diff --git a/ROADMAP.md b/ROADMAP.md
index 9d2455b5..31fb27f4 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -127,7 +127,7 @@ Ranked; detail in [docs/roadmap.md](docs/roadmap.md) and [docs/gaps.md](docs/gap
 
 | Date | What landed |
 |---|---|
-| 2026-10-11 | Effect › Brush Strokes: Accented Edges, Angled Strokes, Crosshatch, Dark Strokes, Ink Outlines, Spatter, Sprayed Strokes, Sumi-e (G2). Command parameters from agents and files checked before anything changes (paint, place, cuts, dashes, crop, asset ids, anchors, paths, distort; #984–#999); command dialogs keep whole numbers whole, so Create Object Mosaic takes the tiles typed (#1000); stepper arrows take Shift (×10) and Ctrl/Cmd (÷10) like the arrow keys (#991). Exports and Rasterize supersample Art Optimized edges, so shapes meeting edge to edge leave no seam (#983). Character and paragraph styles take leading, kerning, mojikumi and the other attributes left out at their defaults (#1001). Drawing, typing and pasting with no layer shown and unlocked is refused instead of adding art to a hidden or locked layer (#1002). MCP `add_text` gives type on or in a path the colour asked for (#1003). MCP `screenshot` of a connected app renders the artboard asked for (#1004). `vectorcraft-cli run` ends quietly when its reader closes early (#1005). Select › All on Active Artboard selects on the artboard made active, not always the first (#1006). Reverse Gradient keeps off-centre midpoints, mirrored (#1007). A polar grid with no radial dividers draws none (#1008). Use Precise Cursors also covers the Pen's join pointer (#1009). SVGs with one absolute and one unitless root side import at their size, unstretched (#1010). DXF US survey inches, yards and miles open at their size and name (#1011). A file placed into a document with no other links follows its first change even while the app sits idle (#1031). PDF import keeps the style a font name says when the file doesn't embed the font (#1023). Shift selects ruler guides and art together, and Delete removes both (#1022). Open filled paths are hit by their fill on every side, the rotate cursor bows around the corner it is at, the flip icons match their flips, the Color Picker previews on the selection, and Properties › Transform reaches Scale Corners and Scale Strokes & Effects (#1036). Offset Path and the other booleans finish on outlines where the sweep used to loop until memory ran out (linesweeper 0.5, #1028). Floating panel groups stack into sets that move together, collapse to their tabs and dock as extra dock columns that scroll (#1020). Ruler guides live on layers: listed in the Layers panel, shown, hidden, locked, duplicated, merged and deleted with their layer, and moved between layers (#1021). A `.ai` whose editing data uses global process colours (`Xk`/`XK`) or pattern fills keeps its sublayers: the colours come in as global swatches at their tint, the patterns as pattern swatches (#1025). A `.ai` in PostScript form opens through its layers, read from the program itself, also when it names the prolog defining its operators without including it, as Rhino and other CAD apps write it (#1027). A fill or stroke chosen while the Type tool has characters selected colours just those characters (#1063). Scaled type shows its scaled font size, leading, baseline shift and horizontal scale in the Character panel, and a size typed there is the size you get (#1034). Character panel menu › Proportional Metrics sets Japanese and Chinese full-width glyphs on the font's proportional widths in horizontal type (#966). Align, Distribute, Move, Arrange, Lock, Hide, Ungroup and other Object commands that would change nothing no longer record an undo step or mark the document changed (#1060). Spot colours defined in Lab open with their Lab values from `.ai` and PDF files, instead of as wrong RGB colours or their CMYK equivalents (#1032). Build scripts leave a generated source they wouldn't change untouched, so the next build doesn't compile most of the workspace again where file times lose their sub-second part (#1051). A fill colour recolours the gradient mesh point last clicked with the Mesh tool or Direct Selection, and a Mesh tool click on a mesh's point selects that mesh (#1052). The All Tools drawer stays two tools wide instead of filling a wide window (#1054). Text Wrap's Make, Release and Options refuse a list of object ids with a malformed or unknown id instead of skipping it (#1055). A freeform gradient line with a malformed point index is refused instead of being shortened to the indices that are valid (#1056). The Corners dialog (`ui.corners`) refuses a malformed object id or a listed anchor that isn't a corner instead of editing the selection or the other corners (#1057). New View refuses a centre that isn't exactly [x, y] and a rotation that isn't a number, instead of trimming the one and saving the other as 0° (#1058). The command sweeps try junk scale, spacing and artboard values too, which they had skipped since before those bugs were fixed (#1059). EPS and PostScript `arc` and `arcn` with huge angles no longer hang the import, and an arc whose angles are whole turns apart is empty, as the PostScript reference defines it (#1062). Align and Distribute Spacing keep the key object still also when it is inside a selected group or compound path (#1074). A `.ai` whose layers can't be read yet still opens with its artboards where they were (in a grid, say), not in a row (#1068). Layer Options (`ui.layerOptions`) refuses a malformed or unknown row id instead of skipping it or opening on the highlighted rows (#1077). Shaper scribbles given a list of object ids refuse a malformed or unknown id instead of skipping it and editing the shapes that remain (#1078). Delete Width Point (`stroke.widthPoint.remove`) refuses a list of indices with a malformed entry instead of deleting the points that remain, and no longer wraps a huge index round on the web (#1079). Preferences' checkboxes have an outline when the pointer isn't over them, in every interface brightness, as the app's other dialogs' checkboxes do (#1080). The last plain checkboxes (Properties panel snapping and Scale Strokes & Effects, Revolve, Save options, Export for Screens, Variables, plug-in forms) keep a visible box at rest in every theme too (#885). Setting or copying a width point with a malformed index is refused instead of adding a new point or wrapping a huge index round (follow-up to #1079). An Illustrator EPS opened through its layers keeps its own page size and the red outline of text stacked over a dark one, as 0.8.0 did (#1102). The macOS DMG is built so the app in it passes `codesign --verify --strict --deep`, and the release checks that it does (#1085). Swatch and graphic style libraries, Libraries panel files, presets and plug-ins dropped on the window open as File › Open opens them instead of being placed on the canvas (#1083). A key object needs another selected object outside it: a change that leaves one object selected lets the key go, and one selected object aligns to the artboard whatever Align To says (#1088). Align to Artboard aligns to the active artboard, and actions play their Align to Artboard, All on Active Artboard and Paste in Place, in Front and in Back steps on the artboard active when they play (#1105). Align refuses a call with neither direction, and Align, Distribute, Reflect and Shear refuse a direction, axis, target or bounds they don't take instead of falling back to a default (#1106). `object.setProps` deselects the objects it hides or locks, the key object included, as the Layers panel's eye and lock do (#1107). Align, Distribute and Distribute Spacing move pattern tiles with the art when General › Transform Pattern Tiles is on (#1108). Object › Lock › All Artwork Above and Object › Hide › All Artwork Above deselect the selected objects they lock or hide, the key object included (#1109). Save Swatch Library's `count` is the number of swatches the file holds: `.gpl` and `.ase` hold solid colors only, and CSS leaves freeform gradients out (#1110). In a rotated view (Rotate View), an artboard's name stays at its own top-left corner (#1095). Ctrl+Shift+L, C, R, J and F align or justify the paragraphs of the selected type, or those the Type tool's selection touches (#1111). On macOS, file dialogs are sheets on the document window, so resizing one no longer crashes the app; while one is open the menus, Quit and Close wait, and its answer goes to the document that asked (#867). Shape Builder merges regions that crossing lines cut along the lines' own edges, so a strip merged across a grid of lines is one outline with no seams left inside (#1081). Proportional Metrics also works in vertical type: upright glyphs take the font's proportional heights (`vpal`), and Line-end Punctuation Half Width takes nothing more off the punctuation it re-spaced (#1082). Plug-in whole-number parameters keep their exact value however large, and stay in the range the manifest gives (#1091). PDF and `.ai` import keeps type spaced glyph by glyph (character tightening, optical kerning) with each glyph in its place, giving each character its own tracking when the file's font is installed, and CJK punctuation closed up by its proportional width continues its line (#1101). Direct Selection: pressing an anchor of a path selected whole keeps all its anchors selected, so the drag moves them all; Alt-dragging by an anchor copies the whole path, held by that anchor, which snaps onto other anchors and onto the original the copy leaves behind; Alt pressed or released during the drag turns the copy on and off, as with the Selection tool, whose copies snap to their original too, and the undo step is named Copy or Move for what the drag did (#1104). The toolbar's Fill/Stroke proxy and Color, Gradient and None buttons grow in two columns, where the three drawing modes sit side by side (#1129). An image copied in a browser that puts its `<img>` markup on the clipboard as text pastes as the picture, not the markup (#1089). `file.place` of an SVG with `crop: "crop"` frames and clips it by its viewBox, so art drawn on a shared canvas keeps its place and scale (#788). While a star is dragged, Ctrl/Cmd keeps its inner radius as the outer one grows and Alt keeps its shoulders straight (#812). Edit Toolbar opens the All Tools drawer beside the toolbar, dims the tools already in it, and adds, removes and moves tools by drag and drop while it is open (#1018). The Selection tool's arrow is black and Direct Selection's white in every theme, as users know them: in the dark themes they looked swapped. The font menu keeps its highlight on the same font when the list changes under it (a family's styles listed above it, fonts that finish loading, a favourite unstarred), and ends the live preview when that font leaves the list (#1116). The Windows installer has a Shortcuts page with a ticked "Create a desktop shortcut" box, and a silent install adds the shortcut unless `INSTALLDESKTOPSHORTCUT=""` is passed (#1128). |
+| 2026-10-11 | Effect › Brush Strokes: Accented Edges, Angled Strokes, Crosshatch, Dark Strokes, Ink Outlines, Spatter, Sprayed Strokes, Sumi-e (G2). Command parameters from agents and files checked before anything changes (paint, place, cuts, dashes, crop, asset ids, anchors, paths, distort; #984–#999); command dialogs keep whole numbers whole, so Create Object Mosaic takes the tiles typed (#1000); stepper arrows take Shift (×10) and Ctrl/Cmd (÷10) like the arrow keys (#991). Exports and Rasterize supersample Art Optimized edges, so shapes meeting edge to edge leave no seam (#983). Character and paragraph styles take leading, kerning, mojikumi and the other attributes left out at their defaults (#1001). Drawing, typing and pasting with no layer shown and unlocked is refused instead of adding art to a hidden or locked layer (#1002). MCP `add_text` gives type on or in a path the colour asked for (#1003). MCP `screenshot` of a connected app renders the artboard asked for (#1004). `vectorcraft-cli run` ends quietly when its reader closes early (#1005). Select › All on Active Artboard selects on the artboard made active, not always the first (#1006). Reverse Gradient keeps off-centre midpoints, mirrored (#1007). A polar grid with no radial dividers draws none (#1008). Use Precise Cursors also covers the Pen's join pointer (#1009). SVGs with one absolute and one unitless root side import at their size, unstretched (#1010). DXF US survey inches, yards and miles open at their size and name (#1011). A file placed into a document with no other links follows its first change even while the app sits idle (#1031). PDF import keeps the style a font name says when the file doesn't embed the font (#1023). Shift selects ruler guides and art together, and Delete removes both (#1022). Open filled paths are hit by their fill on every side, the rotate cursor bows around the corner it is at, the flip icons match their flips, the Color Picker previews on the selection, and Properties › Transform reaches Scale Corners and Scale Strokes & Effects (#1036). Offset Path and the other booleans finish on outlines where the sweep used to loop until memory ran out (linesweeper 0.5, #1028). Floating panel groups stack into sets that move together, collapse to their tabs and dock as extra dock columns that scroll (#1020). Ruler guides live on layers: listed in the Layers panel, shown, hidden, locked, duplicated, merged and deleted with their layer, and moved between layers (#1021). A `.ai` whose editing data uses global process colours (`Xk`/`XK`) or pattern fills keeps its sublayers: the colours come in as global swatches at their tint, the patterns as pattern swatches (#1025). A `.ai` in PostScript form opens through its layers, read from the program itself, also when it names the prolog defining its operators without including it, as Rhino and other CAD apps write it (#1027). A fill or stroke chosen while the Type tool has characters selected colours just those characters (#1063). Scaled type shows its scaled font size, leading, baseline shift and horizontal scale in the Character panel, and a size typed there is the size you get (#1034). Character panel menu › Proportional Metrics sets Japanese and Chinese full-width glyphs on the font's proportional widths in horizontal type (#966). Align, Distribute, Move, Arrange, Lock, Hide, Ungroup and other Object commands that would change nothing no longer record an undo step or mark the document changed (#1060). Spot colours defined in Lab open with their Lab values from `.ai` and PDF files, instead of as wrong RGB colours or their CMYK equivalents (#1032). Build scripts leave a generated source they wouldn't change untouched, so the next build doesn't compile most of the workspace again where file times lose their sub-second part (#1051). A fill colour recolours the gradient mesh point last clicked with the Mesh tool or Direct Selection, and a Mesh tool click on a mesh's point selects that mesh (#1052). The All Tools drawer stays two tools wide instead of filling a wide window (#1054). Text Wrap's Make, Release and Options refuse a list of object ids with a malformed or unknown id instead of skipping it (#1055). A freeform gradient line with a malformed point index is refused instead of being shortened to the indices that are valid (#1056). The Corners dialog (`ui.corners`) refuses a malformed object id or a listed anchor that isn't a corner instead of editing the selection or the other corners (#1057). New View refuses a centre that isn't exactly [x, y] and a rotation that isn't a number, instead of trimming the one and saving the other as 0° (#1058). The command sweeps try junk scale, spacing and artboard values too, which they had skipped since before those bugs were fixed (#1059). EPS and PostScript `arc` and `arcn` with huge angles no longer hang the import, and an arc whose angles are whole turns apart is empty, as the PostScript reference defines it (#1062). Align and Distribute Spacing keep the key object still also when it is inside a selected group or compound path (#1074). A `.ai` whose layers can't be read yet still opens with its artboards where they were (in a grid, say), not in a row (#1068). Layer Options (`ui.layerOptions`) refuses a malformed or unknown row id instead of skipping it or opening on the highlighted rows (#1077). Shaper scribbles given a list of object ids refuse a malformed or unknown id instead of skipping it and editing the shapes that remain (#1078). Delete Width Point (`stroke.widthPoint.remove`) refuses a list of indices with a malformed entry instead of deleting the points that remain, and no longer wraps a huge index round on the web (#1079). Preferences' checkboxes have an outline when the pointer isn't over them, in every interface brightness, as the app's other dialogs' checkboxes do (#1080). The last plain checkboxes (Properties panel snapping and Scale Strokes & Effects, Revolve, Save options, Export for Screens, Variables, plug-in forms) keep a visible box at rest in every theme too (#885). Setting or copying a width point with a malformed index is refused instead of adding a new point or wrapping a huge index round (follow-up to #1079). An Illustrator EPS opened through its layers keeps its own page size and the red outline of text stacked over a dark one, as 0.8.0 did (#1102). The macOS DMG is built so the app in it passes `codesign --verify --strict --deep`, and the release checks that it does (#1085). Swatch and graphic style libraries, Libraries panel files, presets and plug-ins dropped on the window open as File › Open opens them instead of being placed on the canvas (#1083). A key object needs another selected object outside it: a change that leaves one object selected lets the key go, and one selected object aligns to the artboard whatever Align To says (#1088). Align to Artboard aligns to the active artboard, and actions play their Align to Artboard, All on Active Artboard and Paste in Place, in Front and in Back steps on the artboard active when they play (#1105). Align refuses a call with neither direction, and Align, Distribute, Reflect and Shear refuse a direction, axis, target or bounds they don't take instead of falling back to a default (#1106). `object.setProps` deselects the objects it hides or locks, the key object included, as the Layers panel's eye and lock do (#1107). Align, Distribute and Distribute Spacing move pattern tiles with the art when General › Transform Pattern Tiles is on (#1108). Object › Lock › All Artwork Above and Object › Hide › All Artwork Above deselect the selected objects they lock or hide, the key object included (#1109). Save Swatch Library's `count` is the number of swatches the file holds: `.gpl` and `.ase` hold solid colors only, and CSS leaves freeform gradients out (#1110). In a rotated view (Rotate View), an artboard's name stays at its own top-left corner (#1095). Ctrl+Shift+L, C, R, J and F align or justify the paragraphs of the selected type, or those the Type tool's selection touches (#1111). On macOS, file dialogs are sheets on the document window, so resizing one no longer crashes the app; while one is open the menus, Quit and Close wait, and its answer goes to the document that asked (#867). Shape Builder merges regions that crossing lines cut along the lines' own edges, so a strip merged across a grid of lines is one outline with no seams left inside (#1081). Proportional Metrics also works in vertical type: upright glyphs take the font's proportional heights (`vpal`), and Line-end Punctuation Half Width takes nothing more off the punctuation it re-spaced (#1082). Plug-in whole-number parameters keep their exact value however large, and stay in the range the manifest gives (#1091). PDF and `.ai` import keeps type spaced glyph by glyph (character tightening, optical kerning) with each glyph in its place, giving each character its own tracking when the file's font is installed, and CJK punctuation closed up by its proportional width continues its line (#1101). Direct Selection: pressing an anchor of a path selected whole keeps all its anchors selected, so the drag moves them all; Alt-dragging by an anchor copies the whole path, held by that anchor, which snaps onto other anchors and onto the original the copy leaves behind; Alt pressed or released during the drag turns the copy on and off, as with the Selection tool, whose copies snap to their original too, and the undo step is named Copy or Move for what the drag did (#1104). The toolbar's Fill/Stroke proxy and Color, Gradient and None buttons grow in two columns, where the three drawing modes sit side by side (#1129). An image copied in a browser that puts its `<img>` markup on the clipboard as text pastes as the picture, not the markup (#1089). `file.place` of an SVG with `crop: "crop"` frames and clips it by its viewBox, so art drawn on a shared canvas keeps its place and scale (#788). While a star is dragged, Ctrl/Cmd keeps its inner radius as the outer one grows and Alt keeps its shoulders straight (#812). Edit Toolbar opens the All Tools drawer beside the toolbar, dims the tools already in it, and adds, removes and moves tools by drag and drop while it is open (#1018). The Selection tool's arrow is black and Direct Selection's white in every theme, as users know them: in the dark themes they looked swapped. The font menu keeps its highlight on the same font when the list changes under it (a family's styles listed above it, fonts that finish loading, a favourite unstarred), and ends the live preview when that font leaves the list (#1116). The Windows installer has a Shortcuts page with a ticked "Create a desktop shortcut" box, and a silent install adds the shortcut unless `INSTALLDESKTOPSHORTCUT=""` is passed (#1128). Image Trace's Noise merges specks until none under its size is left beside another colour, so a higher Noise never gives more paths (#1130). |
 | 2026-10-10 | Initial live Revolve (Effect › 3D and Materials, #846, #605), in its own `three-d` crate. Progress docs re-measured and restructured to the craftrules standard (this page, `docs/target-app-parity.md`, `gaps.md`, `ui-parity.md`, the format, hardware, localization, effects and type checklists). Same day: v0.8.0; Effect › Distort, Pixelate and Texture filters (13); German interface; Variables (data merge); Graph Type value axes and tick marks; restart when the first frame never reaches the screen (#964) |
 | 2026-10-09 | Radial Blur, Smart Blur, Unsharp Mask (gap 2 begins); 340 commits, the busiest day |
 | 2026-10-08 | v0.5.0–v0.7.0; community contributions: Pen and shape-tool modifiers, Layers, Artboards, Japanese composition, Hebrew/Arabic type, interface languages, saved selections |
diff --git a/crates/trace/src/quantize.rs b/crates/trace/src/quantize.rs
index 0460ef62..01c6d2e6 100644
--- a/crates/trace/src/quantize.rs
+++ b/crates/trace/src/quantize.rs
@@ -376,10 +376,26 @@ fn refine(used: &[Used], mut centers: Vec<[f64; 3]>) -> Vec<[f64; 3]> {
 
 /// Merge 4-connected same-label components smaller than `min_area` pixels into their most common
 /// neighbouring label. Transparent pixels are never relabelled.
+///
+/// A pass can merge a speck into a small region that it merges away later, leaving the speck behind
+/// as a new island of that region's old label (#819: more noise removal gave more paths). Passes
+/// repeat until one changes nothing: each merge joins two components, so they always end.
 pub fn denoise(labels: &mut [u16], w: usize, h: usize, min_area: usize) {
-    if min_area <= 1 || w == 0 || h == 0 {
+    if min_area <= 1 || w == 0 || h == 0 || labels.len() < w.saturating_mul(h) {
         return;
     }
+    // A backstop only: real images settle in a few passes.
+    const MAX_PASSES: usize = 64;
+    for _ in 0..MAX_PASSES {
+        if !denoise_pass(labels, w, h, min_area) {
+            break;
+        }
+    }
+}
+
+/// One [`denoise`] pass over every component; true when it relabelled any.
+fn denoise_pass(labels: &mut [u16], w: usize, h: usize, min_area: usize) -> bool {
+    let mut changed = false;
     let mut seen = vec![false; w * h];
     let mut stack: Vec<usize> = Vec::new();
     let mut comp: Vec<usize> = Vec::new();
@@ -433,6 +449,8 @@ pub fn denoise(labels: &mut [u16], w: usize, h: usize, min_area: usize) {
             for &i in &comp {
                 labels[i] = to;
             }
+            changed = true;
         }
     }
+    changed
 }
diff --git a/crates/trace/src/tests.rs b/crates/trace/src/tests.rs
index dfc22aa5..c921f49b 100644
--- a/crates/trace/src/tests.rs
+++ b/crates/trace/src/tests.rs
@@ -557,3 +557,121 @@ fn create_strokes_survives_noise_and_tiny_images() {
         }
     }
 }
+
+/// The 4-connected same-label components of `labels` (transparent pixels left out): each one's size
+/// and whether it touches a pixel of another opaque label.
+fn components(labels: &[u16], w: usize, h: usize) -> Vec<(usize, bool)> {
+    let mut seen = vec![false; w * h];
+    let mut out = vec![];
+    for start in 0..w * h {
+        if seen[start] || labels[start] == TRANSPARENT {
+            continue;
+        }
+        let l = labels[start];
+        let (mut size, mut touches, mut stack) = (0, false, vec![start]);
+        seen[start] = true;
+        while let Some(i) = stack.pop() {
+            size += 1;
+            let (x, y) = (i % w, i / w);
+            let near = [(x > 0).then(|| i - 1), (x + 1 < w).then(|| i + 1), (y > 0).then(|| i - w), (y + 1 < h).then(|| i + w)];
+            for j in near.into_iter().flatten() {
+                if labels[j] == l {
+                    if !seen[j] {
+                        seen[j] = true;
+                        stack.push(j);
+                    }
+                } else if labels[j] != TRANSPARENT {
+                    touches = true;
+                }
+            }
+        }
+        out.push((size, touches));
+    }
+    out
+}
+
+/// #819: a speck merged into a small region that is itself merged later was left behind as a new
+/// island of the small region's old label.
+#[test]
+fn denoise_leaves_no_island_behind_a_merged_region() {
+    // One row: a 1-pixel speck, a 2-pixel region, then a large one; nothing under 3 pixels may stay.
+    let mut labels = vec![0, 1, 1, 2, 2, 2, 2, 2];
+    denoise(&mut labels, 8, 1, 3);
+    assert_eq!(labels, vec![2; 8]);
+}
+
+/// On noise, Remove Noise leaves no region under the minimum that could be merged, and a larger
+/// minimum never leaves more regions (#819: more noise removal gave more paths).
+#[test]
+fn denoise_merges_every_small_region_and_more_noise_never_means_more_regions() {
+    let (w, h) = (48, 40);
+    let mut seed = 0x2545_f491_u32;
+    let mut next = || {
+        seed ^= seed << 13;
+        seed ^= seed >> 17;
+        seed ^= seed << 5;
+        seed
+    };
+    for colors in [2u16, 3, 5, 8] {
+        // Blocky noise: random 1-4 pixel runs, so regions of every size touch each other.
+        let mut base = vec![0u16; w * h];
+        let mut i = 0;
+        while i < w * h {
+            let (l, run) = ((next() % u32::from(colors)) as u16, 1 + next() as usize % 4);
+            for p in base.iter_mut().skip(i).take(run) {
+                *p = l;
+            }
+            i += run;
+        }
+        let mut last = usize::MAX;
+        for min_area in [1usize, 2, 4, 8, 16, 32, 64, 128] {
+            let mut labels = base.clone();
+            denoise(&mut labels, w, h, min_area);
+            let comps = components(&labels, w, h);
+            if min_area > 1 {
+                assert!(
+                    comps.iter().all(|&(size, touches)| size >= min_area || !touches),
+                    "{colors} colours, min {min_area}: a region under the minimum is left: {comps:?}"
+                );
+            }
+            assert!(comps.len() <= last, "{colors} colours: min {min_area} leaves {} regions, more than the {last} a smaller one left", comps.len());
+            last = comps.len();
+        }
+    }
+}
+
+/// #819: on noisy scan-like images, raising Noise never gives more paths. Before the fix, these
+/// two went from 70 paths to 126 to 206 as Noise rose from 50 to 200 (and 22 to 25).
+#[test]
+fn more_noise_removal_never_gives_more_paths() {
+    for (seed0, colors) in [(15u32, 2usize), (9, 6)] {
+        let mut seed = seed0.wrapping_mul(0x9e37_79b9) | 1;
+        let mut next = move || {
+            seed ^= seed << 13;
+            seed ^= seed >> 17;
+            seed ^= seed << 5;
+            seed
+        };
+        let ink: Vec<[u8; 4]> = (0..colors)
+            .map(|_| {
+                let v = next();
+                [(v & 255) as u8, (v >> 8 & 255) as u8, (v >> 16 & 255) as u8, 255]
+            })
+            .collect();
+        // Diagonal bands of ink with a quarter of the pixels speckled at random.
+        let (w, h) = (121, 101);
+        let px: Vec<[u8; 4]> = (0..w * h)
+            .map(|i| {
+                let band = ((i % w) / 7 + (i / w) / 5) % colors;
+                if next() % 4 == 0 { ink[next() as usize % colors] } else { ink[band] }
+            })
+            .collect();
+        let img = Raster::from_fn(120, 100, |x, y| px[y as usize * w + x as usize]);
+        let mut last = (0, usize::MAX);
+        for noise in [1, 4, 8, 12, 25, 50, 100, 200] {
+            let n = trace(&img, &TraceParams { noise, ..TraceParams::default() }).paths.len();
+            assert!(n <= last.1, "image {seed0}: Noise {noise} gives {n} paths, more than the {} of Noise {}", last.1, last.0);
+            last = (noise, n);
+        }
+    }
+}