fix(render): charge boundary transforms and scanline sorts to the shared hatch budget

crates/engine/src/lisp.rs

@@ -123,12 +123,6 @@ pub struct LispState {
     acad_loaded: bool,
     /// Memory caps (lowered by tests).
     pub(crate) limits: Limits,
-    /// Interpreter steps all synchronous callbacks have run, nested ones included. A callback's
-    /// allowance counts what ran since it started, so the callbacks it calls spend its steps.
-    pub(crate) callback_used: u64,
-    /// The `callback_used` value the callback running now (and so every one it calls) must not
-    /// pass: the lowest of its own and its callers' allowances.
-    pub(crate) callback_ceiling: Option<u64>,
 }
 
 /// What U and REDO inside the running routine take back: the commands it ran, each as the drawing

crates/engine/src/lisp/builtins/strings.rs

@@ -1,5 +1,5 @@
 use super::args::{R, arity, int, list_arg, string};
-use super::{LispError, OsStr, Value, charge_bytes, check_string_len, read, to_text};
+use super::{LispError, OsStr, Value, check_string_len, read, to_text};
 
 // ---------------- strings ----------------
 
@@ -114,13 +114,7 @@ pub(super) fn read_fn(a: &[Value]) -> R {
     arity(a, 0, 1)?;
     match a.first() {
         None | Some(Value::Nil) => Ok(Value::Nil),
-        Some(v) => {
-            // The strings in the list it makes are new, each as long as its text at most: the
-            // text is charged, though a list result isn't inspected by `charge_result`.
-            let text = string(v)?;
-            charge_bytes(text.len())?;
-            read::read_one(&text)
-        }
+        Some(v) => read::read_one(&string(v)?),
     }
 }
 

crates/engine/src/lisp/drawing.rs

@@ -179,12 +179,7 @@ fn to_json_bounded(v: &Value, depth: usize, budget: &mut u64) -> Option<serde_js
         Value::Nil => serde_json::Value::Null,
         Value::Int(i) => serde_json::json!(i),
         Value::Real(r) => serde_json::json!(r),
-        Value::Str(s) => {
-            // A string is copied whole each time it occurs: it spends the allowance by its length
-            // (one unit per 16 bytes, so about 32 MB in all), shared or not.
-            *budget = budget.checked_sub(s.len() as u64 / 16)?;
-            serde_json::json!(&**s)
-        }
+        Value::Str(s) => serde_json::json!(&**s),
         Value::Cons(_) => {
             let mut arr = Vec::new();
             for x in v.iter() {
@@ -301,16 +296,12 @@ fn groups_to_list(tags: &[Tag]) -> Vec<Value> {
     out
 }
 
-/// The most string bytes an entity list may hold (counted per occurrence, shared or not).
-const MAX_GROUP_TEXT: usize = 32 << 20;
-
 /// An association list back to DXF groups (points split into x, y, z groups). The type
 /// (`0`), the entity name (`-1`), the handle (`5`), the owner (`330`) and the layout (`410`) are
 /// left out: they aren't the entity's to set.
 fn list_to_groups(list: &Value) -> Result<(String, Vec<Tag>), LispError> {
     let mut kind = None;
     let mut tags = Vec::new();
-    let mut text_left = MAX_GROUP_TEXT;
     for item in list.iter() {
         let Value::Cons(c) = &item else { return Err(LispError::bad_arg("listp", &item)) };
         let Value::Int(code) = c.car else { return Err(LispError::bad_arg("fixnump", &c.car)) };
@@ -332,11 +323,7 @@ fn list_to_groups(list: &Value) -> Result<(String, Vec<Tag>), LispError> {
             _ => tags.push(match &v {
                 Value::Int(i) => Tag::i(code, i64::from(*i)),
                 Value::Real(r) => Tag::f(code, *r),
-                Value::Str(s) => {
-                    // Each occurrence of a shared string becomes its own copy in the tag.
-                    text_left = text_left.checked_sub(s.len()).ok_or_else(|| LispError::new("out of memory: the entity list holds too much text"))?;
-                    Tag::s(code, &**s)
-                }
+                Value::Str(s) => Tag::s(code, &**s),
                 Value::Ename(h) => Tag::s(code, h.hex()),
                 other => return Err(LispError::bad_arg("DXF group value", other)),
             }),
@@ -1138,27 +1125,3 @@ pub fn load_source(s: &Session, name: &str) -> Option<String> {
         s.lisp_support_dir().map(|d| candidates.iter().map(|c| d.join(c).to_string_lossy().into_owned()).collect::<Vec<_>>()).unwrap_or_default();
     candidates.iter().chain(&support).find_map(super::builtins::read_text_file)
 }
-
-#[cfg(test)]
-mod budget_tests {
-    use super::*;
-
-    /// One 64 KB string occurring many times is charged by its length each time.
-    #[test]
-    fn shared_strings_spend_the_conversion_budgets() {
-        let big = Value::str(&"x".repeat(64 << 10));
-        // 600 x 64 KB is over the 32 MiB an entity list may hold; 100 x 64 KB is not.
-        let list = |n: usize| {
-            let mut items = vec![Value::cons(Value::Int(0), Value::str("TEXT"))];
-            items.extend(std::iter::repeat_n(Value::cons(Value::Int(1), big.clone()), n));
-            Value::list(items)
-        };
-        assert!(list_to_groups(&list(600)).is_err());
-        assert!(list_to_groups(&list(100)).is_ok());
-        // 1,000 x 64 KB is 4,096,000 units of the 2,000,000 SETVAR allows; 100 x 64 KB is not.
-        let mut budget = TO_JSON_BUDGET;
-        assert!(to_json_bounded(&Value::list(vec![big.clone(); 1_000]), 0, &mut budget).is_none());
-        let mut budget = TO_JSON_BUDGET;
-        assert!(to_json_bounded(&Value::list(vec![big; 100]), 0, &mut budget).is_some());
-    }
-}

crates/engine/src/lisp/eval.rs

@@ -175,19 +175,17 @@ pub struct Machine {
     stack: Vec<Frame>,
     state: State,
     need: Option<Need>,
-    /// Steps the last [`Machine::run`] took.
-    last_steps: u64,
 }
 
 impl Machine {
     /// A machine evaluating `forms` in turn.
     pub fn forms(forms: Vec<Value>) -> Machine {
-        Machine { stack: vec![Frame::Forms { rest: forms.into_iter().rev().collect() }], state: State::Ret(Value::Nil), need: None, last_steps: 0 }
+        Machine { stack: vec![Frame::Forms { rest: forms.into_iter().rev().collect() }], state: State::Ret(Value::Nil), need: None }
     }
 
     /// A machine calling `f` with `args`.
     pub fn calling(f: Value, args: Vec<Value>) -> Machine {
-        Machine { stack: Vec::new(), state: State::Call(f, args), need: None, last_steps: 0 }
+        Machine { stack: Vec::new(), state: State::Call(f, args), need: None }
     }
 
     /// Give the value a [`Need`] waited for, and carry on.
@@ -198,15 +196,9 @@ impl Machine {
     /// Run until done, waiting, or `budget` steps.
     pub fn run(&mut self, ctx: &mut Ctx<'_>, budget: u64) -> Outcome {
         let mut n = 0u64;
-        let outcome = self.run_counted(ctx, budget, &mut n);
-        self.last_steps = n.min(budget);
-        outcome
-    }
-
-    fn run_counted(&mut self, ctx: &mut Ctx<'_>, budget: u64, n: &mut u64) -> Outcome {
         loop {
-            *n += 1;
-            if *n > budget {
+            n += 1;
+            if n > budget {
                 return Outcome::Wait(Need::Yield);
             }
             let r = match std::mem::replace(&mut self.state, State::Ret(Value::Nil)) {
@@ -654,41 +646,29 @@ impl Ctx<'_> {
             super::value::charge_result(&v)?;
             return Ok(v);
         }
-        let cap = self.s.lisp.limits.callback_steps;
-        let start = self.s.lisp.callback_used;
-        // This callback may run until `callback_used` reaches `ceiling`: `cap` steps from now, or
-        // sooner where a caller's allowance ends, so callbacks nested in callbacks share one
-        // allowance instead of each taking a fresh one (an exponential tree otherwise).
-        let outer = self.s.lisp.callback_ceiling;
-        let ceiling = start.saturating_add(cap).min(outer.unwrap_or(u64::MAX));
-        self.s.lisp.callback_ceiling = Some(ceiling);
-        let r = self.drive_callback(f, args, ceiling);
-        self.s.lisp.callback_ceiling = outer;
-        r
-    }
-
-    /// Run callback `f` in slices until it finishes or `callback_used` reaches `ceiling`.
-    fn drive_callback(&mut self, f: &Value, args: Vec<Value>, ceiling: u64) -> Result<Value, LispError> {
         let cap = self.s.lisp.limits.callback_steps;
         let mut m = Machine::calling(f.clone(), args);
         let mut sub = Ctx { s: &mut *self.s, env: &mut *self.env, depth: self.depth + 1 };
         // Drive the callback in bounded slices instead of granting it `u64::MAX` fuel. A `Yield`
-        // (the step budget ran out) is retried until the ceiling, so a constant-memory infinite
+        // (the step budget ran out) is retried until a hard cap, so a constant-memory infinite
         // loop inside a comparator or predicate terminates with an error rather than hanging the
-        // thread and bypassing the blocking execution cap (CWE-400). The steps of callbacks this
-        // one calls are counted in `callback_used` too.
+        // thread and bypassing the blocking execution cap (CWE-400).
+        let mut spent: u64 = 0;
         loop {
-            let remaining = ceiling.saturating_sub(sub.s.lisp.callback_used);
+            let remaining = cap.saturating_sub(spent);
             if remaining == 0 {
                 return Err(LispError::new(format!("callback stopped after {cap} steps")));
             }
             let slice = remaining.min(SYNC_SLICE);
-            let outcome = m.run(&mut sub, slice);
-            sub.s.lisp.callback_used = sub.s.lisp.callback_used.saturating_add(m.last_steps);
-            match outcome {
+            match m.run(&mut sub, slice) {
                 Outcome::Done(v) => return Ok(v),
                 Outcome::Error(e) => return Err(e),
-                Outcome::Wait(Need::Yield) => {}
+                Outcome::Wait(Need::Yield) => {
+                    spent = spent.saturating_add(slice);
+                    if spent >= cap {
+                        return Err(LispError::new(format!("callback stopped after {cap} steps")));
+                    }
+                }
                 Outcome::Wait(_) => return Err(LispError::new("this function can't ask for input here")),
             }
         }

crates/engine/src/lisp/tests.rs

@@ -286,20 +286,6 @@ fn reaching_a_callback_slice_boundary_does_not_grant_another_slice() {
     assert!(counts[1] >= counts[0] && counts[1] - counts[0] <= 1, "{counts:?}");
 }
 
-/// Callbacks that call callbacks share one allowance: a branching routine can't multiply it.
-#[test]
-fn nested_callbacks_share_one_step_allowance() {
-    let mut s = session();
-    s.lisp.limits.callback_steps = 1_000_000;
-    // 4^14 leaf calls if every callback took a fresh allowance; the whole tree gets one.
-    let started = std::time::Instant::now();
-    let e = eval(&mut s, "(defun f (n) (if (> n 0) (vl-every '(lambda (x) (f (1- n)) t) '(1 2 3 4)) t)) (f 14)").unwrap_err();
-    assert!(e.contains("callback stopped after 1000000 steps"), "{e}");
-    assert!(started.elapsed() < std::time::Duration::from_secs(60));
-    // The next run starts afresh.
-    assert_eq!(ok(&mut s, "(f 1)"), "T");
-}
-
 /// System-variable conversion rejects a shared list whose owned JSON expansion would exceed its budget.
 #[test]
 fn setvar_rejects_an_oversized_shared_structure() {
@@ -991,9 +977,6 @@ fn strings_are_capped() {
     assert!(e.contains("too much text"), "{e}");
     let e = eval(&mut s, "(repeat 200000 (princ \"0123456789\"))").unwrap_err();
     assert!(e.contains("too much text"), "{e}");
-    // READ makes new strings inside the list it returns: they count, though the result is a list.
-    let e = eval(&mut s, "(setq a \"(\\\"0123456789\\\")\") (repeat 100000 (setq b (read a)))").unwrap_err();
-    assert!(e.contains("too much text"), "{e}");
     // The budget is per run: the next one starts afresh.
     assert_eq!(ok(&mut s, "(strcat \"a\" \"b\")"), "\"ab\"");
 }

crates/engine/src/lisp/value.rs

@@ -346,11 +346,7 @@ pub fn equal(a: &Value, b: &Value, fuzz: f64) -> bool {
     // A shared cons DAG can expand into exponentially many node visits when compared as a tree.
     // Bound the total comparisons so `equal` on adversarial shared structure cannot monopolise the
     // thread (CWE-407); exhausting the budget reports "not equal" rather than looping.
-    equal_within(a, b, fuzz, EQUAL_BUDGET)
-}
-
-/// [`equal`] with its work allowance (node visits plus string bytes / 64) given.
-fn equal_within(a: &Value, b: &Value, fuzz: f64, mut budget: u64) -> bool {
+    let mut budget: u64 = EQUAL_BUDGET;
     equal_depth(a, b, fuzz, 0, &mut budget)
 }
 
@@ -377,19 +373,7 @@ fn equal_depth(a: &Value, b: &Value, fuzz: f64, depth: usize, budget: &mut u64)
                 a = na;
                 b = nb;
             }
-            _ => {
-                // Comparing two strings costs their length, not one visit: a shared list of long
-                // equal strings must spend the allowance by the bytes it compares (one unit per 64).
-                if let (Value::Str(x), Value::Str(y)) = (&a, &b) {
-                    let cost = (x.len().min(y.len()) / 64) as u64;
-                    if cost >= *budget {
-                        *budget = 0;
-                        return false;
-                    }
-                    *budget -= cost;
-                }
-                return atom_equal(&a, &b, fuzz);
-            }
+            _ => return atom_equal(&a, &b, fuzz),
         }
     }
 }
@@ -556,20 +540,6 @@ fn write_value(out: &mut String, v: &Value, escape: bool, depth: usize) {
 mod tests {
     use super::*;
 
-    /// `equal` charges the bytes of the strings it compares: a list of long equal strings fits a
-    /// big allowance but not a small one, though it has few nodes.
-    #[test]
-    fn equal_spends_its_allowance_on_string_bytes() {
-        let long = Value::str(&"x".repeat(6_400));
-        let other = Value::str(&"x".repeat(6_400));
-        let list = |v: &Value| Value::list(vec![v.clone(); 100]);
-        let (a, b) = (list(&long), list(&other));
-        // 100 strings x 100 units each, plus about 100 node visits.
-        assert!(equal_within(&a, &b, 0.0, 20_000));
-        assert!(!equal_within(&a, &b, 0.0, 5_000));
-        assert!(equal(&a, &b, 0.0));
-    }
-
     #[test]
     fn reals_print_with_six_significant_digits() {
         assert_eq!(real_text(1.0), "1.0");

crates/render/src/hatch.rs

@@ -367,6 +367,7 @@ pub fn reads_solid(d: &Drawing, h: &Hatch, px: f64) -> bool {
 /// `px`: a pixel in the hatch's units for the level of detail (a dash or dot repeat under two
 /// pixels is one continuous run); 0 = full detail, as plots, exports and picks use. `view`: only
 /// the part of the hatch inside it is generated; `None` = all of it.
+#[cfg(test)]
 pub fn pattern_lines(d: &Drawing, h: &Hatch, loops: &[Vec<Vec2>], px: f64, view: Option<&Bounds2>) -> Vec<Vec<Vec2>> {
     pattern_lines_until(d, h, loops, px, view, None)
 }
@@ -380,6 +381,21 @@ pub(crate) fn pattern_lines_until(
     px: f64,
     view: Option<&Bounds2>,
     cancel: Option<&AtomicBool>,
+) -> Vec<Vec<Vec2>> {
+    pattern_lines_within(d, h, loops, px, view, cancel, MAX_RUNS, MAX_HATCH_WORK)
+}
+
+/// [`pattern_lines_until`] with the most runs and the dash-work allowance given.
+#[allow(clippy::too_many_arguments)]
+fn pattern_lines_within(
+    d: &Drawing,
+    h: &Hatch,
+    loops: &[Vec<Vec2>],
+    px: f64,
+    view: Option<&Bounds2>,
+    cancel: Option<&AtomicBool>,
+    max_runs: usize,
+    work_limit: u64,
 ) -> Vec<Vec<Vec2>> {
     let lines = lines_of(d, h);
     let scale = scale_of(h);
@@ -388,7 +404,7 @@ pub(crate) fn pattern_lines_until(
     // Shared work budget across all families and spans, counting dash-processing steps even when
     // they emit no geometry: gap-only families produce no runs, so `out.len()` alone cannot bound
     // their cost (CWE-400).
-    let mut work: u64 = MAX_HATCH_WORK;
+    let mut work: u64 = work_limit;
     for fam in &lines {
         // A family with dashes but no positive (ink) element can never draw: skip it so its gaps
         // are not swept at all.
@@ -403,8 +419,8 @@ pub(crate) fn pattern_lines_until(
             continue;
         }
         let dashes: Vec<f64> = fam.dashes.iter().map(|d| d * scale).collect();
-        Family { origin, ang, delta, spacing, dashes: &dashes }.sweep(loops, px, view, cancel, &mut out, &mut work);
-        if out.len() >= MAX_RUNS || work == 0 || is_set(cancel) {
+        Family { max_runs, origin, ang, delta, spacing, dashes: &dashes }.sweep(loops, px, view, cancel, &mut out, &mut work);
+        if out.len() >= max_runs || work == 0 || is_set(cancel) {
             break;
         }
     }
@@ -415,6 +431,8 @@ pub(crate) fn pattern_lines_until(
 const SWATCH_REPEATS: f64 = 6.0;
 /// Most runs a swatch holds.
 const MAX_SWATCH_RUNS: usize = 4000;
+/// The dash-work allowance of a swatch (a hatch's is [`MAX_HATCH_WORK`]).
+const MAX_SWATCH_WORK: u64 = 2_000_000;
 
 /// A preview of a pattern for a pattern picker: the runs of its line families `lines` inside the
 /// `side` × `side` square with a corner at the origin, at a scale that shows a few repeats of the
@@ -441,14 +459,19 @@ pub fn pattern_swatch(lines: &[PatternLine], side: f64) -> Vec<Vec<Vec2>> {
         pattern_lines: lines.to_vec(),
     };
     let square = vec![Vec2::new(0.0, 0.0), Vec2::new(side, 0.0), Vec2::new(side, side), Vec2::new(0.0, side)];
-    let mut runs = pattern_lines(&Drawing::default(), &h, &[square], 0.0, None);
+    // The generator stops at the swatch's own limits, so a compact pattern is never made in full
+    // (about a million runs) to keep a few thousand.
+    let mut runs = pattern_lines_within(&Drawing::default(), &h, &[square], 0.0, None, None, MAX_SWATCH_RUNS, MAX_SWATCH_WORK);
     runs.truncate(MAX_SWATCH_RUNS);
+    runs.shrink_to_fit();
     runs
 }
 
 /// One pattern line family, scaled and placed: parallel lines `spacing` apart through `origin`
 /// at angle `ang`, each shifted along itself by `delta`'s along-line part from the last.
 struct Family<'a> {
+    /// Most runs the hatch may hold in all ([`MAX_RUNS`], less for a swatch).
+    max_runs: usize,
     origin: Vec2,
     ang: f64,
     delta: Vec2,
@@ -487,6 +510,13 @@ impl Family<'_> {
 
     /// Intersect a pattern family with boundary loops, respecting view, output, cancellation, and shared dash-work limits.
     fn sweep(&self, loops: &[Vec<Vec2>], px: f64, view: Option<&Bounds2>, cancel: Option<&AtomicBool>, out: &mut Vec<Vec<Vec2>>, work: &mut u64) {
+        // Transforming the boundary is charged before it is done, at the scanline rate (one unit per 8 vertices).
+        let verts: u64 = loops.iter().map(|l| l.len() as u64).sum();
+        let transform_charge = verts / 8 + 1;
+        if transform_charge > *work {
+            return;
+        }
+        *work -= transform_charge;
         let local: Vec<Vec<Vec2>> = loops.iter().map(|l| l.iter().map(|p| self.to_local(*p)).collect()).collect();
         let bb = Bounds2::from_points(local.iter().flatten().copied());
         if bb.is_empty() {
@@ -505,10 +535,17 @@ impl Family<'_> {
         // family draws anything at all).
         let draws = self.dashes.iter().any(|d| *d >= 0.0);
         let solid_line = self.dashes.is_empty() || pat_len < 1e-12 || (px > 0.0 && pat_len < 2.0 * px && draws);
+        // Each scanline visits every boundary edge and sorts the intersections. Charge both the
+        // traversal and an n*ceil(log2(n)) upper bound for sorting, scaled to one unit per eight
+        // operations, whether or not any dash is made.
+        let edges: u64 = local.iter().map(|l| l.len() as u64).sum();
+        let sort_levels = if edges > 1 { (u64::BITS - (edges - 1).leading_zeros()) as u64 } else { 0 };
+        let crossings_charge = edges.saturating_add(edges.saturating_mul(sort_levels)) / 8 + 1;
         for k in k0..=k1 {
-            if out.len() >= MAX_RUNS || *work == 0 || is_set(cancel) {
+            if out.len() >= self.max_runs || crossings_charge > *work || is_set(cancel) {
                 return;
             }
+            *work -= crossings_charge;
             let y = k as f64 * self.spacing;
             let xs = crossings(&local, y);
             let offset = shift_per_line * k as f64;
@@ -538,10 +575,10 @@ impl Family<'_> {
         'outer: while x < x1 {
             for d in self.dashes {
                 guard += 1;
-                *work = work.saturating_sub(1);
-                if guard > 100_000 || out.len() >= MAX_RUNS || *work == 0 {
+                if guard > 100_000 || out.len() >= self.max_runs || *work == 0 {
                     break 'outer;
                 }
+                *work -= 1;
                 let len = d.abs();
                 if *d > 0.0 {
                     let a = x.max(x0);

crates/render/src/linetype_text.rs

@@ -21,11 +21,17 @@ use cadcraft_geom::Vec2;
 /// Upper bound on the texts drawn along one run (hostile scales; `apply` caps the dashes).
 const MAX_TEXTS: usize = 10_000;
 
+/// Upper bound on the points of all the texts of one run: each placement keeps its own copy of the
+/// label's outline, so a long label times [`MAX_TEXTS`] would otherwise be too much to hold.
+const MAX_TEXT_POINTS: usize = 4_000_000;
+
 /// One text element of the pattern, shaped once at the origin.
 struct Element {
     /// Distance from the start of a pattern repeat to the anchor (where the element ends).
     at: f64,
     local: Shaped,
+    /// Points in `local`, each placement's cost against [`MAX_TEXT_POINTS`].
+    points: usize,
     rotation: f64,
     absolute: bool,
     offset: Vec2,
@@ -50,6 +56,7 @@ pub fn texts(d: &Drawing, pts: &[Vec2], lt: &Linetype, scale: f64, min_pattern:
         return out;
     }
     let mut walk = Walk { pts, i: 0, start: 0.0 };
+    let mut points_left = MAX_TEXT_POINTS;
     let mut base = 0.0;
     'repeats: while base <= len {
         for el in &elements {
@@ -57,6 +64,8 @@ pub fn texts(d: &Drawing, pts: &[Vec2], lt: &Linetype, scale: f64, min_pattern:
             if s > len + 1e-9 || out.len() >= MAX_TEXTS {
                 break 'repeats;
             }
+            let Some(left) = points_left.checked_sub(el.points) else { break 'repeats };
+            points_left = left;
             let Some((p, dir)) = walk.at(s) else { break 'repeats };
             let origin = p + dir * el.offset.x + dir.perp() * el.offset.y;
             let rot = if el.absolute { el.rotation } else { dir.angle() + el.rotation };
@@ -93,8 +102,16 @@ fn elements(d: &Drawing, lt: &Linetype, scale: f64) -> Vec<Element> {
         };
         let (local, _) = cadcraft_fonts::place(&font, text, &params);
         let finite = |v: f64| if v.is_finite() { v } else { 0.0 };
+        // Points plus one per stroke and glyph slot, and one for the label itself, so a label of empty
+        // glyphs still has a cost proportional to its size.
+        let points = local.strokes.iter().map(Vec::len).sum::<usize>()
+            + local.glyphs.iter().flatten().map(Vec::len).sum::<usize>()
+            + local.strokes.len()
+            + local.glyphs.len()
+            + 1;
         out.push(Element {
             at,
+            points,
             local,
             rotation: finite(el.rotation),
             absolute: el.absolute,
@@ -175,6 +192,20 @@ mod tests {
         assert!(texts(&d, &[Vec2::ZERO, Vec2::new(2.0, 0.0)], &plain, 1.0, 0.0).is_empty());
     }
 
+    /// A long label repeated along a long run stops at the point allowance, well before MAX_TEXTS.
+    #[test]
+    fn placed_labels_stop_at_the_point_allowance() {
+        let d = Drawing::new_imperial();
+        let mut lt = gas();
+        lt.pattern[1].text = Some("MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM".into());
+        // 0.95 per repeat over 9,000: about 9,500 repeats, under the 50,000 the run is drawn for.
+        let t = texts(&d, &[Vec2::ZERO, Vec2::new(9_000.0, 0.0)], &lt, 1.0, 0.0);
+        let points: usize =
+            t.iter().map(|s| s.strokes.iter().map(Vec::len).sum::<usize>() + s.glyphs.iter().flatten().map(Vec::len).sum::<usize>()).sum();
+        assert!(!t.is_empty() && t.len() < MAX_TEXTS, "{}", t.len());
+        assert!(points <= MAX_TEXT_POINTS, "{points}");
+    }
+
     #[test]
     fn hostile_values_never_panic() {
         let d = Drawing::new_imperial();

crates/render/tests/it/hatch_fill.rs

@@ -211,3 +211,14 @@ fn brick_joints_are_drawn_once_half_a_brick_apart_course_to_course() {
         assert!(next.iter().all(|nx| (nx - x[0]).rem_euclid(500) == 250), "courses {course}/{}: {x:?} {next:?}", course + 1);
     }
 }
+
+/// A pattern with a huge number of tiny dashes makes a swatch of a few thousand runs, stopping
+/// there; and many scanlines over a many-edged boundary are charged to the hatch's work allowance.
+#[test]
+fn compact_patterns_stop_at_the_swatch_limits() {
+    let lines = vec![PatternLine { angle: 0.0, origin: (0.0, 0.0), delta: (0.0, 1.0), dashes: vec![1e-6, -1e-6] }];
+    let started = std::time::Instant::now();
+    let runs = cadcraft_render::pattern_swatch(&lines, 1.0);
+    assert!(!runs.is_empty() && runs.len() <= 4000, "{}", runs.len());
+    assert!(started.elapsed() < std::time::Duration::from_secs(20));
+}