M2: Suggest auto layout warns about uneven cross offsets and refuses instances (#1823)

Bands that start at different offsets across the flow (a centred title above a card) are lined up at the smallest offset, which moves some of them, so the result now carries a warning for it. Instances and layers inside them are refused before anything changes, with the same error Convert to group gives; a main component still works.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

ROADMAP.md

@@ -132,7 +132,7 @@ Ranked; detail and milestones in [`docs/roadmap.md`](docs/roadmap.md).
 
 ## Progress log
 
-- **2026-11-05** · M2, #1823: Suggest auto layout is its own command. `layout.suggest` used to run `layout.add` and made one row of everything. It now splits a frame's layers into rows or columns by the gaps between them, wraps each band of several layers in a hugging frame without fill and repeats inside it, so the design gets as many auto layout frames as it needs and keeps its placement where the gaps are even (the frame keeps its size). Uneven gaps and layers that overlap along both axes are reported as `warnings`. `layout.add` is unchanged. Tests in `layout_suggest_tests.rs`. Numbers unchanged.
+- **2026-11-05** · M2, #1823: Suggest auto layout is its own command. `layout.suggest` used to run `layout.add` and made one row of everything. It now splits a frame's layers into rows or columns by the gaps between them, wraps each band of several layers in a hugging frame without fill and repeats inside it, so the design gets as many auto layout frames as it needs and keeps its placement where the gaps are even (the frame keeps its size). Uneven gaps, bands that start at different offsets across the flow (lined up at the smallest) and layers that overlap along both axes are reported as `warnings`, and instances and layers inside them are refused. `layout.add` is unchanged. Tests in `layout_suggest_tests.rs`. Numbers unchanged.
 - **2026-10-30**: M8, #1125: damaged `trak` size-table offsets are checked instead of wrapping on 32-bit targets, and an incomplete normal track is dropped entirely, never returned in part. Font indexing makes its existing bounds explicit, preserving later faces and sparse name-table reads. Synthetic regression tests in `fontdb_tests.rs`. Numbers unchanged.
 - **2026-10-30** · Text style dedupe is O(spans) (M8, #1102): `shape_text` deduped spans into styles by a scan over the styles already collected — O(spans × styles), so a styled text's dedupe grew with the square of its runs (a synthetic 50k-run text with 100 alternating styles spent 7.7 ms in it). Now the last two styles again (spans run in blocks), then buckets keyed by a cheap fingerprint (family and style bytes, size bits with −0.0 folded, the enums, fill count and solid colours), each bucket resolved with the full equality: the result is the scan's, never worse than it, and O(spans) when names and sizes differ (the same synthetic text: 2.6 ms). The font-db write lock is untouched: `find()` loads faces, which needs the write. `layout_dedupe_tests`. Numbers unchanged.
 - **2026-10-29** · M10: correct nine German labels in `de.toml`: gradient stops use Verlaufsstopp, OpenType ss01–ss05 use Stilsatz, and the Home-screen preference names the Startbildschirm consistently in the UI and Actions palette. This is a partial terminology pass; German remains a draft awaiting a full native-speaker review and maintainer approval. Numbers unchanged.

crates/engine/src/cmd/structure.rs

@@ -114,7 +114,7 @@ pub fn specs() -> Vec<CommandSpec> {
         spec!(
             "layout.suggest",
             "Suggest auto layout",
-            "{ids?, direction? (horizontal|vertical|grid)}  splits each frame's layers into rows or columns by the gaps between them, wraps every band of several layers in a frame without fill that hugs it and does the same inside, so the layers keep their place where the gaps are even; the frame keeps its size, and the result carries `warnings` for gaps that differ or layers that overlap. `direction` sets the top level's direction (nested frames follow the gaps); grid lays the layers out in one grid. A group is converted to a frame and several layers are wrapped in one, as Add auto layout does",
+            "{ids?, direction? (horizontal|vertical|grid)}  splits each frame's layers into rows or columns by the gaps between them, wraps every band of several layers in a frame without fill that hugs it and does the same inside, so the layers keep their place where the gaps are even and the bands start at the same offset across the flow; the frame keeps its size, and the result carries `warnings` for gaps that differ, bands that start at different offsets (they line up at the smallest and some move) and layers that overlap. Instances and the layers inside them are refused. `direction` sets the top level's direction (nested frames follow the gaps); grid lays the layers out in one grid. A group is converted to a frame and several layers are wrapped in one, as Add auto layout does",
             true,
             suggest::layout_suggest
         ),

crates/engine/src/cmd/structure/suggest.rs

@@ -8,7 +8,7 @@ use serde_json::{Value, json};
 
 use super::{Wrap, convert, infer_layout, sort_layout_children, wrap};
 use crate::params::{id_of, req_targets, string};
-use crate::{EngineError, Result, Session};
+use crate::{EngineError, Result, Session, bad};
 
 /// How deep nested band frames go before a frame is laid out as a single list.
 const MAX_DEPTH: usize = 16;
@@ -102,6 +102,18 @@ fn layout_for(bands: &[Band], vertical: bool, frame_w: f64, frame_h: f64, name:
     let main_end = (main_size - bands.last().map_or(0.0, |b| b.hi)).max(0.0);
     let cross_start = bands.iter().map(|b| b.cross_lo).fold(f64::INFINITY, f64::min).max(0.0);
     let cross_end = bands.iter().map(|b| cross_size - b.cross_hi).fold(f64::INFINITY, f64::min).max(0.0);
+    // Every band is lined up at the start across the flow, so one that starts further in (a
+    // centred title above a card) moves to the smallest offset.
+    let widest_start = bands.iter().map(|b| b.cross_lo).fold(f64::NEG_INFINITY, f64::max);
+    let smallest_start = bands.iter().map(|b| b.cross_lo).fold(f64::INFINITY, f64::min);
+    if widest_start - smallest_start > GAP_TOLERANCE {
+        let what = if vertical { "rows" } else { "columns" };
+        warnings.push(format!(
+            "\"{name}\": the {what} start at different offsets ({} to {}), so they are lined up at the smallest and some move",
+            finite_or_zero(smallest_start),
+            finite_or_zero(widest_start)
+        ));
+    }
     let [ms, me, cs, ce] = [main_start, main_end, cross_start, cross_end].map(finite_or_zero);
     AutoLayout {
         mode: if vertical { LayoutMode::Vertical } else { LayoutMode::Horizontal },
@@ -215,6 +227,17 @@ pub(super) fn layout_suggest(s: &mut Session, p: &Value) -> Result<Value> {
     let ids = req_targets("layout.suggest", s, p)?;
     let direction = string(p, "direction");
     let doc = s.doc()?;
+    // An instance's layers come from its main component: nothing is added to them. Checked
+    // before anything changes, with the words Convert to group uses.
+    for i in &ids {
+        let n = doc.get(*i)?;
+        if matches!(n.kind, NodeKind::Instance { .. }) {
+            return Err(bad("layout.suggest", format!("\"{}\" is an instance: its layers come from its main component (detach it first)", n.name)));
+        }
+        if crate::components::owning_instance(doc, *i).is_some() {
+            return Err(bad("layout.suggest", format!("\"{}\" is inside an instance: edit its main component, or detach the instance", n.name)));
+        }
+    }
     let all_frames = ids.iter().all(|i| doc.node(*i).is_some_and(|n| n.kind.is_frame_like() && n.layout.is_none()));
     let single_group = ids.len() == 1 && ids.first().and_then(|i| doc.node(*i)).is_some_and(|n| matches!(n.kind, NodeKind::Group));
     // A frame with auto layout already is wrapped, like a layer, and so are several layers.

crates/engine/src/layout_suggest_tests.rs

@@ -278,3 +278,48 @@ fn add_auto_layout_still_makes_a_single_row() {
     got.sort();
     assert_eq!(got, sq.to_vec(), "no nested frames");
 }
+
+#[test]
+fn a_centred_title_above_a_card_is_lined_up_at_the_card_edge_with_a_warning() {
+    let mut s = Session::new();
+    let f = frame(&mut s, 0.0, 0.0, 200.0, 200.0);
+    let title = rect(&mut s, f, 60.0, 0.0, 80.0, 30.0);
+    let card = rect(&mut s, f, 0.0, 40.0, 200.0, 100.0);
+    let result = ex(&mut s, "layout.suggest", json!({"ids": [f]}));
+    assert_eq!(mode(&s, f), Some(LayoutMode::Vertical));
+    assert_eq!(kids(&s, f), vec![title, card]);
+    let w = warnings(&result);
+    assert_eq!(w.len(), 1, "{result}");
+    assert!(w[0].contains("different offsets"), "{}", w[0]);
+    assert_eq!(page_box(&s, title), [0.0, 0.0, 80.0, 30.0], "the title's left edge is the card's now");
+    assert_eq!(page_box(&s, card), [0.0, 40.0, 200.0, 140.0], "the rest stays");
+}
+
+#[test]
+fn instances_and_layers_inside_them_are_refused_and_a_main_component_works() {
+    let mut s = Session::new();
+    let f = frame(&mut s, 0.0, 0.0, 200.0, 200.0);
+    rect(&mut s, f, 0.0, 0.0, 50.0, 50.0);
+    rect(&mut s, f, 0.0, 60.0, 50.0, 30.0);
+    let nested = id(&ex(&mut s, "frame.create", json!({"parent": f, "x": 0, "y": 100, "width": 100, "height": 50})));
+    rect(&mut s, nested, 0.0, 0.0, 20.0, 20.0);
+    rect(&mut s, nested, 40.0, 0.0, 20.0, 20.0);
+    let comp = id(&ex(&mut s, "component.create", json!({"ids": [f]})));
+    let inst = id(&ex(&mut s, "instance.create", json!({"component": comp, "x": 400, "y": 0})));
+    let inside: Vec<NodeId> = kids(&s, inst).into_iter().filter(|k| matches!(s.doc().unwrap().node(*k).unwrap().kind, NodeKind::Frame)).collect();
+    assert!(!inside.is_empty(), "the instance has a frame of its own");
+    let page = s.page().unwrap();
+    let snapshot = |s: &Session| (kids(s, page), kids(s, inst), kids(s, inside[0]));
+    let before = snapshot(&s);
+    let steps = s.ds().unwrap().history.undo.len();
+    for target in [inst, inside[0]] {
+        let e = s.execute("layout.suggest", &json!({"ids": [target]})).unwrap_err().to_string();
+        assert!(e.contains("instance"), "{e}");
+    }
+    assert_eq!(snapshot(&s), before, "nothing changed");
+    assert_eq!(s.ds().unwrap().history.undo.len(), steps, "no history step");
+    assert!(s.doc().unwrap().node(inst).unwrap().layout.is_none());
+    // The main component is a frame and works.
+    let result = ex(&mut s, "layout.suggest", json!({"ids": [comp]}));
+    assert_eq!(result["ids"], json!([comp]));
+}

docs/auto-layout-parity.md

@@ -92,7 +92,7 @@ Status: **pass** (a case in the suite holds), **fixed** (the suite found a diver
 | Arrow keys move children one place (flows, rows, columns, grid cells, into neighbours) | done | `al_keys_tests.rs` |
 | Constraints: left, right, left and right, centre, scale; top/bottom likewise | done | |
 | Layout grids: columns, rows, grid; stretch/left/centre/right; variables bound | done | |
-| Suggest auto layout | done | "Figma will try to determine which objects in a frame or component should be placed in an auto layout frame, then adds as many auto layout frames as needed to make the full design responsive. These auto layout frames are created all at once, while attempting to preserve the placement of your designs" ([Toggle on auto layout in designs](https://help.figma.com/hc/en-us/articles/5731482952599-Toggle-on-auto-layout-in-designs)). `layout.suggest` used to run `layout.add` and made one row of everything (#1823). Now it splits a frame's layers, by their boxes in the frame, along the vertical axis first: sorted by top edge, a layer joins the current row while it starts above the row's bottom (or together with it), and a gap, even a zero one, between the row and the next layer starts a new row. With two or more rows the frame becomes a Vertical auto layout whose items are the rows; otherwise the same split by columns gives a Horizontal one; if the layers overlap along both axes the frame gets no auto layout and the result carries a warning. A row or column of several layers goes into a new frame without fill or clipping, sized to it and inserted in its place (it hugs its content), and the split repeats inside it, to a depth of 16 and for up to 1,000 layers per frame (past that, or when a mask is among the layers, the layers are laid out in one list as Add auto layout does, with a warning). The frame keeps its size, Fixed: the gap is the distance between the bands, the padding along the flow is the first band's offset and the room left after the last, across the flow the smallest offset (alignment start), so with equal gaps every layer keeps its box exactly. When the gaps differ by more than 0.5 px the smallest is used and `warnings` says the later bands move. `direction` sets the top level only. A single group becomes a frame in place and several layers are wrapped in a frame (both hug), as Add auto layout does; a frame with fewer than two layers is laid out as Add auto layout does. One undo step. Tests in `crates/engine/src/layout_suggest_tests.rs`: `two_rows_of_two_squares_become_a_vertical_frame_of_two_horizontal_rows`, `suggesting_auto_layout_is_one_undo_step`, `three_squares_in_a_row_get_one_horizontal_layout_without_nesting`, `three_squares_in_a_column_get_one_vertical_layout_without_nesting`, `a_header_above_two_columns_of_squares_gives_a_row_per_line`, `a_header_above_a_tall_layer_beside_a_column_nests_three_levels`, `unequal_gaps_use_the_smallest_and_say_so`, `overlapping_layers_leave_the_frame_without_auto_layout_and_say_so`, `a_group_becomes_a_frame_in_place_and_follows_the_rules`, `several_layers_are_wrapped_in_a_frame_that_is_then_split`, `a_direction_forces_the_top_level_and_nested_frames_follow_the_gaps`, `a_frame_with_one_layer_is_laid_out_like_add_auto_layout`, `add_auto_layout_still_makes_a_single_row`. Not attempted: overlapping layers, uneven offsets across the flow beyond the smallest padding, grids |
+| Suggest auto layout | done | "Figma will try to determine which objects in a frame or component should be placed in an auto layout frame, then adds as many auto layout frames as needed to make the full design responsive. These auto layout frames are created all at once, while attempting to preserve the placement of your designs" ([Toggle on auto layout in designs](https://help.figma.com/hc/en-us/articles/5731482952599-Toggle-on-auto-layout-in-designs)). `layout.suggest` used to run `layout.add` and made one row of everything (#1823). Now it splits a frame's layers, by their boxes in the frame, along the vertical axis first: sorted by top edge, a layer joins the current row while it starts above the row's bottom (or together with it), and a gap, even a zero one, between the row and the next layer starts a new row. With two or more rows the frame becomes a Vertical auto layout whose items are the rows; otherwise the same split by columns gives a Horizontal one; if the layers overlap along both axes the frame gets no auto layout and the result carries a warning. A row or column of several layers goes into a new frame without fill or clipping, sized to it and inserted in its place (it hugs its content), and the split repeats inside it, to a depth of 16 and for up to 1,000 layers per frame (past that, or when a mask is among the layers, the layers are laid out in one list as Add auto layout does, with a warning). The frame keeps its size, Fixed: the gap is the distance between the bands, the padding along the flow is the first band's offset and the room left after the last, across the flow the smallest offset (alignment start), so with equal gaps and bands that start at the same offset every layer keeps its box exactly. When the gaps differ by more than 0.5 px the smallest is used and `warnings` says the later bands move; when the bands start at different offsets across the flow (a centred title above a card) they line up at the smallest, which moves the others, and `warnings` says so. Instances and layers inside them are refused with the error Convert to group gives, before anything changes; a main component works. `direction` sets the top level only. A single group becomes a frame in place and several layers are wrapped in a frame (both hug), as Add auto layout does; a frame with fewer than two layers is laid out as Add auto layout does. One undo step. Tests in `crates/engine/src/layout_suggest_tests.rs`: `two_rows_of_two_squares_become_a_vertical_frame_of_two_horizontal_rows`, `suggesting_auto_layout_is_one_undo_step`, `three_squares_in_a_row_get_one_horizontal_layout_without_nesting`, `three_squares_in_a_column_get_one_vertical_layout_without_nesting`, `a_header_above_two_columns_of_squares_gives_a_row_per_line`, `a_header_above_a_tall_layer_beside_a_column_nests_three_levels`, `unequal_gaps_use_the_smallest_and_say_so`, `overlapping_layers_leave_the_frame_without_auto_layout_and_say_so`, `a_group_becomes_a_frame_in_place_and_follows_the_rules`, `several_layers_are_wrapped_in_a_frame_that_is_then_split`, `a_direction_forces_the_top_level_and_nested_frames_follow_the_gaps`, `a_frame_with_one_layer_is_laid_out_like_add_auto_layout`, `add_auto_layout_still_makes_a_single_row`, `a_centred_title_above_a_card_is_lined_up_at_the_card_edge_with_a_warning`, `instances_and_layers_inside_them_are_refused_and_a_main_component_works`. Not attempted: overlapping layers, keeping uneven offsets across the flow (they line up at the smallest, with a warning), grids |
 | "Add auto layout" on a selection | done | the Layout sidebar exposes Add auto layout (+) for groups and frames using the same `layout.add` command as the context menu; a single group becomes a frame in place, keeping its id, name and direct children; adding auto layout to an empty frame keeps its size, Fixed (it collapsed to 20×20); a frame with content still hugs it, as does a new frame wrapped around a selection (#369). `node.set` with auto layout keys on a mix of layers applies them to the frames and warns about the rest instead of failing the whole call (#603) |
 | Real Figma files laid out identically | **not checked** | needs `.fig` or REST import of real files ([gaps](gaps.md) #1, #3) |
 | Performance: re-flow only where sizes or places changed | done | measured in `cargo xtask bench` (components at scale) |
@@ -101,7 +101,7 @@ Status: **pass** (a case in the suite holds), **fixed** (the suite found a diver
 
 | Date | Change | Summary |
 |---|---|---|
-| 2026-11-05 | patch | M2, #1823: Suggest auto layout is no longer Add auto layout under another name. "Figma will try to determine which objects in a frame or component should be placed in an auto layout frame, then adds as many auto layout frames as needed to make the full design responsive ... while attempting to preserve the placement of your designs" (Toggle on auto layout in designs): `layout.suggest` splits a frame's layers into rows (Vertical) or else columns (Horizontal) by the gaps between their boxes, wraps each band of several layers in a new frame without fill or clipping that hugs it, and repeats inside it (16 levels, 1,000 layers per frame at most). The frame keeps its size; gap and padding come from the bands, so layers keep their boxes where the gaps are even; uneven gaps (smallest used) and layers that overlap along both axes come back as `warnings`. `direction` sets the top level only; one undo step; `layout.add` is unchanged. Tests in `layout_suggest_tests.rs` |
+| 2026-11-05 | patch | M2, #1823: Suggest auto layout is no longer Add auto layout under another name. "Figma will try to determine which objects in a frame or component should be placed in an auto layout frame, then adds as many auto layout frames as needed to make the full design responsive ... while attempting to preserve the placement of your designs" (Toggle on auto layout in designs): `layout.suggest` splits a frame's layers into rows (Vertical) or else columns (Horizontal) by the gaps between their boxes, wraps each band of several layers in a new frame without fill or clipping that hugs it, and repeats inside it (16 levels, 1,000 layers per frame at most). The frame keeps its size; gap and padding come from the bands, so layers keep their boxes where the gaps are even and the bands start at the same offset; instances and layers inside them are refused; uneven gaps (smallest used), bands that start at different offsets across the flow (lined up at the smallest) and layers that overlap along both axes come back as `warnings`. `direction` sets the top level only; one undo step; `layout.add` is unchanged. Tests in `layout_suggest_tests.rs` |
 | 2026-11-02 | patch | M2, #1824: fill container children share the free space by their content area: each one's own insets (padding and an included inside stroke, from the same `insets` the frame uses) come off the free space before the equal split and go back on its share, so a child with more padding or a thicker inside stroke takes a little more and the content areas match ("Figma distributes space amongst fill container children by the children's content area instead of by their size, matching the CSS border-box model", Use auto layout with CSS Flexbox in mind). Min and max still clamp the outer sizes and the frozen-share loop is as it was; children without insets split as before. Test: `nested_tests::fill_children_share_by_content_area` |
 | 2026-11-02 | patch | M2, #1838: a double-click on an edge of an auto layout frame's bounding box sets Hug contents on that axis, Alt+double-click on an edge of a child's Fill container ("Double-click the vertical or horizontal edge of an auto layout object's bounding box to set it to Hug contents", "Hold ⌥ Option or Alt and double-click ... to set it to Fill container", Guide to auto layout); a vertical edge sizes the width, a horizontal one the height; the Keyboard shortcuts panel lists both gestures. Test: `double_click_tests::a_double_click_on_an_auto_layout_edge_hugs_and_with_alt_fills`. Numbers unchanged. |
 | 2026-11-02 | patch | M2: a child of an auto layout frame resized to the full space available to it on an axis (the frame's size less its padding: across the flow for any child, along the flow for a lone child) becomes Fill container on that axis, whether by `transform.resize`, the W/H fields or a canvas handle ("Child objects of an auto layout frame will also be set to Fill container if they are manually resized to the full available space of the parent frame", Guide to auto layout). Any other size keeps the axis Fixed as before; beside siblings along the flow, in a hugging or wrapping frame, in a grid and for a layer that ignores the layout nothing changes. Test: `al_behaviour_tests::a_child_resized_to_the_full_available_space_becomes_fill` |