.ai import: multi-layer masks open as a clipping group in each layer

Squashed from #5117 onto main.

crates/engine/tests/import_fuzz.rs

@@ -3322,6 +3322,48 @@ proptest! {
         let text = mutate_text(NAMED_PROLOG_AI, cut, &edits);
         survive("mutated PostScript-form .ai", || vectorcraft_engine::cmd::fileio::load("x.ai", text.as_bytes()).ok().map(|l| l.doc))?;
     }
+
+    /// Multi-layer masks (`Mb` <path> `W n` `Md` … `MB`) over any number of layers, with tokens
+    /// dropped or put anywhere (the mask operators, layer ends, groups, clipping paths) and the
+    /// data cut short.
+    #[test]
+    fn ai_multi_layer_masks_never_panic(
+        layers in 1usize..5,
+        aliases in any::<bool>(),
+        edits in prop::collection::vec((0usize..64, prop::sample::select(vec!["", "Mb", "Md", "MB", "Mi", "LB", "u", "U", "q", "Q", "W n", "h W n"])), 0..4),
+        cut in prop::option::of(0usize..64),
+    ) {
+        use vectorcraft_testkit::ai;
+        let (begin, define) = if aliases { ("Mv", "ME") } else { ("Mb", "Md") };
+        let mut tokens: Vec<String> = vec![];
+        for i in 0..layers {
+            if i > 0 {
+                tokens.push(format!("LB\n%AI5_EndLayer--\n%AI5_BeginLayer\n1 1 1 1 0 1 1 79 128 255 Lb\n(L{i}) Ln\n"));
+            } else {
+                tokens.extend([begin.to_string(), "40 40 m 120 40 L 120 120 L 40 120 L h W n".into(), define.to_string()]);
+            }
+            let x = 10 * i;
+            tokens.push(format!("0.5 0 0 0 k {x} {x} m {} {x} L {} {} L f", x + 140, x + 140, x + 140));
+        }
+        tokens.extend(["MB".to_string(), "150 150 m 190 150 L 190 190 L f".into()]);
+        for (at, with) in &edits {
+            let at = at % (tokens.len() + 1);
+            if with.is_empty() {
+                if at < tokens.len() {
+                    tokens.remove(at);
+                }
+            } else {
+                tokens.insert(at, with.to_string());
+            }
+        }
+        if let Some(cut) = cut {
+            tokens.truncate(cut);
+        }
+        let data = ai::editing_data(200.0, 100.0, &format!("%AI5_BeginLayer\n1 1 1 1 0 1 1 79 128 255 Lb\n(L0) Ln\n{}\nLB\n", tokens.join("\n")));
+        survive("multi-layer masks", || Some(vectorcraft_eps::layered_ai(data.as_bytes(), Document::new(200.0, 100.0), vec![], false, false, 1.0).0))?;
+        let eps = ai::eps(data.as_bytes(), ai::page_ps());
+        survive("multi-layer masks in an EPS", || vectorcraft_engine::cmd::fileio::load("x.eps", &eps).ok().map(|l| l.doc))?;
+    }
 }
 
 /// An operand of a layer's options (`Lb`): a flag, a colour index or component, a percentage, or
@@ -3390,6 +3432,13 @@ fn arb_ai_token() -> impl Strategy<Value = String> {
             "Lb",
             "Ln",
             "(name) Ln",
+            "\n%AI5_BeginLayer\n1 1 1 1 0 1 1 79 128 255 Lb\n",
+            "Mb",
+            "Mv",
+            "Md",
+            "ME",
+            "Mi",
+            "MB",
             "g",
             "G",
             "k",

crates/eps/src/import/ai/read.rs

@@ -4,6 +4,8 @@
 //! - Layers: `%AI5_BeginLayer`, `visible preview unlocked printing dimmed … colorIndex r g b
 //!   template dimPercent … Lb` (ten operands in the legacy format, without the one before the
 //!   colour index; see `Reader::layer_attrs`), `(name) Ln`, its art, `LB`.
+//! - Multi-layer masks `Mb` <path> `W n` `Md` … `MB`, whose objects can go on past `LB` into the
+//!   next layers: a clipping group in each layer, read by [`masks`].
 //! - Ruler guides: a straight `(N) *` guide path, directly on a layer, that runs across the whole
 //!   canvas (16,383 points around the template box's centre) or from edge to edge of one artboard
 //!   is a ruler guide on that layer ([`Document::guides`]); other guide paths stay paths.
@@ -87,6 +89,7 @@ mod art;
 mod containers;
 mod directives;
 mod document;
+mod masks;
 mod on_path;
 mod ops;
 mod types;
@@ -308,6 +311,8 @@ struct Reader<'a> {
     type_state: legacy_text::TypeState,
     /// The graph being read (see [`Reader::graph_record`]).
     graph: Option<Graph>,
+    /// The multi-layer mask being read (`Mb` … `MB`), which goes on past a layer's end.
+    multi_mask: Option<masks::MultiMask>,
 }
 
 /// A section comment's marker without its `AI<version>_` prefix and value (`AI14_BeginSymbol` →
@@ -406,6 +411,7 @@ impl<'a> Reader<'a> {
             text: None,
             type_state: legacy_text::TypeState::default(),
             graph: None,
+            multi_mask: None,
         }
     }
 
@@ -436,6 +442,9 @@ impl<'a> Reader<'a> {
         if self.frames.iter().any(|f| matches!(f.kind, Kind::Layer(_))) {
             return Err("it ends inside a layer".into());
         }
+        if self.multi_mask.is_some() {
+            return Err("it ends inside a multi-layer mask".into());
+        }
         Ok(())
     }
 }

crates/eps/src/import/ai/read/containers.rs

@@ -75,6 +75,7 @@ impl<'a> Reader<'a> {
     }
 
     pub(super) fn end_container(&mut self, what: &str, hidden: bool) -> Result<(), String> {
+        self.multi_mask_container_ends()?;
         let f = match what {
             "U" => self.close(what, |k| matches!(k, Kind::Group))?,
             "*U" => self.close(what, |k| matches!(k, Kind::Compound))?,

crates/eps/src/import/ai/read/directives.rs

@@ -130,7 +130,10 @@ impl<'a> Reader<'a> {
             _ => {}
         }
         if line.starts_with("AI5_BeginLayer") {
-            return self.open(Kind::Layer(Box::default()), false);
+            self.multi_mask_layer_starts()?;
+            self.open(Kind::Layer(Box::default()), false)?;
+            self.multi_mask_go_on();
+            return Ok(());
         }
         if line.starts_with("AI5_BeginRaster") {
             self.raster = Some(Raster::default());

crates/eps/src/import/ai/read/masks.rs

@@ -0,0 +1,185 @@
+//! Multi-layer masks in the legacy format (version 7 specification §10): `Mb`, the mask's path
+//! painted with `W`, `Md`, the masked objects (in that layer and, past its `LB`, in the layers
+//! after it), `MB`. The objects of each layer the mask covers become one clipping group in that
+//! layer, its clipping path a copy of the mask's.
+
+use super::types::{Frame, Kind, MAX_NODES};
+use super::{Arc, Node, NodeKind, Reader};
+
+/// The note for a file with a multi-layer mask.
+pub(crate) const PER_LAYER: &str = "a mask that covers several layers comes in as a clipping group in each layer it covers";
+
+/// A multi-layer mask being read.
+#[derive(Debug)]
+pub(super) struct MultiMask {
+    /// The mask's clipping path, once `Md` has defined it.
+    mask: Option<Node>,
+    /// What each copy of the mask adds to the objects read: its objects and their points.
+    weight: usize,
+    /// How many frames were open when the masked objects started in the frame they go in; 0
+    /// outside the layers, until a layer starts.
+    depth: usize,
+    /// Where the masked objects start among that frame's children.
+    start: usize,
+}
+
+impl Reader<'_> {
+    /// A multi-layer mask's operator `w`: `Mb` (or `Mv`) starts the mask, `Md` (or `ME`) defines
+    /// it, `MB` ends it, and `Mi` changes nothing here.
+    pub(super) fn multi_mask_op(&mut self, w: &str) -> Result<(), String> {
+        match w {
+            "Mb" | "Mv" => self.begin_multi_mask(),
+            "Md" | "ME" => self.define_multi_mask(),
+            "MB" => self.end_multi_mask(),
+            _ => Ok(()),
+        }
+    }
+
+    /// `LB`: the layer ends, and a multi-layer mask goes on in the frame around it.
+    pub(super) fn end_layer_in_mask(&mut self) -> Result<(), String> {
+        self.multi_mask_layer_ends()?;
+        self.end_layer()?;
+        self.multi_mask_go_on();
+        Ok(())
+    }
+
+    /// `Mb`: a multi-layer mask starts.
+    fn begin_multi_mask(&mut self) -> Result<(), String> {
+        if self.multi_mask.is_some() {
+            return Err("a multi-layer mask's operators are out of order".into());
+        }
+        self.end_path_quietly();
+        let start = self.frames.last().map_or(0, |f| f.children.len());
+        self.multi_mask = Some(MultiMask { mask: None, weight: 0, depth: self.frames.len(), start });
+        Ok(())
+    }
+
+    /// `Md`: the clipping path painted last since `Mb`, in the same group or layer, is the mask.
+    fn define_multi_mask(&mut self) -> Result<(), String> {
+        let depth = self.frames.len();
+        let Some(m) = self.multi_mask.as_mut() else { return Err("a multi-layer mask's operators are out of order".into()) };
+        if m.mask.is_some() || depth == 0 {
+            return Err("a multi-layer mask's operators are out of order".into());
+        }
+        if m.depth != depth {
+            return Err("a group crosses a multi-layer mask".into());
+        }
+        let Some(f) = self.frames.last_mut() else { return Err("a multi-layer mask's operators are out of order".into()) };
+        let Some(at) = f.clips.iter().copied().filter(|i| *i >= m.start && *i < f.children.len()).max() else {
+            return Err("a multi-layer mask needs one clipping path".into());
+        };
+        let mask = f.children.remove(at);
+        f.clips.retain(|i| *i != at);
+        for i in &mut f.clips {
+            if *i > at {
+                *i -= 1;
+            }
+        }
+        let mut weight = mask.count_with_masks();
+        mask.walk(&mut |n| {
+            if let NodeKind::Path { path, .. } = &n.kind {
+                weight = weight.saturating_add(path.anchor_count());
+            }
+        });
+        m.weight = weight;
+        m.mask = Some(mask);
+        self.after_object = false;
+        Ok(())
+    }
+
+    /// `MB`: the masked objects end.
+    fn end_multi_mask(&mut self) -> Result<(), String> {
+        if !self.multi_mask.as_ref().is_some_and(|m| m.mask.is_some()) {
+            return Err("a multi-layer mask's operators are out of order".into());
+        }
+        self.wrap_masked()?;
+        self.multi_mask = None;
+        Ok(())
+    }
+
+    /// `%AI5_BeginLayer` in a multi-layer mask, before the layer opens: the objects masked so far
+    /// in the frame around it are grouped, and the mask goes on in the new layer.
+    pub(super) fn multi_mask_layer_starts(&mut self) -> Result<(), String> {
+        let Some(m) = self.multi_mask.as_ref() else { return Ok(()) };
+        if m.depth != 0 {
+            if m.mask.is_none() {
+                return Err("a multi-layer mask's operators are out of order".into());
+            }
+            self.wrap_masked()?;
+        }
+        Ok(())
+    }
+
+    /// A layer opened or closed in a multi-layer mask: the masked objects go on in the frame now
+    /// innermost.
+    pub(super) fn multi_mask_go_on(&mut self) {
+        let (depth, start) = (self.frames.len(), self.frames.last().map_or(0, |f| f.children.len()));
+        if let Some(m) = self.multi_mask.as_mut() {
+            (m.depth, m.start) = (depth, start);
+        }
+    }
+
+    /// `LB` in a multi-layer mask, before the layer closes: its masked objects are grouped.
+    fn multi_mask_layer_ends(&mut self) -> Result<(), String> {
+        let Some(m) = self.multi_mask.as_ref() else { return Ok(()) };
+        if m.mask.is_none() {
+            return Err("a multi-layer mask's operators are out of order".into());
+        }
+        if !matches!(self.frames.last(), Some(Frame { kind: Kind::Layer(_), .. })) {
+            return Err("a group crosses a multi-layer mask".into());
+        }
+        self.wrap_masked()
+    }
+
+    /// A group, compound path or clipping group closing: it must have opened inside the mask.
+    pub(super) fn multi_mask_container_ends(&self) -> Result<(), String> {
+        match &self.multi_mask {
+            Some(m) if m.depth == self.frames.len() => Err("a group crosses a multi-layer mask".into()),
+            _ => Ok(()),
+        }
+    }
+
+    /// The masked objects in the innermost frame become a clipping group, a copy of the mask first.
+    fn wrap_masked(&mut self) -> Result<(), String> {
+        let Some(m) = self.multi_mask.as_ref() else { return Ok(()) };
+        if m.depth == 0 {
+            return Ok(());
+        }
+        if m.depth != self.frames.len() {
+            return Err("a group crosses a multi-layer mask".into());
+        }
+        let Some(mut mask) = m.mask.clone() else { return Err("a multi-layer mask's operators are out of order".into()) };
+        let (start, weight) = (m.start, m.weight);
+        let Some(f) = self.frames.last_mut() else { return Ok(()) };
+        if start >= f.children.len() {
+            return Ok(());
+        }
+        // A clipping path painted among the masked objects clips the whole layer or group, as
+        // outside a mask: it stays in the frame, outside the masked objects' group.
+        let painted: std::collections::HashSet<usize> = f.clips.iter().filter_map(|i| i.checked_sub(start)).collect();
+        let (clips, kids): (Vec<_>, Vec<_>) = f.children.split_off(start).into_iter().enumerate().partition(|(i, _)| painted.contains(i));
+        let (clips, kids): (Vec<Node>, Vec<Node>) = (clips.into_iter().map(|(_, k)| k).collect(), kids.into_iter().map(|(_, k)| k).collect());
+        f.clips.retain(|i| *i < start);
+        if !kids.is_empty() {
+            self.nodes = self.nodes.saturating_add(weight).saturating_add(1);
+            if self.nodes > MAX_NODES {
+                return Err(format!("it has more than {MAX_NODES} objects"));
+            }
+            self.reid(&mut mask);
+            let children = std::iter::once(mask).chain(kids).map(Arc::new).collect();
+            let group = Node::new(self.doc.alloc_id(), NodeKind::Group { children, clip: true });
+            if let Some(f) = self.frames.last_mut() {
+                f.children.push(group);
+            }
+            self.warn(PER_LAYER);
+        }
+        if let Some(f) = self.frames.last_mut() {
+            for c in clips {
+                f.clips.push(f.children.len());
+                f.children.push(c);
+            }
+        }
+        self.after_object = false;
+        Ok(())
+    }
+}

crates/eps/src/import/ai/read/ops.rs

@@ -154,7 +154,7 @@ impl<'a> Reader<'a> {
                     self.graph = None;
                     self.warn(GRAPH_UNENDED);
                 }
-                self.end_layer()?
+                self.end_layer_in_mask()?
             }
             // Paths.
             "m" | "l" | "L" | "c" | "C" | "v" | "V" | "y" | "Y" => self.path_op(w, &vals)?,
@@ -162,6 +162,7 @@ impl<'a> Reader<'a> {
             // Ends a path that stays open.
             "H" => {}
             "W" => self.clip_next = true,
+            "Mb" | "Mv" | "Md" | "ME" | "MB" | "Mi" => self.multi_mask_op(w)?,
             // A text object's frame or path.
             "N" | "n" | "F" | "f" | "S" | "s" | "B" | "b" if self.in_text_path() => self.text_path(),
             "N" | "n" | "F" | "f" | "S" | "s" | "B" | "b" => self.paint(w, hidden, false)?,

crates/eps/src/import/ai/tests.rs

@@ -3953,3 +3953,224 @@ fn a_graphs_records_take_their_operands() {
     assert_eq!(paths(&a[0]), 1, "the empty groups hold no art");
     assert_eq!(r.warnings, [GRAPH_PLAIN]);
 }
+
+/// Editing data in the legacy format (`%AI5_FileFormat 2.0`, ten `Lb` operands), then `body`.
+fn mask_stream7(body: &str) -> String {
+    format!(
+        "%!PS-Adobe-3.0\n%%Creator: test\n%%BoundingBox: 0 0 200 200\n%AI5_FileFormat 2.0\n%AI5_ArtSize: 200 200\n\
+         %AI3_TemplateBox: 100 100 100 100\n%%EndComments\n%%BeginProlog\n%%EndProlog\n%%BeginSetup\n%%EndSetup\n{body}\n\
+         %%PageTrailer\ngsave annotatepage grestore showpage\n%%Trailer\n%%EOF\n"
+    )
+}
+
+/// The start of a legacy layer named `name`, `masks` its multi-layer mask flag (`Lb`'s sixth operand).
+fn begin7(name: &str, masks: u8) -> String {
+    format!("%AI5_BeginLayer\n1 1 1 1 0 {masks} 1 79 128 255 Lb\n({name}) Ln\n")
+}
+
+const END7: &str = "LB\n%AI5_EndLayer--\n";
+
+/// `Mb`, an 80 by 80 point mask path painted `W n`, `Md` (the version 7 specification's §10.4 order).
+fn mask_start() -> String {
+    format!("Mb\n{}h\nW\nn\nMd\n", rect_path(40.0, 40.0, 120.0, 120.0))
+}
+
+/// A filled square at `x`.
+fn masked(x: f64) -> String {
+    format!("0.5 0 0 0 k\n{}f\n", rect_path(x, x, x + 140.0, x + 140.0))
+}
+
+/// A layer's objects as a tree: `p` a path, `c` a clipping path, `o` a compound path, `g[…]` a
+/// group, `k[…]` a clipping group, `l[…]` a sublayer.
+fn mask_tree(nodes: &[Arc<Node>]) -> String {
+    let one = |n: &Arc<Node>| match &n.kind {
+        NodeKind::Layer { children, .. } => format!("l[{}]", mask_tree(children)),
+        NodeKind::Group { children, clip: false } => format!("g[{}]", mask_tree(children)),
+        NodeKind::Group { children, clip: true } => format!("k[{}]", mask_tree(children)),
+        NodeKind::Path { clipping: true, .. } => "c".into(),
+        NodeKind::Path { .. } => "p".into(),
+        NodeKind::Compound { .. } => "o".into(),
+        k => format!("{k:?}"),
+    };
+    nodes.iter().map(one).collect::<Vec<_>>().join(" ")
+}
+
+fn read7(body: &str) -> Structure {
+    match read(mask_stream7(body).as_bytes()) {
+        Ok(r) => r,
+        Err(e) => panic!("{e}"),
+    }
+}
+
+/// Each layer's tree, and whether the layer itself clips.
+fn layer_trees(doc: &Document) -> Vec<(String, String, bool)> {
+    doc.layers
+        .iter()
+        .map(|l| {
+            let NodeKind::Layer { children, clip, .. } = &l.kind else { panic!("a layer") };
+            (l.name.clone().unwrap_or_default(), mask_tree(children), *clip)
+        })
+        .collect()
+}
+
+/// A multi-layer mask (version 7 specification §10.4: `Mb`, the mask path, `Md`, objects in two
+/// layers, `MB`) comes in as a clipping group in each layer it covers, each clipped by a copy of
+/// the mask's path; what follows `MB` isn't clipped.
+#[test]
+fn a_multi_layer_mask_clips_each_layer_it_covers() {
+    let body = format!("{}{}{}{END7}{}{}MB\n{}{END7}", begin7("A", 1), mask_start(), masked(15.0), begin7("B", 1), masked(30.0), masked(150.0));
+    let r = read7(&body);
+    assert_eq!(layer_trees(&r.doc), [("A".to_string(), "k[c p]".to_string(), false), ("B".to_string(), "k[c p] p".to_string(), false)]);
+    let mask = |l: usize| r.doc.layers[l].children().unwrap()[0].children().unwrap()[0].clone();
+    let (a, b) = (mask(0), mask(1));
+    assert_ne!(a.id, b.id, "each layer has a copy of its own");
+    assert_eq!(a.geometric_bounds(), b.geometric_bounds());
+    let bounds = a.geometric_bounds().unwrap();
+    assert_eq!((bounds.width(), bounds.height()), (80.0, 80.0));
+    assert!(r.warnings.iter().any(|w| w.contains("clipping group in each layer")), "{:?}", r.warnings);
+    // The layers' flag saying they have multi-layer masks changes nothing.
+    let unflagged = read7(&body.replace(&begin7("A", 1), &begin7("A", 0)).replace(&begin7("B", 1), &begin7("B", 0)));
+    assert_eq!(format!("{:?}", unflagged.doc.layers), format!("{:?}", r.doc.layers));
+}
+
+#[test]
+fn a_multi_layer_mask_in_one_layer_or_over_three() {
+    let one = format!("{}{}{}MB\n{}{END7}", begin7("A", 1), mask_start(), masked(15.0), masked(150.0));
+    assert_eq!(layer_trees(&read7(&one).doc), [("A".to_string(), "k[c p] p".to_string(), false)]);
+    let three = format!(
+        "{}{}{}{END7}{}{}{END7}{}{}MB\n{END7}",
+        begin7("A", 1),
+        mask_start(),
+        masked(15.0),
+        begin7("B", 1),
+        masked(30.0),
+        begin7("C", 1),
+        masked(45.0)
+    );
+    let trees: Vec<_> = layer_trees(&read7(&three).doc).into_iter().map(|(_, t, clip)| (t, clip)).collect();
+    assert_eq!(trees, vec![("k[c p]".to_string(), false); 3]);
+    // Objects before the mask's path are masked too; a layer between with nothing in it stays empty.
+    let before = format!(
+        "{}Mb\n{}{}h\nW\nn\nMd\n{END7}{}{END7}{}{}MB\n{END7}",
+        begin7("A", 1),
+        masked(15.0),
+        rect_path(40.0, 40.0, 120.0, 120.0),
+        begin7("B", 1),
+        begin7("C", 1),
+        masked(45.0)
+    );
+    let trees: Vec<_> = layer_trees(&read7(&before).doc).into_iter().map(|(_, t, _)| t).collect();
+    assert_eq!(trees, ["k[c p]", "", "k[c p]"]);
+}
+
+#[test]
+fn a_multi_layer_mask_in_a_group_or_sublayer() {
+    // Begun and ended in a group of one layer.
+    let grouped = format!("{}u\n{}{}MB\n{}U\n{END7}", begin7("A", 1), mask_start(), masked(15.0), masked(150.0));
+    assert_eq!(layer_trees(&read7(&grouped).doc)[0].1, "g[k[c p] p]");
+    // A sublayer in the mask: what the mask covers in the layer around it and in the sublayer.
+    let nested = format!("{}{}{}{}{}{END7}{}MB\n{END7}", begin7("A", 1), mask_start(), masked(15.0), begin7("S", 1), masked(30.0), masked(45.0));
+    assert_eq!(layer_trees(&read7(&nested).doc)[0].1, "k[c p] l[k[c p]] k[c p]");
+}
+
+#[test]
+fn a_multi_layer_masks_path_can_be_painted_or_compound() {
+    // `W f`: the path also paints, under what the mask covers.
+    let painted = format!("{}Mb\n0 0 0 1 k\n{}h\nW\nf\nMd\n{}MB\n{END7}", begin7("A", 1), rect_path(40.0, 40.0, 120.0, 120.0), masked(15.0));
+    let doc = read7(&painted).doc;
+    assert_eq!(layer_trees(&doc)[0].1, "k[c p p]");
+    let group = doc.layers[0].children().unwrap()[0].clone();
+    let kids = group.children().unwrap();
+    assert_eq!(fill(&kids[1]).color(), Some(Color::cmyk(0.0, 0.0, 0.0, 1.0)), "the painted path first");
+    // A compound path of clipping paths.
+    let compound = format!(
+        "{}Mb\n*u\n{}h\nW\nn\n{}h\nW\nn\n*U\nMd\n{}MB\n{END7}",
+        begin7("A", 1),
+        rect_path(40.0, 40.0, 80.0, 80.0),
+        rect_path(90.0, 90.0, 120.0, 120.0),
+        masked(15.0)
+    );
+    assert_eq!(layer_trees(&read7(&compound).doc)[0].1, "k[o p]");
+}
+
+/// `Mv` starts a mask as `Mb` does, `ME` defines one as `Md` does, and `Mi` changes nothing.
+#[test]
+fn other_multi_layer_mask_operators() {
+    let body = format!("{}{}{}{END7}{}{}MB\n{}{END7}", begin7("A", 1), mask_start(), masked(15.0), begin7("B", 1), masked(30.0), masked(150.0));
+    let plain = format!("{:?}", read7(&body).doc.layers);
+    let aliases = body.replace("Mb\n", "Mv\n").replace("Md\n", "ME\n");
+    assert_eq!(format!("{:?}", read7(&aliases).doc.layers), plain);
+    let with_mi = body.replace("Md\n", "Md\nMi\n").replace("MB\n", "Mi\nMB\n");
+    assert_eq!(format!("{:?}", read7(&with_mi).doc.layers), plain);
+}
+
+#[test]
+fn a_malformed_multi_layer_mask_is_an_error() {
+    let path = format!("{}h\nW\nn\n", rect_path(40.0, 40.0, 120.0, 120.0));
+    let sq = masked(15.0);
+    let cases = [
+        ("an end without a start", format!("{sq}MB\n")),
+        ("a definition without a start", format!("{path}Md\n{sq}")),
+        ("no mask path", format!("Mb\n{sq}Md\n{sq}MB\n")),
+        ("a start inside another", format!("Mb\nMb\n{path}Md\n{sq}MB\n")),
+        ("an end before the definition", format!("Mb\n{path}MB\n")),
+        ("a definition in another group", format!("Mb\nu\n{path}Md\n{sq}MB\nU\n")),
+        ("a group crossing the end", format!("{}u\n{sq}MB\nU\n", mask_start())),
+        ("a group crossing the start", format!("u\n{}{sq}U\nMB\n", mask_start())),
+    ];
+    for (why, art) in cases {
+        let body = format!("{}{art}{END7}", begin7("A", 1));
+        let e = read(mask_stream7(&body).as_bytes()).unwrap_err();
+        assert!(e.contains("mask"), "{why}: {e}");
+    }
+    let layered = [
+        ("a layer ends before the definition", format!("{}Mb\n{sq}{END7}{}{path}Md\nMB\n{END7}", begin7("A", 1), begin7("B", 1))),
+        ("a group open at the layer's end", format!("{}{}u\n{sq}{END7}{}U\nMB\n{END7}", begin7("A", 1), mask_start(), begin7("B", 1))),
+        ("the end of the file inside the mask", format!("{}{}{sq}{END7}", begin7("A", 1), mask_start())),
+    ];
+    for (why, body) in layered {
+        let e = read(mask_stream7(&body).as_bytes()).unwrap_err();
+        assert!(e.contains("mask"), "{why}: {e}");
+    }
+    // Outside the layers, `Md` has nowhere to take its path from.
+    let outside = format!("Mb\nMd\n{}{path}{sq}MB\n{END7}", begin7("A", 1));
+    let e = read(mask_stream7(&outside).as_bytes()).unwrap_err();
+    assert!(e.contains("mask"), "{e}");
+}
+
+/// A clipping path painted among the masked objects clips its whole layer, as outside a mask.
+#[test]
+fn a_layers_clipping_path_in_a_multi_layer_mask_clips_the_layer() {
+    let path = format!("{}h\nW\nn\n", rect_path(10.0, 10.0, 190.0, 190.0));
+    let body = format!("{}{}{}{path}{}MB\n{END7}", begin7("A", 1), mask_start(), masked(15.0), masked(30.0));
+    assert_eq!(layer_trees(&read7(&body).doc), [("A".to_string(), "c k[c p p]".to_string(), true)]);
+}
+
+/// `Mb` before the first layer it covers and `MB` after the last one's `LB`.
+#[test]
+fn a_multi_layer_mask_begun_or_ended_between_layers() {
+    let body = format!(
+        "Mb\n{}{}h\nW\nn\nMd\n{}{END7}{}{}{END7}MB\n{}{}{END7}",
+        begin7("A", 1),
+        rect_path(40.0, 40.0, 120.0, 120.0),
+        masked(15.0),
+        begin7("B", 1),
+        masked(30.0),
+        begin7("C", 1),
+        masked(150.0)
+    );
+    let trees: Vec<_> = layer_trees(&read7(&body).doc).into_iter().map(|(_, t, _)| t).collect();
+    assert_eq!(trees, ["k[c p]", "k[c p]", "p"]);
+}
+
+/// Each copy of the mask counts toward the most objects read, with its points.
+#[test]
+fn copies_of_a_multi_layer_mask_count_toward_the_limit() {
+    let points: String = (0..2_000_001).map(|i| format!("{} 40 L\n", 40 + i % 80)).collect();
+    let mask = format!("Mb\n40 40 m\n{points}h\nW\nn\nMd\n");
+    let one = format!("{}{mask}{}MB\n{END7}", begin7("A", 1), masked(15.0));
+    assert_eq!(layer_trees(&read7(&one).doc)[0].1, "k[c p]");
+    let two = format!("{}{mask}{}{END7}{}{}MB\n{END7}", begin7("A", 1), masked(15.0), begin7("B", 1), masked(30.0));
+    let e = read(mask_stream7(&two).as_bytes()).unwrap_err();
+    assert!(e.contains("objects"), "{e}");
+}

crates/eps/src/import/tests_illustrator.rs

@@ -163,6 +163,25 @@ fn a_postscript_ai_whose_layers_cant_be_read_says_why() {
     assert!(e.contains("`Adobe_packedarray`") && e.contains("its layers couldn't be read either") && e.contains("`frobnicate`"), "{e}");
 }
 
+/// A `.ai` in PostScript form with a multi-layer mask (`Mb`, its path, `Md`, objects in both
+/// layers, `MB`) opens through its layers: a clipping group in each, and what follows `MB` unclipped.
+#[test]
+fn a_postscript_ai_with_a_multi_layer_mask_opens_with_its_layers() {
+    let src = NAMED_PROLOG
+        .replace("0 D\n10 10 m", "0 D\nMb\n20 20 m\n180 20 L\n180 80 L\n20 80 L\nh\nW\nn\nMd\n10 10 m")
+        .replace("190 90 L\nS\nLB", "190 90 L\nS\nMB\n150 50 m\n195 95 L\nS\nLB");
+    let r = import(src.as_bytes()).unwrap();
+    assert!(!r.preview, "read through the layers, not a fallback preview");
+    let d = &r.document;
+    let names: Vec<_> = d.layers.iter().map(|l| l.name.clone().unwrap_or_default()).collect();
+    assert_eq!(names, ["SECTION::Cut", "SECTION::Hatch"]);
+    assert_eq!(tree(d.layers[0].children().unwrap()), "k[c p]");
+    assert_eq!(tree(d.layers[1].children().unwrap()), "k[c p] p");
+    let mask = d.layers[1].children().unwrap()[0].children().unwrap()[0].clone();
+    assert_eq!(mask.geometric_bounds(), Some(Rect::new(20.0, 20.0, 180.0, 80.0)));
+    assert!(r.warnings.iter().any(|w| w.contains("clipping group in each layer")), "{:?}", r.warnings);
+}
+
 /// A `.ai` in PostScript form (read through its layers) whose text carries hyphenation and
 /// tab-ruler attributes: `XL` (hyphenation language), `Xb`/`XB` (a tab definition) and `Th`
 /// (hyphen control). These keep no geometry, so the reader drops them rather than failing the

crates/ui-egui/src/i18n/ca.tsv

@@ -4814,6 +4814,7 @@ digits	Malayalam	Malaiàlam
 @msg	`{to}` is not an available name	`{to}` no és un nom disponible
 @msg	`{what}` closes nothing	`{what}` no tanca res
 @msg	`{what}` closes something it didn't open	`{what}` tanca una cosa que no havia obert
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	una màscara que cobreix diverses capes entra com un grup de retall a cada capa que cobreix
 @msg	a graph's records don't end where they should: its art was read as it is	els registres d’un gràfic no acaben on haurien: la seva il·lustració s’ha llegit tal com és
 @msg	`{w}` takes no operands	`{w}` no admet operands
 @msg	a wraparound group is inside a compound path	un grup d’ajustament del text és dins d’un traçat compost
@@ -5050,6 +5051,10 @@ digits	Malayalam	Malaiàlam
 @msg	is not an image VectorCraft reads	no és una imatge que VectorCraft pugui llegir
 @msg	it decompresses to more than {_1} MB	es descomprimeix fins a més de {_1} MB
 @msg	it ends inside a layer	acaba dins d’una capa
+@msg	it ends inside a multi-layer mask	acaba dins d’una màscara multicapa
+@msg	a multi-layer mask's operators are out of order	els operadors d’una màscara multicapa estan desordenats
+@msg	a multi-layer mask needs one clipping path	una màscara multicapa necessita un traçat de retall
+@msg	a group crosses a multi-layer mask	un grup travessa una màscara multicapa
 @msg	it has art outside its layers	té art fora de les seves capes
 @msg	it has more than one artboard	té més d’un tauler
 @msg	it has more than {MAX_NODES} objects	té més de {MAX_NODES} objectes

crates/ui-egui/src/i18n/cs.tsv

@@ -4872,11 +4872,16 @@ imageTrace	Outline	Obrys
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	nejde o logo s plnými barvami ({_1} % jeho plných ploch odpovídá několika plným barvám), takže režim Ploché logo by z jeho přechodů udělal skvrny: použijte místo toho režim Barva
 @msg	`{what}` closes nothing	`{what}` nic neuzavírá
 @msg	`{what}` closes something it didn't open	`{what}` uzavírá něco, co neotevřel
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	maska, která pokrývá několik vrstev, se načte jako ořezová skupina v každé vrstvě, kterou pokrývá
 @msg	a graph's records don't end where they should: its art was read as it is	záznamy grafu nekončí tam, kde mají: jeho kresba byla načtena tak, jak je
 @msg	`{w}` takes no operands	`{w}` nepřijímá žádné operandy
 @msg	a wraparound group is inside a compound path	skupina obtékání textu je uvnitř složené cesty
 @msg	a path has too many points	cesta má příliš mnoho bodů
 @msg	it ends inside a layer	končí uvnitř vrstvy
+@msg	it ends inside a multi-layer mask	končí uvnitř masky přes více vrstev
+@msg	a multi-layer mask's operators are out of order	operátory masky přes více vrstev jsou ve špatném pořadí
+@msg	a multi-layer mask needs one clipping path	maska přes více vrstev potřebuje jednu ořezovou cestu
+@msg	a group crosses a multi-layer mask	skupina přesahuje masku přes více vrstev
 @msg	it has art outside its layers	má kresbu mimo své vrstvy
 @msg	it has more than {MAX_NODES} objects	má více než {MAX_NODES} objektů
 @msg	it has no layers	nemá žádné vrstvy

crates/ui-egui/src/i18n/de.tsv

@@ -4481,11 +4481,16 @@ theme	Appearance	Erscheinungsbild
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	dies ist kein Logo aus flächigen Farben ({_1} % seiner einfarbigen Bereiche entsprechen wenigen flächigen Farben), daher würde der Modus „Flaches Logo“ seine Verläufe in Flecken zerlegen: Verwenden Sie stattdessen den Modus „Farbe“
 @msg	`{what}` closes nothing	`{what}` schließt nichts
 @msg	`{what}` closes something it didn't open	`{what}` schließt etwas, das es nicht geöffnet hat
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	eine Maske über mehrere Ebenen wird in jeder Ebene, die sie abdeckt, zu einer Schnittgruppe
 @msg	a graph's records don't end where they should: its art was read as it is	die Datensätze eines Diagramms enden nicht dort, wo sie sollten: seine Grafik wurde so gelesen, wie sie ist
 @msg	`{w}` takes no operands	`{w}` nimmt keine Operanden
 @msg	a wraparound group is inside a compound path	eine Textumfluss-Gruppe liegt in einem zusammengesetzten Pfad
 @msg	a path has too many points	ein Pfad hat zu viele Punkte
 @msg	it ends inside a layer	es endet innerhalb einer Ebene
+@msg	it ends inside a multi-layer mask	es endet innerhalb einer ebenenübergreifenden Maske
+@msg	a multi-layer mask's operators are out of order	die Operatoren einer ebenenübergreifenden Maske stehen in falscher Reihenfolge
+@msg	a multi-layer mask needs one clipping path	eine ebenenübergreifende Maske braucht genau einen Schnittpfad
+@msg	a group crosses a multi-layer mask	eine Gruppe überschneidet eine ebenenübergreifende Maske
 @msg	it has art outside its layers	es enthält Grafik außerhalb seiner Ebenen
 @msg	it has more than {MAX_NODES} objects	es enthält mehr als {MAX_NODES} Objekte
 @msg	it has no layers	es enthält keine Ebenen

crates/ui-egui/src/i18n/el.tsv

@@ -4514,11 +4514,16 @@ digits	Malayalam	Μαλαγιάλαμ
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	αυτό δεν είναι λογότυπο επίπεδων χρωμάτων ({_1}% των συμπαγών περιοχών του αντιστοιχούν σε λίγα χρώματα), επομένως η λειτουργία Επίπεδο λογότυπο θα μετατρέψει τα ντεγκραντέ σε κηλίδες: χρησιμοποιήστε τη λειτουργία Χρώμα
 @msg	`{what}` closes nothing	το `{what}` δεν κλείνει κανένα στοιχείο
 @msg	`{what}` closes something it didn't open	το `{what}` κλείνει στοιχείο που δεν άνοιξε
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	μια μάσκα που καλύπτει πολλά επίπεδα εισάγεται ως ομάδα αποκοπής σε κάθε επίπεδο που καλύπτει
 @msg	a graph's records don't end where they should: its art was read as it is	οι εγγραφές ενός γραφήματος δεν τελειώνουν εκεί που πρέπει: το έργο του διαβάστηκε όπως είναι
 @msg	`{w}` takes no operands	το `{w}` δεν δέχεται τελεστέους
 @msg	a wraparound group is inside a compound path	μια ομάδα αναδίπλωσης κειμένου βρίσκεται μέσα σε σύνθετη διαδρομή
 @msg	a path has too many points	η διαδρομή έχει υπερβολικά πολλά σημεία
 @msg	it ends inside a layer	τερματίζει μέσα σε επίπεδο
+@msg	it ends inside a multi-layer mask	τερματίζει μέσα σε μάσκα πολλών επιπέδων
+@msg	a multi-layer mask's operators are out of order	οι τελεστές μιας μάσκας πολλών επιπέδων είναι σε λάθος σειρά
+@msg	a multi-layer mask needs one clipping path	μια μάσκα πολλών επιπέδων χρειάζεται μία διαδρομή αποκοπής
+@msg	a group crosses a multi-layer mask	μια ομάδα διασχίζει μια μάσκα πολλών επιπέδων
 @msg	it has art outside its layers	περιέχει σχέδιο εκτός των επιπέδων του
 @msg	it has more than {MAX_NODES} objects	περιέχει περισσότερα από {MAX_NODES} αντικείμενα
 @msg	it has no layers	δεν περιέχει επίπεδα

crates/ui-egui/src/i18n/es.tsv

@@ -4566,11 +4566,16 @@ axis	Both	Ambos
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	esto no es un logotipo de colores planos ({_1}% de sus zonas sólidas coinciden con unos pocos colores planos), así que el modo Logotipo plano convertiría sus degradados en manchas: usa el modo Color
 @msg	`{what}` closes nothing	`{what}` no cierra nada
 @msg	`{what}` closes something it didn't open	`{what}` cierra algo que no abrió
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	una máscara que cubre varias capas entra como un grupo de recorte en cada capa que cubre
 @msg	a graph's records don't end where they should: its art was read as it is	los registros de un gráfico no terminan donde deberían: su ilustración se leyó tal cual
 @msg	`{w}` takes no operands	`{w}` no admite operandos
 @msg	a wraparound group is inside a compound path	un grupo de ceñir texto está dentro de un trazado compuesto
 @msg	a path has too many points	un trazado tiene demasiados puntos
 @msg	it ends inside a layer	terminan dentro de una capa
+@msg	it ends inside a multi-layer mask	terminan dentro de una máscara de varias capas
+@msg	a multi-layer mask's operators are out of order	los operadores de una máscara de varias capas están desordenados
+@msg	a multi-layer mask needs one clipping path	una máscara de varias capas necesita un trazado de recorte
+@msg	a group crosses a multi-layer mask	un grupo atraviesa una máscara de varias capas
 @msg	it has art outside its layers	tienen ilustraciones fuera de sus capas
 @msg	it has more than {MAX_NODES} objects	tienen más de {MAX_NODES} objetos
 @msg	it has no layers	no tienen capas

crates/ui-egui/src/i18n/fi.tsv

@@ -4774,11 +4774,16 @@ imageTrace	Outline	Ääriviiva
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	tämä ei ole tasavärinen logo ({_1} % sen yhtenäisistä alueista vastaa muutamaa tasaväriä), joten Tasavärilogo-tila muuttaisi sen liukuvärit laikuiksi: käytä sen sijaan Väri-tilaa
 @msg	`{what}` closes nothing	`{what}` ei sulje mitään
 @msg	`{what}` closes something it didn't open	`{what}` sulkee jotain, mitä se ei avannut
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	useita tasoja peittävä maski tuodaan leikkausryhmänä jokaiseen tasoon, jonka se peittää
 @msg	a graph's records don't end where they should: its art was read as it is	kaavion tietueet eivät pääty siihen, mihin niiden pitäisi: sen piirros luettiin sellaisenaan
 @msg	`{w}` takes no operands	`{w}` ei ota operandeja
 @msg	a wraparound group is inside a compound path	tekstin rivitysryhmä on yhdistelmäpolun sisällä
 @msg	a path has too many points	polulla on liian monta pistettä
 @msg	it ends inside a layer	se päättyy tason sisään
+@msg	it ends inside a multi-layer mask	se päättyy monitasoisen maskin sisään
+@msg	a multi-layer mask's operators are out of order	monitasoisen maskin operaattorit ovat väärässä järjestyksessä
+@msg	a multi-layer mask needs one clipping path	monitasoinen maski tarvitsee yhden leikkauspolun
+@msg	a group crosses a multi-layer mask	ryhmä ylittää monitasoisen maskin rajan
 @msg	it has art outside its layers	siinä on kuvitusta tasojensa ulkopuolella
 @msg	it has more than {MAX_NODES} objects	siinä on yli {MAX_NODES} objektia
 @msg	it has no layers	siinä ei ole tasoja

crates/ui-egui/src/i18n/fr.tsv

@@ -4556,11 +4556,16 @@ axis	Both	Les deux
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	ce n’est pas un logo en aplats ({_1} % de ses zones pleines correspondent à quelques couleurs unies), donc le mode Logo en aplats transformerait ses dégradés en taches : utilisez le mode Couleur
 @msg	`{what}` closes nothing	`{what}` ne ferme rien
 @msg	`{what}` closes something it didn't open	`{what}` ferme quelque chose qu’il n’a pas ouvert
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	un masque qui couvre plusieurs calques est importé comme un groupe de découpe dans chaque calque qu’il couvre
 @msg	a graph's records don't end where they should: its art was read as it is	les enregistrements d’un graphe ne se terminent pas là où ils le devraient : son illustration a été lue telle quelle
 @msg	`{w}` takes no operands	`{w}` n’accepte aucun opérande
 @msg	a wraparound group is inside a compound path	un groupe d’habillage de texte se trouve dans un tracé transparent
 @msg	a path has too many points	un tracé a trop de points
 @msg	it ends inside a layer	elles se terminent à l’intérieur d’un calque
+@msg	it ends inside a multi-layer mask	elles se terminent à l’intérieur d’un masque multicalque
+@msg	a multi-layer mask's operators are out of order	les opérateurs d’un masque multicalque sont dans le désordre
+@msg	a multi-layer mask needs one clipping path	un masque multicalque nécessite un seul tracé d’écrêtage
+@msg	a group crosses a multi-layer mask	un groupe chevauche un masque multicalque
 @msg	it has art outside its layers	elles contiennent des illustrations hors de leurs calques
 @msg	it has more than {MAX_NODES} objects	elles contiennent plus de {MAX_NODES} objets
 @msg	it has no layers	elles n’ont aucun calque

crates/ui-egui/src/i18n/hu.tsv

@@ -4557,6 +4557,7 @@ imageTrace	Outline	Körvonal
 @msg	`{to}` is not an available name	ez a név nem használható: `{to}`
 @msg	`{what}` closes nothing	`{what}` semmit sem zár le
 @msg	`{what}` closes something it didn't open	`{what}` olyat zár le, amit nem nyitott meg
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	a több réteget lefedő maszk minden általa lefedett rétegben vágócsoportként jön be
 @msg	a graph's records don't end where they should: its art was read as it is	egy grafikon rekordjai nem ott érnek véget, ahol kellene: a grafikája úgy lett beolvasva, ahogy van
 @msg	`{w}` takes no operands	`{w}` nem fogad operandusokat
 @msg	a wraparound group is inside a compound path	egy szövegkörbefuttatási csoport összetett útvonalon belül van
@@ -4772,6 +4773,10 @@ imageTrace	Outline	Körvonal
 @msg	invalid restored panel group	érvénytelen visszaállított panelcsoport
 @msg	is not an image VectorCraft reads	nem olyan kép, amelyet a VectorCraft olvas
 @msg	it ends inside a layer	egy rétegen belül ér véget
+@msg	it ends inside a multi-layer mask	egy többrétegű maszkon belül ér véget
+@msg	a multi-layer mask's operators are out of order	egy többrétegű maszk operátorai rossz sorrendben vannak
+@msg	a multi-layer mask needs one clipping path	egy többrétegű maszkhoz egy vágóútvonal kell
+@msg	a group crosses a multi-layer mask	egy csoport átnyúlik egy többrétegű maszkon
 @msg	it has art outside its layers	a rétegein kívül is van grafikája
 @msg	it has more than one artboard	egynél több rajztáblája van
 @msg	it has more than {MAX_NODES} objects	túl sok objektumot tartalmaz (legfeljebb {MAX_NODES})

crates/ui-egui/src/i18n/it.tsv

@@ -4607,11 +4607,16 @@ axis	Both	Entrambi
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	questo non è un logo a colori piatti ({_1}% delle sue aree piene corrisponde a pochi colori piatti), quindi la modalità Logo piatto trasformerebbe i suoi sfumati in macchie: usa la modalità Colore
 @msg	`{what}` closes nothing	`{what}` non chiude nulla
 @msg	`{what}` closes something it didn't open	`{what}` chiude qualcosa che non ha aperto
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	una maschera che copre più livelli viene importata come gruppo di ritaglio in ogni livello che copre
 @msg	a graph's records don't end where they should: its art was read as it is	i record di un grafico non finiscono dove dovrebbero: la sua grafica è stata letta così com’è
 @msg	`{w}` takes no operands	`{w}` non accetta operandi
 @msg	a wraparound group is inside a compound path	un gruppo di testo attorno si trova in un tracciato composto
 @msg	a path has too many points	un tracciato ha troppi punti
 @msg	it ends inside a layer	terminano all'interno di un livello
+@msg	it ends inside a multi-layer mask	terminano all'interno di una maschera multilivello
+@msg	a multi-layer mask's operators are out of order	gli operatori di una maschera multilivello non sono in ordine
+@msg	a multi-layer mask needs one clipping path	una maschera multilivello richiede un solo tracciato di ritaglio
+@msg	a group crosses a multi-layer mask	un gruppo attraversa una maschera multilivello
 @msg	it has art outside its layers	contengono grafica al di fuori dei loro livelli
 @msg	it has more than {MAX_NODES} objects	contengono più di {MAX_NODES} oggetti
 @msg	it has no layers	non hanno livelli

crates/ui-egui/src/i18n/ja.tsv

@@ -4311,11 +4311,16 @@ swatch	Bright Violet	ビビッドバイオレット
 @msg	unknown command `{0}`; did you mean `{1}`?	`{0}` は不明なコマンドです。`{1}` のことですか?
 @msg	`{what}` closes nothing	`{what}` に対応する開始部分がありません
 @msg	`{what}` closes something it didn't open	`{what}` が対応しない開始部分を閉じています
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	複数のレイヤーにまたがるマスクは、覆う各レイヤーでクリップグループとして読み込まれます
 @msg	a graph's records don't end where they should: its art was read as it is	グラフのレコードが正しい位置で終わっていません: アートはそのまま読み込まれました
 @msg	`{w}` takes no operands	`{w}` はオペランドを取りません
 @msg	a wraparound group is inside a compound path	テキストの回り込みグループが複合パスの中にあります
 @msg	a path has too many points	ポイントが多すぎるパスがあります
 @msg	it ends inside a layer	レイヤーの途中で終わっています
+@msg	it ends inside a multi-layer mask	複数レイヤーにまたがるマスクの途中で終わっています
+@msg	a multi-layer mask's operators are out of order	複数レイヤーにまたがるマスクの演算子の順序が正しくありません
+@msg	a multi-layer mask needs one clipping path	複数レイヤーにまたがるマスクにはクリッピングパスが 1 つ必要です
+@msg	a group crosses a multi-layer mask	グループが複数レイヤーにまたがるマスクと交差しています
 @msg	it has art outside its layers	レイヤーの外にアートがあります
 @msg	it has more than {MAX_NODES} objects	オブジェクトが {MAX_NODES} 個を超えています
 @msg	it has no layers	レイヤーがありません

crates/ui-egui/src/i18n/ka.tsv

@@ -4305,11 +4305,16 @@ font-technology	Variable	ცვლადი
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	ეს ერთფეროვანი ლოგო არ არის (მისი მყარი არეების {_1}% რამდენიმე ერთგვაროვან ფერს ემთხვევა), ამიტომ Flat Logo რეჟიმი მის გრადიენტებს ლაქებად აქცევდა: გამოიყენეთ Color რეჟიმი
 @msg	`{what}` closes nothing	`{what}` არაფერს ხურავს
 @msg	`{what}` closes something it didn't open	`{what}` ხურავს იმას, რაც არ გაუხსნია
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	რამდენიმე ფენის დამფარავი ნიღაბი შემოდის როგორც ჩამოჭრის ჯგუფი თითოეულ ფენაში, რომელსაც ფარავს
 @msg	a graph's records don't end where they should: its art was read as it is	დიაგრამის ჩანაწერები იქ არ მთავრდება, სადაც უნდა: მისი გრაფიკა წაკითხულია ისე, როგორც არის
 @msg	`{w}` takes no operands	`{w}` ოპერანდებს არ იღებს
 @msg	a wraparound group is inside a compound path	ტექსტის გარსშემოვლების ჯგუფი შედგენილი ტრაექტორიის შიგნითაა
 @msg	a path has too many points	ტრაექტორიას ზედმეტად ბევრი წერტილი აქვს
 @msg	it ends inside a layer	ის შრის შიგნით მთავრდება
+@msg	it ends inside a multi-layer mask	ის მრავალშრიანი ნიღბის შიგნით მთავრდება
+@msg	a multi-layer mask's operators are out of order	მრავალშრიანი ნიღბის ოპერატორები არასწორი თანმიმდევრობითაა
+@msg	a multi-layer mask needs one clipping path	მრავალშრიან ნიღაბს ერთი მომჭრელი ტრაექტორია სჭირდება
+@msg	a group crosses a multi-layer mask	ჯგუფი მრავალშრიან ნიღაბს კვეთს
 @msg	it has art outside its layers	მას შრეების გარეთ ნახატი აქვს
 @msg	it has more than {MAX_NODES} objects	მას {MAX_NODES}-ზე მეტი ობიექტი აქვს
 @msg	it has no layers	მას შრეები არ აქვს

crates/ui-egui/src/i18n/ko.tsv

@@ -4238,11 +4238,16 @@ theme	Appearance	외관
 @msg	unknown command `{0}`; did you mean `{1}`?	알 수 없는 명령 `{0}`: `{1}`을(를) 의미하셨습니까?
 @msg	`{what}` closes nothing	`{what}`이(가) 닫는 항목이 없습니다
 @msg	`{what}` closes something it didn't open	`{what}`이(가) 열지 않은 항목을 닫습니다
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	여러 레이어에 걸친 마스크는 덮는 각 레이어에서 클리핑 그룹으로 들어옵니다
 @msg	a graph's records don't end where they should: its art was read as it is	그래프의 레코드가 끝나야 할 곳에서 끝나지 않습니다: 아트는 있는 그대로 읽었습니다
 @msg	`{w}` takes no operands	`{w}`은(는) 피연산자를 받지 않습니다
 @msg	a wraparound group is inside a compound path	문자 감싸기 그룹이 컴파운드 패스 안에 있습니다
 @msg	a path has too many points	패스의 점이 너무 많습니다
 @msg	it ends inside a layer	레이어 안에서 끝납니다
+@msg	it ends inside a multi-layer mask	여러 레이어 마스크 안에서 끝납니다
+@msg	a multi-layer mask's operators are out of order	여러 레이어 마스크의 연산자 순서가 잘못되었습니다
+@msg	a multi-layer mask needs one clipping path	여러 레이어 마스크에는 클리핑 패스가 하나 필요합니다
+@msg	a group crosses a multi-layer mask	그룹이 여러 레이어 마스크에 걸쳐 있습니다
 @msg	it has art outside its layers	레이어 밖에 아트웍이 있습니다
 @msg	it has more than {MAX_NODES} objects	개체가 {MAX_NODES}개를 넘습니다
 @msg	it has no layers	레이어가 없습니다

crates/ui-egui/src/i18n/pl.tsv

@@ -4698,11 +4698,16 @@ imageTrace	Outline	Kontur
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	to nie jest logo z płaskimi kolorami ({_1}% jego jednolitych obszarów pasuje do kilku płaskich kolorów), więc tryb Płaskie logo zamieniłby jego gradienty w plamy: użyj trybu Kolor
 @msg	`{what}` closes nothing	`{what}` niczego nie zamyka
 @msg	`{what}` closes something it didn't open	`{what}` zamyka coś, czego nie otworzył
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	maska obejmująca kilka warstw jest wczytywana jako grupa przycinająca w każdej obejmowanej warstwie
 @msg	a graph's records don't end where they should: its art was read as it is	rekordy wykresu nie kończą się tam, gdzie powinny: jego grafika została wczytana tak, jak jest
 @msg	`{w}` takes no operands	`{w}` nie przyjmuje operandów
 @msg	a wraparound group is inside a compound path	grupa oblewania tekstem jest wewnątrz ścieżki złożonej
 @msg	a path has too many points	ścieżka ma zbyt wiele punktów
 @msg	it ends inside a layer	kończy się wewnątrz warstwy
+@msg	it ends inside a multi-layer mask	kończy się wewnątrz maski wielowarstwowej
+@msg	a multi-layer mask's operators are out of order	operatory maski wielowarstwowej są w złej kolejności
+@msg	a multi-layer mask needs one clipping path	maska wielowarstwowa wymaga jednej ścieżki przycinającej
+@msg	a group crosses a multi-layer mask	grupa przecina maskę wielowarstwową
 @msg	it has art outside its layers	ma kompozycję poza warstwami
 @msg	it has more than {MAX_NODES} objects	ma ponad {MAX_NODES} obiektów
 @msg	it has no layers	nie ma warstw

crates/ui-egui/src/i18n/pt-br.tsv

@@ -4148,11 +4148,16 @@ axis	Both	Ambos
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	este não é um logotipo de cores chapadas ({_1}% de suas áreas sólidas correspondem a poucas cores chapadas), então o modo Logotipo plano transformaria seus gradientes em manchas: use o modo Cor
 @msg	`{what}` closes nothing	`{what}` não fecha nada
 @msg	`{what}` closes something it didn't open	`{what}` fecha algo que não abriu
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	uma máscara que cobre várias camadas entra como um grupo de recorte em cada camada que cobre
 @msg	a graph's records don't end where they should: its art was read as it is	os registros de um gráfico não terminam onde deveriam: sua arte foi lida como está
 @msg	`{w}` takes no operands	`{w}` não aceita operandos
 @msg	a wraparound group is inside a compound path	um grupo de quebra de texto está dentro de um traçado composto
 @msg	a path has too many points	um traçado tem pontos demais
 @msg	it ends inside a layer	termina dentro de uma camada
+@msg	it ends inside a multi-layer mask	termina dentro de uma máscara de várias camadas
+@msg	a multi-layer mask's operators are out of order	os operadores de uma máscara de várias camadas estão fora de ordem
+@msg	a multi-layer mask needs one clipping path	uma máscara de várias camadas precisa de um caminho de recorte
+@msg	a group crosses a multi-layer mask	um grupo atravessa uma máscara de várias camadas
 @msg	it has art outside its layers	tem arte fora de suas camadas
 @msg	it has more than {MAX_NODES} objects	tem mais de {MAX_NODES} objetos
 @msg	it has no layers	não tem camadas

crates/ui-egui/src/i18n/ru.tsv

@@ -4602,11 +4602,16 @@ axis	Both	Оба
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	это не логотип из плоских цветов ({_1}% его сплошных областей совпадает с несколькими плоскими цветами), поэтому режим «Плоский логотип» превратил бы градиенты в пятна: используйте режим «Цвет»
 @msg	`{what}` closes nothing	`{what}` ничего не закрывает
 @msg	`{what}` closes something it didn't open	`{what}` закрывает то, что не открывал
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	маска, охватывающая несколько слоёв, переносится как обтравочная группа в каждый слой, который она охватывает
 @msg	a graph's records don't end where they should: its art was read as it is	записи диаграммы не заканчиваются там, где должны: её графика прочитана как есть
 @msg	`{w}` takes no operands	`{w}` не принимает операндов
 @msg	a wraparound group is inside a compound path	группа обтекания текстом находится внутри составного контура
 @msg	a path has too many points	в контуре слишком много точек
 @msg	it ends inside a layer	они заканчиваются внутри слоя
+@msg	it ends inside a multi-layer mask	они заканчиваются внутри многослойной маски
+@msg	a multi-layer mask's operators are out of order	операторы многослойной маски идут в неправильном порядке
+@msg	a multi-layer mask needs one clipping path	многослойной маске нужен один контур обрезки
+@msg	a group crosses a multi-layer mask	группа пересекает многослойную маску
 @msg	it has art outside its layers	в них есть графика вне слоёв
 @msg	it has more than {MAX_NODES} objects	в них больше {MAX_NODES} объектов
 @msg	it has no layers	в них нет слоёв

crates/ui-egui/src/i18n/sv.tsv

@@ -4465,11 +4465,16 @@ axis	Both	Båda
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	det här är ingen logotyp i platta färger ({_1} % av dess enfärgade ytor matchar några få platta färger), så läget Platt logotyp skulle göra om dess gradienter till fläckar: använd läget Färg i stället
 @msg	`{what}` closes nothing	`{what}` stänger ingenting
 @msg	`{what}` closes something it didn't open	`{what}` stänger något som den inte öppnade
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	en mask som täcker flera lager kommer in som en urklippsgrupp i varje lager den täcker
 @msg	a graph's records don't end where they should: its art was read as it is	ett diagrams poster slutar inte där de ska: dess grafik lästes som den är
 @msg	`{w}` takes no operands	`{w}` tar inga operander
 @msg	a wraparound group is inside a compound path	en textombrytningsgrupp ligger inuti en sammansatt bana
 @msg	a path has too many points	en bana har för många punkter
 @msg	it ends inside a layer	den slutar inuti ett lager
+@msg	it ends inside a multi-layer mask	den slutar inuti en flerlagersmask
+@msg	a multi-layer mask's operators are out of order	operatorerna för en flerlagersmask står i fel ordning
+@msg	a multi-layer mask needs one clipping path	en flerlagersmask behöver en klippbana
+@msg	a group crosses a multi-layer mask	en grupp korsar en flerlagersmask
 @msg	it has art outside its layers	den har grafik utanför sina lager
 @msg	it has more than {MAX_NODES} objects	den har fler än {MAX_NODES} objekt
 @msg	it has no layers	den har inga lager

crates/ui-egui/src/i18n/tr.tsv

@@ -4303,11 +4303,16 @@ axis	Both	Her İkisi
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	bu düz renkli bir logo değildir (düz alanların %{_1}'si birkaç düz renkle eşleşir), dolayısıyla Düz Logo modu degradelerini yamalara dönüştürür: bunun yerine Renk modunu kullanın
 @msg	`{what}` closes nothing	`{what}` hiçbir şeyi kapatmaz
 @msg	`{what}` closes something it didn't open	`{what}` açmadığı bir şeyi kapatıyor
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	birkaç katmanı kaplayan bir maske, kapladığı her katmana bir kırpma grubu olarak gelir
 @msg	a graph's records don't end where they should: its art was read as it is	bir grafiğin kayıtları bitmesi gereken yerde bitmiyor: resmi olduğu gibi okundu
 @msg	`{w}` takes no operands	`{w}` işlenen almaz
 @msg	a wraparound group is inside a compound path	bir metin kaydırma grubu bileşik bir yolun içinde
 @msg	a path has too many points	bir yolun çok fazla noktası var
 @msg	it ends inside a layer	bir katmanın içinde bitiyor
+@msg	it ends inside a multi-layer mask	çok katmanlı bir maskenin içinde bitiyor
+@msg	a multi-layer mask's operators are out of order	çok katmanlı bir maskenin işleçleri yanlış sırada
+@msg	a multi-layer mask needs one clipping path	çok katmanlı bir maskenin bir kırpma yoluna ihtiyacı var
+@msg	a group crosses a multi-layer mask	bir grup çok katmanlı bir maskeyi kesiyor
 @msg	it has art outside its layers	katmanlarının dışında sanat var
 @msg	it has more than {MAX_NODES} objects	{MAX_NODES}'den daha fazla nesneye sahip
 @msg	it has no layers	katmanı yok

crates/ui-egui/src/i18n/uk.tsv

@@ -4591,11 +4591,16 @@ axis	Both	Обидві
 @msg	this isn't a flat-colour logo ({_1}% of its solid areas match a few flat colours), so Flat Logo mode would turn its gradients into patches: use Color mode instead	це не логотип із плоских кольорів ({_1}% його суцільних областей збігається з кількома плоскими кольорами), тому режим «Плоский логотип» перетворив би градієнти на плями: використовуйте режим «Колір»
 @msg	`{what}` closes nothing	`{what}` нічого не закриває
 @msg	`{what}` closes something it didn't open	`{what}` закриває те, що не відкривав
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	маску, що охоплює кілька шарів, перенесено як групу відсікання в кожен шар, який вона охоплює
 @msg	a graph's records don't end where they should: its art was read as it is	записи діаграми не закінчуються там, де мають: її графіку прочитано як є
 @msg	`{w}` takes no operands	`{w}` не приймає операндів
 @msg	a wraparound group is inside a compound path	група обтікання текстом розташована всередині складеного контуру
 @msg	a path has too many points	у контурі занадто багато точок
 @msg	it ends inside a layer	вони закінчуються всередині шару
+@msg	it ends inside a multi-layer mask	вони закінчуються всередині багатошарової маски
+@msg	a multi-layer mask's operators are out of order	оператори багатошарової маски йдуть у неправильному порядку
+@msg	a multi-layer mask needs one clipping path	багатошаровій масці потрібен один відсічний контур
+@msg	a group crosses a multi-layer mask	група перетинає багатошарову маску
 @msg	it has art outside its layers	у них є графіка поза шарами
 @msg	it has more than {MAX_NODES} objects	в них більше {MAX_NODES} об’єктів
 @msg	it has no layers	у них немає шарів

crates/ui-egui/src/i18n/vi.tsv

@@ -4209,6 +4209,7 @@ theme	Appearance	Giao diện
 @msg	`{to}` is not an available name	`{to}` không phải là tên khả dụng
 @msg	`{what}` closes nothing	`{what}` không đóng gì
 @msg	`{what}` closes something it didn't open	`{what}` đóng thứ nó chưa mở
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	một mặt nạ phủ nhiều lớp được nhập thành một nhóm cắt xén trong mỗi lớp mà nó phủ
 @msg	a graph's records don't end where they should: its art was read as it is	các bản ghi của một biểu đồ không kết thúc đúng chỗ: hình vẽ của nó được đọc nguyên trạng
 @msg	`{w}` takes no operands	`{w}` không nhận toán hạng
 @msg	a wraparound group is inside a compound path	một nhóm bao văn bản nằm trong một đường dẫn phức
@@ -4422,6 +4423,10 @@ theme	Appearance	Giao diện
 @msg	invalid restored panel group	nhóm bảng được phục hồi không hợp lệ
 @msg	is not an image VectorCraft reads	không phải ảnh mà VectorCraft đọc được
 @msg	it ends inside a layer	nó kết thúc bên trong một lớp
+@msg	it ends inside a multi-layer mask	nó kết thúc bên trong một mặt nạ nhiều lớp
+@msg	a multi-layer mask's operators are out of order	các toán tử của mặt nạ nhiều lớp không đúng thứ tự
+@msg	a multi-layer mask needs one clipping path	mặt nạ nhiều lớp cần một đường dẫn cắt
+@msg	a group crosses a multi-layer mask	một nhóm vắt ngang mặt nạ nhiều lớp
 @msg	it has art outside its layers	nó có tác phẩm ngoài các lớp
 @msg	it has more than one artboard	nó có nhiều hơn một bảng vẽ
 @msg	it has more than {MAX_NODES} objects	nó có hơn {MAX_NODES} đối tượng

crates/ui-egui/src/i18n/zh-hans.tsv

@@ -4036,11 +4036,16 @@ imageTrace	Outline	轮廓
 @msg	unknown command `{0}`; did you mean `{1}`?	未知命令 `{0}`；您是否想输入 `{1}`？
 @msg	`{what}` closes nothing	`{what}` 没有可结束的内容
 @msg	`{what}` closes something it didn't open	`{what}` 结束了并非由它开始的内容
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	覆盖多个图层的蒙版会在其覆盖的每个图层中作为剪切组导入
 @msg	a graph's records don't end where they should: its art was read as it is	图表的记录没有在应有的位置结束：其图稿按原样读取
 @msg	`{w}` takes no operands	`{w}` 不接受操作数
 @msg	a wraparound group is inside a compound path	文本绕排组位于复合路径内
 @msg	a path has too many points	某条路径的点过多
 @msg	it ends inside a layer	它在图层内部结束
+@msg	it ends inside a multi-layer mask	它在跨图层蒙版内部结束
+@msg	a multi-layer mask's operators are out of order	跨图层蒙版的运算符顺序错误
+@msg	a multi-layer mask needs one clipping path	跨图层蒙版需要一条剪切路径
+@msg	a group crosses a multi-layer mask	编组跨越了跨图层蒙版
 @msg	it has art outside its layers	它有位于图层之外的图稿
 @msg	it has more than {MAX_NODES} objects	它包含超过 {MAX_NODES} 个对象
 @msg	it has no layers	它没有图层

crates/ui-egui/src/i18n/zh-hant.tsv

@@ -1958,11 +1958,16 @@ file-filter	Templates	範本
 @msg	unknown command `{0}`; did you mean `{1}`?	未知的指令 `{0}`；您是指 `{1}` 嗎？
 @msg	`{what}` closes nothing	`{what}` 沒有可結束的內容
 @msg	`{what}` closes something it didn't open	`{what}` 結束了並非由它開始的內容
+@msg	a mask that covers several layers comes in as a clipping group in each layer it covers	覆蓋多個圖層的遮色片會在其覆蓋的每個圖層中作為剪裁群組匯入
 @msg	a graph's records don't end where they should: its art was read as it is	圖表的記錄沒有在應有的位置結束：其圖稿按原樣讀取
 @msg	`{w}` takes no operands	`{w}` 不接受運算元
 @msg	a wraparound group is inside a compound path	文字繞圖群組位於複合路徑內
 @msg	a path has too many points	有一條路徑的點過多
 @msg	it ends inside a layer	它在圖層內部結束
+@msg	it ends inside a multi-layer mask	它在跨圖層遮色片內部結束
+@msg	a multi-layer mask's operators are out of order	跨圖層遮色片的運算子順序錯誤
+@msg	a multi-layer mask needs one clipping path	跨圖層遮色片需要一條剪裁路徑
+@msg	a group crosses a multi-layer mask	群組跨越了跨圖層遮色片
 @msg	it has art outside its layers	它有位於圖層之外的圖稿
 @msg	it has more than {MAX_NODES} objects	它有超過 {MAX_NODES} 個物件
 @msg	it has no layers	它沒有圖層

docs/file-format-parity.md

@@ -43,6 +43,8 @@ private editing data. VectorCraft:
   write) is its own editing data: it opens through the layers its program has, compared with its page
   when the program runs, from the layers alone when it names its prolog without including it (#1027), and with its art on one
   layer when it has no layers (Illustrator 3, and image editors' exported paths: storytold/photocraft#6036).
+  A multi-layer mask (`Mb` … `Md` … `MB`) comes in as a clipping group in each layer it covers, each
+  clipped by a copy of the mask's path.
   RGB in the PDF page's `ICCBased` spaces keeps the file's numbers in a `.ai` (the `uncalibrated_rgb`
   import option, on for editor documents, off for PDFs), so `.ai` files tagged with a non-sRGB RGB profile
   open with different, unconverted RGB colours than before.