Merge pull request #2253 from storytold/fix/sec-grid-snap-budget

layout: bound the snap lines a frame's grids generate

crates/layout/src/depth_tests.rs

@@ -93,3 +93,15 @@ fn deeply_nested_fill_frames_lay_out_without_running_out_of_stack() {
         assert_eq!(width(&d, chain[DEEP - 1]), 10.0, "past the nesting the layout follows, layers stay");
     });
 }
+
+#[test]
+fn snap_lines_are_bounded_across_a_frames_grids() {
+    use figcraft_doc::{Document, GridKind, LayoutGrid, NodeKind};
+    let mut d = Document::new("t");
+    let p = d.first_page().unwrap();
+    let f = d.create(p, NodeKind::Frame, "F", 0.0, 0.0, 4000.0, 4000.0).unwrap();
+    d.get_mut(f).unwrap().grids = vec![LayoutGrid { kind: GridKind::Grid, size: 1.0, visible: true, ..LayoutGrid::default() }; 1000];
+    let (xs, ys) = crate::grid_snap_lines(&d, f);
+    assert!(xs.len() + ys.len() <= 200_000, "{}", xs.len() + ys.len());
+    assert!(xs.len() > 4000 && ys.len() > 4000, "the first grids still give their lines");
+}

crates/layout/src/lib.rs

@@ -1159,6 +1159,9 @@ pub fn grid_snap_lines(doc: &Document, frame: NodeId) -> (Vec<f64>, Vec<f64>) {
     grid_snap_lines_in(doc, frame, doc.world_transform(frame))
 }
 
+/// The most snap coordinates a frame's grids give together (a few dozen grids' worth of lines).
+const MAX_SNAP_LINES: usize = 200_000;
+
 /// [`grid_snap_lines`] mapped from the frame's coordinates by `xf` (the frame's world transform
 /// for page lines).
 pub fn grid_snap_lines_in(doc: &Document, frame: NodeId, xf: Affine) -> (Vec<f64>, Vec<f64>) {
@@ -1166,7 +1169,13 @@ pub fn grid_snap_lines_in(doc: &Document, frame: NodeId, xf: Affine) -> (Vec<f64
     let mut xs = Vec::new();
     let mut ys = Vec::new();
     for g in f.grids.iter().filter(|g| g.visible) {
-        for r in grid_lines(g, f.width, f.height) {
+        // A frame-wide budget: each grid adds up to ~17,000 lines, and a file can hold any number of grids;
+        // a grid that would pass it is left out whole.
+        let lines = grid_lines(g, f.width, f.height);
+        if xs.len() + ys.len() + 2 * lines.len() > MAX_SNAP_LINES {
+            break;
+        }
+        for r in lines {
             let a = xf * Point::new(r.x0, r.y0);
             let b = xf * Point::new(r.x1, r.y1);
             match g.kind {