Table multiple headers and subheaders (#6168)

4 files changed, 1028 insertions, 320 deletions

diff --git a/crates/typst-layout/src/grid/layouter.rs b/crates/typst-layout/src/grid/layouter.rs
index 99b85edd..42fe38db 100644
--- a/crates/typst-layout/src/grid/layouter.rs
+++ b/crates/typst-layout/src/grid/layouter.rs
@@ -3,7 +3,9 @@ use std::fmt::Debug;
 use typst_library::diag::{bail, SourceResult};
 use typst_library::engine::Engine;
 use typst_library::foundations::{Resolve, StyleChain};
-use typst_library::layout::grid::resolve::{Cell, CellGrid, LinePosition, Repeatable};
+use typst_library::layout::grid::resolve::{
+    Cell, CellGrid, Header, LinePosition, Repeatable,
+};
 use typst_library::layout::{
     Abs, Axes, Dir, Fr, Fragment, Frame, FrameItem, Length, Point, Region, Regions, Rel,
     Size, Sizing,
@@ -30,10 +32,8 @@ pub struct GridLayouter<'a> {
     pub(super) rcols: Vec<Abs>,
     /// The sum of `rcols`.
     pub(super) width: Abs,
-    /// Resolve row sizes, by region.
+    /// Resolved row sizes, by region.
     pub(super) rrows: Vec<Vec<RowPiece>>,
-    /// Rows in the current region.
-    pub(super) lrows: Vec<Row>,
     /// The amount of unbreakable rows remaining to be laid out in the
     /// current unbreakable row group. While this is positive, no region breaks
     /// should occur.
@@ -41,24 +41,155 @@ pub struct GridLayouter<'a> {
     /// Rowspans not yet laid out because not all of their spanned rows were
     /// laid out yet.
     pub(super) rowspans: Vec<Rowspan>,
-    /// The initial size of the current region before we started subtracting.
-    pub(super) initial: Size,
+    /// Grid layout state for the current region.
+    pub(super) current: Current,
     /// Frames for finished regions.
     pub(super) finished: Vec<Frame>,
+    /// The amount and height of header rows on each finished region.
+    pub(super) finished_header_rows: Vec<FinishedHeaderRowInfo>,
     /// Whether this is an RTL grid.
     pub(super) is_rtl: bool,
-    /// The simulated header height.
-    /// This field is reset in `layout_header` and properly updated by
+    /// Currently repeating headers, one per level. Sorted by increasing
+    /// levels.
+    ///
+    /// Note that some levels may be absent, in particular level 0, which does
+    /// not exist (so all levels are >= 1).
+    pub(super) repeating_headers: Vec<&'a Header>,
+    /// Headers, repeating or not, awaiting their first successful layout.
+    /// Sorted by increasing levels.
+    pub(super) pending_headers: &'a [Repeatable<Header>],
+    /// Next headers to be processed.
+    pub(super) upcoming_headers: &'a [Repeatable<Header>],
+    /// State of the row being currently laid out.
+    ///
+    /// This is kept as a field to avoid passing down too many parameters from
+    /// `layout_row` into called functions, which would then have to pass them
+    /// down to `push_row`, which reads these values.
+    pub(super) row_state: RowState,
+    /// The span of the grid element.
+    pub(super) span: Span,
+}
+
+/// Grid layout state for the current region. This should be reset or updated
+/// on each region break.
+pub(super) struct Current {
+    /// The initial size of the current region before we started subtracting.
+    pub(super) initial: Size,
+    /// The height of the region after repeated headers were placed and footers
+    /// prepared. This also includes pending repeating headers from the start,
+    /// even if they were not repeated yet, since they will be repeated in the
+    /// next region anyway (bar orphan prevention).
+    ///
+    /// This is used to quickly tell if any additional space in the region has
+    /// been occupied since then, meaning that additional space will become
+    /// available after a region break (see
+    /// [`GridLayouter::may_progress_with_repeats`]).
+    pub(super) initial_after_repeats: Abs,
+    /// Whether `layouter.regions.may_progress()` was `true` at the top of the
+    /// region.
+    pub(super) could_progress_at_top: bool,
+    /// Rows in the current region.
+    pub(super) lrows: Vec<Row>,
+    /// The amount of repeated header rows at the start of the current region.
+    /// Thus, excludes rows from pending headers (which were placed for the
+    /// first time).
+    ///
+    /// Note that `repeating_headers` and `pending_headers` can change if we
+    /// find a new header inside the region (not at the top), so this field
+    /// is required to access information from the top of the region.
+    ///
+    /// This information is used on finish region to calculate the total height
+    /// of resolved header rows at the top of the region, which is used by
+    /// multi-page rowspans so they can properly skip the header rows at the
+    /// top of each region during layout.
+    pub(super) repeated_header_rows: usize,
+    /// The end bound of the row range of the last repeating header at the
+    /// start of the region.
+    ///
+    /// The last row might have disappeared from layout due to being empty, so
+    /// this is how we can become aware of where the last header ends without
+    /// having to check the vector of rows. Line layout uses this to determine
+    /// when to prioritize the last lines under a header.
+    ///
+    /// A value of zero indicates no repeated headers were placed.
+    pub(super) last_repeated_header_end: usize,
+    /// Stores the length of `lrows` before a sequence of rows equipped with
+    /// orphan prevention was laid out. In this case, if no more rows without
+    /// orphan prevention are laid out after those rows before the region ends,
+    /// the rows will be removed, and there may be an attempt to place them
+    /// again in the new region. Effectively, this is the mechanism used for
+    /// orphan prevention of rows.
+    ///
+    /// At the moment, this is only used by repeated headers (they aren't laid
+    /// out if alone in the region) and by new headers, which are moved to the
+    /// `pending_headers` vector and so will automatically be placed again
+    /// until they fit and are not orphans in at least one region (or exactly
+    /// one, for non-repeated headers).
+    pub(super) lrows_orphan_snapshot: Option<usize>,
+    /// The height of effectively repeating headers, that is, ignoring
+    /// non-repeating pending headers, in the current region.
+    ///
+    /// This is used by multi-page auto rows so they can inform cell layout on
+    /// how much space should be taken by headers if they break across regions.
+    /// In particular, non-repeating headers only occupy the initial region,
+    /// but disappear on new regions, so they can be ignored.
+    ///
+    /// This field is reset on each new region and properly updated by
     /// `layout_auto_row` and `layout_relative_row`, and should not be read
     /// before all header rows are fully laid out. It is usually fine because
     /// header rows themselves are unbreakable, and unbreakable rows do not
     /// need to read this field at all.
-    pub(super) header_height: Abs,
+    ///
+    /// This height is not only computed at the beginning of the region. It is
+    /// updated whenever a new header is found, subtracting the height of
+    /// headers which stopped repeating and adding the height of all new
+    /// headers.
+    pub(super) repeating_header_height: Abs,
+    /// The height for each repeating header that was placed in this region.
+    /// Note that this includes headers not at the top of the region, before
+    /// their first repetition (pending headers), and excludes headers removed
+    /// by virtue of a new, conflicting header being found (short-lived
+    /// headers).
+    ///
+    /// This is used to know how much to update `repeating_header_height` by
+    /// when finding a new header and causing existing repeating headers to
+    /// stop.
+    pub(super) repeating_header_heights: Vec<Abs>,
     /// The simulated footer height for this region.
+    ///
     /// The simulation occurs before any rows are laid out for a region.
     pub(super) footer_height: Abs,
-    /// The span of the grid element.
-    pub(super) span: Span,
+}
+
+/// Data about the row being laid out right now.
+#[derive(Debug, Default)]
+pub(super) struct RowState {
+    /// If this is `Some`, this will be updated by the currently laid out row's
+    /// height if it is auto or relative. This is used for header height
+    /// calculation.
+    pub(super) current_row_height: Option<Abs>,
+    /// This is `true` when laying out non-short lived headers and footers.
+    /// That is, headers and footers which are not immediately followed or
+    /// preceded (respectively) by conflicting headers and footers of same or
+    /// lower level, or the end or start of the table (respectively), which
+    /// would cause them to never repeat, even once.
+    ///
+    /// If this is `false`, the next row to be laid out will remove an active
+    /// orphan snapshot and will flush pending headers, as there is no risk
+    /// that they will be orphans anymore.
+    pub(super) in_active_repeatable: bool,
+}
+
+/// Data about laid out repeated header rows for a specific finished region.
+#[derive(Debug, Default)]
+pub(super) struct FinishedHeaderRowInfo {
+    /// The amount of repeated headers at the top of the region.
+    pub(super) repeated_amount: usize,
+    /// The end bound of the row range of the last repeated header at the top
+    /// of the region.
+    pub(super) last_repeated_header_end: usize,
+    /// The total height of repeated headers at the top of the region.
+    pub(super) repeated_height: Abs,
 }
 
 /// Details about a resulting row piece.
@@ -114,14 +245,27 @@ impl<'a> GridLayouter<'a> {
             rcols: vec![Abs::zero(); grid.cols.len()],
             width: Abs::zero(),
             rrows: vec![],
-            lrows: vec![],
             unbreakable_rows_left: 0,
             rowspans: vec![],
-            initial: regions.size,
             finished: vec![],
+            finished_header_rows: vec![],
             is_rtl: TextElem::dir_in(styles) == Dir::RTL,
-            header_height: Abs::zero(),
-            footer_height: Abs::zero(),
+            repeating_headers: vec![],
+            upcoming_headers: &grid.headers,
+            pending_headers: Default::default(),
+            row_state: RowState::default(),
+            current: Current {
+                initial: regions.size,
+                initial_after_repeats: regions.size.y,
+                could_progress_at_top: regions.may_progress(),
+                lrows: vec![],
+                repeated_header_rows: 0,
+                last_repeated_header_end: 0,
+                lrows_orphan_snapshot: None,
+                repeating_header_height: Abs::zero(),
+                repeating_header_heights: vec![],
+                footer_height: Abs::zero(),
+            },
             span,
         }
     }
@@ -130,38 +274,57 @@ impl<'a> GridLayouter<'a> {
     pub fn layout(mut self, engine: &mut Engine) -> SourceResult<Fragment> {
         self.measure_columns(engine)?;
 
-        if let Some(Repeatable::Repeated(footer)) = &self.grid.footer {
-            // Ensure rows in the first region will be aware of the possible
-            // presence of the footer.
-            self.prepare_footer(footer, engine, 0)?;
-            if matches!(self.grid.header, None | Some(Repeatable::NotRepeated(_))) {
-                // No repeatable header, so we won't subtract it later.
-                self.regions.size.y -= self.footer_height;
+        if let Some(footer) = &self.grid.footer {
+            if footer.repeated {
+                // Ensure rows in the first region will be aware of the
+                // possible presence of the footer.
+                self.prepare_footer(footer, engine, 0)?;
+                self.regions.size.y -= self.current.footer_height;
+                self.current.initial_after_repeats = self.regions.size.y;
             }
         }
 
-        for y in 0..self.grid.rows.len() {
-            if let Some(Repeatable::Repeated(header)) = &self.grid.header {
-                if y < header.end {
-                    if y == 0 {
-                        self.layout_header(header, engine, 0)?;
-                        self.regions.size.y -= self.footer_height;
-                    }
+        let mut y = 0;
+        let mut consecutive_header_count = 0;
+        while y < self.grid.rows.len() {
+            if let Some(next_header) = self.upcoming_headers.get(consecutive_header_count)
+            {
+                if next_header.range.contains(&y) {
+                    self.place_new_headers(&mut consecutive_header_count, engine)?;
+                    y = next_header.range.end;
+
                     // Skip header rows during normal layout.
                     continue;
                 }
             }
 
-            if let Some(Repeatable::Repeated(footer)) = &self.grid.footer {
-                if y >= footer.start {
+            if let Some(footer) = &self.grid.footer {
+                if footer.repeated && y >= footer.start {
                     if y == footer.start {
                         self.layout_footer(footer, engine, self.finished.len())?;
+                        self.flush_orphans();
                     }
+                    y = footer.end;
                     continue;
                 }
             }
 
             self.layout_row(y, engine, 0)?;
+
+            // After the first non-header row is placed, pending headers are no
+            // longer orphans and can repeat, so we move them to repeating
+            // headers.
+            //
+            // Note that this is usually done in `push_row`, since the call to
+            // `layout_row` above might trigger region breaks (for multi-page
+            // auto rows), whereas this needs to be called as soon as any part
+            // of a row is laid out. However, it's possible a row has no
+            // visible output and thus does not push any rows even though it
+            // was successfully laid out, in which case we additionally flush
+            // here just in case.
+            self.flush_orphans();
+
+            y += 1;
         }
 
         self.finish_region(engine, true)?;
@@ -184,13 +347,47 @@ impl<'a> GridLayouter<'a> {
         self.render_fills_strokes()
     }
 
-    /// Layout the given row.
+    /// Layout a row with a certain initial state, returning the final state.
+    #[inline]
+    pub(super) fn layout_row_with_state(
+        &mut self,
+        y: usize,
+        engine: &mut Engine,
+        disambiguator: usize,
+        initial_state: RowState,
+    ) -> SourceResult<RowState> {
+        // Keep a copy of the previous value in the stack, as this function can
+        // call itself recursively (e.g. if a region break is triggered and a
+        // header is placed), so we shouldn't outright overwrite it, but rather
+        // save and later restore the state when back to this call.
+        let previous = std::mem::replace(&mut self.row_state, initial_state);
+
+        // Keep it as a separate function to allow inlining the return below,
+        // as it's usually not needed.
+        self.layout_row_internal(y, engine, disambiguator)?;
+
+        Ok(std::mem::replace(&mut self.row_state, previous))
+    }
+
+    /// Layout the given row with the default row state.
+    #[inline]
     pub(super) fn layout_row(
         &mut self,
         y: usize,
         engine: &mut Engine,
         disambiguator: usize,
     ) -> SourceResult<()> {
+        self.layout_row_with_state(y, engine, disambiguator, RowState::default())?;
+        Ok(())
+    }
+
+    /// Layout the given row using the current state.
+    pub(super) fn layout_row_internal(
+        &mut self,
+        y: usize,
+        engine: &mut Engine,
+        disambiguator: usize,
+    ) -> SourceResult<()> {
         // Skip to next region if current one is full, but only for content
         // rows, not for gutter rows, and only if we aren't laying out an
         // unbreakable group of rows.
@@ -206,13 +403,18 @@ impl<'a> GridLayouter<'a> {
         }
 
         // Don't layout gutter rows at the top of a region.
-        if is_content_row || !self.lrows.is_empty() {
+        if is_content_row || !self.current.lrows.is_empty() {
             match self.grid.rows[y] {
                 Sizing::Auto => self.layout_auto_row(engine, disambiguator, y)?,
                 Sizing::Rel(v) => {
                     self.layout_relative_row(engine, disambiguator, v, y)?
                 }
-                Sizing::Fr(v) => self.lrows.push(Row::Fr(v, y, disambiguator)),
+                Sizing::Fr(v) => {
+                    if !self.row_state.in_active_repeatable {
+                        self.flush_orphans();
+                    }
+                    self.current.lrows.push(Row::Fr(v, y, disambiguator))
+                }
             }
         }
 
@@ -225,8 +427,13 @@ impl<'a> GridLayouter<'a> {
     fn render_fills_strokes(mut self) -> SourceResult<Fragment> {
         let mut finished = std::mem::take(&mut self.finished);
         let frame_amount = finished.len();
-        for ((frame_index, frame), rows) in
-            finished.iter_mut().enumerate().zip(&self.rrows)
+        for (((frame_index, frame), rows), finished_header_rows) in
+            finished.iter_mut().enumerate().zip(&self.rrows).zip(
+                self.finished_header_rows
+                    .iter()
+                    .map(Some)
+                    .chain(std::iter::repeat(None)),
+            )
         {
             if self.rcols.is_empty() || rows.is_empty() {
                 continue;
@@ -347,7 +554,8 @@ impl<'a> GridLayouter<'a> {
             let hline_indices = rows
                 .iter()
                 .map(|piece| piece.y)
-                .chain(std::iter::once(self.grid.rows.len()));
+                .chain(std::iter::once(self.grid.rows.len()))
+                .enumerate();
 
             // Converts a row to the corresponding index in the vector of
             // hlines.
@@ -372,7 +580,7 @@ impl<'a> GridLayouter<'a> {
             };
 
             let mut prev_y = None;
-            for (y, dy) in hline_indices.zip(hline_offsets) {
+            for ((i, y), dy) in hline_indices.zip(hline_offsets) {
                 // Position of lines below the row index in the previous iteration.
                 let expected_prev_line_position = prev_y
                     .map(|prev_y| {
@@ -383,47 +591,40 @@ impl<'a> GridLayouter<'a> {
                     })
                     .unwrap_or(LinePosition::Before);
 
-                // FIXME: In the future, directly specify in 'self.rrows' when
-                // we place a repeated header rather than its original rows.
-                // That would let us remove most of those verbose checks, both
-                // in 'lines.rs' and here. Those checks also aren't fully
-                // accurate either, since they will also trigger when some rows
-                // have been removed between the header and what's below it.
-                let is_under_repeated_header = self
-                    .grid
-                    .header
-                    .as_ref()
-                    .and_then(Repeatable::as_repeated)
-                    .zip(prev_y)
-                    .is_some_and(|(header, prev_y)| {
-                        // Note: 'y == header.end' would mean we're right below
-                        // the NON-REPEATED header, so that case should return
-                        // false.
-                        prev_y < header.end && y > header.end
-                    });
+                // Header's lines at the bottom have priority when repeated.
+                // This will store the end bound of the last header if the
+                // current iteration is calculating lines under it.
+                let last_repeated_header_end_above = match finished_header_rows {
+                    Some(info) if prev_y.is_some() && i == info.repeated_amount => {
+                        Some(info.last_repeated_header_end)
+                    }
+                    _ => None,
+                };
 
                 // If some grid rows were omitted between the previous resolved
                 // row and the current one, we ensure lines below the previous
                 // row don't "disappear" and are considered, albeit with less
                 // priority. However, don't do this when we're below a header,
                 // as it must have more priority instead of less, so it is
-                // chained later instead of before. The exception is when the
+                // chained later instead of before (stored in the
+                // 'header_hlines' variable below). The exception is when the
                 // last row in the header is removed, in which case we append
                 // both the lines under the row above us and also (later) the
                 // lines under the header's (removed) last row.
-                let prev_lines = prev_y
-                    .filter(|prev_y| {
-                        prev_y + 1 != y
-                            && (!is_under_repeated_header
-                                || self
-                                    .grid
-                                    .header
-                                    .as_ref()
-                                    .and_then(Repeatable::as_repeated)
-                                    .is_some_and(|header| prev_y + 1 != header.end))
-                    })
-                    .map(|prev_y| get_hlines_at(prev_y + 1))
-                    .unwrap_or(&[]);
+                let prev_lines = match prev_y {
+                    Some(prev_y)
+                        if prev_y + 1 != y
+                            && last_repeated_header_end_above.is_none_or(
+                                |last_repeated_header_end| {
+                                    prev_y + 1 != last_repeated_header_end
+                                },
+                            ) =>
+                    {
+                        get_hlines_at(prev_y + 1)
+                    }
+
+                    _ => &[],
+                };
 
                 let expected_hline_position =
                     expected_line_position(y, y == self.grid.rows.len());
@@ -441,15 +642,13 @@ impl<'a> GridLayouter<'a> {
                 };
 
                 let mut expected_header_line_position = LinePosition::Before;
-                let header_hlines = if let Some((Repeatable::Repeated(header), prev_y)) =
-                    self.grid.header.as_ref().zip(prev_y)
-                {
-                    if is_under_repeated_header
-                        && (!self.grid.has_gutter
+                let header_hlines = match (last_repeated_header_end_above, prev_y) {
+                    (Some(header_end_above), Some(prev_y))
+                        if !self.grid.has_gutter
                             || matches!(
                                 self.grid.rows[prev_y],
                                 Sizing::Rel(length) if length.is_zero()
-                            ))
+                            ) =>
                     {
                         // For lines below a header, give priority to the
                         // lines originally below the header rather than
@@ -468,15 +667,13 @@ impl<'a> GridLayouter<'a> {
                         // column-gutter is specified, for example. In that
                         // case, we still repeat the line under the gutter.
                         expected_header_line_position = expected_line_position(
-                            header.end,
-                            header.end == self.grid.rows.len(),
+                            header_end_above,
+                            header_end_above == self.grid.rows.len(),
                         );
-                        get_hlines_at(header.end)
-                    } else {
-                        &[]
+                        get_hlines_at(header_end_above)
                     }
-                } else {
-                    &[]
+
+                    _ => &[],
                 };
 
                 // The effective hlines to be considered at this row index are
@@ -529,6 +726,7 @@ impl<'a> GridLayouter<'a> {
                             grid,
                             rows,
                             local_top_y,
+                            last_repeated_header_end_above,
                             in_last_region,
                             y,
                             x,
@@ -941,15 +1139,9 @@ impl<'a> GridLayouter<'a> {
             let frame = self.layout_single_row(engine, disambiguator, first, y)?;
             self.push_row(frame, y, true);
 
-            if self
-                .grid
-                .header
-                .as_ref()
-                .and_then(Repeatable::as_repeated)
-                .is_some_and(|header| y < header.end)
-            {
-                // Add to header height.
-                self.header_height += first;
+            if let Some(row_height) = &mut self.row_state.current_row_height {
+                // Add to header height, as we are in a header row.
+                *row_height += first;
             }
 
             return Ok(());
@@ -958,19 +1150,21 @@ impl<'a> GridLayouter<'a> {
         // Expand all but the last region.
         // Skip the first region if the space is eaten up by an fr row.
         let len = resolved.len();
-        for ((i, region), target) in self
-            .regions
-            .iter()
-            .enumerate()
-            .zip(&mut resolved[..len - 1])
-            .skip(self.lrows.iter().any(|row| matches!(row, Row::Fr(..))) as usize)
+        for ((i, region), target) in
+            self.regions
+                .iter()
+                .enumerate()
+                .zip(&mut resolved[..len - 1])
+                .skip(self.current.lrows.iter().any(|row| matches!(row, Row::Fr(..)))
+                    as usize)
         {
             // Subtract header and footer heights from the region height when
-            // it's not the first.
+            // it's not the first. Ignore non-repeating headers as they only
+            // appear on the first region by definition.
             target.set_max(
                 region.y
                     - if i > 0 {
-                        self.header_height + self.footer_height
+                        self.current.repeating_header_height + self.current.footer_height
                     } else {
                         Abs::zero()
                     },
@@ -1181,25 +1375,19 @@ impl<'a> GridLayouter<'a> {
         let resolved = v.resolve(self.styles).relative_to(self.regions.base().y);
         let frame = self.layout_single_row(engine, disambiguator, resolved, y)?;
 
-        if self
-            .grid
-            .header
-            .as_ref()
-            .and_then(Repeatable::as_repeated)
-            .is_some_and(|header| y < header.end)
-        {
-            // Add to header height.
-            self.header_height += resolved;
+        if let Some(row_height) = &mut self.row_state.current_row_height {
+            // Add to header height, as we are in a header row.
+            *row_height += resolved;
         }
 
         // Skip to fitting region, but only if we aren't part of an unbreakable
-        // row group. We use 'in_last_with_offset' so our 'in_last' call
-        // properly considers that a header and a footer would be added on each
-        // region break.
+        // row group. We use 'may_progress_with_repeats' to stop trying if we
+        // would skip to a region with the same height and where the same
+        // headers would be repeated.
         let height = frame.height();
         while self.unbreakable_rows_left == 0
             && !self.regions.size.y.fits(height)
-            && !in_last_with_offset(self.regions, self.header_height + self.footer_height)
+            && self.may_progress_with_repeats()
         {
             self.finish_region(engine, false)?;
 
@@ -1323,8 +1511,13 @@ impl<'a> GridLayouter<'a> {
     /// will be pushed for this particular row. It can be `false` for rows
     /// spanning multiple regions.
     fn push_row(&mut self, frame: Frame, y: usize, is_last: bool) {
+        if !self.row_state.in_active_repeatable {
+            // There is now a row after the rows equipped with orphan
+            // prevention, so no need to keep moving them anymore.
+            self.flush_orphans();
+        }
         self.regions.size.y -= frame.height();
-        self.lrows.push(Row::Frame(frame, y, is_last));
+        self.current.lrows.push(Row::Frame(frame, y, is_last));
     }
 
     /// Finish rows for one region.
@@ -1333,68 +1526,73 @@ impl<'a> GridLayouter<'a> {
         engine: &mut Engine,
         last: bool,
     ) -> SourceResult<()> {
+        // The latest rows have orphan prevention (headers) and no other rows
+        // were placed, so remove those rows and try again in a new region,
+        // unless this is the last region.
+        if let Some(orphan_snapshot) = self.current.lrows_orphan_snapshot.take() {
+            if !last {
+                self.current.lrows.truncate(orphan_snapshot);
+                self.current.repeated_header_rows =
+                    self.current.repeated_header_rows.min(orphan_snapshot);
+
+                if orphan_snapshot == 0 {
+                    // Removed all repeated headers.
+                    self.current.last_repeated_header_end = 0;
+                }
+            }
+        }
+
         if self
+            .current
             .lrows
             .last()
             .is_some_and(|row| self.grid.is_gutter_track(row.index()))
         {
             // Remove the last row in the region if it is a gutter row.
-            self.lrows.pop().unwrap();
+            self.current.lrows.pop().unwrap();
+            self.current.repeated_header_rows =
+                self.current.repeated_header_rows.min(self.current.lrows.len());
         }
 
-        // If no rows other than the footer have been laid out so far, and
-        // there are rows beside the footer, then don't lay it out at all.
-        // This check doesn't apply, and is thus overridden, when there is a
-        // header.
-        let mut footer_would_be_orphan = self.lrows.is_empty()
-            && !in_last_with_offset(
-                self.regions,
-                self.header_height + self.footer_height,
-            )
-            && self
-                .grid
-                .footer
-                .as_ref()
-                .and_then(Repeatable::as_repeated)
-                .is_some_and(|footer| footer.start != 0);
-
-        if let Some(Repeatable::Repeated(header)) = &self.grid.header {
-            if self.grid.rows.len() > header.end
-                && self
-                    .grid
-                    .footer
-                    .as_ref()
-                    .and_then(Repeatable::as_repeated)
-                    .is_none_or(|footer| footer.start != header.end)
-                && self.lrows.last().is_some_and(|row| row.index() < header.end)
-                && !in_last_with_offset(
-                    self.regions,
-                    self.header_height + self.footer_height,
-                )
-            {
-                // Header and footer would be alone in this region, but there are more
-                // rows beyond the header and the footer. Push an empty region.
-                self.lrows.clear();
-                footer_would_be_orphan = true;
-            }
-        }
+        // If no rows other than the footer have been laid out so far
+        // (e.g. due to header orphan prevention), and there are rows
+        // beside the footer, then don't lay it out at all.
+        //
+        // It is worth noting that the footer is made non-repeatable at
+        // the grid resolving stage if it is short-lived, that is, if
+        // it is at the start of the table (or right after headers at
+        // the start of the table).
+        //
+        // TODO(subfooters): explicitly check for short-lived footers.
+        // TODO(subfooters): widow prevention for non-repeated footers with a
+        // similar mechanism / when implementing multiple footers.
+        let footer_would_be_widow = matches!(&self.grid.footer, Some(footer) if footer.repeated)
+            && self.current.lrows.is_empty()
+            && self.current.could_progress_at_top;
 
         let mut laid_out_footer_start = None;
-        if let Some(Repeatable::Repeated(footer)) = &self.grid.footer {
-            // Don't layout the footer if it would be alone with the header in
-            // the page, and don't layout it twice.
-            if !footer_would_be_orphan
-                && self.lrows.iter().all(|row| row.index() < footer.start)
-            {
-                laid_out_footer_start = Some(footer.start);
-                self.layout_footer(footer, engine, self.finished.len())?;
+        if !footer_would_be_widow {
+            if let Some(footer) = &self.grid.footer {
+                // Don't layout the footer if it would be alone with the header
+                // in the page (hence the widow check), and don't layout it
+                // twice (check below).
+                //
+                // TODO(subfooters): this check can be replaced by a vector of
+                // repeating footers in the future, and/or some "pending
+                // footers" vector for footers we're about to place.
+                if footer.repeated
+                    && self.current.lrows.iter().all(|row| row.index() < footer.start)
+                {
+                    laid_out_footer_start = Some(footer.start);
+                    self.layout_footer(footer, engine, self.finished.len())?;
+                }
             }
         }
 
         // Determine the height of existing rows in the region.
         let mut used = Abs::zero();
         let mut fr = Fr::zero();
-        for row in &self.lrows {
+        for row in &self.current.lrows {
             match row {
                 Row::Frame(frame, _, _) => used += frame.height(),
                 Row::Fr(v, _, _) => fr += *v,
@@ -1403,9 +1601,9 @@ impl<'a> GridLayouter<'a> {
 
         // Determine the size of the grid in this region, expanding fully if
         // there are fr rows.
-        let mut size = Size::new(self.width, used).min(self.initial);
-        if fr.get() > 0.0 && self.initial.y.is_finite() {
-            size.y = self.initial.y;
+        let mut size = Size::new(self.width, used).min(self.current.initial);
+        if fr.get() > 0.0 && self.current.initial.y.is_finite() {
+            size.y = self.current.initial.y;
         }
 
         // The frame for the region.
@@ -1413,9 +1611,10 @@ impl<'a> GridLayouter<'a> {
         let mut pos = Point::zero();
         let mut rrows = vec![];
         let current_region = self.finished.len();
+        let mut repeated_header_row_height = Abs::zero();
 
         // Place finished rows and layout fractional rows.
-        for row in std::mem::take(&mut self.lrows) {
+        for (i, row) in std::mem::take(&mut self.current.lrows).into_iter().enumerate() {
             let (frame, y, is_last) = match row {
                 Row::Frame(frame, y, is_last) => (frame, y, is_last),
                 Row::Fr(v, y, disambiguator) => {
@@ -1426,6 +1625,9 @@ impl<'a> GridLayouter<'a> {
             };
 
             let height = frame.height();
+            if i < self.current.repeated_header_rows {
+                repeated_header_row_height += height;
+            }
 
             // Ensure rowspans which span this row will have enough space to
             // be laid out over it later.
@@ -1504,7 +1706,11 @@ impl<'a> GridLayouter<'a> {
                     // we have to check the same index again in the next
                     // iteration.
                     let rowspan = self.rowspans.remove(i);
-                    self.layout_rowspan(rowspan, Some((&mut output, &rrows)), engine)?;
+                    self.layout_rowspan(
+                        rowspan,
+                        Some((&mut output, repeated_header_row_height)),
+                        engine,
+                    )?;
                 } else {
                     i += 1;
                 }
@@ -1515,21 +1721,40 @@ impl<'a> GridLayouter<'a> {
             pos.y += height;
         }
 
-        self.finish_region_internal(output, rrows);
+        self.finish_region_internal(
+            output,
+            rrows,
+            FinishedHeaderRowInfo {
+                repeated_amount: self.current.repeated_header_rows,
+                last_repeated_header_end: self.current.last_repeated_header_end,
+                repeated_height: repeated_header_row_height,
+            },
+        );
 
         if !last {
+            self.current.repeated_header_rows = 0;
+            self.current.last_repeated_header_end = 0;
+            self.current.repeating_header_height = Abs::zero();
+            self.current.repeating_header_heights.clear();
+
             let disambiguator = self.finished.len();
-            if let Some(Repeatable::Repeated(footer)) = &self.grid.footer {
+            if let Some(footer) =
+                self.grid.footer.as_ref().and_then(Repeatable::as_repeated)
+            {
                 self.prepare_footer(footer, engine, disambiguator)?;
             }
 
-            if let Some(Repeatable::Repeated(header)) = &self.grid.header {
-                // Add a header to the new region.
-                self.layout_header(header, engine, disambiguator)?;
-            }
-
             // Ensure rows don't try to overrun the footer.
-            self.regions.size.y -= self.footer_height;
+            // Note that header layout will only subtract this again if it has
+            // to skip regions to fit headers, so there is no risk of
+            // subtracting this twice.
+            self.regions.size.y -= self.current.footer_height;
+            self.current.initial_after_repeats = self.regions.size.y;
+
+            if !self.repeating_headers.is_empty() || !self.pending_headers.is_empty() {
+                // Add headers to the new region.
+                self.layout_active_headers(engine)?;
+            }
         }
 
         Ok(())
@@ -1541,11 +1766,26 @@ impl<'a> GridLayouter<'a> {
         &mut self,
         output: Frame,
         resolved_rows: Vec<RowPiece>,
+        header_row_info: FinishedHeaderRowInfo,
     ) {
         self.finished.push(output);
         self.rrows.push(resolved_rows);
         self.regions.next();
-        self.initial = self.regions.size;
+        self.current.initial = self.regions.size;
+
+        // Repeats haven't been laid out yet, so in the meantime, this will
+        // represent the initial height after repeats laid out so far, and will
+        // be gradually updated when preparing footers and repeating headers.
+        self.current.initial_after_repeats = self.current.initial.y;
+
+        self.current.could_progress_at_top = self.regions.may_progress();
+
+        if !self.grid.headers.is_empty() {
+            self.finished_header_rows.push(header_row_info);
+        }
+
+        // Ensure orphan prevention is handled before resolving rows.
+        debug_assert!(self.current.lrows_orphan_snapshot.is_none());
     }
 }
 
@@ -1560,13 +1800,3 @@ pub(super) fn points(
         offset
     })
 }
-
-/// Checks if the first region of a sequence of regions is the last usable
-/// region, assuming that the last region will always be occupied by some
-/// specific offset height, even after calling `.next()`, due to some
-/// additional logic which adds content automatically on each region turn (in
-/// our case, headers).
-pub(super) fn in_last_with_offset(regions: Regions<'_>, offset: Abs) -> bool {
-    regions.backlog.is_empty()
-        && regions.last.is_none_or(|height| regions.size.y + offset == height)
-}
diff --git a/crates/typst-layout/src/grid/lines.rs b/crates/typst-layout/src/grid/lines.rs
index 7549673f..d5da7e26 100644
--- a/crates/typst-layout/src/grid/lines.rs
+++ b/crates/typst-layout/src/grid/lines.rs
@@ -391,10 +391,12 @@ pub fn vline_stroke_at_row(
 ///
 /// This function assumes columns are sorted by increasing `x`, and rows are
 /// sorted by increasing `y`.
+#[allow(clippy::too_many_arguments)]
 pub fn hline_stroke_at_column(
     grid: &CellGrid,
     rows: &[RowPiece],
     local_top_y: Option<usize>,
+    header_end_above: Option<usize>,
     in_last_region: bool,
     y: usize,
     x: usize,
@@ -499,17 +501,15 @@ pub fn hline_stroke_at_column(
     // Top border stroke and header stroke are generally prioritized, unless
     // they don't have explicit hline overrides and one or more user-provided
     // hlines would appear at the same position, which then are prioritized.
-    let top_stroke_comes_from_header = grid
-        .header
-        .as_ref()
-        .and_then(Repeatable::as_repeated)
-        .zip(local_top_y)
-        .is_some_and(|(header, local_top_y)| {
-            // Ensure the row above us is a repeated header.
-            // FIXME: Make this check more robust when headers at arbitrary
-            // positions are added.
-            local_top_y < header.end && y > header.end
-        });
+    let top_stroke_comes_from_header = header_end_above.zip(local_top_y).is_some_and(
+        |(last_repeated_header_end, local_top_y)| {
+            // Check if the last repeated header row is above this line.
+            //
+            // Note that `y == last_repeated_header_end` is impossible for a
+            // strictly repeated header (not in its original position).
+            local_top_y < last_repeated_header_end && y > last_repeated_header_end
+        },
+    );
 
     // Prioritize the footer's top stroke as well where applicable.
     let bottom_stroke_comes_from_footer = grid
@@ -637,7 +637,7 @@ mod test {
             },
             vec![],
             vec![],
-            None,
+            vec![],
             None,
             entries,
         )
@@ -1175,7 +1175,7 @@ mod test {
             },
             vec![],
             vec![],
-            None,
+            vec![],
             None,
             entries,
         )
@@ -1268,6 +1268,7 @@ mod test {
                         grid,
                         &rows,
                         y.checked_sub(1),
+                        None,
                         true,
                         y,
                         x,
@@ -1461,6 +1462,7 @@ mod test {
                         grid,
                         &rows,
                         y.checked_sub(1),
+                        None,
                         true,
                         y,
                         x,
@@ -1506,6 +1508,7 @@ mod test {
                     grid,
                     &rows,
                     if y == 4 { Some(2) } else { y.checked_sub(1) },
+                    None,
                     true,
                     y,
                     x,
diff --git a/crates/typst-layout/src/grid/repeated.rs b/crates/typst-layout/src/grid/repeated.rs
index 22d2a09e..8db33df5 100644
--- a/crates/typst-layout/src/grid/repeated.rs
+++ b/crates/typst-layout/src/grid/repeated.rs
@@ -1,57 +1,446 @@
+use std::ops::Deref;
+
 use typst_library::diag::SourceResult;
 use typst_library::engine::Engine;
 use typst_library::layout::grid::resolve::{Footer, Header, Repeatable};
 use typst_library::layout::{Abs, Axes, Frame, Regions};
 
-use super::layouter::GridLayouter;
+use super::layouter::{GridLayouter, RowState};
 use super::rowspans::UnbreakableRowGroup;
 
-impl GridLayouter<'_> {
-    /// Layouts the header's rows.
-    /// Skips regions as necessary.
-    pub fn layout_header(
+impl<'a> GridLayouter<'a> {
+    /// Checks whether a region break could help a situation where we're out of
+    /// space for the next row. The criteria are:
+    ///
+    /// 1. If we could progress at the top of the region, that indicates the
+    ///    region has a backlog, or (if we're at the first region) a region break
+    ///    is at all possible (`regions.last` is `Some()`), so that's sufficient.
+    ///
+    /// 2. Otherwise, we may progress if another region break is possible
+    ///    (`regions.last` is still `Some()`) and non-repeating rows have been
+    ///    placed, since that means the space they occupy will be available in the
+    ///    next region.
+    #[inline]
+    pub fn may_progress_with_repeats(&self) -> bool {
+        // TODO(subfooters): check below isn't enough to detect non-repeating
+        // footers... we can also change 'initial_after_repeats' to stop being
+        // calculated if there were any non-repeating footers.
+        self.current.could_progress_at_top
+            || self.regions.last.is_some()
+                && self.regions.size.y != self.current.initial_after_repeats
+    }
+
+    pub fn place_new_headers(
+        &mut self,
+        consecutive_header_count: &mut usize,
+        engine: &mut Engine,
+    ) -> SourceResult<()> {
+        *consecutive_header_count += 1;
+        let (consecutive_headers, new_upcoming_headers) =
+            self.upcoming_headers.split_at(*consecutive_header_count);
+
+        if new_upcoming_headers.first().is_some_and(|next_header| {
+            consecutive_headers.last().is_none_or(|latest_header| {
+                !latest_header.short_lived
+                    && next_header.range.start == latest_header.range.end
+            }) && !next_header.short_lived
+        }) {
+            // More headers coming, so wait until we reach them.
+            return Ok(());
+        }
+
+        self.upcoming_headers = new_upcoming_headers;
+        *consecutive_header_count = 0;
+
+        let [first_header, ..] = consecutive_headers else {
+            self.flush_orphans();
+            return Ok(());
+        };
+
+        // Assuming non-conflicting headers sorted by increasing y, this must
+        // be the header with the lowest level (sorted by increasing levels).
+        let first_level = first_header.level;
+
+        // Stop repeating conflicting headers, even if the new headers are
+        // short-lived or won't repeat.
+        //
+        // If we go to a new region before the new headers fit alongside their
+        // children (or in general, for short-lived), the old headers should
+        // not be displayed anymore.
+        let first_conflicting_pos =
+            self.repeating_headers.partition_point(|h| h.level < first_level);
+        self.repeating_headers.truncate(first_conflicting_pos);
+
+        // Ensure upcoming rows won't see that these headers will occupy any
+        // space in future regions anymore.
+        for removed_height in
+            self.current.repeating_header_heights.drain(first_conflicting_pos..)
+        {
+            self.current.repeating_header_height -= removed_height;
+        }
+
+        // Layout short-lived headers immediately.
+        if consecutive_headers.last().is_some_and(|h| h.short_lived) {
+            // No chance of orphans as we're immediately placing conflicting
+            // headers afterwards, which basically are not headers, for all intents
+            // and purposes. It is therefore guaranteed that all new headers have
+            // been placed at least once.
+            self.flush_orphans();
+
+            // Layout each conflicting header independently, without orphan
+            // prevention (as they don't go into 'pending_headers').
+            // These headers are short-lived as they are immediately followed by a
+            // header of the same or lower level, such that they never actually get
+            // to repeat.
+            self.layout_new_headers(consecutive_headers, true, engine)?;
+        } else {
+            // Let's try to place pending headers at least once.
+            // This might be a waste as we could generate an orphan and thus have
+            // to try to place old and new headers all over again, but that happens
+            // for every new region anyway, so it's rather unavoidable.
+            let snapshot_created =
+                self.layout_new_headers(consecutive_headers, false, engine)?;
+
+            // Queue the new headers for layout. They will remain in this
+            // vector due to orphan prevention.
+            //
+            // After the first subsequent row is laid out, move to repeating, as
+            // it's then confirmed the headers won't be moved due to orphan
+            // prevention anymore.
+            self.pending_headers = consecutive_headers;
+
+            if !snapshot_created {
+                // Region probably couldn't progress.
+                //
+                // Mark new pending headers as final and ensure there isn't a
+                // snapshot.
+                self.flush_orphans();
+            }
+        }
+
+        Ok(())
+    }
+
+    /// Lays out rows belonging to a header, returning the calculated header
+    /// height only for that header. Indicates to the laid out rows that they
+    /// should inform their laid out heights if appropriate (auto or fixed
+    /// size rows only).
+    #[inline]
+    fn layout_header_rows(
         &mut self,
         header: &Header,
         engine: &mut Engine,
         disambiguator: usize,
-    ) -> SourceResult<()> {
-        let header_rows =
-            self.simulate_header(header, &self.regions, engine, disambiguator)?;
+        as_short_lived: bool,
+    ) -> SourceResult<Abs> {
+        let mut header_height = Abs::zero();
+        for y in header.range.clone() {
+            header_height += self
+                .layout_row_with_state(
+                    y,
+                    engine,
+                    disambiguator,
+                    RowState {
+                        current_row_height: Some(Abs::zero()),
+                        in_active_repeatable: !as_short_lived,
+                    },
+                )?
+                .current_row_height
+                .unwrap_or_default();
+        }
+        Ok(header_height)
+    }
+
+    /// This function should be called each time an additional row has been
+    /// laid out in a region to indicate that orphan prevention has succeeded.
+    ///
+    /// It removes the current orphan snapshot and flushes pending headers,
+    /// such that a non-repeating header won't try to be laid out again
+    /// anymore, and a repeating header will begin to be part of
+    /// `repeating_headers`.
+    pub fn flush_orphans(&mut self) {
+        self.current.lrows_orphan_snapshot = None;
+        self.flush_pending_headers();
+    }
+
+    /// Indicates all currently pending headers have been successfully placed
+    /// once, since another row has been placed after them, so they are
+    /// certainly not orphans.
+    pub fn flush_pending_headers(&mut self) {
+        if self.pending_headers.is_empty() {
+            return;
+        }
+
+        for header in self.pending_headers {
+            if header.repeated {
+                // Vector remains sorted by increasing levels:
+                // - 'pending_headers' themselves are sorted, since we only
+                // push non-mutually-conflicting headers at a time.
+                // - Before pushing new pending headers in
+                // 'layout_new_pending_headers', we truncate repeating headers
+                // to remove anything with the same or higher levels as the
+                // first pending header.
+                // - Assuming it was sorted before, that truncation only keeps
+                // elements with a lower level.
+                // - Therefore, by pushing this header to the end, it will have
+                // a level larger than all the previous headers, and is thus
+                // in its 'correct' position.
+                self.repeating_headers.push(header);
+            }
+        }
+
+        self.pending_headers = Default::default();
+    }
+
+    /// Lays out the rows of repeating and pending headers at the top of the
+    /// region.
+    ///
+    /// Assumes the footer height for the current region has already been
+    /// calculated. Skips regions as necessary to fit all headers and all
+    /// footers.
+    pub fn layout_active_headers(&mut self, engine: &mut Engine) -> SourceResult<()> {
+        // Generate different locations for content in headers across its
+        // repetitions by assigning a unique number for each one.
+        let disambiguator = self.finished.len();
+
+        let header_height = self.simulate_header_height(
+            self.repeating_headers
+                .iter()
+                .copied()
+                .chain(self.pending_headers.iter().map(Repeatable::deref)),
+            &self.regions,
+            engine,
+            disambiguator,
+        )?;
+
+        // We already take the footer into account below.
+        // While skipping regions, footer height won't be automatically
+        // re-calculated until the end.
         let mut skipped_region = false;
         while self.unbreakable_rows_left == 0
-            && !self.regions.size.y.fits(header_rows.height + self.footer_height)
-            && self.regions.may_progress()
+            && !self.regions.size.y.fits(header_height)
+            && self.may_progress_with_repeats()
         {
             // Advance regions without any output until we can place the
             // header and the footer.
-            self.finish_region_internal(Frame::soft(Axes::splat(Abs::zero())), vec![]);
+            self.finish_region_internal(
+                Frame::soft(Axes::splat(Abs::zero())),
+                vec![],
+                Default::default(),
+            );
+
+            // TODO(layout model): re-calculate heights of headers and footers
+            // on each region if 'full' changes? (Assuming height doesn't
+            // change for now...)
+            //
+            // Would remove the footer height update below (move it here).
             skipped_region = true;
-        }
 
-        // Reset the header height for this region.
-        // It will be re-calculated when laying out each header row.
-        self.header_height = Abs::zero();
+            self.regions.size.y -= self.current.footer_height;
+            self.current.initial_after_repeats = self.regions.size.y;
+        }
 
-        if let Some(Repeatable::Repeated(footer)) = &self.grid.footer {
-            if skipped_region {
+        if let Some(footer) = &self.grid.footer {
+            if footer.repeated && skipped_region {
                 // Simulate the footer again; the region's 'full' might have
                 // changed.
-                self.footer_height = self
+                self.regions.size.y += self.current.footer_height;
+                self.current.footer_height = self
                     .simulate_footer(footer, &self.regions, engine, disambiguator)?
                     .height;
+                self.regions.size.y -= self.current.footer_height;
             }
         }
 
-        // Header is unbreakable.
+        let repeating_header_rows =
+            total_header_row_count(self.repeating_headers.iter().copied());
+
+        let pending_header_rows =
+            total_header_row_count(self.pending_headers.iter().map(Repeatable::deref));
+
+        // Group of headers is unbreakable.
         // Thus, no risk of 'finish_region' being recursively called from
         // within 'layout_row'.
-        self.unbreakable_rows_left += header.end;
-        for y in 0..header.end {
-            self.layout_row(y, engine, disambiguator)?;
+        self.unbreakable_rows_left += repeating_header_rows + pending_header_rows;
+
+        self.current.last_repeated_header_end =
+            self.repeating_headers.last().map(|h| h.range.end).unwrap_or_default();
+
+        // Reset the header height for this region.
+        // It will be re-calculated when laying out each header row.
+        self.current.repeating_header_height = Abs::zero();
+        self.current.repeating_header_heights.clear();
+
+        debug_assert!(self.current.lrows.is_empty());
+        debug_assert!(self.current.lrows_orphan_snapshot.is_none());
+        let may_progress = self.may_progress_with_repeats();
+
+        if may_progress {
+            // Enable orphan prevention for headers at the top of the region.
+            // Otherwise, we will flush pending headers below, after laying
+            // them out.
+            //
+            // It is very rare for this to make a difference as we're usually
+            // at the 'last' region after the first skip, at which the snapshot
+            // is handled by 'layout_new_headers'. Either way, we keep this
+            // here for correctness.
+            self.current.lrows_orphan_snapshot = Some(self.current.lrows.len());
+        }
+
+        // Use indices to avoid double borrow. We don't mutate headers in
+        // 'layout_row' so this is fine.
+        let mut i = 0;
+        while let Some(&header) = self.repeating_headers.get(i) {
+            let header_height =
+                self.layout_header_rows(header, engine, disambiguator, false)?;
+            self.current.repeating_header_height += header_height;
+
+            // We assume that this vector will be sorted according
+            // to increasing levels like 'repeating_headers' and
+            // 'pending_headers' - and, in particular, their union, as this
+            // vector is pushed repeating heights from both.
+            //
+            // This is guaranteed by:
+            // 1. We always push pending headers after repeating headers,
+            // as we assume they don't conflict because we remove
+            // conflicting repeating headers when pushing a new pending
+            // header.
+            //
+            // 2. We push in the same order as each.
+            //
+            // 3. This vector is also modified when pushing a new pending
+            // header, where we remove heights for conflicting repeating
+            // headers which have now stopped repeating. They are always at
+            // the end and new pending headers respect the existing sort,
+            // so the vector will remain sorted.
+            self.current.repeating_header_heights.push(header_height);
+
+            i += 1;
+        }
+
+        self.current.repeated_header_rows = self.current.lrows.len();
+        self.current.initial_after_repeats = self.regions.size.y;
+
+        let mut has_non_repeated_pending_header = false;
+        for header in self.pending_headers {
+            if !header.repeated {
+                self.current.initial_after_repeats = self.regions.size.y;
+                has_non_repeated_pending_header = true;
+            }
+            let header_height =
+                self.layout_header_rows(header, engine, disambiguator, false)?;
+            if header.repeated {
+                self.current.repeating_header_height += header_height;
+                self.current.repeating_header_heights.push(header_height);
+            }
+        }
+
+        if !has_non_repeated_pending_header {
+            self.current.initial_after_repeats = self.regions.size.y;
         }
+
+        if !may_progress {
+            // Flush pending headers immediately, as placing them again later
+            // won't help.
+            self.flush_orphans();
+        }
+
         Ok(())
     }
 
+    /// Lays out headers found for the first time during row layout.
+    ///
+    /// If 'short_lived' is true, these headers are immediately followed by
+    /// a conflicting header, so it is assumed they will not be pushed to
+    /// pending headers.
+    ///
+    /// Returns whether orphan prevention was successfully setup, or couldn't
+    /// due to short-lived headers or the region couldn't progress.
+    pub fn layout_new_headers(
+        &mut self,
+        headers: &'a [Repeatable<Header>],
+        short_lived: bool,
+        engine: &mut Engine,
+    ) -> SourceResult<bool> {
+        // At first, only consider the height of the given headers. However,
+        // for upcoming regions, we will have to consider repeating headers as
+        // well.
+        let header_height = self.simulate_header_height(
+            headers.iter().map(Repeatable::deref),
+            &self.regions,
+            engine,
+            0,
+        )?;
+
+        while self.unbreakable_rows_left == 0
+            && !self.regions.size.y.fits(header_height)
+            && self.may_progress_with_repeats()
+        {
+            // Note that, after the first region skip, the new headers will go
+            // at the top of the region, but after the repeating headers that
+            // remained (which will be automatically placed in 'finish_region').
+            self.finish_region(engine, false)?;
+        }
+
+        // Remove new headers at the end of the region if the upcoming row
+        // doesn't fit.
+        // TODO(subfooters): what if there is a footer right after it?
+        let should_snapshot = !short_lived
+            && self.current.lrows_orphan_snapshot.is_none()
+            && self.may_progress_with_repeats();
+
+        if should_snapshot {
+            // If we don't enter this branch while laying out non-short lived
+            // headers, that means we will have to immediately flush pending
+            // headers and mark them as final, since trying to place them in
+            // the next page won't help get more space.
+            self.current.lrows_orphan_snapshot = Some(self.current.lrows.len());
+        }
+
+        let mut at_top = self.regions.size.y == self.current.initial_after_repeats;
+
+        self.unbreakable_rows_left +=
+            total_header_row_count(headers.iter().map(Repeatable::deref));
+
+        for header in headers {
+            let header_height = self.layout_header_rows(header, engine, 0, false)?;
+
+            // Only store this header height if it is actually going to
+            // become a pending header. Otherwise, pretend it's not a
+            // header... This is fine for consumers of 'header_height' as
+            // it is guaranteed this header won't appear in a future
+            // region, so multi-page rows and cells can effectively ignore
+            // this header.
+            if !short_lived && header.repeated {
+                self.current.repeating_header_height += header_height;
+                self.current.repeating_header_heights.push(header_height);
+                if at_top {
+                    self.current.initial_after_repeats = self.regions.size.y;
+                }
+            } else {
+                at_top = false;
+            }
+        }
+
+        Ok(should_snapshot)
+    }
+
+    /// Calculates the total expected height of several headers.
+    pub fn simulate_header_height<'h: 'a>(
+        &self,
+        headers: impl IntoIterator<Item = &'h Header>,
+        regions: &Regions<'_>,
+        engine: &mut Engine,
+        disambiguator: usize,
+    ) -> SourceResult<Abs> {
+        let mut height = Abs::zero();
+        for header in headers {
+            height +=
+                self.simulate_header(header, regions, engine, disambiguator)?.height;
+        }
+        Ok(height)
+    }
+
     /// Simulate the header's group of rows.
     pub fn simulate_header(
         &self,
@@ -66,8 +455,8 @@ impl GridLayouter<'_> {
         // assume that the amount of unbreakable rows following the first row
         // in the header will be precisely the rows in the header.
         self.simulate_unbreakable_row_group(
-            0,
-            Some(header.end),
+            header.range.start,
+            Some(header.range.end - header.range.start),
             regions,
             engine,
             disambiguator,
@@ -91,11 +480,22 @@ impl GridLayouter<'_> {
         {
             // Advance regions without any output until we can place the
             // footer.
-            self.finish_region_internal(Frame::soft(Axes::splat(Abs::zero())), vec![]);
+            self.finish_region_internal(
+                Frame::soft(Axes::splat(Abs::zero())),
+                vec![],
+                Default::default(),
+            );
             skipped_region = true;
         }
 
-        self.footer_height = if skipped_region {
+        // TODO(subfooters): Consider resetting header height etc. if we skip
+        // region. (Maybe move that step to `finish_region_internal`.)
+        //
+        // That is unnecessary at the moment as 'prepare_footers' is only
+        // called at the start of the region, so header height is always zero
+        // and no headers were placed so far, but what about when we can have
+        // footers in the middle of the region? Let's think about this then.
+        self.current.footer_height = if skipped_region {
             // Simulate the footer again; the region's 'full' might have
             // changed.
             self.simulate_footer(footer, &self.regions, engine, disambiguator)?
@@ -118,12 +518,22 @@ impl GridLayouter<'_> {
         // Ensure footer rows have their own height available.
         // Won't change much as we're creating an unbreakable row group
         // anyway, so this is mostly for correctness.
-        self.regions.size.y += self.footer_height;
+        self.regions.size.y += self.current.footer_height;
 
+        let repeats = self.grid.footer.as_ref().is_some_and(|f| f.repeated);
         let footer_len = self.grid.rows.len() - footer.start;
         self.unbreakable_rows_left += footer_len;
+
         for y in footer.start..self.grid.rows.len() {
-            self.layout_row(y, engine, disambiguator)?;
+            self.layout_row_with_state(
+                y,
+                engine,
+                disambiguator,
+                RowState {
+                    in_active_repeatable: repeats,
+                    ..Default::default()
+                },
+            )?;
         }
 
         Ok(())
@@ -144,10 +554,18 @@ impl GridLayouter<'_> {
         // in the footer will be precisely the rows in the footer.
         self.simulate_unbreakable_row_group(
             footer.start,
-            Some(self.grid.rows.len() - footer.start),
+            Some(footer.end - footer.start),
             regions,
             engine,
             disambiguator,
         )
     }
 }
+
+/// The total amount of rows in the given list of headers.
+#[inline]
+pub fn total_header_row_count<'h>(
+    headers: impl IntoIterator<Item = &'h Header>,
+) -> usize {
+    headers.into_iter().map(|h| h.range.end - h.range.start).sum()
+}
diff --git a/crates/typst-layout/src/grid/rowspans.rs b/crates/typst-layout/src/grid/rowspans.rs
index 5ab0417d..02ea1481 100644
--- a/crates/typst-layout/src/grid/rowspans.rs
+++ b/crates/typst-layout/src/grid/rowspans.rs
@@ -4,7 +4,7 @@ use typst_library::foundations::Resolve;
 use typst_library::layout::grid::resolve::Repeatable;
 use typst_library::layout::{Abs, Axes, Frame, Point, Region, Regions, Size, Sizing};
 
-use super::layouter::{in_last_with_offset, points, Row, RowPiece};
+use super::layouter::{points, Row};
 use super::{layout_cell, Cell, GridLayouter};
 
 /// All information needed to layout a single rowspan.
@@ -90,10 +90,10 @@ pub struct CellMeasurementData<'layouter> {
 
 impl GridLayouter<'_> {
     /// Layout a rowspan over the already finished regions, plus the current
-    /// region's frame and resolved rows, if it wasn't finished yet (because
-    /// we're being called from `finish_region`, but note that this function is
-    /// also called once after all regions are finished, in which case
-    /// `current_region_data` is `None`).
+    /// region's frame and height of resolved header rows, if it wasn't
+    /// finished yet (because we're being called from `finish_region`, but note
+    /// that this function is also called once after all regions are finished,
+    /// in which case `current_region_data` is `None`).
     ///
     /// We need to do this only once we already know the heights of all
     /// spanned rows, which is only possible after laying out the last row
@@ -101,7 +101,7 @@ impl GridLayouter<'_> {
     pub fn layout_rowspan(
         &mut self,
         rowspan_data: Rowspan,
-        current_region_data: Option<(&mut Frame, &[RowPiece])>,
+        current_region_data: Option<(&mut Frame, Abs)>,
         engine: &mut Engine,
     ) -> SourceResult<()> {
         let Rowspan {
@@ -146,11 +146,31 @@ impl GridLayouter<'_> {
 
         // Push the layouted frames directly into the finished frames.
         let fragment = layout_cell(cell, engine, disambiguator, self.styles, pod)?;
-        let (current_region, current_rrows) = current_region_data.unzip();
-        for ((i, finished), frame) in self
+        let (current_region, current_header_row_height) = current_region_data.unzip();
+
+        // Clever trick to process finished header rows:
+        // - If there are grid headers, the vector will be filled with one
+        // finished header row height per region, so, chaining with the height
+        // for the current one, we get the header row height for each region.
+        //
+        // - But if there are no grid headers, the vector will be empty, so in
+        // theory the regions and resolved header row heights wouldn't match.
+        // But that's fine - 'current_header_row_height' can only be either
+        // 'Some(zero)' or 'None' in such a case, and for all other rows we
+        // append infinite zeros. That is, in such a case, the resolved header
+        // row height is always zero, so that's our fallback.
+        let finished_header_rows = self
+            .finished_header_rows
+            .iter()
+            .map(|info| info.repeated_height)
+            .chain(current_header_row_height)
+            .chain(std::iter::repeat(Abs::zero()));
+
+        for ((i, (finished, header_dy)), frame) in self
             .finished
             .iter_mut()
             .chain(current_region.into_iter())
+            .zip(finished_header_rows)
             .skip(first_region)
             .enumerate()
             .zip(fragment)
@@ -162,22 +182,9 @@ impl GridLayouter<'_> {
             } else {
                 // The rowspan continuation starts after the header (thus,
                 // at a position after the sum of the laid out header
-                // rows).
-                if let Some(Repeatable::Repeated(header)) = &self.grid.header {
-                    let header_rows = self
-                        .rrows
-                        .get(i)
-                        .map(Vec::as_slice)
-                        .or(current_rrows)
-                        .unwrap_or(&[])
-                        .iter()
-                        .take_while(|row| row.y < header.end);
-
-                    header_rows.map(|row| row.height).sum()
-                } else {
-                    // Without a header, start at the very top of the region.
-                    Abs::zero()
-                }
+                // rows). Without a header, this is zero, so the rowspan can
+                // start at the very top of the region as usual.
+                header_dy
             };
 
             finished.push_frame(Point::new(dx, dy), frame);
@@ -231,15 +238,13 @@ impl GridLayouter<'_> {
             // current row is dynamic and depends on the amount of upcoming
             // unbreakable cells (with or without a rowspan setting).
             let mut amount_unbreakable_rows = None;
-            if let Some(Repeatable::NotRepeated(header)) = &self.grid.header {
-                if current_row < header.end {
-                    // Non-repeated header, so keep it unbreakable.
-                    amount_unbreakable_rows = Some(header.end);
-                }
-            }
-            if let Some(Repeatable::NotRepeated(footer)) = &self.grid.footer {
-                if current_row >= footer.start {
+            if let Some(footer) = &self.grid.footer {
+                if !footer.repeated && current_row >= footer.start {
                     // Non-repeated footer, so keep it unbreakable.
+                    //
+                    // TODO(subfooters): This will become unnecessary
+                    // once non-repeated footers are treated differently and
+                    // have widow prevention.
                     amount_unbreakable_rows = Some(self.grid.rows.len() - footer.start);
                 }
             }
@@ -254,10 +259,7 @@ impl GridLayouter<'_> {
 
             // Skip to fitting region.
             while !self.regions.size.y.fits(row_group.height)
-                && !in_last_with_offset(
-                    self.regions,
-                    self.header_height + self.footer_height,
-                )
+                && self.may_progress_with_repeats()
             {
                 self.finish_region(engine, false)?;
             }
@@ -396,16 +398,29 @@ impl GridLayouter<'_> {
             // auto rows don't depend on the backlog, as they only span one
             // region.
             if breakable
-                && (matches!(self.grid.header, Some(Repeatable::Repeated(_)))
-                    || matches!(self.grid.footer, Some(Repeatable::Repeated(_))))
+                && (!self.repeating_headers.is_empty()
+                    || !self.pending_headers.is_empty()
+                    || matches!(&self.grid.footer, Some(footer) if footer.repeated))
             {
                 // Subtract header and footer height from all upcoming regions
                 // when measuring the cell, including the last repeated region.
                 //
                 // This will update the 'custom_backlog' vector with the
                 // updated heights of the upcoming regions.
+                //
+                // We predict that header height will only include that of
+                // repeating headers, as we can assume non-repeating headers in
+                // the first region have been successfully placed, unless
+                // something didn't fit on the first region of the auto row,
+                // but we will only find that out after measurement, and if
+                // that happens, we discard the measurement and try again.
                 let mapped_regions = self.regions.map(&mut custom_backlog, |size| {
-                    Size::new(size.x, size.y - self.header_height - self.footer_height)
+                    Size::new(
+                        size.x,
+                        size.y
+                            - self.current.repeating_header_height
+                            - self.current.footer_height,
+                    )
                 });
 
                 // Callees must use the custom backlog instead of the current
@@ -459,6 +474,7 @@ impl GridLayouter<'_> {
             // Height of the rowspan covered by spanned rows in the current
             // region.
             let laid_out_height: Abs = self
+                .current
                 .lrows
                 .iter()
                 .filter_map(|row| match row {
@@ -506,7 +522,12 @@ impl GridLayouter<'_> {
                     .iter()
                     .copied()
                     .chain(std::iter::once(if breakable {
-                        self.initial.y - self.header_height - self.footer_height
+                        // Here we are calculating the available height for a
+                        // rowspan from the top of the current region, so
+                        // we have to use initial header heights (note that
+                        // header height can change in the middle of the
+                        // region).
+                        self.current.initial_after_repeats
                     } else {
                         // When measuring unbreakable auto rows, infinite
                         // height is available for content to expand.
@@ -518,11 +539,13 @@ impl GridLayouter<'_> {
                     // rowspan's already laid out heights with the current
                     // region's height and current backlog to ensure a good
                     // level of accuracy in the measurements.
-                    let backlog = self
-                        .regions
-                        .backlog
-                        .iter()
-                        .map(|&size| size - self.header_height - self.footer_height);
+                    //
+                    // Assume only repeating headers will survive starting at
+                    // the next region.
+                    let backlog = self.regions.backlog.iter().map(|&size| {
+                        size - self.current.repeating_header_height
+                            - self.current.footer_height
+                    });
 
                     heights_up_to_current_region.chain(backlog).collect::<Vec<_>>()
                 } else {
@@ -536,10 +559,10 @@ impl GridLayouter<'_> {
                 height = *rowspan_height;
                 backlog = None;
                 full = rowspan_full;
-                last = self
-                    .regions
-                    .last
-                    .map(|size| size - self.header_height - self.footer_height);
+                last = self.regions.last.map(|size| {
+                    size - self.current.repeating_header_height
+                        - self.current.footer_height
+                });
             } else {
                 // The rowspan started in the current region, as its vector
                 // of heights in regions is currently empty.
@@ -741,10 +764,11 @@ impl GridLayouter<'_> {
             simulated_regions.next();
             disambiguator += 1;
 
-            // Subtract the initial header and footer height, since that's the
-            // height we used when subtracting from the region backlog's
+            // Subtract the repeating header and footer height, since that's
+            // the height we used when subtracting from the region backlog's
             // heights while measuring cells.
-            simulated_regions.size.y -= self.header_height + self.footer_height;
+            simulated_regions.size.y -=
+                self.current.repeating_header_height + self.current.footer_height;
         }
 
         if let Some(original_last_resolved_size) = last_resolved_size {
@@ -876,12 +900,8 @@ impl GridLayouter<'_> {
         // which, when used and combined with upcoming spanned rows, covers all
         // of the requested rowspan height, we give up.
         for _attempt in 0..5 {
-            let rowspan_simulator = RowspanSimulator::new(
-                disambiguator,
-                simulated_regions,
-                self.header_height,
-                self.footer_height,
-            );
+            let rowspan_simulator =
+                RowspanSimulator::new(disambiguator, simulated_regions, &self.current);
 
             let total_spanned_height = rowspan_simulator.simulate_rowspan_layout(
                 y,
@@ -963,7 +983,8 @@ impl GridLayouter<'_> {
             {
                 extra_amount_to_grow -= simulated_regions.size.y.max(Abs::zero());
                 simulated_regions.next();
-                simulated_regions.size.y -= self.header_height + self.footer_height;
+                simulated_regions.size.y -=
+                    self.current.repeating_header_height + self.current.footer_height;
                 disambiguator += 1;
             }
             simulated_regions.size.y -= extra_amount_to_grow;
@@ -980,10 +1001,17 @@ struct RowspanSimulator<'a> {
     finished: usize,
     /// The state of regions during the simulation.
     regions: Regions<'a>,
-    /// The height of the header in the currently simulated region.
+    /// The total height of headers in the currently simulated region.
     header_height: Abs,
-    /// The height of the footer in the currently simulated region.
+    /// The total height of footers in the currently simulated region.
     footer_height: Abs,
+    /// Whether `self.regions.may_progress()` was `true` at the top of the
+    /// region, indicating we can progress anywhere in the current region,
+    /// even right after a repeated header.
+    could_progress_at_top: bool,
+    /// Available height after laying out repeated headers at the top of the
+    /// currently simulated region.
+    initial_after_repeats: Abs,
     /// The total spanned height so far in the simulation.
     total_spanned_height: Abs,
     /// Height of the latest spanned gutter row in the simulation.
@@ -997,14 +1025,19 @@ impl<'a> RowspanSimulator<'a> {
     fn new(
         finished: usize,
         regions: Regions<'a>,
-        header_height: Abs,
-        footer_height: Abs,
+        current: &super::layouter::Current,
     ) -> Self {
         Self {
             finished,
             regions,
-            header_height,
-            footer_height,
+            // There can be no new headers or footers within a multi-page
+            // rowspan, since headers and footers are unbreakable, so
+            // assuming the repeating header height and footer height
+            // won't change is safe.
+            header_height: current.repeating_header_height,
+            footer_height: current.footer_height,
+            could_progress_at_top: current.could_progress_at_top,
+            initial_after_repeats: current.initial_after_repeats,
             total_spanned_height: Abs::zero(),
             latest_spanned_gutter_height: Abs::zero(),
         }
@@ -1053,10 +1086,7 @@ impl<'a> RowspanSimulator<'a> {
                     0,
                 )?;
                 while !self.regions.size.y.fits(row_group.height)
-                    && !in_last_with_offset(
-                        self.regions,
-                        self.header_height + self.footer_height,
-                    )
+                    && self.may_progress_with_repeats()
                 {
                     self.finish_region(layouter, engine)?;
                 }
@@ -1078,10 +1108,7 @@ impl<'a> RowspanSimulator<'a> {
                     let mut skipped_region = false;
                     while unbreakable_rows_left == 0
                         && !self.regions.size.y.fits(height)
-                        && !in_last_with_offset(
-                            self.regions,
-                            self.header_height + self.footer_height,
-                        )
+                        && self.may_progress_with_repeats()
                     {
                         self.finish_region(layouter, engine)?;
 
@@ -1127,23 +1154,37 @@ impl<'a> RowspanSimulator<'a> {
         // our simulation checks what happens AFTER the auto row, so we can
         // just use the original backlog from `self.regions`.
         let disambiguator = self.finished;
-        let header_height =
-            if let Some(Repeatable::Repeated(header)) = &layouter.grid.header {
-                layouter
-                    .simulate_header(header, &self.regions, engine, disambiguator)?
-                    .height
-            } else {
-                Abs::zero()
-            };
 
-        let footer_height =
-            if let Some(Repeatable::Repeated(footer)) = &layouter.grid.footer {
-                layouter
-                    .simulate_footer(footer, &self.regions, engine, disambiguator)?
-                    .height
-            } else {
-                Abs::zero()
-            };
+        let (repeating_headers, header_height) = if !layouter.repeating_headers.is_empty()
+            || !layouter.pending_headers.is_empty()
+        {
+            // Only repeating headers have survived after the first region
+            // break.
+            let repeating_headers = layouter.repeating_headers.iter().copied().chain(
+                layouter.pending_headers.iter().filter_map(Repeatable::as_repeated),
+            );
+
+            let header_height = layouter.simulate_header_height(
+                repeating_headers.clone(),
+                &self.regions,
+                engine,
+                disambiguator,
+            )?;
+
+            (Some(repeating_headers), header_height)
+        } else {
+            (None, Abs::zero())
+        };
+
+        let footer_height = if let Some(footer) =
+            layouter.grid.footer.as_ref().and_then(Repeatable::as_repeated)
+        {
+            layouter
+                .simulate_footer(footer, &self.regions, engine, disambiguator)?
+                .height
+        } else {
+            Abs::zero()
+        };
 
         let mut skipped_region = false;
 
@@ -1156,19 +1197,24 @@ impl<'a> RowspanSimulator<'a> {
             skipped_region = true;
         }
 
-        if let Some(Repeatable::Repeated(header)) = &layouter.grid.header {
+        if let Some(repeating_headers) = repeating_headers {
             self.header_height = if skipped_region {
                 // Simulate headers again, at the new region, as
                 // the full region height may change.
-                layouter
-                    .simulate_header(header, &self.regions, engine, disambiguator)?
-                    .height
+                layouter.simulate_header_height(
+                    repeating_headers,
+                    &self.regions,
+                    engine,
+                    disambiguator,
+                )?
             } else {
                 header_height
             };
         }
 
-        if let Some(Repeatable::Repeated(footer)) = &layouter.grid.footer {
+        if let Some(footer) =
+            layouter.grid.footer.as_ref().and_then(Repeatable::as_repeated)
+        {
             self.footer_height = if skipped_region {
                 // Simulate footers again, at the new region, as
                 // the full region height may change.
@@ -1185,6 +1231,7 @@ impl<'a> RowspanSimulator<'a> {
         // header or footer (as an invariant, any rowspans spanning any header
         // or footer rows are fully contained within that header's or footer's rows).
         self.regions.size.y -= self.header_height + self.footer_height;
+        self.initial_after_repeats = self.regions.size.y;
 
         Ok(())
     }
@@ -1201,8 +1248,18 @@ impl<'a> RowspanSimulator<'a> {
         self.regions.next();
         self.finished += 1;
 
+        self.could_progress_at_top = self.regions.may_progress();
         self.simulate_header_footer_layout(layouter, engine)
     }
+
+    /// Similar to [`GridLayouter::may_progress_with_repeats`] but for rowspan
+    /// simulation.
+    #[inline]
+    fn may_progress_with_repeats(&self) -> bool {
+        self.could_progress_at_top
+            || self.regions.last.is_some()
+                && self.regions.size.y != self.initial_after_repeats
+    }
 }
 
 /// Subtracts some size from the end of a vector of sizes.