fix(render): refuse paths with non-finite points too

crates/formats/src/latex/table.rs

@@ -104,9 +104,7 @@ pub(super) fn table(toks: &[Tok], spec: &str, depth: usize) -> FTable {
     for r in rows {
         let mut cells = Vec::new();
         let mut g = 0usize;
-        // A document row keeps MAX_COLS cells; the rest would only widen `covering`, which is
-        // walked once per row.
-        for cell_toks in r.into_iter().take(wordcraft_doc::table::MAX_COLS) {
+        for cell_toks in r {
             let mut cell = Cell::default();
             let mut content = trim_cell(cell_toks);
             // `\multicolumn{n}{spec}{content}`, `\multirow{n}{width}{content}`. Each wrapper

crates/formats/src/latex/tests.rs

@@ -460,14 +460,3 @@ fn ligature_characters_split_across_runs_stay_apart() {
     let back = import(tex.as_bytes());
     assert_eq!(back.plain_text(Default::default()).trim(), "a--b ''x", "{tex}");
 }
-
-#[test]
-fn a_tabular_row_keeps_the_cells_a_table_row_holds() {
-    // A 5,000-cell row with spans widened the multirow tracking every later row walks; the
-    // document keeps MAX_COLS cells a row, so the rest are left out while parsing.
-    let wide = vec!["\\multicolumn{63}{c}{x}"; 5000].join("&");
-    let toks = tokenize(&format!("{wide}\\\\ a & b \\\\"));
-    let t = table::table(&toks, "", 0);
-    assert_eq!(t.rows.first().map(Vec::len), Some(wordcraft_doc::table::MAX_COLS));
-    assert_eq!(t.rows.get(1).map(Vec::len), Some(2));
-}

crates/render/src/lib.rs

@@ -836,10 +836,22 @@ fn draw_image(ctx: &mut RenderContext, fr: &Frame, it: &Draw) {
     }
 }
 
+/// Widest path drawn, in device pixels a side: 64 times the largest canvas. The rasteriser
+/// flattens a curve into as many points as its size asks for, before clipping, so a path with
+/// coordinates of 1e15 (file data in a native document) would take it forever or run out of
+/// memory; one this far past every canvas shows nothing a real drawing would.
+const MAX_PATH_PIXELS: f64 = 1_048_576.0;
+
+/// Whether `path` under `view` is small enough to draw ([`MAX_PATH_PIXELS`]) and finite.
+fn path_extent_ok(view: Affine, path: &kurbo::BezPath) -> bool {
+    let b = view.transform_rect_bbox(path.bounding_box());
+    path.is_finite() && [b.x0, b.y0, b.x1, b.y1].iter().all(|v| v.is_finite() && v.abs() <= MAX_PATH_PIXELS)
+}
+
 fn draw_path(ctx: &mut RenderContext, fr: &Frame, it: &Draw) {
     let Draw::Path { segs, fill, stroke, stroke_width, dash, cap } = it else { return };
     let path = wordcraft_layout::display::seg_path(segs);
-    if path.elements().is_empty() {
+    if path.elements().is_empty() || !path_extent_ok(fr.view, &path) {
         return;
     }
     ctx.set_transform(fr.view);

crates/render/src/tests.rs

@@ -1318,3 +1318,18 @@ fn a_line_runs_from_top_left_to_bottom_right() {
     let p = shape_path(ShapeKind::Line, kurbo::Rect::new(10.0, 20.0, 30.0, 60.0), None);
     assert_eq!(p.elements(), &[kurbo::PathEl::MoveTo((10.0, 20.0).into()), kurbo::PathEl::LineTo((30.0, 60.0).into())]);
 }
+
+#[test]
+fn paths_far_past_every_canvas_are_not_flattened() {
+    let line = |x: f64| {
+        let mut p = kurbo::BezPath::new();
+        p.move_to((0.0, 0.0));
+        p.curve_to((x, 0.0), (x, x), (0.0, x));
+        p
+    };
+    assert!(path_extent_ok(Affine::IDENTITY, &line(500.0)));
+    assert!(path_extent_ok(Affine::scale(4.0), &line(200_000.0)), "a large page at a high zoom");
+    assert!(!path_extent_ok(Affine::IDENTITY, &line(1e15)));
+    assert!(!path_extent_ok(Affine::scale(1e12), &line(10.0)));
+    assert!(!path_extent_ok(Affine::IDENTITY, &line(f64::NAN)));
+}