Merge pull request #930 from storytold/feat/pixelate-effects

Part of gap 2: Effect › Pixelate (Color Halftone, Crystallize, Mezzotint, Pointillize)
2026-10-10 15:47:10 +07:00
commit 04eb5e52c8
@@ -4,7 +4,7 @@ VectorCraft is a clean-room, open-source, pure-Rust reimplementation of the Adob

 This file tracks **how far we are and what's left**. Time estimates are wall-clock hours of continuous Claude Opus 5.5 agent work (including builds and the CI gate), given both for **one agent** and for **4–6 parallel agents** on disjoint crates. They are counted from the remaining work (see [Parity estimate](#parity-estimate)), calibrated against measured throughput, and updated as work lands.

-_Last updated: 2026-10-10 (after placed documents (File › Place of a `.vectorcraft` file, linked), M4.14–M4.98, M8.1–M8.20, M14.4–M14.7, the MCP prompts, resource templates, completions and logging, the 2026-10-07 issue fixes, the Layers panel rework and the 2026-10-08 community contributions: Pen and shape-tool modifiers, path editing, Layers, Artboards, Swatches/Brushes and dialogs, Japanese composition and PDF text, Hebrew/Arabic type, interface languages (Spanish among them), the font menu, saved selections, MCP and EPS, the missing-font export warning (#319), open paths in the Shape Builder (#374), PDF/`.ai` import keeping strokes live and hidden and nested layers (#372), per-corner Live Corners (#381), SVG type opening at the size it draws at (#396), the Wayland clipboard with copied-file paste (#398), ruler guides that can be selected, moved and deleted (#414), two batches of Preferences options that were stored but unused (#394), skeleton reads with `document.find` for large documents over MCP (#416) and anchors dragged with Direct Selection snapping to points, segments and smart guides, clipped SVG layers opening as clipping layers (#420), PDF/`.ai` layers read on pages of tens of millions of operators (#419), Document Color Mode putting RGB greys on the black plate on request and converting pattern tiles (#421) and movable dialogs with Offset Path's Joins dropdown (#423) and numeric fields scrubbed by dragging their label (#400), stroke weight presets in the stroke unit (#426), the Appearance panel's Opacity popup (#430), type on a path brackets, flip and Type on a Path Options that keep the type in place (#429), Layers rows dragged with a ghost and dropped on the trash or New Layer (#435), tool flyouts opening on a right or corner press (#436), tool flyouts torn off into floating toolbars (#437), the Shape Builder's erase mode deleting edges too (#439), installed fonts registered outside the font folders and fonts installed while the app runs listed in the font menus (#443), alike circular corners on rectangles that aren't square (#442), tool cursors as OS cursors so the pointer no longer trails over the canvas (#444), artboards copied and pasted with their art (#446), guides dragged out of the rulers snapping to the art's side midpoints and the artboards, artboard guides (#451), the toolbar's double arrow and Window › Toolbars › Double Column switching between one and two columns in any window height (#455), the Smart Guides display options and Snapping Tolerance (#394), Font Size and Leading combo boxes with preset lists in the Character and Properties panels and the Control bar (#458), screenshots pasted from the clipboard on macOS, Windows and the web (#457), the Properties panel's Fill and Stroke matching the Control bar's, Illustrator's Window menu panel keys (Shift+F7 for Align…) and Alt-wheel zoom whatever the wheel preference (Discord feedback), the point/area type widget (Discord feedback), groups in legacy Illustrator .ai files (Discord feedback), a rotating desktop log file (#465), image controls in the Control bar and Properties panel: Image Trace with its presets, Mask, Crop Image, Embed/Unembed, and an Image Trace object's preset, Expand and Release (Discord feedback), the Pen working as the Anchor Point tool with Alt held over a selected path's handles and anchors, and anchor buttons that convert, connect and cut paths at the selected anchors (Discord feedback), Japanese hanging punctuation (burasagari, #463), Escape leaving Presentation Mode with no screen mode saved across restarts, documents dropped on the desktop app opening as tabs of their own and a note that an `.ai` file's art off its artboards isn't in the part read (#472), Add/Delete Anchor Point tool icons drawn from the Pen tool's (#479), EPS import running more of PostScript Level 3 (patterns, Type 3 fonts, mesh shadings, masked images, VM and resource probes), and a preview that stands in saying why (Discord feedback, #466, #469, #474), chords with modifiers recorded in Edit › Keyboard Shortcuts (#487), Type Object Selection by Path Only (#394), Anti-aliased Artwork (#394), Show Pixel Grid (#394), pen and touch taps pressed and lifted within one frame clicking where they tapped and the Linux/Wayland pen-tablet workaround (#491), bounding-box resizes landing on the other objects' anchors and centres with labels, and the Rotate, Scale, Shear and Reflect tools snapping their drags (#482), Shift-drag marquees that toggle the objects or anchors they reach and a Lasso whose Alt subtraction keeps the rest of the selection (#483), the mouse wheel stepping the focused numeric field, the dialogs' and preferences' drag values made such fields (#485), Show The Home Screen When No Documents Are Open (#394), Numbers Without Units Are Points (#394), Auto-Collapse Iconic Panels (#394), the Contextual Task Bar moved by its handle and its More Options menu pinning and resetting its position, a designed macOS DMG windoLine truncated
+_Last updated: 2026-10-10 (after placed documents (File › Place of a `.vectorcraft` file, linked), M4.14–M4.98, M8.1–M8.20, M14.4–M14.7, the MCP prompts, resource templates, completions and logging, the 2026-10-07 issue fixes, the Layers panel rework and the 2026-10-08 community contributions: Pen and shape-tool modifiers, path editing, Layers, Artboards, Swatches/Brushes and dialogs, Japanese composition and PDF text, Hebrew/Arabic type, interface languages (Spanish among them), the font menu, saved selections, MCP and EPS, the missing-font export warning (#319), open paths in the Shape Builder (#374), PDF/`.ai` import keeping strokes live and hidden and nested layers (#372), per-corner Live Corners (#381), SVG type opening at the size it draws at (#396), the Wayland clipboard with copied-file paste (#398), ruler guides that can be selected, moved and deleted (#414), two batches of Preferences options that were stored but unused (#394), skeleton reads with `document.find` for large documents over MCP (#416) and anchors dragged with Direct Selection snapping to points, segments and smart guides, clipped SVG layers opening as clipping layers (#420), PDF/`.ai` layers read on pages of tens of millions of operators (#419), Document Color Mode putting RGB greys on the black plate on request and converting pattern tiles (#421) and movable dialogs with Offset Path's Joins dropdown (#423) and numeric fields scrubbed by dragging their label (#400), stroke weight presets in the stroke unit (#426), the Appearance panel's Opacity popup (#430), type on a path brackets, flip and Type on a Path Options that keep the type in place (#429), Layers rows dragged with a ghost and dropped on the trash or New Layer (#435), tool flyouts opening on a right or corner press (#436), tool flyouts torn off into floating toolbars (#437), the Shape Builder's erase mode deleting edges too (#439), installed fonts registered outside the font folders and fonts installed while the app runs listed in the font menus (#443), alike circular corners on rectangles that aren't square (#442), tool cursors as OS cursors so the pointer no longer trails over the canvas (#444), artboards copied and pasted with their art (#446), guides dragged out of the rulers snapping to the art's side midpoints and the artboards, artboard guides (#451), the toolbar's double arrow and Window › Toolbars › Double Column switching between one and two columns in any window height (#455), the Smart Guides display options and Snapping Tolerance (#394), Font Size and Leading combo boxes with preset lists in the Character and Properties panels and the Control bar (#458), screenshots pasted from the clipboard on macOS, Windows and the web (#457), the Properties panel's Fill and Stroke matching the Control bar's, Illustrator's Window menu panel keys (Shift+F7 for Align…) and Alt-wheel zoom whatever the wheel preference (Discord feedback), the point/area type widget (Discord feedback), groups in legacy Illustrator .ai files (Discord feedback), a rotating desktop log file (#465), image controls in the Control bar and Properties panel: Image Trace with its presets, Mask, Crop Image, Embed/Unembed, and an Image Trace object's preset, Expand and Release (Discord feedback), the Pen working as the Anchor Point tool with Alt held over a selected path's handles and anchors, and anchor buttons that convert, connect and cut paths at the selected anchors (Discord feedback), Japanese hanging punctuation (burasagari, #463), Escape leaving Presentation Mode with no screen mode saved across restarts, documents dropped on the desktop app opening as tabs of their own and a note that an `.ai` file's art off its artboards isn't in the part read (#472), Add/Delete Anchor Point tool icons drawn from the Pen tool's (#479), EPS import running more of PostScript Level 3 (patterns, Type 3 fonts, mesh shadings, masked images, VM and resource probes), and a preview that stands in saying why (Discord feedback, #466, #469, #474), chords with modifiers recorded in Edit › Keyboard Shortcuts (#487), Type Object Selection by Path Only (#394), Anti-aliased Artwork (#394), Show Pixel Grid (#394), pen and touch taps pressed and lifted within one frame clicking where they tapped and the Linux/Wayland pen-tablet workaround (#491), bounding-box resizes landing on the other objects' anchors and centres with labels, and the Rotate, Scale, Shear and Reflect tools snapping their drags (#482), Shift-drag marquees that toggle the objects or anchors they reach and a Lasso whose Alt subtraction keeps the rest of the selection (#483), the mouse wheel stepping the focused numeric field, the dialogs' and preferences' drag values made such fields (#485), Show The Home Screen When No Documents Are Open (#394), Numbers Without Units Are Points (#394), Auto-Collapse Iconic Panels (#394), the Contextual Task Bar moved by its handle and its More Options menu pinning and resetting its position, a designed macOS DMG windoLine truncated

 ## Where we are

@@ -35,7 +35,7 @@ since 2026-10-01.
 |---|---|---|
 | **Breadth:** menus, tools and panels exist | ~90% | 13 menu items still stubbed; every tool implemented except Touch Type; 51 panel modules |
 | **Depth:** each feature behaves like Illustrator | ~69–75% | Strong: paint, appearance and colour (M3), Pathfinder and booleans, selection, drawing, files (M4). Weak: advanced type (~45%; inline symbols in text are beyond parity and don't raise it), brushes and symbols (in progress), raster effects (~20%) |
-| **Large missing subsystems** | 0–20% | 3D & Materials (0%), Photoshop-style raster effects and the Effect Gallery (~4 of ~56 filters), SVG Filters, CJK composition (vertical type with kinsoku, tate-chu-yoko and the font's vertical metrics; ruby, mojikumi and proportional vertical metrics open), Variables (data merge), scripting |
+| **Large missing subsystems** | 0–20% | 3D & Materials (0%), Photoshop-style raster effects and the Effect Gallery (~8 of ~56 filters), SVG Filters, CJK composition (vertical type with kinsoku, tate-chu-yoko and the font's vertical metrics; ruby, mojikumi and proportional vertical metrics open), Variables (data merge), scripting |
 | **Interaction fidelity:** modifiers, cursors, small behaviours | ~30–40% | The dedicated pass hasn't started, and there has been no side-by-side session with Illustrator yet. A power user notices this first |
 | **Look & feel** | ~75–80% | Measured against Illustrator 2026 screenshots (2026-10-02); the panels added since haven't been re-measured |
 | **File interop** | ~85% | SVG/SVGZ, PDF and PDF-compatible `.ai`, EPS, DXF, EMF/WMF, raster formats, PSD export, Place and Links, Package, Print, clipboard flavours. Affinity documents (Affinity 1–3) open natively as editable art, checked against 51 pinned public files (33 current `.af`), with selected saved-thumbnail comparisons and every-board native/SVG/PDF/PSD checks for current files; Affinity export is missing and effects, adjustments and brushes don't import. Affinity isn't an Illustrator feature, so this doesn't raise the parity score. The editing copy inside an Illustrator EPS or `.ai` is read for its structure: layers, groups, names, hidden objects and type, colours, gradients, transparency, images and every artboard (see Out of scope for what it doesn't read yet); DWG has no open spec |
@@ -53,12 +53,13 @@ Ordered by how much each gap blocks someone from switching. Sizes are one-agent
 1. **Interaction fidelity:** go tool by tool and panel by panel against `plan/illustrator/05-tools.md`,
   `06-panels.md` and `09-shortcuts.md`, covering modifier keys, cursors, the Properties panel per context and
   isolation mode. The Shaper’s rough-square recognition and shape orientation steps are corrected; Shaper Groups now retain editable originals for region merges/punches and separate fill/stroke edits; their construction-mode widget and gesture refinements remain. 60–90 h.
-2. **Photoshop-style raster effects and the Effect Gallery:** about 51 filters (Artistic, Brush Strokes, Distort,
-   Pixelate, Sketch, Stylize, Texture, Video) and the Effect Gallery. The pixel-filter pipeline is in place
+2. **Photoshop-style raster effects and the Effect Gallery:** about 47 filters (Artistic, Brush Strokes, Distort,
+   Sketch, Stylize, Texture, Video) and the Effect Gallery. The pixel-filter pipeline is in place
   (`vectorcraft_effects::pixel`: the object rendered offscreen, filtered in stack order with Gaussian Blur and
   Feather, cached while panning, images in PDF/SVG/Expand Appearance) with Blur › Radial Blur and Smart Blur
-   (Normal mode only), Sharpen › Unsharp Mask and Stylize › Glowing Edges; each new filter is now one function, a catalogue row, menu and
-   translations. Parallelizes well across agents. 26–40 h.
+   (Normal mode only), Pixelate › Color Halftone, Crystallize, Mezzotint and Pointillize, Sharpen › Unsharp Mask and
+   Stylize › Glowing Edges; each new filter is now one function, a catalogue row, menu and translations. Parallelizes
+   well across agents. 24–37 h.
 3. **3D and Materials:** Extrude & Bevel, Revolve, Inflate and Rotate with lighting and materials, using a software
   renderer in its own crate (layering allows it below L6), with output in SVG/PDF as rasters or projected vectors.
   The largest single gap. 50–80 h.
@@ -222,7 +223,7 @@ about 1–1.5 agent-hours each, so the other rows (estimated on the older scale)
 | Strokes, brushes, width profiles | 5 | 89% | Scatter, Art and Pattern Brush Options (Calligraphic and Bristle done), brush libraries (generated in code), pen pressure on macOS (the windowing layer reports none there), brushes driven by pen tilt, bearing and barrel rotation (6D art pens) | 10–18 |
 | Appearance, transparency, graphic styles, masks | 5 | 98% | raster effect reach in preview bounds (flattener presets apply in PDF, EPS and print) | 1–2 |
 | Live vector effects | 5 | 85% | Outline Object, Pathfinder Hard/Soft Mix and Trap, SVG Filters, the Transform effect's Transform Objects/Patterns and Scale Strokes & Effects options | 6–10 |
-| Raster effects (Effect Gallery, Document Raster Effects Settings) | 4 | 25% | ~51 Photoshop-style filters (Artistic, Brush Strokes, Distort, Pixelate, Sketch, Stylize, Texture, Video), Smart Blur's Edge Only / Overlay Edge modes and the Effect Gallery; Document Raster Effects Settings, raster effects in PDF, the pixel-filter pipeline, Radial Blur, Smart Blur, Unsharp Mask and Glowing Edges are done | 26–40 |
+| Raster effects (Effect Gallery, Document Raster Effects Settings) | 4 | 28% | ~47 Photoshop-style filters (Artistic, Brush Strokes, Distort, Sketch, Stylize, Texture, Video), Smart Blur's Edge Only / Overlay Edge modes and the Effect Gallery; Document Raster Effects Settings, raster effects in PDF, the pixel-filter pipeline, Radial Blur, Smart Blur, Unsharp Mask, Glowing Edges and Pixelate (Color Halftone, Crystallize, Mezzotint, Pointillize) are done | 24–37 |
 | 3D and Materials | 4 | 0% | Extrude & Bevel, Revolve, Inflate, Rotate, lighting, materials (software renderer) | 50–80 |
 | Type core | 9 | 80% | Middle Eastern features beyond bidi layout and Paragraph Direction (Character Direction, digit types, kashidas, the Middle Eastern composers, editable bidirectional SVG text, a split caret where directions meet); Hyphenation… and Justification… options (Every-line Composer for justified and ragged text, per object, is done; it is tuned by eye, not yet compared side by side with Illustrator; mixed type sizes in a paragraph still break single-line), Optical Margin Alignment, paragraph spacing limit for vertically justified area type, hidden characters, paragraph attributes in the Type tool's copy and paste (the characters keep their styles, the paragraphs take the destination's), mixed-value display in the Paragraph panel for a selection across differing paragraphs, Transform Again after a type-area resize (it scales the type), partial selection of type-area anchors by marquee | 14–19 |
 | Type advanced | 4 | 50% | CJK composition for vertical type (ruby, mojikumi beyond Line-end Punctuation Half Width — the other sets (and their paragraph-start bracket and indent rules), custom kinsoku sets (beyond Hard, Soft and None) and the Mojikumi Settings dialog —, proportional vertical metrics, manual tate-chu-yoko), variable font axis sliders (named instances are styles), tab leaders, spell check (open dictionary), Touch Type, Retype; vertical point/area/path type and Type Orientation have initial support (beyond parity, not scored: inline symbols in text) | 20–28 |
@@ -6,7 +6,8 @@
 //! - **Geometry effects** (Distort & Transform, Path, Convert to Shape, Round Corners, Scribble,
 //!   Warp) rewrite a path: [`apply_geometry`] evaluates them in stack order.
 //! - **Raster effects** (Drop Shadow, Inner/Outer Glow, Feather, Gaussian Blur, and the
-//!   Photoshop-style filters of [`pixel`]: Radial Blur, Smart Blur, Unsharp Mask and Glowing Edges) are described by
+//!   Photoshop-style filters of [`pixel`]: Radial Blur, Smart Blur, Color Halftone, Crystallize, Mezzotint, Pointillize,
+//!   Unsharp Mask and Glowing Edges) are described by
 //!   [`raster_effects`] and painted by the renderer; [`outset`] says how far they reach beyond
 //!   the geometry.
 //! - **Stroke geometry** ([`stroke`]): arrowheads, dash patterns and width profiles, shared by the
@@ -27,7 +28,8 @@
 //!   renderer and the exporters.
 //!
 //! Everything is deterministic: "random" effects (Roughen, Tweak, Scribble) use a seeded hash
-//! noise (`seed` parameter, default 0).
+//! noise (`seed` parameter, default 0); the random Pixelate filters hash their pattern's cells,
+//! anchored at the object's centre.
 #![forbid(unsafe_code)]

 mod adjust;
@@ -126,6 +128,8 @@ fn lengths_of(id: &str) -> Lengths {
        "stylize.dropShadow" => always(&["x", "y", "blur"]),
        "stylize.innerGlow" | "stylize.outerGlow" => always(&["blur"]),
        "stylize.glowingEdges" => always(&["edgeWidth", "smoothness"]),
+        "pixelate.colorHalftone" => always(&["maxRadius"]),
+        "pixelate.crystallize" | "pixelate.pointillize" => always(&["cellSize"]),
        _ => Lengths::default(),
    }
 }
@@ -139,6 +143,7 @@ const STYLIZE: &[&str] = &["Effect", "Stylize"];
 const WARP: &[&str] = &["Effect", "Warp"];
 const BLUR: &[&str] = &["Effect", "Blur"];
 const SHARPEN: &[&str] = &["Effect", "Sharpen"];
+const PIXELATE: &[&str] = &["Effect", "Pixelate"];
 const PATHFINDER: &[&str] = &["Effect", "Pathfinder"];
 const PLUGINS: &[&str] = &["Effect", "Plug-ins"];
 const ADJUST: &[&str] = &["Effect", "Color Adjustments"];
@@ -298,6 +303,34 @@ pub fn effect_catalog() -> Vec<EffectInfo> {
            "{edgeWidth: pt 1..14 (2), edgeBrightness: 0..20 (6), smoothness: pt 1..15 (5)} finds alpha-weighted Sobel edges and draws bright coloured outlines on black",
            json!({"edgeWidth": 2.0, "edgeBrightness": 6.0, "smoothness": 5.0}),
        ),
+        r(
+            "pixelate.colorHalftone",
+            "Color Halftone…",
+            PIXELATE,
+            "{maxRadius: pt 4..127 (8; the radius of a dot at full strength, which fills its square cell), channel1: screen angle deg -360..360 (108), channel2: deg (162), channel3: deg (90), channel4: deg (45)} screens each colour channel (red, green, blue: channels 1 to 3; in CMYK documents cyan, magenta, yellow, black: 1 to 4) at its angle into dots whose area follows the channel's mean over their cell",
+            json!({"maxRadius": 8.0, "channel1": 108.0, "channel2": 162.0, "channel3": 90.0, "channel4": 45.0}),
+        ),
+        r(
+            "pixelate.crystallize",
+            "Crystallize…",
+            PIXELATE,
+            "{cellSize: pt 3..300 (10)} redraws the object as polygon crystals of solid colour around random points about cellSize apart",
+            json!({"cellSize": 10.0}),
+        ),
+        r(
+            "pixelate.mezzotint",
+            "Mezzotint…",
+            PIXELATE,
+            "{type: \"fineDots\"|\"mediumDots\"|\"grainyDots\"|\"coarseDots\"|\"shortLines\"|\"mediumLines\"|\"longLines\"|\"shortStrokes\"|\"mediumStrokes\"|\"longStrokes\" (\"fineDots\")} turns each colour channel fully on or off against a random pattern of dots, lines or strokes: fully saturated colours",
+            json!({"type": "fineDots"}),
+        ),
+        r(
+            "pixelate.pointillize",
+            "Pointillize…",
+            PIXELATE,
+            "{cellSize: pt 3..300 (5)} redraws the object as randomly placed dots of its colours on a white canvas",
+            json!({"cellSize": 5.0}),
+        ),
    ];
    v.extend([
        g(
@@ -1,5 +1,6 @@
-//! Photoshop-style raster effects (Effect › Blur › Radial Blur and Smart Blur, Sharpen › Unsharp
-//! Mask, and Stylize › Glowing Edges): filters over premultiplied RGBA8 pixels.
+//! Photoshop-style raster effects (Effect › Blur › Radial Blur and Smart Blur, Pixelate › Color
+//! Halftone, Crystallize, Mezzotint and Pointillize, Sharpen › Unsharp Mask, and Stylize › Glowing
+//! Edges): filters over premultiplied RGBA8 pixels.
 //!
 //! - Every distance is in document units (points) and becomes pixels through the raster's
 //!   [`PixelSpace::px`], so an effect looks the same at any zoom and at any Document Raster Effects
@@ -10,6 +11,7 @@

 mod blur;
 mod edges;
+mod pixelate;
 mod sharpen;

 use serde_json::Value;
@@ -17,8 +19,19 @@ use vectorcraft_geom::{Affine, Point, Rect};

 use crate::util::{num, text};

+pub use pixelate::{MEZZOTINT_TYPES, Mezzotint};
+
 /// The Photoshop-style effect ids (all raster effects, see [`crate::is_raster`]).
-pub const PIXEL_EFFECTS: [&str; 4] = ["blur.radial", "blur.smart", "sharpen.unsharpMask", "stylize.glowingEdges"];
+pub const PIXEL_EFFECTS: [&str; 8] = [
+    "blur.radial",
+    "blur.smart",
+    "pixelate.colorHalftone",
+    "pixelate.crystallize",
+    "pixelate.mezzotint",
+    "pixelate.pointillize",
+    "sharpen.unsharpMask",
+    "stylize.glowingEdges",
+];

 /// A Photoshop-style raster effect with its parameters read and clamped to their ranges. Lengths
 /// are in document units.
@@ -36,6 +49,31 @@ pub enum PixelFx {
    UnsharpMask { amount: f64, radius: f64, threshold: f64 },
    /// Stylize › Glowing Edges: bright coloured Sobel outlines on black.
    GlowingEdges { width: f64, brightness: f64, smoothness: f64 },
+    /// Pixelate › Color Halftone: each colour channel screened at its angle (`angles`° of channels
+    /// 1 to 4) into dots of up to `max_radius`, whose area follows the channel's strength.
+    ColorHalftone { max_radius: f64, angles: [f64; 4] },
+    /// Pixelate › Crystallize: polygons of solid colour around random points about `cell` apart.
+    Crystallize { cell: f64 },
+    /// Pixelate › Mezzotint: every colour channel fully on or off against a random pattern.
+    Mezzotint { kind: Mezzotint },
+    /// Pixelate › Pointillize: random dots about `cell` across of the object's colours on a white
+    /// canvas.
+    Pointillize { cell: f64 },
+}
+
+/// What a raster's colour channels hold, for the filters that treat them apart (Color Halftone
+/// screens each channel, Mezzotint thresholds each).
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
+pub enum Channels {
+    /// Red, green and blue light.
+    #[default]
+    Rgb,
+    /// Screen colours of a CMYK document: treated as its cyan, magenta, yellow and black inks.
+    Cmyk,
+    /// The complemented C, M and Y inks (a CMYK document drawn ink plane by ink plane).
+    CmyPlane,
+    /// The complemented K ink, as a grey.
+    KPlane,
 }

 /// Where a raster's pixels lie in the document.
@@ -46,8 +84,11 @@ pub struct PixelSpace {
    pub to_doc: Affine,
    /// The size of a pixel in document units.
    pub px: f64,
-    /// The object's centre (document coordinates): where Radial Blur blurs around.
+    /// The object's centre (document coordinates): where Radial Blur blurs around, and where the
+    /// Pixelate filters' patterns are anchored (so they move with the object).
    pub center: Point,
+    /// What the colour channels hold.
+    pub channels: Channels,
 }

 /// Effect `id`'s parameters `p` (defaults merged in) as a [`PixelFx`]; `None` for other effects.
@@ -77,6 +118,14 @@ pub(crate) fn parse(id: &str, p: &Value) -> Option<PixelFx> {
            brightness: num(p, "edgeBrightness", 6.0).clamp(0.0, 20.0),
            smoothness: num(p, "smoothness", 5.0).clamp(1.0, 15.0),
        },
+        "pixelate.colorHalftone" => PixelFx::ColorHalftone {
+            max_radius: num(p, "maxRadius", 8.0).clamp(4.0, 127.0),
+            angles: [("channel1", 108.0), ("channel2", 162.0), ("channel3", 90.0), ("channel4", 45.0)]
+                .map(|(k, d)| num(p, k, d).clamp(-360.0, 360.0)),
+        },
+        "pixelate.crystallize" => PixelFx::Crystallize { cell: num(p, "cellSize", 10.0).clamp(3.0, 300.0) },
+        "pixelate.mezzotint" => PixelFx::Mezzotint { kind: Mezzotint::parse(text(p, "type", "fineDots")) },
+        "pixelate.pointillize" => PixelFx::Pointillize { cell: num(p, "cellSize", 5.0).clamp(3.0, 300.0) },
        _ => return None,
    })
 }
@@ -94,6 +143,9 @@ impl PixelFx {
            PixelFx::SmartBlur { radius, .. } => radius,
            PixelFx::UnsharpMask { .. } => 0.0,
            PixelFx::GlowingEdges { width, smoothness, .. } => width.max(smoothness * 3.0),
+            PixelFx::ColorHalftone { .. } | PixelFx::Mezzotint { .. } => 0.0,
+            // A crystal's or dot's point inside the object reaches out by up to its cell.
+            PixelFx::Crystallize { cell } | PixelFx::Pointillize { cell } => 1.5 * cell,
        }
    }

@@ -105,6 +157,12 @@ impl PixelFx {
            PixelFx::SmartBlur { radius, .. } => Some(radius),
            PixelFx::UnsharpMask { radius, .. } => Some(3.0 * radius),
            PixelFx::GlowingEdges { width, smoothness, .. } => Some(width.max(smoothness * 3.0)),
+            // The cells around the pixel's, and the cells around theirs.
+            PixelFx::ColorHalftone { max_radius, .. } => Some(3.0 * std::f64::consts::SQRT_2 * max_radius),
+            PixelFx::Crystallize { cell } => Some(1.5 * cell),
+            PixelFx::Mezzotint { .. } => Some(0.0),
+            // The dots' points, and the softened colour around them.
+            PixelFx::Pointillize { cell } => Some(2.5 * cell),
        }
    }

@@ -118,6 +176,10 @@ impl PixelFx {
            PixelFx::SmartBlur { radius, threshold, samples } => blur::smart(px, w, h, to_px(radius), threshold, samples),
            PixelFx::UnsharpMask { amount, radius, threshold } => sharpen::unsharp(px, w, h, amount, to_px(radius), threshold),
            PixelFx::GlowingEdges { width, brightness, smoothness } => edges::glow(px, w, h, to_px(width), brightness, to_px(smoothness)),
+            PixelFx::ColorHalftone { max_radius, angles } => pixelate::color_halftone(px, w, h, space, max_radius, angles),
+            PixelFx::Crystallize { cell } => pixelate::crystallize(px, w, h, space, cell),
+            PixelFx::Mezzotint { kind } => pixelate::mezzotint(px, w, h, space, kind),
+            PixelFx::Pointillize { cell } => pixelate::pointillize(px, w, h, space, cell),
        }
    }
 }
@@ -0,0 +1,531 @@
+//! Pixelate › Color Halftone, Crystallize, Mezzotint and Pointillize.
+//!
+//! Their patterns (screens, crystals, grains and dots) lie in document space around the object's
+//! centre, so they keep their size at any zoom or resolution and move with the object. The random
+//! ones hash the pattern's cell indices: every redraw gives the same result.
+
+use std::sync::OnceLock;
+
+use vectorcraft_geom::{Affine, Point};
+
+use super::{Channels, PixelSpace, gaussian, to16};
+use crate::util::noise;
+
+/// Mezzotint's patterns, in its Type menu's order: (label, parameter value).
+pub const MEZZOTINT_TYPES: [(&str, &str); 10] = [
+    ("Fine Dots", "fineDots"),
+    ("Medium Dots", "mediumDots"),
+    ("Grainy Dots", "grainyDots"),
+    ("Coarse Dots", "coarseDots"),
+    ("Short Lines", "shortLines"),
+    ("Medium Lines", "mediumLines"),
+    ("Long Lines", "longLines"),
+    ("Short Strokes", "shortStrokes"),
+    ("Medium Strokes", "mediumStrokes"),
+    ("Long Strokes", "longStrokes"),
+];
+
+/// A Mezzotint pattern ([`MEZZOTINT_TYPES`]): random dots, or horizontal lines or strokes.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum Mezzotint {
+    /// Dots `size` points across (smooth blobs when `smooth`), plus fine grain when `grainy`.
+    Dots { size: u8, smooth: bool, grainy: bool },
+    /// Horizontal streaks about `length` points long and `width` points thick.
+    Lines { length: u8, width: u8 },
+}
+
+/// The patterns of [`MEZZOTINT_TYPES`], in the same order.
+const MEZZOTINT_KINDS: [Mezzotint; 10] = {
+    const fn dots(size: u8, smooth: bool, grainy: bool) -> Mezzotint {
+        Mezzotint::Dots { size, smooth, grainy }
+    }
+    const fn lines(length: u8, width: u8) -> Mezzotint {
+        Mezzotint::Lines { length, width }
+    }
+    [
+        dots(1, false, false),
+        dots(2, true, false),
+        dots(3, true, true),
+        dots(4, true, false),
+        lines(4, 1),
+        lines(8, 1),
+        lines(16, 1),
+        lines(6, 2),
+        lines(12, 2),
+        lines(24, 2),
+    ]
+};
+
+impl Mezzotint {
+    /// Fine Dots, the first type.
+    pub const FINE_DOTS: Mezzotint = Mezzotint::Dots { size: 1, smooth: false, grainy: false };
+
+    /// The pattern of Type `value` (a [`MEZZOTINT_TYPES`] value, any case); Fine Dots otherwise.
+    pub fn parse(value: &str) -> Self {
+        MEZZOTINT_TYPES.iter().zip(MEZZOTINT_KINDS).find(|((_, v), _)| v.eq_ignore_ascii_case(value)).map_or(Self::FINE_DOTS, |(_, kind)| kind)
+    }
+}
+
+/// Seeds of the filters' noise ("PIXELATE" and a filter number).
+const SEED: u64 = 0x5049_5845_4C41_5445;
+
+/// A random number in [0, 1) for cell (`i`, `j`) of pattern `salt`; `k` picks one of several.
+fn rand(salt: u64, i: i64, j: i64, k: u64) -> f64 {
+    0.5 * (noise(SEED ^ salt, i as u64, j as u64, k) + 1.0)
+}
+
+/// The cell holding coordinate `v` (in cells); `None` far beyond any raster (or not finite).
+fn cell(v: f64) -> Option<i64> {
+    let f = v.floor();
+    (f.abs() < 1e15).then_some(f as i64)
+}
+
+/// Where a raster's pixels lie relative to the object's centre, in document units.
+struct Place {
+    /// Pixel coordinates → document coordinates relative to the centre.
+    to_rel: Affine,
+    /// The other way.
+    to_px: Affine,
+    /// A pixel's size in document units.
+    px: f64,
+    w: usize,
+    h: usize,
+}
+
+impl Place {
+    fn new(space: &PixelSpace, w: usize, h: usize) -> Option<Self> {
+        let to_rel = Affine::translate(-space.center.to_vec2()) * space.to_doc;
+        let to_px = to_rel.inverse();
+        (to_rel.is_finite() && to_px.is_finite() && space.px.is_finite() && space.px > 0.0).then_some(Self { to_rel, to_px, px: space.px, w, h })
+    }
+
+    /// The centre of pixel (`x`, `y`).
+    fn at(&self, x: usize, y: usize) -> Point {
+        self.to_rel * Point::new(x as f64 + 0.5, y as f64 + 0.5)
+    }
+
+    /// The index of the pixel holding point `p`; `None` outside the raster.
+    fn index(&self, p: Point) -> Option<usize> {
+        let q = self.to_px * p;
+        (q.x >= 0.0 && q.y >= 0.0 && q.x < self.w as f64 && q.y < self.h as f64).then(|| q.y as usize * self.w + q.x as usize)
+    }
+
+    /// Run `f(x, y, pixel)` on every pixel.
+    fn each(&self, px: &mut [[u8; 4]], mut f: impl FnMut(usize, usize, &mut [u8; 4])) {
+        for (y, row) in px.chunks_exact_mut(self.w.max(1)).enumerate().take(self.h) {
+            for (x, p) in row.iter_mut().enumerate() {
+                f(x, y, p);
+            }
+        }
+    }
+}
+
+/// The cells around a pixel's cell, in the order they can hold its nearest random point: the
+/// cell itself, its 8 neighbours, then the ring around them.
+const AROUND: [(i64, i64); 25] = [
+    (0, 0),
+    (-1, 0),
+    (1, 0),
+    (0, -1),
+    (0, 1),
+    (-1, -1),
+    (1, -1),
+    (-1, 1),
+    (1, 1),
+    (-2, -2),
+    (-1, -2),
+    (0, -2),
+    (1, -2),
+    (2, -2),
+    (-2, -1),
+    (2, -1),
+    (-2, 0),
+    (2, 0),
+    (-2, 1),
+    (2, 1),
+    (-2, 2),
+    (-1, 2),
+    (0, 2),
+    (1, 2),
+    (2, 2),
+];
+
+/// What the cells [`AROUND`] one cell hold, made when first asked for and kept while consecutive
+/// pixels stay in that cell.
+struct Around<T> {
+    cell: Option<(i64, i64)>,
+    items: [Option<T>; 25],
+}
+
+impl<T: Copy> Around<T> {
+    fn new() -> Self {
+        Self { cell: None, items: [None; 25] }
+    }
+
+    /// Item `k` of [`AROUND`] cell (`i`, `j`): `make(cell i', j')`.
+    fn get(&mut self, (i, j): (i64, i64), k: usize, make: impl FnOnce(i64, i64) -> T) -> Option<T> {
+        if self.cell != Some((i, j)) {
+            self.cell = Some((i, j));
+            self.items = [None; 25];
+        }
+        let (di, dj) = AROUND.get(k)?;
+        let slot = self.items.get_mut(k)?;
+        Some(*slot.get_or_insert_with(|| make(i.wrapping_add(*di), j.wrapping_add(*dj))))
+    }
+}
+
+/// The random point of cell (`i`, `j`) of pattern `salt`, in cells.
+fn point_in(salt: u64, i: i64, j: i64) -> Point {
+    Point::new(i as f64 + rand(salt, i, j, 0), j as f64 + rand(salt, i, j, 1))
+}
+
+/// Crystallize: every pixel takes the colour at the nearest of one random point per `cell` ×
+/// `cell` square (a Voronoi diagram over a jittered grid): polygon crystals of solid colour.
+pub(super) fn crystallize(px: &mut [[u8; 4]], w: usize, h: usize, space: &PixelSpace, cell_size: f64) {
+    let Some(place) = Place::new(space, w, h) else { return };
+    if !(cell_size.is_finite() && cell_size > 0.0) {
+        return;
+    }
+    let src = px.to_vec();
+    let mut around = Around::new();
+    // How far cell `c` lies from coordinate `t` (in cells) along one axis.
+    let gap = |c: i64, t: f64| (c as f64 - t).max(t - c as f64 - 1.0).max(0.0);
+    place.each(px, |x, y, out| {
+        let q = place.at(x, y);
+        let (u, v) = (q.x / cell_size, q.y / cell_size);
+        let (Some(i), Some(j)) = (cell(u), cell(v)) else { return };
+        let mut best = (f64::INFINITY, None);
+        for (k, (di, dj)) in AROUND.iter().enumerate() {
+            // A cell farther than the best point so far can't hold a nearer one.
+            let (ci, cj) = (i.wrapping_add(*di), j.wrapping_add(*dj));
+            if gap(ci, u).hypot(gap(cj, v)) >= best.0 {
+                continue;
+            }
+            if let Some(p) = around.get((i, j), k, |a, b| point_in(1, a, b)) {
+                let d = (p.x - u).hypot(p.y - v);
+                if d < best.0 {
+                    best = (d, Some(p));
+                }
+            }
+        }
+        if let Some(p) = best.1 {
+            let at = Point::new(p.x * cell_size, p.y * cell_size);
+            *out = place.index(at).and_then(|i| src.get(i)).copied().unwrap_or([0; 4]);
+        }
+    });
+}
+
+/// One of Pointillize's dots: where (in cells), its radius (document units), its stacking order
+/// and its colour (premultiplied, 0..1).
+#[derive(Clone, Copy)]
+struct Dot {
+    at: Point,
+    radius: f64,
+    z: f64,
+    colour: [f32; 4],
+}
+
+/// The smallest dot radius and the spread above it, in cells.
+const DOT_RADIUS: (f64, f64) = (0.45, 0.25);
+
+/// Pointillize: a dot at one random point per `cell` × `cell` square, of random size around the
+/// cell's, coloured by the (softened) object there, over a white canvas where the object is.
+pub(super) fn pointillize(px: &mut [[u8; 4]], w: usize, h: usize, space: &PixelSpace, cell_size: f64) {
+    let Some(place) = Place::new(space, w, h) else { return };
+    if !(cell_size.is_finite() && cell_size > 0.0) {
+        return;
+    }
+    // Each dot takes the colour around its centre, not of a single pixel there, and is as opaque
+    // as the object at its centre (whole dots on the object, none beside it).
+    let alpha: Vec<u8> = px.iter().map(|p| p[3]).collect();
+    let mut soft = to16(px);
+    gaussian(&mut soft, w, cell_size / place.px / 4.0);
+    let dot = |i: i64, j: i64| {
+        let at = point_in(2, i, j);
+        let k = place.index(Point::new(at.x * cell_size, at.y * cell_size));
+        let a = k.and_then(|k| alpha.get(k)).map_or(0.0, |a| f32::from(*a) / 255.0);
+        let colour = match k.and_then(|k| soft.get(k)) {
+            Some(p) if p[3] > 0 => {
+                let s = a / f32::from(p[3]);
+                [f32::from(p[0]) * s, f32::from(p[1]) * s, f32::from(p[2]) * s, a]
+            }
+            _ => [0.0; 4],
+        };
+        Dot { at, radius: (DOT_RADIUS.0 + DOT_RADIUS.1 * rand(2, i, j, 2)) * cell_size, z: rand(2, i, j, 3), colour }
+    };
+    let mut around = Around::new();
+    place.each(px, |x, y, out| {
+        let q = place.at(x, y);
+        let (u, v) = (q.x / cell_size, q.y / cell_size);
+        let (Some(i), Some(j)) = (cell(u), cell(v)) else { return };
+        // The dots covering the pixel (only the 3 × 3 cells around it reach it), bottom first.
+        let mut hits: [(f64, f32, [f32; 4]); 9] = [(0.0, 0.0, [0.0; 4]); 9];
+        let mut n = 0;
+        for k in 0..9 {
+            let Some(d) = around.get((i, j), k, dot) else { continue };
+            let dist = (d.at.x - u).hypot(d.at.y - v) * cell_size;
+            let cover = ((d.radius - dist) / place.px + 0.5).clamp(0.0, 1.0) as f32;
+            if cover > 0.0
+                && d.colour[3] > 0.0
+                && let Some(slot) = hits.get_mut(n)
+            {
+                *slot = (d.z, cover, d.colour);
+                n += 1;
+            }
+        }
+        let hits = hits.get_mut(..n).unwrap_or_default();
+        hits.sort_by(|a, b| a.0.total_cmp(&b.0));
+        let alpha = f32::from(out[3]) / 255.0;
+        let mut acc = [alpha; 4];
+        for (_, cover, c) in hits.iter() {
+            let keep = 1.0 - c[3] * cover;
+            for (a, v) in acc.iter_mut().zip(c) {
+                *a = v * cover + *a * keep;
+            }
+        }
+        let a = (acc[3].clamp(0.0, 1.0) * 255.0).round();
+        let v = |c: f32| (c.clamp(0.0, 1.0) * 255.0).round().min(a) as u8;
+        *out = [v(acc[0]), v(acc[1]), v(acc[2]), a as u8];
+    });
+}
+
+/// A pixel's colour as the channels the Pixelate filters treat apart (straight, 0..1; see
+/// [`Channels`]), and how many of the four there are.
+fn split(p: [u8; 4], channels: Channels) -> ([f32; 4], usize) {
+    let a = f32::from(p[3]);
+    let [r, g, b] = [p[0], p[1], p[2]].map(|v| if a > 0.0 { (f32::from(v) / a).min(1.0) } else { 0.0 });
+    match channels {
+        Channels::Rgb => ([r, g, b, 0.0], 3),
+        Channels::Cmyk => {
+            // A light black generation, as separations print: black ink takes over in the
+            // shadows, coloured inks build the midtones.
+            let k = (1.0 - r.max(g).max(b)).powi(2);
+            let ink = |v: f32| if k < 1.0 { ((1.0 - v - k) / (1.0 - k)).clamp(0.0, 1.0) } else { 0.0 };
+            ([ink(r), ink(g), ink(b), k], 4)
+        }
+        Channels::CmyPlane => ([1.0 - r, 1.0 - g, 1.0 - b, 0.0], 3),
+        Channels::KPlane => ([1.0 - r, 0.0, 0.0, 0.0], 1),
+    }
+}
+
+/// The pixel of channel values `v` ([`split`]'s) at coverage `alpha` (premultiplied).
+fn join(v: [f32; 4], channels: Channels, alpha: u8) -> [u8; 4] {
+    let [a, b, c, d] = v.map(|x| x.clamp(0.0, 1.0));
+    let rgb = match channels {
+        Channels::Rgb => [a, b, c],
+        Channels::Cmyk => [(1.0 - a) * (1.0 - d), (1.0 - b) * (1.0 - d), (1.0 - c) * (1.0 - d)],
+        Channels::CmyPlane => [1.0 - a, 1.0 - b, 1.0 - c],
+        Channels::KPlane => [1.0 - a; 3],
+    };
+    let al = f32::from(alpha);
+    let [r, g, b] = rgb.map(|x| (x * al).round().clamp(0.0, al) as u8);
+    [r, g, b, alpha]
+}
+
+/// Which of Color Halftone's four screen angles channel `i` of `channels` uses: the K plane's
+/// only channel is the fourth (black) one.
+fn angle_of(channels: Channels, i: usize) -> usize {
+    if channels == Channels::KPlane { 3 } else { i }
+}
+
+/// The share of a `1` × `1` square that a circle of radius `rho` around its centre covers.
+fn circle_in_square(rho: f64) -> f64 {
+    let half = 0.5;
+    if rho <= half {
+        std::f64::consts::PI * rho * rho
+    } else if rho < std::f64::consts::FRAC_1_SQRT_2 {
+        // The circle less the four caps beyond the square's sides.
+        let cap = rho * rho * (half / rho).acos() - half * (rho * rho - half * half).sqrt();
+        std::f64::consts::PI * rho * rho - 4.0 * cap
+    } else {
+        1.0
+    }
+}
+
+/// The radius (in cells) of the dot that covers share `v` of its cell.
+fn dot_radius(v: f64) -> f64 {
+    const STEPS: usize = 256;
+    static TABLE: OnceLock<[f64; STEPS + 1]> = OnceLock::new();
+    let table = TABLE.get_or_init(|| {
+        std::array::from_fn(|k| {
+            let target = k as f64 / STEPS as f64;
+            let (mut lo, mut hi) = (0.0, std::f64::consts::FRAC_1_SQRT_2);
+            for _ in 0..48 {
+                let mid = 0.5 * (lo + hi);
+                if circle_in_square(mid) < target {
+                    lo = mid;
+                } else {
+                    hi = mid;
+                }
+            }
+            hi
+        })
+    });
+    let x = if v.is_finite() { v.clamp(0.0, 1.0) * STEPS as f64 } else { 0.0 };
+    let k = (x.floor() as usize).min(STEPS - 1);
+    let (a, b) = (table.get(k).copied().unwrap_or(0.0), table.get(k + 1).copied().unwrap_or(0.0));
+    a + (b - a) * (x - k as f64)
+}
+
+/// One channel's halftone screen: square cells at an angle, each with the dot of its mean value.
+struct Screen {
+    /// Document coordinates relative to the centre → cells.
+    to_cells: Affine,
+    /// The first cell's indices and the grid's size in cells.
+    origin: (i64, i64),
+    size: (usize, usize),
+    /// Per cell: the channel's sum (× coverage) and the coverage's (then the dot's radius in
+    /// document units, in `sums[k][0]`).
+    sums: Vec<[f32; 2]>,
+}
+
+impl Screen {
+    /// The screen at `angle`° with cells `side` wide over the raster `place` covers; `None` when
+    /// it would have more than `limit` cells.
+    fn new(place: &Place, angle: f64, side: f64, limit: usize) -> Option<Self> {
+        let to_cells = Affine::scale(1.0 / side) * Affine::rotate(angle.to_radians());
+        let corners = [(0.0, 0.0), (place.w as f64, 0.0), (0.0, place.h as f64), (place.w as f64, place.h as f64)];
+        let pts = corners.map(|(x, y)| to_cells * (place.to_rel * Point::new(x, y)));
+        let (lo, hi) = pts.iter().fold(((f64::INFINITY, f64::INFINITY), (f64::NEG_INFINITY, f64::NEG_INFINITY)), |(lo, hi), p| {
+            ((lo.0.min(p.x), lo.1.min(p.y)), (hi.0.max(p.x), hi.1.max(p.y)))
+        });
+        let (i0, j0, i1, j1) = (cell(lo.0)?.checked_sub(1)?, cell(lo.1)?.checked_sub(1)?, cell(hi.0)?.checked_add(1)?, cell(hi.1)?.checked_add(1)?);
+        let gw = usize::try_from(i1.checked_sub(i0)?.checked_add(1)?).ok()?;
+        let gh = usize::try_from(j1.checked_sub(j0)?.checked_add(1)?).ok()?;
+        (gw.checked_mul(gh)? <= limit).then(|| Self { to_cells, origin: (i0, j0), size: (gw, gh), sums: vec![[0.0; 2]; gw * gh] })
+    }
+
+    /// The index of cell (`i`, `j`) in the grid.
+    fn slot(&self, i: i64, j: i64) -> Option<usize> {
+        let x = usize::try_from(i.checked_sub(self.origin.0)?).ok().filter(|x| *x < self.size.0)?;
+        let y = usize::try_from(j.checked_sub(self.origin.1)?).ok().filter(|y| *y < self.size.1)?;
+        Some(y * self.size.0 + x)
+    }
+}
+
+/// Color Halftone: each channel screened at its angle in square cells sized so that a dot of
+/// `max_radius` fills one; each cell's dot covers the share of it that is the channel's mean
+/// there (white stays white, black black). Coverage stays as it is.
+pub(super) fn color_halftone(px: &mut [[u8; 4]], w: usize, h: usize, space: &PixelSpace, max_radius: f64, angles: [f64; 4]) {
+    let Some(place) = Place::new(space, w, h) else { return };
+    let side = max_radius * std::f64::consts::SQRT_2;
+    // Cells under 3 pixels can't show their dots: on average a screen is the image itself.
+    if !(side.is_finite() && side / place.px >= 3.0) {
+        return;
+    }
+    let channels = space.channels;
+    let n = split([0; 4], channels).1;
+    let limit = w.saturating_mul(h).saturating_add(4096);
+    let mut screens = Vec::with_capacity(n);
+    for i in 0..n {
+        let angle = angles.get(angle_of(channels, i)).copied().unwrap_or(0.0);
+        let Some(s) = Screen::new(&place, angle, side, limit) else { return };
+        screens.push(s);
+    }
+    // Each cell's mean of each channel, weighted by coverage.
+    place.each(px, |x, y, p| {
+        if p[3] == 0 {
+            return;
+        }
+        let (v, _) = split(*p, channels);
+        let a = f32::from(p[3]) / 255.0;
+        let q = place.at(x, y);
+        for (s, v) in screens.iter_mut().zip(v) {
+            let c = s.to_cells * q;
+            if let (Some(i), Some(j)) = (cell(c.x), cell(c.y))
+                && let Some(sum) = s.slot(i, j).and_then(|k| s.sums.get_mut(k))
+            {
+                sum[0] += v * a;
+                sum[1] += a;
+            }
+        }
+    });
+    for s in &mut screens {
+        for sum in &mut s.sums {
+            let mean = if sum[1] > 1e-6 { f64::from(sum[0] / sum[1]) } else { 0.0 };
+            // Full strength fills the cell, corners too; none leaves no speck.
+            let radius = match mean {
+                m if m >= 254.5 / 255.0 => f64::INFINITY,
+                m if m <= 0.5 / 255.0 => 0.0,
+                m => dot_radius(m) * side,
+            };
+            sum[0] = radius as f32;
+        }
+    }
+    place.each(px, |x, y, p| {
+        if p[3] == 0 {
+            return;
+        }
+        let q = place.at(x, y);
+        let mut v = [0.0f32; 4];
+        for (s, out) in screens.iter().zip(v.iter_mut()) {
+            let c = s.to_cells * q;
+            let (Some(i), Some(j)) = (cell(c.x), cell(c.y)) else { continue };
+            // A dot reaches past its cell into the neighbours on the pixel's side only.
+            let (si, sj) = (if c.x - (i as f64) < 0.5 { -1 } else { 1 }, if c.y - (j as f64) < 0.5 { -1 } else { 1 });
+            for (di, dj) in [(0, 0), (si, 0), (0, sj), (si, sj)] {
+                let (ci, cj) = (i.wrapping_add(di), j.wrapping_add(dj));
+                let radius = s.slot(ci, cj).and_then(|k| s.sums.get(k)).map_or(0.0, |sum| f64::from(sum[0]));
+                if radius <= 0.0 {
+                    continue;
+                }
+                let dist = (c.x - (ci as f64 + 0.5)).hypot(c.y - (cj as f64 + 0.5)) * side;
+                *out = out.max(((radius - dist) / place.px + 0.5).clamp(0.0, 1.0) as f32);
+            }
+        }
+        *p = join(v, channels, p[3]);
+    });
+}
+
+/// Mezzotint: every channel turned fully on or off where it is above or below a random threshold
+/// pattern (each channel its own), so the image becomes dots or streaks of pure colours.
+pub(super) fn mezzotint(px: &mut [[u8; 4]], w: usize, h: usize, space: &PixelSpace, kind: Mezzotint) {
+    let Some(place) = Place::new(space, w, h) else { return };
+    let channels = space.channels;
+    place.each(px, |x, y, p| {
+        if p[3] == 0 {
+            return;
+        }
+        let q = place.at(x, y);
+        let (mut v, n) = split(*p, channels);
+        for (c, value) in v.iter_mut().enumerate().take(n) {
+            let t = threshold(kind, 16 + c as u64, q);
+            *value = if f64::from(*value) > t { 1.0 } else { 0.0 };
+        }
+        *p = join(v, channels, p[3]);
+    });
+}
+
+/// Mezzotint's threshold in [0, 1) at point `q` (document units around the centre) of pattern
+/// `salt`.
+fn threshold(kind: Mezzotint, salt: u64, q: Point) -> f64 {
+    let smooth = |t: f64| t * t * (3.0 - 2.0 * t);
+    // Random values at whole coordinates, blended smoothly between them along x (and y).
+    let blend = |x: f64, y: f64, along_y: bool| {
+        let (Some(i), Some(j)) = (cell(x), cell(y)) else { return 0.5 };
+        let (fx, fy) = (smooth(x - i as f64), smooth(y - j as f64));
+        let at = |di: i64, dj: i64| rand(salt, i.wrapping_add(di), j.wrapping_add(dj), 0);
+        let top = at(0, 0) + (at(1, 0) - at(0, 0)) * fx;
+        if !along_y {
+            return top;
+        }
+        let bottom = at(0, 1) + (at(1, 1) - at(0, 1)) * fx;
+        top + (bottom - top) * fy
+    };
+    let grain = |size: f64| match (cell(q.x / size), cell(q.y / size)) {
+        (Some(i), Some(j)) => rand(salt, i, j, 1),
+        _ => 0.5,
+    };
+    match kind {
+        Mezzotint::Dots { size, smooth: false, .. } => grain(f64::from(size)),
+        Mezzotint::Dots { size, grainy, .. } => {
+            let s = f64::from(size);
+            let blob = blend(q.x / s, q.y / s, true);
+            if grainy { 0.5 * (blob + grain(1.0)) } else { blob }
+        }
+        Mezzotint::Lines { length, width } => {
+            let row = (q.y / f64::from(width)).floor();
+            blend(q.x / f64::from(length), row, false)
+        }
+    }
+}
@@ -7,7 +7,7 @@ use crate::{RasterFx, raster_effects};

 /// A `w` × `h` raster whose pixels are document points (origin top-left).
 fn space(w: usize, h: usize) -> PixelSpace {
-    PixelSpace { to_doc: Affine::IDENTITY, px: 1.0, center: Point::new(w as f64 / 2.0, h as f64 / 2.0) }
+    PixelSpace { to_doc: Affine::IDENTITY, px: 1.0, center: Point::new(w as f64 / 2.0, h as f64 / 2.0), channels: Channels::Rgb }
 }

 fn image(w: usize, h: usize, f: impl Fn(usize, usize) -> [u8; 4]) -> Vec<u8> {
@@ -224,7 +224,7 @@ fn lengths_are_document_units() {
    let edge = |scale: usize| image(40 * scale, 4, move |x, _| grey(if x < 20 * scale { 100 } else { 150 }));
    let run = |scale: usize| {
        let mut d = edge(scale);
-        let s = PixelSpace { to_doc: Affine::scale(1.0 / scale as f64), px: 1.0 / scale as f64, center: Point::ZERO };
+        let s = PixelSpace { to_doc: Affine::scale(1.0 / scale as f64), px: 1.0 / scale as f64, center: Point::ZERO, channels: Channels::Rgb };
        fx("sharpen.unsharpMask", json!({"amount": 100, "radius": 2})).apply(&mut d, 40 * scale, 4, &s);
        (0..40 * scale).filter(|x| at(&d, 40 * scale, *x, 2)[0] < 99).count()
    };
@@ -253,7 +253,7 @@ fn gaussian_and_plane_blurs_keep_their_mass() {
 fn pixel_timings() {
    let (w, h) = (2000, 2000);
    let src = image(w, h, |x, y| [(x % 256) as u8, (y % 256) as u8, ((x ^ y) % 256) as u8, 255]);
-    let s = PixelSpace { to_doc: Affine::IDENTITY, px: 1.0, center: Point::new(1000.0, 1000.0) };
+    let s = PixelSpace { to_doc: Affine::IDENTITY, px: 1.0, center: Point::new(1000.0, 1000.0), channels: Channels::Rgb };
    let cases = [
        ("blur.radial", json!({"quality": "draft"})),
        ("blur.radial", json!({"quality": "good"})),
@@ -261,6 +261,12 @@ fn pixel_timings() {
        ("blur.smart", json!({"quality": "low"})),
        ("blur.smart", json!({"quality": "high", "radius": 30})),
        ("sharpen.unsharpMask", json!({"radius": 20})),
+        ("pixelate.colorHalftone", json!({"maxRadius": 4})),
+        ("pixelate.crystallize", json!({"cellSize": 3})),
+        ("pixelate.crystallize", json!({"cellSize": 300})),
+        ("pixelate.mezzotint", json!({"type": "grainyDots"})),
+        ("pixelate.pointillize", json!({"cellSize": 3})),
+        ("pixelate.pointillize", json!({"cellSize": 300})),
    ];
    for (id, p) in cases {
        let mut d = src.clone();
@@ -269,3 +275,205 @@ fn pixel_timings() {
        println!("{id} {p}: {:?}", t.elapsed());
    }
 }
+
+#[test]
+fn pixelate_params_take_defaults_and_stay_in_range() {
+    assert_eq!(fx("pixelate.colorHalftone", json!({})), PixelFx::ColorHalftone { max_radius: 8.0, angles: [108.0, 162.0, 90.0, 45.0] });
+    assert_eq!(
+        fx("pixelate.colorHalftone", json!({"maxRadius": 1e9, "channel1": -1e9, "channel2": 30, "channel4": "x"})),
+        PixelFx::ColorHalftone { max_radius: 127.0, angles: [-360.0, 30.0, 90.0, 45.0] }
+    );
+    assert_eq!(fx("pixelate.colorHalftone", json!({"maxRadius": 0})), PixelFx::ColorHalftone { max_radius: 4.0, angles: [108.0, 162.0, 90.0, 45.0] });
+    assert_eq!(fx("pixelate.crystallize", json!({})), PixelFx::Crystallize { cell: 10.0 });
+    assert_eq!(fx("pixelate.crystallize", json!({"cellSize": -4})), PixelFx::Crystallize { cell: 3.0 });
+    assert_eq!(fx("pixelate.pointillize", json!({})), PixelFx::Pointillize { cell: 5.0 });
+    assert_eq!(fx("pixelate.pointillize", json!({"cellSize": 1e300})), PixelFx::Pointillize { cell: 300.0 });
+    assert_eq!(fx("pixelate.mezzotint", json!({})), PixelFx::Mezzotint { kind: Mezzotint::FINE_DOTS });
+    assert_eq!(fx("pixelate.mezzotint", json!({"type": "LONGSTROKES"})), PixelFx::Mezzotint { kind: Mezzotint::Lines { length: 24, width: 2 } });
+    for junk in [json!({"type": 7}), json!({"type": "nonsense"})] {
+        assert_eq!(fx("pixelate.mezzotint", junk), PixelFx::Mezzotint { kind: Mezzotint::FINE_DOTS });
+    }
+    // Every Type is a pattern of its own, documented in the catalogue.
+    let doc = crate::effect_info("pixelate.mezzotint").unwrap().params;
+    let kinds: Vec<Mezzotint> = MEZZOTINT_TYPES.iter().map(|(_, v)| Mezzotint::parse(v)).collect();
+    for (i, (_, v)) in MEZZOTINT_TYPES.iter().enumerate() {
+        assert!(doc.contains(&format!("\"{v}\"")), "{v}");
+        assert!(kinds.iter().skip(i + 1).all(|k| *k != kinds[i]), "{v}");
+    }
+    // Dots and crystals reach beyond the object; screens and grain stay on it.
+    let b = Rect::new(0.0, 0.0, 100.0, 50.0);
+    assert_eq!(fx("pixelate.crystallize", json!({"cellSize": 20})).outset(b), 30.0);
+    assert_eq!(fx("pixelate.pointillize", json!({"cellSize": 20})).outset(b), 30.0);
+    assert_eq!(fx("pixelate.colorHalftone", json!({})).outset(b), 0.0);
+    assert_eq!(fx("pixelate.mezzotint", json!({})).reach(), Some(0.0));
+}
+
+/// Fraction of `d`'s pixels for which `f` holds.
+fn share(d: &[u8], f: impl Fn(&[u8; 4]) -> bool) -> f64 {
+    let px = d.as_chunks::<4>().0;
+    px.iter().filter(|p| f(p)).count() as f64 / px.len() as f64
+}
+
+#[test]
+fn color_halftone_screens_midtones_into_dots_and_keeps_white_and_black() {
+    let (w, h) = (64, 64);
+    let halftone = fx("pixelate.colorHalftone", json!({}));
+    for v in [0, 255] {
+        let mut d = image(w, h, |_, _| grey(v));
+        halftone.apply(&mut d, w, h, &space(w, h));
+        assert_eq!(d, image(w, h, |_, _| grey(v)), "{v} stays");
+    }
+    // Mid grey: each channel's dots cover about half its screen, so the tone stays.
+    let mut d = image(w, h, |_, _| grey(128));
+    halftone.apply(&mut d, w, h, &space(w, h));
+    let px = d.as_chunks::<4>().0;
+    for c in 0..3 {
+        let mean = px.iter().map(|p| f64::from(p[c])).sum::<f64>() / px.len() as f64;
+        assert!((mean - 128.0).abs() < 16.0, "channel {c}: {mean}");
+    }
+    assert!(share(&d, |p| p[0] == 255) > 0.25 && share(&d, |p| p[0] == 0) > 0.25, "dots, not grey");
+    assert!(share(&d, |p| p[0] != p[1]) > 0.1, "the channels' screens lie at different angles");
+    assert!(px.iter().all(|p| p[3] == 255), "coverage stays");
+    // Transparency stays transparent.
+    let mut half = image(w, h, |x, _| if x < 32 { grey(160) } else { [0; 4] });
+    halftone.apply(&mut half, w, h, &space(w, h));
+    assert!((0..h).all(|y| (32..w).all(|x| at(&half, w, x, y) == [0; 4])));
+    // Dots are bigger where the image is brighter.
+    let mut ramp = image(w, h, |x, _| grey((x * 4) as u8));
+    halftone.apply(&mut ramp, w, h, &space(w, h));
+    let lit = |x0: usize| (0..h).flat_map(|y| (x0..x0 + 16).map(move |x| (x, y))).filter(|(x, y)| at(&ramp, w, *x, *y)[0] > 127).count();
+    assert!(lit(8) < lit(40), "{} < {}", lit(8), lit(40));
+}
+
+#[test]
+fn color_halftone_screens_inks_in_cmyk_documents() {
+    let (w, h) = (64, 64);
+    let halftone = fx("pixelate.colorHalftone", json!({}));
+    let cmyk = PixelSpace { channels: Channels::Cmyk, ..space(w, h) };
+    // A neutral grey prints with all four inks: dots of each on white paper, black where they
+    // all overlap.
+    let mut d = image(w, h, |_, _| grey(128));
+    halftone.apply(&mut d, w, h, &cmyk);
+    assert!(share(&d, |p| *p == grey(255)) > 0.02 && share(&d, |p| *p == grey(0)) > 0.02);
+    for (ink, colour) in [("cyan", [0, 255, 255, 255]), ("magenta", [255, 0, 255, 255]), ("yellow", [255, 255, 0, 255])] {
+        assert!(share(&d, |p| *p == colour) > 0.0, "{ink} dots alone");
+    }
+    // White paper stays bare; pure cyan ink fills its cells.
+    let mut white = image(w, h, |_, _| grey(255));
+    halftone.apply(&mut white, w, h, &cmyk);
+    assert_eq!(white, image(w, h, |_, _| grey(255)));
+    let mut cyan = image(w, h, |_, _| [0, 255, 255, 255]);
+    halftone.apply(&mut cyan, w, h, &cmyk);
+    assert_eq!(cyan, image(w, h, |_, _| [0, 255, 255, 255]));
+    // Ink planes: the complemented K plane screens one grey channel at the black angle (45°,
+    // the same in every quarter turn).
+    let mut k = image(w, h, |_, _| grey(128));
+    halftone.apply(&mut k, w, h, &PixelSpace { channels: Channels::KPlane, ..space(w, h) });
+    assert!(k.as_chunks::<4>().0.iter().all(|p| p[0] == p[1] && p[1] == p[2]), "one grey channel");
+    assert!(share(&k, |p| p[0] == 255) > 0.25 && share(&k, |p| p[0] == 0) > 0.25);
+    let mut turned = image(w, h, |_, _| grey(128));
+    fx("pixelate.colorHalftone", json!({"channel4": 135})).apply(&mut turned, w, h, &PixelSpace { channels: Channels::KPlane, ..space(w, h) });
+    let mut other = image(w, h, |_, _| grey(128));
+    fx("pixelate.colorHalftone", json!({"channel4": 30})).apply(&mut other, w, h, &PixelSpace { channels: Channels::KPlane, ..space(w, h) });
+    assert_eq!(turned, k, "channel 4 sets the K plane's angle");
+    assert_ne!(other, k);
+}
+
+#[test]
+fn crystallize_redraws_in_solid_polygons() {
+    let (w, h) = (48, 48);
+    let crystals = fx("pixelate.crystallize", json!({"cellSize": 6}));
+    // One colour stays that colour (away from the raster's edges, where crystals around points
+    // beyond it take the transparency there).
+    let mut d = image(w, h, |_, _| [200, 100, 50, 255]);
+    crystals.apply(&mut d, w, h, &space(w, h));
+    assert!((9..39).all(|y| (9..39).all(|x| at(&d, w, x, y) == [200, 100, 50, 255])));
+    // Two halves: every pixel takes one of the colours, and the border between them zigzags.
+    let (red, blue) = ([200, 0, 0, 255], [0, 0, 200, 255]);
+    let src = image(w, h, |x, _| if x < 24 { red } else { blue });
+    let mut d = src.clone();
+    crystals.apply(&mut d, w, h, &space(w, h));
+    assert!((9..39).all(|y| (9..39).all(|x| [red, blue].contains(&at(&d, w, x, y)))));
+    let crossed = (9..39).flat_map(|y| (9..39).map(move |x| (x, y))).filter(|(x, y)| at(&d, w, *x, *y) != at(&src, w, *x, *y)).count();
+    assert!(crossed > 10, "{crossed}");
+    let border: std::collections::BTreeSet<usize> = (9..39).map(|y| (9..39).find(|x| at(&d, w, *x, y) == blue).unwrap()).collect();
+    assert!(border.len() > 2, "{border:?}");
+}
+
+#[test]
+fn mezzotint_turns_channels_fully_on_or_off() {
+    let (w, h) = (64, 64);
+    let grey_square = image(w, h, |x, y| if (8..56).contains(&x) && (8..56).contains(&y) { grey(128) } else { [0; 4] });
+    let mut seen = Vec::new();
+    for (_, kind) in MEZZOTINT_TYPES {
+        let f = fx("pixelate.mezzotint", json!({ "type": kind }));
+        for v in [0, 255] {
+            let mut d = image(w, h, |_, _| grey(v));
+            f.apply(&mut d, w, h, &space(w, h));
+            assert_eq!(d, image(w, h, |_, _| grey(v)), "{kind}: {v} stays");
+        }
+        let mut d = grey_square.clone();
+        f.apply(&mut d, w, h, &space(w, h));
+        let px = d.as_chunks::<4>().0;
+        assert!(px.iter().all(|p| p[..3].iter().all(|c| *c == 0 || *c == p[3])), "{kind}: pure colours");
+        let on = px.iter().filter(|p| p[3] > 0 && p[0] > 0).count() as f64 / (48.0 * 48.0);
+        assert!((0.25..0.75).contains(&on), "{kind}: {on}");
+        assert!(px.iter().any(|p| p[3] > 0 && p[0] != p[1]), "{kind}: each channel its own pattern");
+        assert!(d.iter().zip(&grey_square).skip(3).step_by(4).all(|(a, b)| a == b), "{kind}: coverage stays");
+        assert!(!seen.contains(&d), "{kind}: a pattern of its own");
+        seen.push(d);
+    }
+}
+
+#[test]
+fn pointillize_paints_dots_on_a_white_canvas() {
+    let (w, h) = (80, 80);
+    let red = [200, 0, 0, 255];
+    let src = image(w, h, |x, y| if (20..60).contains(&x) && (20..60).contains(&y) { red } else { [0; 4] });
+    let mut d = src.clone();
+    fx("pixelate.pointillize", json!({})).apply(&mut d, w, h, &space(w, h));
+    let inside: Vec<[u8; 4]> = (26..54).flat_map(|y| (26..54).map(move |x| (x, y))).map(|(x, y)| at(&d, w, x, y)).collect();
+    let canvas = inside.iter().filter(|p| **p == grey(255)).count();
+    let dots = inside.iter().filter(|p| **p == red).count();
+    assert!(canvas > inside.len() / 20 && dots > inside.len() / 3, "{canvas} canvas, {dots} dots of {}", inside.len());
+    assert!(inside.iter().all(|p| p[3] == 255 && p[1] == p[2] && p[0] >= p[1]), "red over white only");
+    // Dots at the edges reach a little past the object; far from it stays transparent.
+    assert!((0..h).any(|y| (14..20).any(|x| at(&d, w, x, y)[3] > 0)));
+    assert!((0..h).all(|y| (0..10).all(|x| at(&d, w, x, y) == [0; 4])));
+    assert!(d.as_chunks::<4>().0.iter().all(|p| p[0] <= p[3] && p[1] <= p[3] && p[2] <= p[3]));
+}
+
+/// The patterns lie in document space around the object's centre: the same at twice the
+/// resolution, and moving with the object.
+#[test]
+fn pixelate_patterns_follow_the_object_at_any_resolution() {
+    let (w, h) = (40, 40);
+    let art = |x: f64, y: f64| -> [u8; 4] {
+        if (8.0..32.0).contains(&x) && (8.0..32.0).contains(&y) { [(x * 6.0) as u8, (y * 6.0) as u8, 120, 255] } else { [0; 4] }
+    };
+    for (id, p) in [
+        ("pixelate.colorHalftone", json!({"maxRadius": 4})),
+        ("pixelate.crystallize", json!({"cellSize": 4})),
+        ("pixelate.mezzotint", json!({"type": "coarseDots"})),
+        ("pixelate.pointillize", json!({"cellSize": 4})),
+    ] {
+        let f = fx(id, p);
+        let mut one = image(w, h, |x, y| art(x as f64 + 0.5, y as f64 + 0.5));
+        f.apply(&mut one, w, h, &space(w, h));
+        // Twice the pixels for the same art, averaged back down.
+        let mut two = image(2 * w, 2 * h, |x, y| art((x as f64 + 0.5) / 2.0, (y as f64 + 0.5) / 2.0));
+        let fine = PixelSpace { to_doc: Affine::scale(0.5), px: 0.5, ..space(w, h) };
+        f.apply(&mut two, 2 * w, 2 * h, &fine);
+        let down = image(w, h, |x, y| {
+            let q = [(0, 0), (1, 0), (0, 1), (1, 1)].map(|(dx, dy)| at(&two, 2 * w, 2 * x + dx, 2 * y + dy));
+            std::array::from_fn(|c| (q.iter().map(|p| u32::from(p[c])).sum::<u32>() / 4) as u8)
+        });
+        let diff = one.iter().zip(&down).map(|(a, b)| f64::from(a.abs_diff(*b))).sum::<f64>() / one.len() as f64;
+        assert!(diff < 24.0, "{id}: {diff}");
+        // The object and its raster 7 × 3 points further: the same pixels.
+        let moved = PixelSpace { to_doc: Affine::translate((7.0, 3.0)), center: Point::new(27.0, 23.0), ..space(w, h) };
+        let mut shifted = image(w, h, |x, y| art(x as f64 + 0.5, y as f64 + 0.5));
+        f.apply(&mut shifted, w, h, &moved);
+        assert_eq!(shifted, one, "{id}");
+    }
+}
@@ -1,6 +1,7 @@
-//! The Photoshop-style raster effects (Effect › Blur › Radial Blur and Smart Blur, Sharpen ›
-//! Unsharp Mask): applied and edited as commands, listed in the catalogue, drawn on the canvas,
-//! and written to PDF and SVG as images of the effected object.
+//! The Photoshop-style raster effects (Effect › Blur › Radial Blur and Smart Blur, Pixelate ›
+//! Color Halftone, Crystallize, Mezzotint and Pointillize, Sharpen › Unsharp Mask): applied and
+//! edited as commands, listed in the catalogue, drawn on the canvas, and written to PDF and SVG
+//! as images of the effected object.

 use serde_json::{Value, json};
 use vectorcraft_doc::NodeKind;
@@ -16,6 +17,10 @@ const EFFECTS: [(&str, &str); 3] = [
    ("sharpen.unsharpMask", r#"{"amount": 300, "radius": 3}"#),
 ];

+/// Effect › Pixelate, at their defaults.
+const PIXELATE: [(&str, &str); 4] =
+    [("pixelate.colorHalftone", "{}"), ("pixelate.crystallize", "{}"), ("pixelate.mezzotint", "{}"), ("pixelate.pointillize", "{}")];
+
 /// A group of a red square and a darker red stripe across it; returns the group's id.
 fn striped() -> (Session, u64) {
    let mut s = Session::new();
@@ -52,6 +57,10 @@ fn listed_applied_edited_and_undone() {
    let menus: Vec<Value> =
        EFFECTS.iter().map(|(id, _)| list["catalog"].as_array().unwrap().iter().find(|e| e["id"] == *id).unwrap()["menu"].clone()).collect();
    assert_eq!(menus, [json!(["Effect", "Blur"]), json!(["Effect", "Blur"]), json!(["Effect", "Sharpen"])]);
+    for (id, _) in PIXELATE {
+        let e = list["catalog"].as_array().unwrap().iter().find(|e| e["id"] == id).unwrap_or_else(|| panic!("{id} listed"));
+        assert_eq!((&e["raster"], &e["menu"]), (&json!(true), &json!(["Effect", "Pixelate"])), "{id}");
+    }
    // Junk parameters are stored as given and read clamped; the canvas still draws.
    for (id, _) in EFFECTS {
        s.execute("effect.apply", &json!({"effect": id, "ids": [g], "params": {"amount": 1e308, "radius": -1e308, "threshold": "x", "quality": 7}}))
@@ -71,7 +80,7 @@ fn listed_applied_edited_and_undone() {

 #[test]
 fn each_effect_changes_the_canvas_and_draws_the_same_twice() {
-    for (id, params) in EFFECTS {
+    for (id, params) in EFFECTS.into_iter().chain(PIXELATE) {
        let (mut s, g) = striped();
        let plain = render(&s);
        let params: Value = serde_json::from_str(params).unwrap();
@@ -100,7 +109,7 @@ fn spin_blur_reaches_past_the_corners() {

 #[test]
 fn pdf_and_svg_write_the_effected_object_as_an_image() {
-    for (id, params) in EFFECTS {
+    for (id, params) in EFFECTS.into_iter().chain(PIXELATE) {
        let (mut s, g) = striped();
        let params: Value = serde_json::from_str(params).unwrap();
        s.execute("effect.apply", &json!({"effect": id, "ids": [g], "params": params})).unwrap();
@@ -278,6 +278,10 @@ fn structured_junk() {
        ("effect.apply", json!({"effect": "blur.radial", "params": {"amount": 1e308, "method": 5, "quality": "best"}})),
        ("effect.apply", json!({"effect": "blur.smart", "params": {"radius": 1e308, "threshold": -1e308, "quality": null}})),
        ("effect.apply", json!({"effect": "sharpen.unsharpMask", "params": {"amount": -1, "radius": "1e999", "threshold": 1e308}})),
+        ("effect.apply", json!({"effect": "pixelate.colorHalftone", "params": {"maxRadius": 1e308, "channel1": "1e999", "channel4": null}})),
+        ("effect.apply", json!({"effect": "pixelate.crystallize", "params": {"cellSize": -1e308}})),
+        ("effect.apply", json!({"effect": "pixelate.mezzotint", "params": {"type": 5}})),
+        ("effect.apply", json!({"effect": "pixelate.pointillize", "params": {"cellSize": "NaN"}})),
        ("effect.apply", json!({"effect": "no.such.effect"})),
        ("effect.remove", json!({"index": 99})),
        ("effect.setParams", json!({"index": 0, "params": null})),
@@ -595,7 +595,13 @@ impl Renderer {
        off.flush();
        let mut pm = vello_cpu::Pixmap::new(wu, hu);
        off.render(&mut pm, &mut self.resources);
-        let space = effects::PixelSpace { to_doc, px, center: content.reach.center() };
+        let channels = match f.ink {
+            Ink::Cmy => effects::pixel::Channels::CmyPlane,
+            Ink::K => effects::pixel::Channels::KPlane,
+            Ink::Display if f.doc.color_mode == vectorcraft_doc::ColorMode::Cmyk => effects::pixel::Channels::Cmyk,
+            Ink::Display => effects::pixel::Channels::Rgb,
+        };
+        let space = effects::PixelSpace { to_doc, px, center: content.reach.center(), channels };
        let (wz, hz) = (wu as usize, hu as usize);
        for fx in chain {
            match fx {
@@ -159,6 +159,7 @@ fn choices(effect: &str, key: &str) -> Option<form::Choices> {
        ("blur.radial", "method") => Some(&[("Spin", "spin"), ("Zoom", "zoom")]),
        ("blur.radial", "quality") => Some(&[("Draft", "draft"), ("Good", "good"), ("Best", "best")]),
        ("blur.smart", "quality") => Some(&[("Low", "low"), ("Medium", "medium"), ("High", "high")]),
+        ("pixelate.mezzotint", "type") => Some(&vectorcraft_effects::pixel::MEZZOTINT_TYPES),
        ("path.offsetPath", "joins") => Some(&[("Miter", "miter"), ("Round", "round"), ("Bevel", "bevel")]),
        ("distort.roughen" | "distort.zigZag", "points") => Some(&[("Smooth", "smooth"), ("Corner", "corner")]),
        _ => None,
@@ -350,6 +350,11 @@ pub(super) fn humanize(k: &str) -> String {
        "Sy" => "Vertical %".into(),
        "Radius1" => "Radius 1".into(),
        "Radius2" => "Radius 2".into(),
+        "Max Radius" => "Max. Radius:".into(),
+        "Channel1" => "Channel 1:".into(),
+        "Channel2" => "Channel 2:".into(),
+        "Channel3" => "Channel 3:".into(),
+        "Channel4" => "Channel 4:".into(),
        "Include Cmy Blacks" => "Include Blacks with CMY:".into(),
        "Align To Path" => "Align to Path:".into(),
        _ => format!("{s}:"),
@@ -168,7 +168,15 @@ fn effect_preview_is_kept_as_one_undo_step() {

 #[test]
 fn raster_filter_dialogs_preview_and_apply() {
-    for (effect, key, value) in [("blur.radial", "method", "zoom"), ("blur.smart", "quality", "high"), ("sharpen.unsharpMask", "amount", "120")] {
+    for (effect, key, value) in [
+        ("blur.radial", "method", "zoom"),
+        ("blur.smart", "quality", "high"),
+        ("sharpen.unsharpMask", "amount", "120"),
+        ("pixelate.colorHalftone", "channel1", "30"),
+        ("pixelate.crystallize", "cellSize", "20"),
+        ("pixelate.mezzotint", "type", "longLines"),
+        ("pixelate.pointillize", "cellSize", "12"),
+    ] {
        let mut app = app();
        let id = app.run("shape.rectangle", json!({"x": 10, "y": 10, "width": 50, "height": 50})).unwrap()["id"].as_u64().unwrap();
        app.run("select.all", json!({})).unwrap();
@@ -188,6 +196,13 @@ fn raster_filter_dialogs_preview_and_apply() {
    let ranks: Vec<usize> = ["radius", "threshold", "quality"].iter().map(|k| super::effect::doc_rank(doc, k)).collect();
    assert!(ranks.windows(2).all(|w| w[0] < w[1]), "{ranks:?}");
    assert_eq!(super::effect::doc_rank(doc, "nope"), usize::MAX);
+    let doc = vectorcraft_effects::effect_info("pixelate.colorHalftone").unwrap().params;
+    let ranks: Vec<usize> = ["maxRadius", "channel1", "channel2", "channel3", "channel4"].iter().map(|k| super::effect::doc_rank(doc, k)).collect();
+    assert!(ranks.windows(2).all(|w| w[0] < w[1]) && ranks[4] < usize::MAX, "{ranks:?}");
+    // Labels as the dialogs show them.
+    assert_eq!(super::form::humanize("maxRadius"), "Max. Radius:");
+    assert_eq!(super::form::humanize("channel3"), "Channel 3:");
+    assert_eq!(super::form::humanize("cellSize"), "Cell Size:");
 }

 #[test]
@@ -652,3 +652,8 @@
 	Smart Blur…	Chytré rozostření…
 	Sharpen	Zostření
 	Unsharp Mask…	Maska rozostření…
+	Pixelate	Pixelizace
+	Color Halftone…	Barevný polotón…
+	Crystallize…	Krystalizace…
+	Mezzotint…	Mezzotinta…
+	Pointillize…	Pointilismus…
@@ -21,6 +21,31 @@
 	Smart Blur…	Desenfoque inteligente…
 	Sharpen	Enfocar
 	Unsharp Mask…	Máscara de enfoque…
+	Pixelate	Pixelizar
+	Color Halftone…	Semitono de color…
+	Crystallize…	Cristalizar…
+	Mezzotint…	Grabado a media tinta…
+	Pointillize…	Puntillismo…
+	Color Halftone	Semitono de color
+	Crystallize	Cristalizar
+	Mezzotint	Grabado a media tinta
+	Pointillize	Puntillismo
+	Max. Radius	Radio máx.
+	Channel 1	Canal 1
+	Channel 2	Canal 2
+	Channel 3	Canal 3
+	Channel 4	Canal 4
+	Cell Size	Tamaño de celda
+	Fine Dots	Puntos finos
+	Medium Dots	Puntos medios
+	Grainy Dots	Puntos granulados
+	Coarse Dots	Puntos gruesos
+	Short Lines	Líneas cortas
+	Medium Lines	Líneas medias
+	Long Lines	Líneas largas
+	Short Strokes	Trazos cortos
+	Medium Strokes	Trazos medios
+	Long Strokes	Trazos largos
 	Radial Blur	Desenfoque radial
 	Smart Blur	Desenfoque inteligente
 	Unsharp Mask	Máscara de enfoque
@@ -22,6 +22,31 @@
 	Smart Blur…	Flou intelligent…
 	Sharpen	Netteté
 	Unsharp Mask…	Masque de netteté…
+	Pixelate	Pixellisation
+	Color Halftone…	Demi-teintes couleur…
+	Crystallize…	Cristalliser…
+	Mezzotint…	Manière noire…
+	Pointillize…	Pointillisme…
+	Color Halftone	Demi-teintes couleur
+	Crystallize	Cristalliser
+	Mezzotint	Manière noire
+	Pointillize	Pointillisme
+	Max. Radius	Rayon max.
+	Channel 1	Couche 1
+	Channel 2	Couche 2
+	Channel 3	Couche 3
+	Channel 4	Couche 4
+	Cell Size	Taille de cellule
+	Fine Dots	Points fins
+	Medium Dots	Points moyens
+	Grainy Dots	Points granuleux
+	Coarse Dots	Gros points
+	Short Lines	Lignes courtes
+	Medium Lines	Lignes moyennes
+	Long Lines	Lignes longues
+	Short Strokes	Traits courts
+	Medium Strokes	Traits moyens
+	Long Strokes	Traits longs
 	Radial Blur	Flou radial
 	Smart Blur	Flou intelligent
 	Unsharp Mask	Masque de netteté
@@ -21,6 +21,31 @@
 	Smart Blur…	Sfocatura intelligente…
 	Sharpen	Nitidezza
 	Unsharp Mask…	Maschera di contrasto…
+	Pixelate	Effetto pixel
+	Color Halftone…	Mezzetinte colore…
+	Crystallize…	Cristallizza…
+	Mezzotint…	Mezzatinta…
+	Pointillize…	Puntinismo…
+	Color Halftone	Mezzetinte colore
+	Crystallize	Cristallizza
+	Mezzotint	Mezzatinta
+	Pointillize	Puntinismo
+	Max. Radius	Raggio max.
+	Channel 1	Canale 1
+	Channel 2	Canale 2
+	Channel 3	Canale 3
+	Channel 4	Canale 4
+	Cell Size	Dimensione cella
+	Fine Dots	Punti fini
+	Medium Dots	Punti medi
+	Grainy Dots	Punti granulosi
+	Coarse Dots	Punti grossi
+	Short Lines	Linee corte
+	Medium Lines	Linee medie
+	Long Lines	Linee lunghe
+	Short Strokes	Tratti corti
+	Medium Strokes	Tratti medi
+	Long Strokes	Tratti lunghi
 	Radial Blur	Sfocatura radiale
 	Smart Blur	Sfocatura intelligente
 	Unsharp Mask	Maschera di contrasto
@@ -3217,6 +3217,31 @@ theme	Appearance	外観
 	Smart Blur…	ぼかし (詳細)…
 	Sharpen	シャープ
 	Unsharp Mask…	アンシャープマスク…
+	Pixelate	ピクセレート
+	Color Halftone…	カラーハーフトーン…
+	Crystallize…	結晶化…
+	Mezzotint…	メゾティント…
+	Pointillize…	点描…
+	Color Halftone	カラーハーフトーン
+	Crystallize	結晶化
+	Mezzotint	メゾティント
+	Pointillize	点描
+	Max. Radius	最大半径
+	Channel 1	チャンネル 1
+	Channel 2	チャンネル 2
+	Channel 3	チャンネル 3
+	Channel 4	チャンネル 4
+	Cell Size	セルの大きさ
+	Fine Dots	細かい点
+	Medium Dots	中程度の点
+	Grainy Dots	粒状の点
+	Coarse Dots	粗い点
+	Short Lines	短い線
+	Medium Lines	中程度の線
+	Long Lines	長い線
+	Short Strokes	短いストローク
+	Medium Strokes	中程度のストローク
+	Long Strokes	長いストローク
 	Radial Blur	ぼかし (放射状)
 	Smart Blur	ぼかし (詳細)
 	Unsharp Mask	アンシャープマスク
@@ -2713,3 +2713,8 @@
 	Smart Blur…	Desfoque Inteligente…
 	Sharpen	Nitidez
 	Unsharp Mask…	Máscara de Nitidez…
+	Pixelate	Pixelizar
+	Color Halftone…	Meio-Tom Colorido…
+	Crystallize…	Cristalizar…
+	Mezzotint…	Meia-Tinta…
+	Pointillize…	Pontilhar…
@@ -19,6 +19,31 @@
 	Smart Blur…	Умное размытие…
 	Sharpen	Резкость
 	Unsharp Mask…	Нерезкая маска…
+	Pixelate	Пикселизация
+	Color Halftone…	Цветные полутона…
+	Crystallize…	Кристаллизация…
+	Mezzotint…	Меццо-тинто…
+	Pointillize…	Пуантилизм…
+	Color Halftone	Цветные полутона
+	Crystallize	Кристаллизация
+	Mezzotint	Меццо-тинто
+	Pointillize	Пуантилизм
+	Max. Radius	Макс. радиус
+	Channel 1	Канал 1
+	Channel 2	Канал 2
+	Channel 3	Канал 3
+	Channel 4	Канал 4
+	Cell Size	Размер ячейки
+	Fine Dots	Мелкие точки
+	Medium Dots	Средние точки
+	Grainy Dots	Зернистые точки
+	Coarse Dots	Крупные точки
+	Short Lines	Короткие линии
+	Medium Lines	Средние линии
+	Long Lines	Длинные линии
+	Short Strokes	Короткие штрихи
+	Medium Strokes	Средние штрихи
+	Long Strokes	Длинные штрихи
 	Radial Blur	Радиальное размытие
 	Smart Blur	Умное размытие
 	Unsharp Mask	Нерезкая маска
@@ -20,6 +20,31 @@
 	Smart Blur…	Розумне розмиття…
 	Sharpen	Різкість
 	Unsharp Mask…	Нерізка маска…
+	Pixelate	Пікселізація
+	Color Halftone…	Кольорові півтони…
+	Crystallize…	Кристалізація…
+	Mezzotint…	Меццо-тинто…
+	Pointillize…	Пуантилізм…
+	Color Halftone	Кольорові півтони
+	Crystallize	Кристалізація
+	Mezzotint	Меццо-тинто
+	Pointillize	Пуантилізм
+	Max. Radius	Макс. радіус
+	Channel 1	Канал 1
+	Channel 2	Канал 2
+	Channel 3	Канал 3
+	Channel 4	Канал 4
+	Cell Size	Розмір комірки
+	Fine Dots	Дрібні точки
+	Medium Dots	Середні точки
+	Grainy Dots	Зернисті точки
+	Coarse Dots	Великі точки
+	Short Lines	Короткі лінії
+	Medium Lines	Середні лінії
+	Long Lines	Довгі лінії
+	Short Strokes	Короткі штрихи
+	Medium Strokes	Середні штрихи
+	Long Strokes	Довгі штрихи
 	Radial Blur	Радіальне розмиття
 	Smart Blur	Розумне розмиття
 	Unsharp Mask	Нерізка маска
@@ -3468,6 +3468,31 @@ axis	Both	两者
 	Smart Blur…	智能模糊…
 	Sharpen	锐化
 	Unsharp Mask…	反锐化遮罩…
+	Pixelate	像素化
+	Color Halftone…	彩色半调…
+	Crystallize…	晶格化…
+	Mezzotint…	铜版雕刻…
+	Pointillize…	点彩…
+	Color Halftone	彩色半调
+	Crystallize	晶格化
+	Mezzotint	铜版雕刻
+	Pointillize	点彩
+	Max. Radius	最大半径
+	Channel 1	色版 1
+	Channel 2	色版 2
+	Channel 3	色版 3
+	Channel 4	色版 4
+	Cell Size	单元格大小
+	Fine Dots	细点
+	Medium Dots	中等点
+	Grainy Dots	颗粒点
+	Coarse Dots	粗点
+	Short Lines	短线
+	Medium Lines	中等线
+	Long Lines	长线
+	Short Strokes	短笔画
+	Medium Strokes	中等笔画
+	Long Strokes	长笔画
 	Radial Blur	径向模糊
 	Smart Blur	智能模糊
 	Unsharp Mask	反锐化遮罩
@@ -3246,6 +3246,31 @@ axis	Both	兩者
 	Smart Blur…	智慧型模糊…
 	Sharpen	銳利化
 	Unsharp Mask…	反銳利化遮罩…
+	Pixelate	像素化
+	Color Halftone…	彩色半色調…
+	Crystallize…	結晶化…
+	Mezzotint…	網線銅版…
+	Pointillize…	點描…
+	Color Halftone	彩色半色調
+	Crystallize	結晶化
+	Mezzotint	網線銅版
+	Pointillize	點描
+	Max. Radius	最大半徑
+	Channel 1	色版 1
+	Channel 2	色版 2
+	Channel 3	色版 3
+	Channel 4	色版 4
+	Cell Size	單元大小
+	Fine Dots	細點
+	Medium Dots	中等點
+	Grainy Dots	顆粒點
+	Coarse Dots	粗點
+	Short Lines	短線
+	Medium Lines	中等線
+	Long Lines	長線
+	Short Strokes	短筆畫
+	Medium Strokes	中等筆畫
+	Long Strokes	長筆畫
 	Radial Blur	放射狀模糊
 	Smart Blur	智慧型模糊
 	Unsharp Mask	反銳利化遮罩
@@ -3305,7 +3305,8 @@ fn font_items(english_names: bool) -> Vec<Item> {

 /// The raster effects' submenus of the Effect menu (the Photoshop-style effects, below the
 /// vector effects): (submenu, the catalogue's menu path of its effects).
-const RASTER_MENUS: [(&str, &[&str]); 2] = [("Blur", &["Effect", "Blur"]), ("Sharpen", &["Effect", "Sharpen"])];
+const RASTER_MENUS: [(&str, &[&str]); 3] =
+    [("Blur", &["Effect", "Blur"]), ("Pixelate", &["Effect", "Pixelate"]), ("Sharpen", &["Effect", "Sharpen"])];

 /// The Effect menu, built from the effects catalogue (vector effects), plus raster effects.
 fn effect_menu() -> Vec<Item> {
@@ -50,6 +50,20 @@ fn effect_menu_has_a_vector_effects_section() {
    assert!(effect.iter().any(|i| matches!(i, Item::Header("Vector Effects"))));
 }

+#[test]
+fn effect_menu_lists_the_pixelate_filters_between_blur_and_sharpen() {
+    let app = app();
+    let entries = menus::menu_entries(&app);
+    let pixelate: Vec<_> = entries.iter().filter(|e| e.path == ["Effect", "Pixelate"]).collect();
+    let labels: Vec<&str> = pixelate.iter().map(|e| e.label.as_str()).collect();
+    assert_eq!(labels, ["Color Halftone…", "Crystallize…", "Mezzotint…", "Pointillize…"]);
+    assert!(pixelate.iter().all(|e| e.command.as_deref() == Some("effect.dialog")));
+    let raster: Vec<&str> =
+        entries.iter().filter_map(|e| e.path.get(1).filter(|_| e.path.len() == 2 && e.path[0] == "Effect")).map(String::as_str).collect();
+    let at = |name: &str| raster.iter().position(|s| *s == name).unwrap();
+    assert!(at("Blur") < at("Pixelate") && at("Pixelate") < at("Sharpen"));
+}
+
 #[test]
 fn library_submenus_are_disabled_placeholders() {
    let app = app();