use cached value in auto row measurement, less todos

crates/typst-layout/src/grid/repeated.rs

@@ -240,6 +240,8 @@ impl<'a> GridLayouter<'a> {
             // 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;
 
             self.regions.size.y -= self.current.footer_height;
@@ -250,7 +252,6 @@ impl<'a> GridLayouter<'a> {
             if skipped_region {
                 // Simulate the footer again; the region's 'full' might have
                 // changed.
-                // TODO: maybe this should go in the loop, a bit hacky as is...
                 self.regions.size.y += self.current.footer_height;
                 self.current.footer_height = self
                     .simulate_footer(footer, &self.regions, engine, disambiguator)?

crates/typst-layout/src/grid/rowspans.rs

@@ -527,23 +527,7 @@ impl GridLayouter<'_> {
                         // we have to use initial header heights (note that
                         // header height can change in the middle of the
                         // region).
-                        // TODO: maybe cache this
-                        // NOTE: it is safe to access 'lrows' here since
-                        // 'breakable' can only be true outside of headers
-                        // and unbreakable rows in general, so there is no risk
-                        // of accessing an incomplete list of rows.
-                        let initial_header_height = self.current.lrows
-                            [..self.current.repeated_header_rows]
-                            .iter()
-                            .map(|row| match row {
-                                Row::Frame(frame, _, _) => frame.height(),
-                                Row::Fr(_, _, _) => Abs::zero(),
-                            })
-                            .sum();
-
-                        self.current.initial.y
-                            - initial_header_height
-                            - self.current.footer_height
+                        self.current.initial_after_repeats
                     } else {
                         // When measuring unbreakable auto rows, infinite
                         // height is available for content to expand.