params {
 impl Default for Params {
     fn default() -> Self {
         Params {
-            coarse: 4,
+            coarse: 1,
-            band: 96,
+            band: 192,
-            mirror_depth: 48,
+            mirror_depth: 0,
             feather: 24,
             stride: 384,
         }
@@ -141,7 +148,10 @@ pub fn fill_border(
     } = params;
     let q = q.max(1);
     let band = band.max(8);
-    let mirror_depth = mirror_depth.max(1);
+    // No ring: the void beyond the band stays unknown, as in the model's
+    // training; with a ring the far side is the coarse fill, presented as
+    // known, which the stock model needed to see something there.
+    let open = mirror_depth == 0;
     if width == 0 || height == 0 || rgb.len() != width * height * 3 || known.len() != width * height
     {
         return Err(PanoError::Input("fill: buffer sizes disagree".into()));
@@ -227,7 +237,11 @@ pub fn fill_border(
         let mut any = false;
         for i in 0..width * height {
             let in_band = !known[i] && dist[i] > lo && dist[i] <= hi;
-            band_known[i] = !in_band;
+            band_known[i] = if open {
+                known[i] || dist[i] <= lo
+            } else {
+                !in_band
+            };
             any |= in_band;
         }
         if !any {
@@ -369,7 +383,7 @@ fn fill_once(
             if known[i] {
                 continue;
             }
-            let p = (yy + RING) * pw + (xx + RING);
+            let p = (yy + ctx.ring) * pw + (xx + ctx.ring);
             if wsum[p] > 0.0 {
                 for ch in 0..3 {
                     rgb[i * 3 + ch] = (acc[p * 3 + ch] / wsum[p]).clamp(0.0, 1.0);
@@ -478,12 +492,25 @@ fn fold(d: usize, depth: usize) -> usize {
 struct MirroredContext {
     width: usize,
     height: usize,
+    /// The padding on every side: `RING` with mirrored context, 0 without.
+    ring: usize,
     rgb: Vec<f32>,
     hole: Vec<bool>,
 }
 
 impl MirroredContext {
     fn build(rgb: &[f32], width: usize, height: usize, known: &[bool], depth: usize) -> Self {
+        if depth == 0 {
+            // Open: the picture as it is, the hole as it is. What the hole
+            // holds does not matter — the model masks it out.
+            return MirroredContext {
+                width,
+                height,
+                ring: 0,
+                rgb: rgb.to_vec(),
+                hole: known.iter().map(|&k| !k).collect(),
+            };
+        }
         let fold = |d: usize| fold(d, depth);
         let (pw, ph) = (width + 2 * RING, height + 2 * RING);
         let mut canvas = vec![0.0f32; pw * ph * 3];
@@ -534,6 +561,7 @@ impl MirroredContext {
         MirroredContext {
             width: pw,
             height: ph,
+            ring: RING,
             rgb: canvas,
             hole,
         }
@@ -634,7 +662,10 @@ mod tests {
             200,
             &known,
             &mut model,
-            test_params(0),
+            Params {
+                mirror_depth: 48,
+                ..test_params(0)
+            },
             &mut |_, _| {},
         )
         .unwrap();
@@ -648,6 +679,42 @@ mod tests {
         }
     }
 
+    #[test]
+    fn an_open_void_reaches_the_tile_edge_and_stays_unknown_beyond_the_band() {
+        // A 150-tall hole above and below; bands of 96. With no ring the
+        // first band's tiles sit at the picture's edge, so a tile's top
+        // row is unknown, and the rows deeper than the band are unknown
+        // too — not "known" coarse fill — exactly as the model was trained.
+        let (mut rgb, known) = picture(200, 500, 150);
+        let mut model = Flat {
+            tile: 64,
+            seen: Vec::new(),
+        };
+        fill_border(
+            &mut rgb,
+            200,
+            500,
+            &known,
+            &mut model,
+            Params {
+                band: 96,
+                ..test_params(0)
+            },
+            &mut |_, _| {},
+        )
+        .unwrap();
+        // The first pass's tile at the picture's top edge is unknown
+        // through and through: the hole is 150 deep, the tile 64, and
+        // nothing beyond the band was presented as known. With a ring, or
+        // with the far side shown as coarse fill, no tile is ever all hole.
+        assert!(model.seen.iter().any(|(_, k)| k.iter().all(|&v| !v)));
+        for i in 0..200 * 500 {
+            if !known[i] {
+                assert!((rgb[i * 3] - 0.5).abs() < 1e-4, "pixel {i}");
+            }
+        }
+    }
+
     #[test]
     fn the_fine_passes_run_in_bands_after_the_coarse_one() {
         // A 150-tall hole above and below a picture: the coarse pass sees
@@ -663,7 +730,12 @@ mod tests {
             500,
             &known,
             &mut model,
-            test_params(0),
+            Params {
+                coarse: 4,
+                band: 96,
+                mirror_depth: 48,
+                ..test_params(0)
+            },
             &mut |_, _| {},
         )
         .unwrap();

docs/panorama.md

@@ -486,3 +486,40 @@ rectangle.
 `models/LICENCE.md`), installed by the PKGBUILD and unpacked by the APK
 beside the face and scene models; `tools/export-migan.sh` regenerates it
 from the upstream checkpoint.
+
+## 14. The fill, trained — 2026-09-20
+
+§13.5 named the remaining fault: in a deep corner the stock model puts its
+Places2 prior — clouds, peaks, a water line — into a hole, because it was
+trained on holes *inside* pictures and a panorama's border is a hole with
+the picture on one side and nothing on the other. Every ring (mirror,
+replicate, detrend) treated the symptom. The fix is a model that has seen
+the real thing: **MI-GAN's 512 generator fine-tuned on border-shaped voids
+cut from the user's own photographs**, in a separate repository
+(`darkroom-infill`, beside this one), so the truth beyond the void is known
+and the model learns one-sided extrapolation.
+
+**What it was trained on.** Voids made the way this merge makes them:
+frames with a yaw, a common pitch and per-frame roll, projected onto the
+cylinder and rasterised, the canvas their union's bounding box, the void
+the canvas outside the union — arcs where straight edges bent, cusps where
+frames meet, the bow-tie wedge at a corner (a third of tiles are cut at a
+canvas corner). Voids to 256 px deep at a 512 tile. Half the deep tiles
+train the *second pass*: a no-grad first pass fills the tile, its nearest
+band (64–256 px) is marked known, and the remaining void is the example —
+so the model continues its own output without drift, which is how `fill`
+runs deep voids. Data: ~7 400 pictures — the 1024-px proxy tier of the
+library and ~2 000 raws sampled evenly across every year, developed at
+half size. Loss: hole-weighted L1, VGG16 perceptual, a hinge PatchGAN.
+One night on the reference desktop's RTX 3050.
+
+**What changed here.** `FillParams::mirror_depth` **0** is now "no ring":
+the void reaches the tile's edge with nothing beyond, and beyond the band
+being filled the void stays *unknown* rather than presented as known coarse
+fill — the two conditions the model was trained under. Defaults: mirror 0,
+coarse 1 (the coarse pass seeds nothing the model is allowed to see), band
+192. The ring remains on the page for the stock model's sake, at any depth
+above zero. The model file is a drop-in (`models/inpaint/migan-512.onnx`,
+same six operators, same tensors) and the engine loads it unchanged.
+
+**Measured.** PLACEHOLDER

docs/traceability.md

@@ -107,7 +107,7 @@ A tag naming an ID `requirements.md` does not define — what renumbering produc
 | FR-MRG-3 | [`core/dr-decode/examples/linear_dng.rs:1`](../core/dr-decode/examples/linear_dng.rs#L1), [`core/dr-decode/src/lib.rs:137`](../core/dr-decode/src/lib.rs#L137), [`core/dr-decode/src/lib.rs:144`](../core/dr-decode/src/lib.rs#L144), [`core/dr-decode/src/lib.rs:598`](../core/dr-decode/src/lib.rs#L598), [`core/dr-decode/src/profile.rs:395`](../core/dr-decode/src/profile.rs#L395), [`core/dr-export/src/dng.rs:1`](../core/dr-export/src/dng.rs#L1), [`core/dr-gpu/src/demosaic.rs:254`](../core/dr-gpu/src/demosaic.rs#L254), [`ui/dr-ui/src/merge.rs:1`](../ui/dr-ui/src/merge.rs#L1) |
 | FR-MRG-4 | [`core/dr-export/src/inscribed.rs:1`](../core/dr-export/src/inscribed.rs#L1), [`core/dr-pano/src/fill.rs:1`](../core/dr-pano/src/fill.rs#L1), [`core/dr-pano/src/migan.rs:1`](../core/dr-pano/src/migan.rs#L1), [`core/dr-pano/src/projection.rs:1`](../core/dr-pano/src/projection.rs#L1), [`ui/dr-ui/src/library.rs:4457`](../ui/dr-ui/src/library.rs#L4457), [`ui/dr-ui/src/library.rs:4461`](../ui/dr-ui/src/library.rs#L4461), [`ui/dr-ui/src/merge.rs:143`](../ui/dr-ui/src/merge.rs#L143), [`ui/dr-ui/src/merge_ui.rs:1`](../ui/dr-ui/src/merge_ui.rs#L1), [`ui/dr-ui/ui/merge.slint:1`](../ui/dr-ui/ui/merge.slint#L1), [`ui/dr-ui/ui/merge.slint:46`](../ui/dr-ui/ui/merge.slint#L46) |
 | FR-MRG-5 | [`core/dr-pano/src/align.rs:1`](../core/dr-pano/src/align.rs#L1), [`ui/dr-ui/src/merge.rs:1`](../ui/dr-ui/src/merge.rs#L1), [`ui/dr-ui/src/merge_ui.rs:1`](../ui/dr-ui/src/merge_ui.rs#L1), [`ui/dr-ui/ui/merge.slint:1`](../ui/dr-ui/ui/merge.slint#L1) |
-| FR-MRG-6 | [`core/dr-pipeline/src/sidecar.rs:1033`](../core/dr-pipeline/src/sidecar.rs#L1033), [`core/dr-pipeline/src/sidecar.rs:113`](../core/dr-pipeline/src/sidecar.rs#L113), [`core/dr-pipeline/src/sidecar.rs:123`](../core/dr-pipeline/src/sidecar.rs#L123), [`core/dr-pipeline/src/sidecar.rs:2241`](../core/dr-pipeline/src/sidecar.rs#L2241), [`core/dr-pipeline/src/sidecar.rs:841`](../core/dr-pipeline/src/sidecar.rs#L841), [`ui/dr-ui/src/merge.rs:838`](../ui/dr-ui/src/merge.rs#L838) |
+| FR-MRG-6 | [`core/dr-pipeline/src/sidecar.rs:1033`](../core/dr-pipeline/src/sidecar.rs#L1033), [`core/dr-pipeline/src/sidecar.rs:113`](../core/dr-pipeline/src/sidecar.rs#L113), [`core/dr-pipeline/src/sidecar.rs:123`](../core/dr-pipeline/src/sidecar.rs#L123), [`core/dr-pipeline/src/sidecar.rs:2241`](../core/dr-pipeline/src/sidecar.rs#L2241), [`core/dr-pipeline/src/sidecar.rs:841`](../core/dr-pipeline/src/sidecar.rs#L841), [`ui/dr-ui/src/merge.rs:842`](../ui/dr-ui/src/merge.rs#L842) |
 | FR-MRG-7 | [`ui/dr-ui/src/merge.rs:1`](../ui/dr-ui/src/merge.rs#L1), [`ui/dr-ui/src/merge_ui.rs:1`](../ui/dr-ui/src/merge_ui.rs#L1), [`ui/dr-ui/ui/app.slint:829`](../ui/dr-ui/ui/app.slint#L829), [`ui/dr-ui/ui/merge.slint:1`](../ui/dr-ui/ui/merge.slint#L1) |
 | FR-MRG-8 | [`core/dr-pano/src/xfeat.rs:1`](../core/dr-pano/src/xfeat.rs#L1), [`core/dr-segment/examples/onnx_probe.rs:1`](../core/dr-segment/examples/onnx_probe.rs#L1) |
 | FR-NC-1 | [`core/dr-sync-nextcloud/src/auth.rs:132`](../core/dr-sync-nextcloud/src/auth.rs#L132), [`core/dr-sync-nextcloud/src/auth.rs:44`](../core/dr-sync-nextcloud/src/auth.rs#L44), [`core/dr-sync-nextcloud/src/provider.rs:1`](../core/dr-sync-nextcloud/src/provider.rs#L1), [`core/dr-sync/src/account.rs:375`](../core/dr-sync/src/account.rs#L375), [`ui/dr-ui/src/launch.rs:316`](../ui/dr-ui/src/launch.rs#L316), [`ui/dr-ui/src/launch.rs:61`](../ui/dr-ui/src/launch.rs#L61), [`ui/dr-ui/src/launch_ui.rs:418`](../ui/dr-ui/src/launch_ui.rs#L418) |

models/LICENCE.md

@@ -104,11 +104,16 @@ the dataset licence restricts models trained on it by name.
 
 | File | Source | Trained on | Used by |
 |---|---|---|---|
-| `inpaint/migan-512.onnx` | `migan_512_places2.pt` from `https://github.com/Picsart-AI-Research/MI-GAN` (Sargsyan et al., ICCV 2023) | Places2, by the authors | the panorama border fill (FR-MRG-4) |
+| `inpaint/migan-512.onnx` | `migan_512_places2.pt` from `https://github.com/Picsart-AI-Research/MI-GAN` (Sargsyan et al., ICCV 2023), **fine-tuned** in the `darkroom-infill` repository (2026-09-20) | Places2 by the authors, then ~7 400 of the maintainer's own photographs with border-shaped voids | the panorama border fill (FR-MRG-4) |
 
-Exported by `tools/export-migan.sh`: the bare 512 generator at a fixed
+The bare 512 generator at a fixed `1×4×512×512`, six operator types; the
-`1×4×512×512`, six operator types. The tiling, the context and the blend are
+tiling, the context and the blend are Rust (`dr_pano::fill`). Since
-Rust (`dr_pano::fill`).
+2026-09-20 the shipped file is the fine-tune (`docs/panorama.md` §14),
+exported by `python -m infill.export` in `darkroom-infill`;
+`tools/export-migan.sh` still produces the stock generator from the upstream
+checkpoint, which the fine-tune starts from. The fine-tuned weights are a
+derivative of the MIT weights trained on photographs the maintainer owns,
+and carry the same MIT grant.
 
 **MIT, code and weights alike** — `LICENSE` and `LICENSE-WEIGHTS` in the
 repository, both read on 2026-09-19, both the plain MIT text with no further

tools/export-migan.sh

@@ -8,6 +8,12 @@
 #
 #   ./tools/export-migan.sh    # -> models/inpaint/migan-512.onnx
 #
+# Since 2026-09-20 the file that ships is not this export but a fine-tune of
+# it on panorama-border voids (docs/panorama.md §14), made in the
+# `darkroom-infill` repository with `python -m infill.export`. This script
+# still yields the stock generator — the fine-tune's starting point, and the
+# model the page's "mirror depth" knob above zero was built around.
+#
 # Requires `uv`. Everything else is fetched into a throwaway venv, including
 # a CPU-only torch and `gdown` for the checkpoint, which the authors keep on
 # Google Drive (models/LICENCE.md has the licence; it is MIT).

ui/dr-ui/src/merge.rs

@@ -181,7 +181,11 @@ impl FillSettings {
             params: dr_pano::FillParams {
                 coarse: self.params.coarse,
                 band: px(self.params.band).max(8),
-                mirror_depth: px(self.params.mirror_depth),
+                mirror_depth: if self.params.mirror_depth == 0 {
+                    0
+                } else {
+                    px(self.params.mirror_depth)
+                },
                 feather: if self.params.feather == 0 {
                     0
                 } else {

ui/dr-ui/src/merge_ui.rs

@@ -339,7 +339,7 @@ pub fn wire<S, C, F>(
                 "erosion" => f.erosion = v,
                 "coarse" => f.params.coarse = v.max(1),
                 "band" => f.params.band = v.max(8),
-                "mirror" => f.params.mirror_depth = v.max(1),
+                "mirror" => f.params.mirror_depth = v,
                 "feather" => f.params.feather = v,
                 _ => return,
             }

ui/dr-ui/ui/merge.slint

@@ -63,9 +63,9 @@ export component MergePage inherits Rectangle {
     /// seam. Working pixels, at the merge's working scale.
     in property <float> fill-scale: 2;
     in property <float> fill-erosion: 4;
-    in property <float> fill-coarse: 4;
+    in property <float> fill-coarse: 1;
-    in property <float> fill-band: 96;
+    in property <float> fill-band: 192;
-    in property <float> fill-mirror: 48;
+    in property <float> fill-mirror: 0;
     in property <float> fill-feather: 48;
 
     /// The composite, once written: its name for the status line, and
@@ -240,26 +240,26 @@ export component MergePage inherits Rectangle {
                         SliderRow {
                             label: "Coarse pass";
                             hint: "reduction of the structure pass; 1 skips it";
-                            value: root.fill-coarse; default-value: 4; minimum: 1; maximum: 8;
+                            value: root.fill-coarse; default-value: 1; minimum: 1; maximum: 8;
                             enabled: !root.running && !root.done;
                             changed(v) => { root.fill-knob("coarse", v); }
-                            reset => { root.fill-knob("coarse", 4); }
+                            reset => { root.fill-knob("coarse", 1); }
                         }
                         SliderRow {
                             label: "Band width";
                             hint: "the fine passes' bands from the edge outward, working pixels";
-                            value: root.fill-band; default-value: 96; minimum: 16; maximum: 384;
+                            value: root.fill-band; default-value: 192; minimum: 16; maximum: 384;
                             enabled: !root.running && !root.done;
                             changed(v) => { root.fill-knob("band", v); }
-                            reset => { root.fill-knob("band", 96); }
+                            reset => { root.fill-knob("band", 192); }
                         }
                         SliderRow {
                             label: "Mirror depth";
-                            hint: "how far into the picture the mirrored context reaches";
+                            hint: "0: the void as it is, what the model was trained on; otherwise how far into the picture a mirrored context reaches";
-                            value: root.fill-mirror; default-value: 48; minimum: 4; maximum: 512;
+                            value: root.fill-mirror; default-value: 0; minimum: 0; maximum: 512;
                             enabled: !root.running && !root.done;
                             changed(v) => { root.fill-knob("mirror", v); }
-                            reset => { root.fill-knob("mirror", 48); }
+                            reset => { root.fill-knob("mirror", 0); }
                         }
                         SliderRow {
                             label: "Seam feather";