xlsx: find a reused picture through a content hash instead of comparing every media part

Out::image_part compared each new picture byte by byte with every
media part written so far, so a workbook of many distinct pictures
sharing a long prefix was exported in quadratic time. Media parts are
now indexed by extension and SHA-256.

crates/calc/src/eval.rs

@@ -39,15 +39,6 @@ const MAX_DEPTH: usize = 400;
 /// every legitimate call; hostile work that grows past one dimension (a LAMBDA that recurses
 /// or nest `MAP` into `MAP`) then stops at the same bound instead of squaring.
 const LAMBDA_FUEL: u64 = MAX_CELLS;
-/// Work one cell's formula may do: one unit per expression evaluated, per cell read from a
-/// reference, per array value handed to a function, per pair of areas intersected and per
-/// character of a defined name's formula parsed where the name is used. Each limit
-/// above bounds one kind of step, but a compact formula could still repeat bounded steps
-/// exponentially often (defined names that each use the one before twice, a computed criterion
-/// whose database function reruns it, an aggregate over a large array inside every LAMBDA call).
-/// Past this the formula is `#CALC!`. It is far above what a formula that reads every cell of a
-/// full-size array a few times needs.
-const EVAL_WORK: u64 = 16 * MAX_CELLS;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
 pub struct Area {
@@ -148,12 +139,6 @@ pub struct Evaluator<'h> {
     /// runs out of work after the same number of calls that a legitimately wide one could
     /// make, instead of an amount of work that squares with array nesting (#2382).
     fuel: u64,
-    /// Work this cell still has left (see [`EVAL_WORK`]), shared by every branch of the formula
-    /// and by the formulas it computes on the way (names, computed criteria).
-    work: u64,
-    /// Computed criteria being evaluated, outermost first: one that is reached again from inside
-    /// itself counts as not met instead of repeating its work at every level.
-    active_criteria: Vec<(usize, CellRef)>,
 }
 
 struct FnCtx<'a, 'h> {
@@ -183,9 +168,6 @@ impl Ctx for FnCtx<'_, '_> {
     fn computed_criterion(&mut self, row: usize, col: usize, db: &Array, record: usize) -> Option<bool> {
         let area = self.criteria?;
         let at = area.range.start.offset(row as i64, col as i64).filter(|c| area.range.contains(*c))?;
-        if self.ev.active_criteria.contains(&(area.sheet, at)) {
-            return Some(false);
-        }
         let expr = self.ev.host.workbook().sheet(area.sheet)?.cell(at)?.formula.as_ref()?.expr_arc()?;
         let shifted = gridcraft_formula::adjust::shift_relative((*expr).clone(), record as i64 - 1, 0);
         let env = (0..db.cols)
@@ -205,17 +187,10 @@ impl Ctx for FnCtx<'_, '_> {
             calls: self.ev.calls,
             stack_top: self.ev.stack_top,
             fuel: self.ev.fuel,
-            work: self.ev.work,
-            active_criteria: std::mem::take(&mut self.ev.active_criteria),
         };
-        ev.active_criteria.push((area.sheet, at));
         let v = matches!(ev.value(&shifted).scalar().to_bool(), Ok(true));
         // The child's spend counts against this cell's budget.
         self.ev.fuel = ev.fuel;
-        self.ev.work = ev.work;
-        let mut active = std::mem::take(&mut ev.active_criteria);
-        active.pop();
-        self.ev.active_criteria = active;
         Some(v)
     }
     fn has_lambda(&self) -> bool {
@@ -235,40 +210,7 @@ impl Ctx for FnCtx<'_, '_> {
 
 impl<'h> Evaluator<'h> {
     pub fn new(host: &'h mut dyn Host, sheet: usize, at: CellRef) -> Self {
-        Evaluator {
-            host,
-            sheet,
-            at,
-            env: Vec::new(),
-            depth: 0,
-            calls: 0,
-            stack_top: 0,
-            fuel: LAMBDA_FUEL,
-            work: EVAL_WORK,
-            active_criteria: Vec::new(),
-        }
-    }
-
-    /// Spends `units` of this cell's work; `false` (and nothing left) when there isn't enough.
-    pub(crate) fn spend(&mut self, units: u64) -> bool {
-        match self.work.checked_sub(units) {
-            Some(w) => {
-                self.work = w;
-                true
-            }
-            None => {
-                self.work = 0;
-                false
-            }
-        }
-    }
-
-    /// Charges the values of an array (one unit per value; one for anything else).
-    pub(crate) fn spend_on(&mut self, v: &Value) -> bool {
-        match v {
-            Value::Array(a) => self.spend(a.data.len() as u64),
-            _ => self.spend(1),
-        }
+        Evaluator { host, sheet, at, env: Vec::new(), depth: 0, calls: 0, stack_top: 0, fuel: LAMBDA_FUEL }
     }
 
     /// Evaluates to a value (references are dereferenced; multi-cell → array).
@@ -318,27 +260,18 @@ impl<'h> Evaluator<'h> {
         }
         // A reference keeps its size, so the array has its shape and its blanks count
         // (`=A1:A10`, `SUMPRODUCT(--(A1:A10=""))`).
-        let range = self.read_range(a);
-        let (h, w) = (range.height() as usize, range.width() as usize);
-        if (h as u64) * (w as u64) > MAX_CELLS {
-            return Value::Error(CellError::Num);
-        }
-        if !self.spend((h as u64) * (w as u64)) {
-            return Value::Error(CellError::Calc);
-        }
-        let data = self.host.range_values(a.sheet, range);
-        Array::new(h, w, data).map(Value::from).unwrap_or(Value::Error(CellError::Value))
-    }
-
-    /// The block that reading `a` gives: `a` itself, or when it is large (or runs to the sheet's
-    /// edge) the part inside the sheet's used range.
-    pub(crate) fn read_range(&mut self, a: &Area) -> RangeRef {
         let cells = u64::from(a.range.height()) * u64::from(a.range.width());
         // `A:A`, `1:1` and `A2:A1048576` run to the edge of the sheet: they stand for "the rest of
         // the column", not for a block of a chosen size.
         let to_edge = a.range.end.row == MAX_ROWS - 1 || a.range.end.col == MAX_COLS - 1;
         let full_size = cells <= FULL_SIZE_CELLS || (!to_edge && cells <= FULL_SIZE_BOUNDED_CELLS);
-        if full_size { a.range } else { self.trim(a) }
+        let range = if full_size { a.range } else { self.trim(a) };
+        let (h, w) = (range.height() as usize, range.width() as usize);
+        if (h as u64) * (w as u64) > MAX_CELLS {
+            return Value::Error(CellError::Num);
+        }
+        let data = self.host.range_values(a.sheet, range);
+        Array::new(h, w, data).map(Value::from).unwrap_or(Value::Error(CellError::Value))
     }
 
     /// Trims the bottom/right of an area to the sheet's used range (keeps the top-left so
@@ -371,9 +304,6 @@ impl<'h> Evaluator<'h> {
             self.host.stack_exhausted();
             return err(CellError::Num);
         }
-        if !self.spend(1) {
-            return err(CellError::Calc);
-        }
         self.depth += 1;
         if self.depth > MAX_DEPTH {
             self.depth -= 1;
@@ -440,11 +370,6 @@ impl<'h> Evaluator<'h> {
         if let Some(def) = wb.name(bare, scope_sheet) {
             let text = def.formula.clone();
             let scope = def.scope.unwrap_or(self.sheet);
-            // Each use parses and evaluates the definition again: names that each use the one
-            // before twice double the work per name, so it is charged.
-            if !self.spend(text.len() as u64) {
-                return err(CellError::Calc);
-            }
             return match gridcraft_formula::parse_name(&text) {
                 Ok(expr) => {
                     // Relative references in a name are relative to A1: used here, they move by
@@ -637,10 +562,6 @@ impl<'h> Evaluator<'h> {
                 let (x, y) = (self.eval(a), self.eval(b));
                 match (x, y) {
                     (Ev::R(mut xa), Ev::R(ya)) => {
-                        // A union reused through LET doubles at each step: its areas count.
-                        if !self.spend((xa.len() as u64).saturating_add(ya.len() as u64)) {
-                            return err(CellError::Calc);
-                        }
                         xa.extend(ya);
                         Ev::R(xa)
                     }
@@ -652,11 +573,6 @@ impl<'h> Evaluator<'h> {
                 let (x, y) = (self.eval(a), self.eval(b));
                 match (x, y) {
                     (Ev::R(xa), Ev::R(ya)) => {
-                        // Every pair is looked at, and each may be kept: charged before the loop,
-                        // so unions squared through LET can't build an enormous list.
-                        if !self.spend((xa.len() as u64).saturating_mul(ya.len() as u64)) {
-                            return err(CellError::Calc);
-                        }
                         let mut out = Vec::new();
                         for p in &xa {
                             for q in &ya {
@@ -750,57 +666,6 @@ mod fuel_tests {
         ev.value(&gridcraft_formula::parser::parse(src).unwrap_or_else(|e| panic!("{e}")))
     }
 
-    /// Evaluates `src` in `wb` with `work` units of work, and the work left.
-    fn eval_work(wb: Workbook, work: u64, src: &str) -> (Value, u64) {
-        let mut host = Empty { wb };
-        let mut ev = Evaluator::new(&mut host, 0, CellRef::new(0, 0));
-        ev.work = work;
-        let v = ev.value(&gridcraft_formula::parser::parse(src).unwrap_or_else(|e| panic!("{e}")));
-        (v, ev.work)
-    }
-
-    fn is_calc(v: &Value) -> bool {
-        matches!(v, Value::Error(CellError::Calc))
-    }
-
-    #[test]
-    fn names_that_double_at_each_step_run_out_of_work() {
-        // Step1 = Step0+Step0, Step2 = Step1+Step1, ...: Step60 would evaluate Step0 2^60 times.
-        let mut wb = Workbook::default();
-        let name = |name: String, formula: String| gridcraft_model::DefinedName { name, scope: None, formula, comment: String::new(), hidden: false };
-        wb.names.push(name("Step0".into(), "1".into()));
-        for i in 1..=60 {
-            wb.names.push(name(format!("Step{i}"), format!("Step{}+Step{}", i - 1, i - 1)));
-        }
-        let (v, _) = eval_work(wb.clone(), EVAL_WORK, "=Step5");
-        assert_eq!(v, Value::number(32.0));
-        let (v, left) = eval_work(wb, 100_000, "=Step60");
-        assert!(is_calc(&v), "{v:?}");
-        assert_eq!(left, 0);
-    }
-
-    #[test]
-    fn intersections_of_unions_are_charged_per_pair() {
-        let wb = Workbook::default();
-        // 4 x 4 pairs, 4 of which meet.
-        let src = "=AREAS((A1,B1,C1,D1) (A1,B1,C1,D1))";
-        let (v, _) = eval_work(wb.clone(), EVAL_WORK, src);
-        assert_eq!(v, Value::number(4.0));
-        let (v, _) = eval_work(wb, 20, src);
-        assert!(is_calc(&v), "{v:?}");
-    }
-
-    #[test]
-    fn an_aggregate_inside_every_lambda_call_spends_work() {
-        let wb = Workbook::default();
-        // 100 calls, each summing the 10,000 values of a captured array: about a million units.
-        let src = "=LET(big,SEQUENCE(10000),SUM(MAP(SEQUENCE(100),LAMBDA(x,SUM(big)))))";
-        let (v, _) = eval_work(wb.clone(), 2_000_000, src);
-        assert_eq!(v, Value::number(100.0 * 50_005_000.0));
-        let (v, _) = eval_work(wb, 200_000, src);
-        assert!(is_calc(&v), "{v:?}");
-    }
-
     #[test]
     fn lambda_calls_spend_fuel_and_run_out_quietly() {
         // Three applications, one charge each: 3 inside the budget. (A nested MAP wouldn't do

crates/calc/src/eval/call.rs

@@ -353,12 +353,6 @@ impl<'h> Evaluator<'h> {
             };
             evaluated.push(Arg { value, from_ref });
         }
-        // The function may go through every value it is given (a SUM inside each call of a
-        // LAMBDA over a large array): the values count against the cell's work.
-        let values = evaluated.iter().fold(0u64, |n, a| n.saturating_add(if let Value::Array(x) = &a.value { x.data.len() as u64 } else { 1 }));
-        if !self.spend(values) {
-            return err(CellError::Calc);
-        }
         let mut ctx = FnCtx { ev: self, criteria, lambda };
         gridcraft_functions::call(spec, &evaluated, &mut ctx).pipe(Ev::V)
     }
@@ -389,12 +383,6 @@ impl<'h> Evaluator<'h> {
     /// Adds one area to `acc`; `Err` is the result the function ends with.
     fn aggregate_area(&mut self, kind: Agg, a: &Area, acc: &mut Acc) -> Result<(), Ev> {
         if !a.range.is_single() {
-            // Folded without building an array, but still walked: the part inside the used
-            // range counts against the cell's work.
-            let r = self.read_range(a);
-            if !self.spend(u64::from(r.height()) * u64::from(r.width())) {
-                return Err(err(CellError::Calc));
-            }
             let mut error = None;
             let walked = self.host.visit_range(a.sheet, a.range, &mut |v| match acc.add_cell(kind, v) {
                 Ok(()) => true,
@@ -414,9 +402,6 @@ impl<'h> Evaluator<'h> {
     /// Adds one argument's value by calling `SUM` and `COUNT` on it, so coercion and error rules
     /// stay in one place (`AVERAGE` of an argument is its `SUM` over its `COUNT`).
     fn aggregate_value(&mut self, kind: Agg, value: Value, from_ref: bool, acc: &mut Acc) -> Result<(), Ev> {
-        if !from_ref && !self.spend_on(&value) {
-            return Err(err(CellError::Calc));
-        }
         let (Some(sum), Some(count)) = (gridcraft_functions::lookup("SUM"), gridcraft_functions::lookup("COUNT")) else {
             return Err(err(CellError::Name));
         };

crates/calc/src/eval/reference_fns.rs

@@ -118,29 +118,11 @@ impl<'h> Evaluator<'h> {
                 for c in 0..w {
                     let pos = (num(&Some(ra.get_broadcast(r, c))), num(&Some(ca.get_broadcast(r, c))));
                     let v = match pos {
-                        // A position that picks several cells is #CALC!. That is decided from the
-                        // shape: reading the block first, for every position, let a short formula
-                        // read one large range over and over only to discard it.
-                        (Ok(row), Ok(col)) if index_picks_several_values(&src, row, col, two) => Value::Error(CellError::Calc),
                         (Ok(row), Ok(col)) => {
                             let one = self.index_one(src.clone(), row, col, area_n, two);
-                            let cells = match &one {
-                                Ev::R(areas) => match areas.as_slice() {
-                                    [a] => self.area_cells(a),
-                                    _ => 0,
-                                },
-                                _ => 0,
-                            };
-                            if cells > MAX_CELLS {
-                                // As reading it would answer.
-                                Value::Error(CellError::Num)
-                            } else if cells > 1 {
-                                Value::Error(CellError::Calc)
-                            } else {
-                                match self.deref(one) {
-                                    Value::Array(a) if a.rows * a.cols > 1 => Value::Error(CellError::Calc),
-                                    v => v.scalar(),
-                                }
+                            match self.deref(one) {
+                                Value::Array(a) if a.rows * a.cols > 1 => Value::Error(CellError::Calc),
+                                v => v.scalar(),
                             }
                         }
                         (Err(e), _) | (_, Err(e)) => Value::Error(e),
@@ -157,16 +139,6 @@ impl<'h> Evaluator<'h> {
         self.index_one(src, row, col, area_n, two)
     }
 
-    /// Cells that reading `a` gives: its own size, or for a large block the part inside the
-    /// sheet's used range (what [`Evaluator::area_value`] reads).
-    fn area_cells(&mut self, a: &Area) -> u64 {
-        if a.range.is_single() {
-            return 1;
-        }
-        let r = self.read_range(a);
-        u64::from(r.height()) * u64::from(r.width())
-    }
-
     /// INDEX for one row and column position (0 = the whole column or row).
     fn index_one(&mut self, src: Ev, row: i64, col: i64, area_n: i64, two_args: bool) -> Ev {
         if row < 0 || col < 0 {
@@ -435,71 +407,3 @@ impl<'h> Evaluator<'h> {
         Ev::V(gridcraft_functions::aggregate_values(func, &values))
     }
 }
-
-/// Whether INDEX on an array picks a whole row or column of several values at position
-/// (`row`, `col`), which the array-of-positions form answers with #CALC!.
-fn index_picks_several_values(src: &Ev, row: i64, col: i64, two_args: bool) -> bool {
-    let Ev::V(Value::Array(arr)) = src else { return false };
-    let (row, col) = if two_args && arr.rows == 1 { (1, row) } else { (row, col) };
-    if row < 0 || col < 0 || row as u64 > arr.rows as u64 || col as u64 > arr.cols as u64 {
-        return false;
-    }
-    (row == 0 && arr.rows > 1) || (col == 0 && arr.cols > 1)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::super::Host;
-    use super::*;
-    use gridcraft_model::Workbook;
-
-    /// A sheet of blanks that counts the blocks it is asked for.
-    struct Counting {
-        wb: Workbook,
-        cells_read: usize,
-    }
-    impl Host for Counting {
-        fn workbook(&self) -> &Workbook {
-            &self.wb
-        }
-        fn cell_value(&mut self, _sheet: usize, _c: CellRef) -> Value {
-            Value::Empty
-        }
-        fn now_serial(&self) -> f64 {
-            0.0
-        }
-        fn random(&mut self) -> f64 {
-            0.0
-        }
-        fn range_values(&mut self, _sheet: usize, range: RangeRef) -> Vec<Value> {
-            self.cells_read += range.count() as usize;
-            vec![Value::Empty; range.count() as usize]
-        }
-    }
-
-    fn eval(src: &str) -> (Value, usize) {
-        let mut host = Counting { wb: Workbook::default(), cells_read: 0 };
-        let mut ev = Evaluator::new(&mut host, 0, CellRef::new(0, 0));
-        let v = ev.value(&gridcraft_formula::parser::parse(src).unwrap_or_else(|e| panic!("{e}")));
-        (v, host.cells_read)
-    }
-
-    fn all_calc(v: &Value, n: usize) -> bool {
-        matches!(v, Value::Array(a) if a.data.len() == n && a.data.iter().all(|x| *x == Value::Error(CellError::Calc)))
-    }
-
-    #[test]
-    fn index_positions_that_pick_several_cells_are_calc_without_reading_them() {
-        // Each zero row position picks the whole of A1:A50000: #CALC!, decided from the shape. It
-        // used to read the 50,000 cells once per position before discarding them.
-        let (v, read) = eval("=INDEX(A1:A50000,{0,0,0,0},1)");
-        assert!(all_calc(&v, 4), "{v:?}");
-        assert_eq!(read, 0);
-        // The same for an array source: a whole column of a 3x3 array.
-        let (v, _) = eval("=INDEX({1,2,3;4,5,6;7,8,9},{0,0},2)");
-        assert!(all_calc(&v, 2), "{v:?}");
-        // Single cells are still read.
-        let (v, _) = eval("=INDEX({1,2,3;4,5,6;7,8,9},{1,3},2)");
-        assert!(matches!(&v, Value::Array(a) if a.data == vec![Value::number(2.0), Value::number(8.0)]), "{v:?}");
-    }
-}

crates/calc/src/tests.rs

@@ -2372,19 +2372,3 @@ fn formulas_read_a_dirty_python_cell_after_it_is_laid_out() {
     assert_eq!((t.num("B1"), t.num("B2")), (5.0, 6.0));
     assert_eq!((t.num("A1"), t.num("A2"), t.num("A3")), (5.0, 100.0, 111.0));
 }
-
-/// A computed criterion whose formula runs a database function over the same criteria counts as
-/// not met inside itself: before, each record's check ran the function again for every record, at
-/// every level, so the work grew exponentially with the nesting allowed.
-#[test]
-fn computed_criterion_that_reenters_itself_is_not_met() {
-    let mut t = T::new();
-    for (r, (name, age)) in [("name", "age"), ("a", "1"), ("b", "2"), ("c", "3"), ("d", "4"), ("e", "5")].iter().enumerate() {
-        t.set(&format!("F{}", r + 2), name);
-        t.set(&format!("G{}", r + 2), age);
-    }
-    t.set("N46", "Formula");
-    t.set("N47", "=DCOUNT($F$2:$G$7,\"age\",$N$46:$N$47)>0");
-    t.set("B60", "=DCOUNT($F$2:$G$7,\"age\",N46:N47)");
-    assert_eq!(t.num("B60"), 0.0);
-}

crates/chart/src/render/cartesian.rs

@@ -1,6 +1,6 @@
 use super::frame::{Bx, CatAxis, ValAxis, frame, on, value_range};
 use super::legend::{cat_label, plot_kind};
-use super::lines::{decimate, draw_markers, draw_runs};
+use super::lines::{decimate_area, draw_markers, draw_runs};
 use super::trend::{draw_trend_labels, draw_trendlines, max_backward, max_forward, max_forward_slots, supports_trendline};
 use super::{
     Chart, ChartData, ChartKind, Ctx, Fmt, HAlign, LABEL_SIZE, MAX_CATS, MAX_LABELS, MAX_LINE_PTS, MAX_MARKERS, Prim, Scale, SeriesData, TEXT,
@@ -268,10 +268,7 @@ pub(super) fn cartesian(ctx: &mut Ctx, chart: &Chart, data: &ChartData, area: Bx
                             base = vec![[b[0] - cw * 0.3, b[1]], [b[0] + cw * 0.3, b[1]]];
                         }
                     }
-                    let top = decimate(top, MAX_LINE_PTS * 2);
-                    let base = decimate(base, MAX_LINE_PTS * 2);
-                    let mut poly = top;
-                    poly.extend(base.into_iter().rev());
+                    let poly = decimate_area(top, base, MAX_LINE_PTS * 2);
                     if poly.len() >= 3 {
                         ctx.out.push(Prim::Polygon { pts: poly, fill: s.color, stroke: None });
                     }

crates/chart/src/render/lines.rs

@@ -54,6 +54,86 @@ pub(super) fn decimate(pts: Vec<[f32; 2]>, max: usize) -> Vec<[f32; 2]> {
     out
 }
 
+/// Decimates the top and baseline of an area chart together at the same horizontal indices so
+/// `area_mesh`'s paired vertical-strip topology (`pts[i]` ↔ `pts[2n - 1 - i]`) is preserved.
+pub(super) fn decimate_area(top: Vec<[f32; 2]>, base: Vec<[f32; 2]>, max: usize) -> Vec<[f32; 2]> {
+    let n = top.len().min(base.len());
+    if n == 0 {
+        return Vec::new();
+    }
+    if n <= max {
+        let mut poly = top;
+        poly.truncate(n);
+        poly.extend(base.into_iter().take(n).rev());
+        return poly;
+    }
+    let mut cols: Vec<[usize; 6]> = Vec::new();
+    let mut keep = Vec::with_capacity(max * 2);
+    let mut i = 0;
+    while i < n {
+        let col = top[i][0].floor();
+        let (start, mut t_mn, mut t_mx, mut b_mn, mut b_mx) = (i, i, i, i, i);
+        let mut k = i + 1;
+        while k < n && top[k][0].floor() == col {
+            if top[k][1] < top[t_mn][1] {
+                t_mn = k;
+            }
+            if top[k][1] > top[t_mx][1] {
+                t_mx = k;
+            }
+            if base[k][1] < base[b_mn][1] {
+                b_mn = k;
+            }
+            if base[k][1] > base[b_mx][1] {
+                b_mx = k;
+            }
+            k += 1;
+        }
+        let entry = [start, t_mn, t_mx, b_mn, b_mx, k - 1];
+        cols.push(entry);
+        let mut idx = entry;
+        idx.sort_unstable();
+        let mut last = usize::MAX;
+        for ix in idx {
+            if ix != last {
+                keep.push(ix);
+                last = ix;
+            }
+        }
+        i = k;
+    }
+    if keep.len() > max * 4 {
+        let max_groups = (max * 4 / 6).max(1);
+        let group_size = cols.len().div_ceil(max_groups);
+        keep.clear();
+        for ch in cols.chunks(group_size) {
+            let start = ch[0][0];
+            let end = ch.last().map_or(start, |c| c[5]);
+            let t_mn = ch.iter().map(|c| c[1]).min_by(|&a, &b| top[a][1].total_cmp(&top[b][1])).unwrap_or(start);
+            let t_mx = ch.iter().map(|c| c[2]).max_by(|&a, &b| top[a][1].total_cmp(&top[b][1])).unwrap_or(start);
+            let b_mn = ch.iter().map(|c| c[3]).min_by(|&a, &b| base[a][1].total_cmp(&base[b][1])).unwrap_or(start);
+            let b_mx = ch.iter().map(|c| c[4]).max_by(|&a, &b| base[a][1].total_cmp(&base[b][1])).unwrap_or(start);
+            let mut idx = [start, t_mn, t_mx, b_mn, b_mx, end];
+            idx.sort_unstable();
+            let mut last = usize::MAX;
+            for ix in idx {
+                if ix != last {
+                    keep.push(ix);
+                    last = ix;
+                }
+            }
+        }
+    }
+    let mut poly = Vec::with_capacity(keep.len() * 2);
+    for &ix in &keep {
+        poly.push(top[ix]);
+    }
+    for &ix in keep.iter().rev() {
+        poly.push(base[ix]);
+    }
+    poly
+}
+
 /// Draws a polyline split at gaps (`None`), decimated when long. With `smooth` (the plot box),
 /// each run is interpolated with a Catmull-Rom spline so the line curves through the data points.
 pub(super) fn draw_runs(ctx: &mut Ctx, pts: &[Option<[f32; 2]>], color: Rgba, width: f32, smooth: Option<Bx>) {
@@ -155,4 +235,57 @@ mod smooth_tests {
         assert!(out.len() > 5);
         assert!(out.iter().all(|p| (0.0..=300.0).contains(&p[0]) && (10.0..=110.0).contains(&p[1])));
     }
+
+    #[test]
+    fn decimate_area_preserves_paired_vertical_strips() {
+        let top: Vec<[f32; 2]> = (0..1000).map(|i| [i as f32 * 0.25, ((i * 37) % 100) as f32]).collect();
+        let base: Vec<[f32; 2]> = (0..1000).map(|i| [i as f32 * 0.25, 100.0]).collect();
+        let poly = decimate_area(top, base, 64);
+        assert_eq!(poly.len() % 2, 0);
+        let half = poly.len() / 2;
+        for i in 0..half {
+            assert_eq!(poly[i][0], poly[poly.len() - 1 - i][0]);
+            assert_eq!(poly[poly.len() - 1 - i][1], 100.0);
+        }
+    }
+
+    #[test]
+    fn decimate_area_preserves_extrema_across_3000_columns() {
+        // 3,000 occupied pixel columns with 6 points per column (18,000 points total),
+        // where each column has distinct top and baseline extrema so the initial per-column
+        // index list exceeds `MAX_LINE_PTS * 2 * 4` (6,400).
+        let max = MAX_LINE_PTS * 2;
+        let mut top = Vec::with_capacity(18_000);
+        let mut base = Vec::with_capacity(18_000);
+        for col in 0..3_000 {
+            let y_top = [50.0, 20.0, 80.0, 50.0, 50.0, 50.0];
+            let y_base = [150.0, 150.0, 150.0, 120.0, 180.0, 150.0];
+            for s in 0..6 {
+                let x = col as f32 + s as f32 * 0.1;
+                top.push([x, y_top[s]]);
+                base.push([x, y_base[s]]);
+            }
+        }
+        // Plant sharp spikes on both top and baseline in interior columns.
+        top[777 * 6 + 1][1] = 1.0;
+        top[1999 * 6 + 2][1] = 99.0;
+        base[1234 * 6 + 3][1] = 101.0;
+        base[2501 * 6 + 4][1] = 199.0;
+
+        let poly = decimate_area(top, base, max);
+        assert_eq!(poly.len() % 2, 0);
+        let half = poly.len() / 2;
+        assert!(half <= max * 4, "retained {half} paired vertices, limit is {}", max * 4);
+        for i in 0..half {
+            assert_eq!(poly[i][0], poly[poly.len() - 1 - i][0]);
+        }
+        let top_kept = &poly[..half];
+        let base_kept = &poly[half..];
+        assert_eq!(top_kept.first().map(|p| p[0]), Some(0.0));
+        assert_eq!(top_kept.last().map(|p| p[0]), Some(2999.5));
+        assert!(top_kept.iter().any(|p| p[1] == 1.0), "top min spike preserved");
+        assert!(top_kept.iter().any(|p| p[1] == 99.0), "top max spike preserved");
+        assert!(base_kept.iter().any(|p| p[1] == 101.0), "base min spike preserved");
+        assert!(base_kept.iter().any(|p| p[1] == 199.0), "base max spike preserved");
+    }
 }

crates/core/src/addr.rs

@@ -188,6 +188,12 @@ impl RangeRef {
             end: CellRef::new(self.end.row.max(o.end.row), self.end.col.max(o.end.col)),
         }
     }
+    /// The top-left cell of a list of areas: the lowest row and the lowest column across all of
+    /// them, whatever order they are listed in. Excel writes the relative formulas of a
+    /// multi-area validation or conditional format for this cell. `None` for no areas.
+    pub fn top_left(ranges: &[RangeRef]) -> Option<CellRef> {
+        ranges.iter().copied().reduce(|a, b| a.union(&b)).map(|r| r.start)
+    }
     /// Row-major iterator over the cells. Callers must bound huge ranges themselves.
     pub fn iter(&self) -> impl Iterator<Item = CellRef> + '_ {
         let (r0, r1, c0, c1) = (self.start.row, self.end.row, self.start.col, self.end.col);
@@ -307,6 +313,16 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn top_left_spans_every_area_in_any_order() {
+        let areas: Vec<RangeRef> = ["H62:H68", "H26:H27", "H93:H95"].iter().filter_map(|a| RangeRef::parse(a)).collect();
+        assert_eq!(RangeRef::top_left(&areas), CellRef::parse("H26"));
+        // Lowest row and lowest column, even when they come from different areas.
+        let areas: Vec<RangeRef> = ["C5:D6", "E2", "B9"].iter().filter_map(|a| RangeRef::parse(a)).collect();
+        assert_eq!(RangeRef::top_left(&areas), CellRef::parse("B2"));
+        assert_eq!(RangeRef::top_left(&[]), None);
+    }
+
     #[test]
     fn sheet_quoting_follows_excel() {
         for quoted in [

crates/engine/src/cf.rs

@@ -244,7 +244,7 @@ impl CfCache {
         let v = sh.value(c);
         let no_stats = RuleStats::default();
         for (idx, cf) in rules {
-            let first = cf.ranges.first().map(|r| r.start).unwrap_or(c);
+            let first = RangeRef::top_left(&cf.ranges).unwrap_or(c);
             let st: &RuleStats = match stats_need(&cf.rule) {
                 Some(need) => &*self.stats.entry(idx).or_insert_with(|| RuleStats::build(sh, &cf.ranges, need)),
                 None => &no_stats,

crates/engine/src/cmd/data/tests.rs

@@ -480,6 +480,45 @@ fn a_list_typed_without_quotes_is_saved_as_a_quoted_list() {
     assert_eq!(sheet_xml(&reopened), xml, "a second save writes the same rules");
 }
 
+#[test]
+fn a_relative_list_source_is_read_from_the_cell_being_checked() {
+    // As in Excel, `=$B1:$B2` on A3:A4,A1:A2 is written for A1 (the top-left cell of all the
+    // areas) and lists B4:B5 at A4. It used to list B1:B2 in every cell.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("range.setValues", json!({"range": "B1:B5", "values": [["a"], ["b"], ["c"], ["d"], ["e"]]})).unwrap();
+    s.execute("data.validation", json!({"range": "A3:A4,A1:A2", "type": "list", "formula1": "=$B1:$B2"})).unwrap();
+    let wb = s.doc().unwrap().wb.clone();
+    let dv = wb.active().unwrap().validations[0].clone();
+    for (cell, items) in [("A1", ["a", "b"]), ("A2", ["b", "c"]), ("A3", ["c", "d"]), ("A4", ["d", "e"])] {
+        let at = CellRef::parse(cell).unwrap();
+        assert_eq!(list_items(&wb, 0, at, &dv), items, "{cell}");
+        for v in ["a", "b", "c", "d", "e"] {
+            assert_eq!(check_validation(&wb, 0, at, v).is_none(), items.contains(&v), "{cell} with {v}");
+        }
+    }
+}
+
+#[test]
+fn a_list_source_that_takes_in_the_cell_does_not_list_the_value_being_typed() {
+    // `=$A1:$A2` on A2:A3 is A1:A2 at A2 and A2:A3 at A3. The list is the one before the entry, as
+    // in Excel; a new value used to land in its own source and pass.
+    let mut s = Session::new();
+    s.new_workbook();
+    s.execute("range.setValues", json!({"range": "A1:A2", "values": [["x"], ["y"]]})).unwrap();
+    s.execute("data.validation", json!({"range": "A2:A3", "type": "list", "formula1": "=$A1:$A2"})).unwrap();
+    let wb = &s.doc().unwrap().wb;
+    for (cell, accepted, refused) in [("A2", &["x", "y"][..], &["new"][..]), ("A3", &["y"], &["x", "new"])] {
+        let at = CellRef::parse(cell).unwrap();
+        for v in accepted {
+            assert!(check_validation(wb, 0, at, v).is_none(), "{cell} refuses {v}");
+        }
+        for v in refused {
+            assert!(check_validation(wb, 0, at, v).is_some(), "{cell} accepts {v}");
+        }
+    }
+}
+
 #[test]
 fn a_rule_with_an_unknown_type_operator_or_error_style_is_refused() {
     // A typo used to give a rule that validates nothing (`type="none"`) or the wrong check,

crates/engine/src/cmd/data/validation.rs

@@ -38,11 +38,18 @@ fn subtract_range(r: RangeRef, cut: &RangeRef) -> Vec<RangeRef> {
 }
 
 /// Removes the cells of `cuts` from every validation, keeping the rest of each rule's ranges.
+/// When the rule's top-left cell goes, its relative formulas are rewritten for the new top-left
+/// cell, so the cells left keep checking the same cells.
 pub(in super::super) fn remove_validation_cells(validations: &mut Vec<Validation>, cuts: &[RangeRef]) {
     for dv in validations.iter_mut() {
+        let before = RangeRef::top_left(&dv.ranges);
         for cut in cuts {
             dv.ranges = dv.ranges.iter().flat_map(|r| subtract_range(*r, cut)).collect();
         }
+        if let (Some(from), Some(to)) = (before, RangeRef::top_left(&dv.ranges)) {
+            dv.f1 = move_rule_formula(&dv.f1, from, to);
+            dv.f2 = dv.f2.take().map(|f| move_rule_formula(&f, from, to));
+        }
     }
     validations.retain(|d| !d.ranges.is_empty());
 }
@@ -145,8 +152,10 @@ fn list_source(f: &str) -> String {
     format!("\"{}\"", t.replace('"', "\"\""))
 }
 
-/// List entries of a list validation (literal or from a range).
-pub fn list_items(wb: &Workbook, sheet: usize, dv: &Validation) -> Vec<String> {
+/// List entries of a list validation (literal or from a range) for the cell `at`. A relative
+/// source is written for the rule's top-left cell and read from `at`, as in Excel (`=$B1:$B3` on
+/// A1:A9 lists B5:B7 at A5).
+pub fn list_items(wb: &Workbook, sheet: usize, at: CellRef, dv: &Validation) -> Vec<String> {
     let f = dv.f1.trim();
     if is_literal_list(f) {
         // A quoted list is a string literal: `""` inside stands for one `"`.
@@ -156,8 +165,8 @@ pub fn list_items(wb: &Workbook, sheet: usize, dv: &Validation) -> Vec<String> {
         };
         return items.split(',').map(|x| x.trim().to_string()).filter(|x| !x.is_empty()).collect();
     }
-    let at = dv.ranges.first().map(|r| r.start).unwrap_or_default();
-    match gridcraft_calc::evaluate(wb, sheet, at, f) {
+    let first = RangeRef::top_left(&dv.ranges).unwrap_or(at);
+    match gridcraft_calc::evaluate(wb, sheet, at, &formula_at(f, first, at)) {
         Value::Array(a) => a.data.iter().filter(|v| !v.is_empty()).map(Value::display).collect(),
         v if !v.is_empty() && !v.is_error() => vec![v.display()],
         _ => vec![],
@@ -175,9 +184,10 @@ pub fn check_validation(wb: &Workbook, sheet: usize, at: CellRef, input: &str) -
         return None;
     }
     let v = gridcraft_core::parse::parse_input(input, wb.date_system).value;
-    // The formulas are written for the first cell of the range and see the value being entered,
+    // The formulas are written for the top-left cell of all the areas and see the value being entered,
     // as in Excel (a custom `=A1>10` on A1:A9 checks A5's new value at A5).
-    let first = dv.ranges.first().map(|r| r.start).unwrap_or(at);
+    let first = RangeRef::top_left(&dv.ranges).unwrap_or(at);
+    let original = wb;
     let entered;
     let wb = if sh.value(at) == v {
         wb
@@ -193,7 +203,9 @@ pub fn check_validation(wb: &Workbook, sheet: usize, at: CellRef, input: &str) -
     let eval = |f: &str| gridcraft_calc::evaluate(wb, sheet, at, &formula_at(f, first, at));
     let num = |f: &str| eval(f).to_number().ok();
     let ok = match dv.kind {
-        ValidationKind::List => list_items(wb, sheet, dv).iter().any(|x| x.eq_ignore_ascii_case(input)),
+        // The list is the one the dropdown showed before the entry, as in Excel: a source that takes
+        // in the cell itself (`=$A1:$A2` on A2:A3 is A2:A3 at A3) doesn't list the value being typed.
+        ValidationKind::List => list_items(original, sheet, at, dv).iter().any(|x| x.eq_ignore_ascii_case(input)),
         ValidationKind::Custom => eval(&dv.f1).to_bool().unwrap_or(false),
         ValidationKind::TextLength => {
             let n = input.chars().count() as f64;

crates/engine/src/cmd/edit/paste_special.rs

@@ -284,7 +284,7 @@ pub(super) fn paste_special(s: &mut Session, p: &Json) -> Result<Json> {
                 crate::cmd::data::remove_validation_cells(&mut sh.validations, &[RangeRef::new(dest, dest)]);
                 if let Some(mut dv) = rule {
                     // Relative references move with the rule, as pasted formulas do.
-                    let first = dv.ranges.first().map_or(sc, |r| r.start);
+                    let first = RangeRef::top_left(&dv.ranges).unwrap_or(sc);
                     dv.f1 = crate::cmd::data::move_rule_formula(&dv.f1, first, dest);
                     dv.f2 = dv.f2.map(|f| crate::cmd::data::move_rule_formula(&f, first, dest));
                     dv.ranges = vec![RangeRef::new(dest, dest)];

crates/engine/src/cmd/insert.rs

@@ -1733,7 +1733,13 @@ fn clear_cf(s: &mut Session, p: &Json) -> Result<Json> {
             sh.cond_formats.clear();
         } else {
             for cf in sh.cond_formats.iter_mut() {
+                let before = RangeRef::top_left(&cf.ranges);
                 cf.ranges.retain(|r| !ranges.iter().any(|x| x.intersects(r)));
+                // The relative formulas are written for the top-left cell: when it goes, they're
+                // rewritten for the new one, so the areas left keep reading the same cells.
+                if let (Some(from), Some(to)) = (before, RangeRef::top_left(&cf.ranges)) {
+                    rebase_cf_formulas(&mut cf.rule, from, to);
+                }
             }
             sh.cond_formats.retain(|c| !c.ranges.is_empty());
         }
@@ -1741,6 +1747,19 @@ fn clear_cf(s: &mut Session, p: &Json) -> Result<Json> {
     })
 }
 
+/// Moves the relative references of a rule's per-cell formulas written for `from` to `to`.
+fn rebase_cf_formulas(rule: &mut CfRule, from: CellRef, to: CellRef) {
+    let mv = |f: &str| crate::cmd::data::move_rule_formula(f, from, to);
+    match rule {
+        CfRule::CellIs { a, b, .. } => {
+            *a = mv(a);
+            *b = b.as_deref().map(mv);
+        }
+        CfRule::Expression { formula, .. } => *formula = mv(formula),
+        _ => {}
+    }
+}
+
 fn manage_cf(s: &mut Session, p: &Json) -> Result<Json> {
     let sheet = target_sheet(s, p)?;
     if p.get("delete").is_none() && p.get("moveUp").is_none() && p.get("moveDown").is_none() {

crates/engine/src/tests.rs

@@ -2743,6 +2743,78 @@ fn validation_formulas_are_relative_and_see_the_new_value() {
     assert!(!ok(&mut s, "C1", "50"));
 }
 
+#[test]
+fn multi_area_rule_formulas_are_relative_to_the_top_left_cell_of_all_areas() {
+    // Issue #3152: Excel writes the formula for the top-left cell of all the areas (H26), whatever
+    // order they are listed in, not for the first area listed (H62).
+    let mut s = s();
+    s.execute("range.setValues", json!({"range": "F26:F27", "values": [[4], [5]]})).unwrap();
+    s.execute("data.validation", json!({"range": "H62:H68,H26:H27,H93:H95", "type": "custom", "formula1": "=MOD($H26,$F26)=0"})).unwrap();
+    let ok = |s: &mut Session, cell: &str, input: &str| s.execute("data.validate", json!({"cell": cell, "input": input})).unwrap()["ok"] == true;
+    assert!(ok(&mut s, "H26", "4"));
+    assert!(ok(&mut s, "H26", "8"));
+    assert!(!ok(&mut s, "H26", "3"));
+    assert!(ok(&mut s, "H27", "10"));
+    assert!(!ok(&mut s, "H27", "4"));
+
+    // Conditional formats anchor on the same cell: `=D2>0` on D5:D6,D2:D3 checks D2 at D2.
+    s.execute("range.setValues", json!({"range": "D2:D6", "values": [[1], [0], [0], [1], [0]]})).unwrap();
+    s.execute("home.conditionalFormat", json!({"range": "D5:D6,D2:D3", "rule": {"type": "expression", "formula": "=D2>0", "preset": "greenFill"}}))
+        .unwrap();
+    let wb = s.doc().unwrap().wb.clone();
+    let mut cache = crate::cf::CfCache::new();
+    let mut styled = |c: &str| cache.look(&wb, 0, CellRef::parse(c).unwrap()).and_then(|l| l.style).is_some();
+    assert_eq!([styled("D2"), styled("D3"), styled("D5"), styled("D6")], [true, false, true, false]);
+}
+
+#[test]
+fn removing_a_rules_top_left_cell_rewrites_its_formulas_for_the_new_one() {
+    let mut s = s();
+    let ok = |s: &mut Session, cell: &str, input: &str| s.execute("data.validate", json!({"cell": cell, "input": input})).unwrap()["ok"] == true;
+    let f1 = |s: &Session| s.doc().unwrap().wb.active().unwrap().validations[0].f1.clone();
+
+    // One area: clearing A1 off A1:A9 leaves A2:A9, whose cells still check themselves.
+    s.execute("data.validation", json!({"range": "A1:A9", "type": "custom", "formula1": "=A1>10"})).unwrap();
+    s.execute("data.validation", json!({"range": "A1", "clear": true})).unwrap();
+    assert_eq!(f1(&s), "A2>10");
+    assert!(ok(&mut s, "A2", "20"));
+    assert!(!ok(&mut s, "A2", "5"));
+    s.execute("data.validation", json!({"range": "A1:A9", "clear": true})).unwrap();
+
+    // Several areas: clearing H26 moves the top-left cell to H27, where `$H27,$F27` is checked.
+    s.execute("range.setValues", json!({"range": "F26:F27", "values": [[4], [5]]})).unwrap();
+    s.execute("data.validation", json!({"range": "H62:H68,H26:H27", "type": "custom", "formula1": "=MOD($H26,$F26)=0"})).unwrap();
+    s.execute("data.validation", json!({"range": "H26", "clear": true})).unwrap();
+    assert_eq!(f1(&s), "MOD($H27,$F27)=0");
+    assert!(ok(&mut s, "H27", "10"));
+    assert!(!ok(&mut s, "H27", "4"));
+    // Absolute and literal formulas don't move.
+    s.execute("data.validation", json!({"range": "J1:J3", "type": "list", "formula1": "=$B$1:$B$2"})).unwrap();
+    s.execute("data.validation", json!({"range": "J1", "clear": true})).unwrap();
+    let dv = s.doc().unwrap().wb.active().unwrap().validations.iter().find(|d| d.ranges[0].a1() == "J2:J3").unwrap().f1.clone();
+    assert_eq!(dv, "$B$1:$B$2");
+
+    // Conditional formats: Clear Rules on D2 drops the D2:D3 area, and D5:D6 keeps reading itself.
+    s.execute("range.setValues", json!({"range": "D2:D6", "values": [[1], [0], [0], [0], [1]]})).unwrap();
+    s.execute("home.conditionalFormat", json!({"range": "D5:D6,D2:D3", "rule": {"type": "expression", "formula": "=D2>0", "preset": "greenFill"}}))
+        .unwrap();
+    s.execute("range.setValues", json!({"range": "E2:E6", "values": [[1], [0], [0], [0], [1]]})).unwrap();
+    s.execute("range.setValues", json!({"range": "G2:G6", "values": [[0], [9], [9], [9], [0]]})).unwrap();
+    s.execute(
+        "home.conditionalFormat",
+        json!({"range": "E5:E6,E2:E3", "rule": {"type": "cellIs", "operator": "greater", "value": "=G2", "preset": "lightRedFill"}}),
+    )
+    .unwrap();
+    s.execute("home.clearRules", json!({"range": "D2,E2"})).unwrap();
+    let rules: Vec<gridcraft_model::CfRule> = s.doc().unwrap().wb.active().unwrap().cond_formats.iter().map(|c| c.rule.clone()).collect();
+    assert!(rules.iter().any(|r| matches!(r, gridcraft_model::CfRule::Expression { formula, .. } if formula == "D5>0")), "{rules:?}");
+    assert!(rules.iter().any(|r| matches!(r, gridcraft_model::CfRule::CellIs { a, .. } if a == "G5")), "{rules:?}");
+    let wb = s.doc().unwrap().wb.clone();
+    let mut cache = crate::cf::CfCache::new();
+    let mut styled = |c: &str| cache.look(&wb, 0, CellRef::parse(c).unwrap()).and_then(|l| l.style).is_some();
+    assert_eq!([styled("D5"), styled("D6"), styled("E5"), styled("E6")], [false, true, false, true]);
+}
+
 #[test]
 fn samples_build() {
     for (name, _) in crate::sample::SAMPLES {

crates/ui-egui/src/grid/editor.rs

@@ -125,7 +125,7 @@ pub(super) fn list_picker(app: &mut SheetApp, ui: &mut egui::Ui, geo: &Geo, was_
         app.grid.list_picker = None;
         return;
     };
-    let items = gridcraft_engine::cmd::data::list_items(&wb, si, &dv);
+    let items = gridcraft_engine::cmd::data::list_items(&wb, si, c, &dv);
     let r = geo.cell_rect(sh, c);
     // Fit the popup to its rows (up to LIST_PICKER_MAX_ROWS); without a minimum the scroll area collapses to its 64 px default.
     let height = list_picker_height(items.len(), LIST_PICKER_ROW_H, ui.spacing().item_spacing.y);

crates/ui-egui/src/ribbon/home.rs

@@ -622,10 +622,13 @@ fn size_combo(app: &mut SheetApp, ui: &mut Ui, st: &Style) {
     let arrow_rect = Rect::from_min_max(egui::pos2(frame.right() - 16.0, frame.top() + 1.0), egui::pos2(frame.right() - 1.0, frame.bottom() - 1.0));
     let mut field_ui =
         ui.new_child(egui::UiBuilder::new().max_rect(text_rect.shrink2(vec2(6.0, 0.0))).layout(egui::Layout::left_to_right(egui::Align::Center)));
+    // The text edit is `interact_size.y` tall and puts its text at the top of that unless told
+    // otherwise: center it, on the Font name's baseline (#3155).
     let out = egui::TextEdit::singleline(&mut text)
         .id(field)
         .font(theme::ui_font(12.5))
         .frame(egui::Frame::NONE)
+        .align(egui::Align2::LEFT_CENTER)
         .desired_width(text_rect.width() - 12.0)
         .show(&mut field_ui);
     let resp = out.response;

crates/ui-egui/tests/it/font_size_box.rs

@@ -1,6 +1,7 @@
-//! Home ▸ Font Size is a box you type a size into, with the standard sizes behind its arrow (#932).
+//! Home ▸ Font Size is a box you type a size into, with the standard sizes behind its arrow (#932),
+//! and the size sits in the middle of that box (#3155).
 
-use egui::{Event, Key, Modifiers, accesskit::Role};
+use egui::{Event, Key, Modifiers, Rect, Shape, accesskit::Role};
 use egui_kittest::kittest::Queryable as _;
 use gridcraft_engine::Session;
 use gridcraft_engine::core::{CellRef, Value};
@@ -124,3 +125,31 @@ fn the_arrow_opens_the_plain_list_of_sizes() {
     h.run_steps(3);
     assert_eq!(size(&h, "A1"), 12.0, "Down from 11 then Enter picks 12");
 }
+
+/// The on-screen box of the painted text `text` that overlaps `within`. The grid's row headers
+/// paint "11" too, so the size has to be looked for inside its own box.
+fn painted_text(h: &Harness, text: &str, within: Rect) -> Rect {
+    h.output()
+        .shapes
+        .iter()
+        .find_map(|s| match &s.shape {
+            Shape::Text(t) if t.galley.job.text == text => {
+                let rect = t.galley.rect.translate(t.pos.to_vec2());
+                within.intersects(rect).then_some(rect)
+            }
+            _ => None,
+        })
+        .unwrap_or_else(|| panic!("{text:?} is painted inside {within:?}"))
+}
+
+#[test]
+/// A text edit aligns its text to the top of its rect unless told otherwise, which left the size
+/// 4 pt above the Font name's baseline.
+fn the_size_is_vertically_centered_in_its_box() {
+    let h = harness();
+    let field = h.get_by_role_and_label(Role::TextInput, "Font Size").rect();
+    let value = painted_text(&h, "11", field);
+    let name = painted_text(&h, "Calibri", Rect::EVERYTHING);
+    assert!((value.center().y - field.center().y).abs() <= 1.0, "the size is centered in its box: {value:?} in {field:?}");
+    assert!((value.center().y - name.center().y).abs() <= 1.0, "the size is on the Font name's baseline: {value:?} against {name:?}");
+}

crates/ui-egui/tests/it/ribbon_layout.rs

@@ -104,7 +104,10 @@ struct Clicks {
 #[test]
 /// The main button clicks once and the arrow twice separately; the tooltip keeps the platform shortcut, and the icon sits above the full-width label.
 fn big_split_button_separates_the_default_action_from_the_menu() {
-    let mut h = crate::common::builder().with_size(vec2(300.0, 200.0)).build_ui_state(
+    // The ribbon picks the shortcut by the OS egui reports, which kittest pins to Nix unless told:
+    // pin macOS, so the check is the same on every host (the other platforms' text is in
+    // `widgets::tests`).
+    let mut h = crate::common::builder().with_size(vec2(300.0, 200.0)).with_os(egui::os::OperatingSystem::Mac).build_ui_state(
         |ui, c: &mut Clicks| {
             let (main, arrow) = widgets::big_split_button(ui, Icon::Sum, "Auto\nSum", "AutoSum");
             c.main += u32::from(main.clicked());
@@ -125,8 +128,7 @@ fn big_split_button_separates_the_default_action_from_the_menu() {
     h.ctx.all_styles_mut(|s| s.interaction.tooltip_delay = 0.0);
     h.get_by_label("Auto Sum").hover();
     h.run_steps(6);
-    let shortcut = if cfg!(target_os = "macos") { "AutoSum (\u{2318}\u{21e7}T)" } else { "AutoSum (Alt+=)" };
-    assert!(h.query_by_value(shortcut).is_some(), "tooltip with the shortcut");
+    assert!(h.query_by_value("AutoSum (\u{2318}\u{21e7}T)").is_some(), "tooltip with the macOS shortcut");
     // The icon part sits above the label part, across the full width.
     let main = h.get_by_label("Auto Sum").rect();
     let arrow = h.get_by_label("Auto Sum options").rect();

crates/xlsx/src/sheet_write/rules.rs

@@ -52,8 +52,10 @@ pub(super) fn x14_cfvo(v: &CfValueKind) -> String {
     format!("<x14:cfvo type=\"{ty}\"><xm:f>{}</xm:f></x14:cfvo>", esc(&val))
 }
 
+/// One `cfRule` element. The formulas generated for text, blank, error and date rules refer to the
+/// top-left cell of all the rule's areas, the cell Excel reads relative references from.
 pub(super) fn cf_rule_xml(cf: &CondFormat, priority: u32, out: &mut Out) -> String {
-    let tl = cf.ranges.first().map(|r| r.start.a1()).unwrap_or_else(|| "A1".into());
+    let tl = RangeRef::top_left(&cf.ranges).map(|c| c.a1()).unwrap_or_else(|| "A1".into());
     let stop = if cf.stop_if_true { " stopIfTrue=\"1\"" } else { "" };
     let mut dxf = |st: &Style| dxf_id(&mut out.dxfs, st);
     let f = |x: &str| format!("<formula>{}</formula>", esc(&text_to_file(x)));

crates/xlsx/src/tests/roundtrip.rs

@@ -1678,3 +1678,21 @@ fn workbook_view_writer_clamps_out_of_range_model_values() {
         assert_eq!(back.view.tab_ratio, 1000);
     }
 }
+
+#[test]
+fn generated_rule_formulas_use_the_top_left_cell_of_every_area() {
+    // Issue #3152: the areas aren't in top-to-bottom order; the formula is written for C2, not C5.
+    let mut wb = Workbook::new();
+    let red = Box::new(Style::default());
+    wb.sheet_mut(0).unwrap().cond_formats.push(CondFormat {
+        ranges: vec![rr("C5:C6"), rr("C2:C3")],
+        rule: CfRule::ContainsText { text: "x".into(), style: red },
+        priority: 1,
+        stop_if_true: false,
+    });
+    let bytes = write_xlsx(&wb).unwrap();
+    let mut z = zip::ZipArchive::new(std::io::Cursor::new(bytes)).unwrap();
+    let mut xml = String::new();
+    z.by_name("xl/worksheets/sheet1.xml").unwrap().read_to_string(&mut xml).unwrap();
+    assert!(xml.contains("<formula>NOT(ISERROR(SEARCH(\"x\",C2)))</formula>"), "{xml}");
+}

crates/xlsx/src/tests/shared_media.rs

@@ -85,3 +85,21 @@ fn different_pictures_with_the_same_length_stay_separate() {
     let back = read_xlsx(&bytes).unwrap().0;
     assert_eq!(back.sheets[0].images.iter().map(|i| i.data.to_vec()).collect::<Vec<_>>(), vec![a, b]);
 }
+
+/// Many distinct pictures that share a long prefix: each is matched against the earlier ones
+/// through a content hash, not by comparing bytes with every one of them.
+#[test]
+fn many_distinct_pictures_with_a_common_prefix_are_each_written_once() {
+    let pictures: Vec<Vec<u8>> = (0..400u32)
+        .map(|i| {
+            let mut v = b"\x89PNG\r\n\x1a\n".to_vec();
+            v.extend(std::iter::repeat_n(7u8, 65_536));
+            v.extend(i.to_le_bytes());
+            v
+        })
+        .collect();
+    let refs: Vec<(u32, &[u8])> = pictures.iter().enumerate().map(|(i, p)| (i as u32 + 1, p.as_slice())).collect();
+    let wb = Workbook { sheets: vec![sheet_with("One", &refs), sheet_with("Two", &refs)], ..Default::default() };
+    let bytes = write_xlsx(&wb).unwrap();
+    assert_eq!(names(&bytes).iter().filter(|n| n.starts_with("xl/media/")).count(), 400);
+}

crates/xlsx/src/write.rs

@@ -6,6 +6,7 @@ use std::fmt::Write as _;
 use gridcraft_core::RangeRef;
 use gridcraft_formula::quote_sheet;
 use gridcraft_model::{CalcMode, CalcSettings, PhoneticString, ShowObjects, Style, Visibility, Workbook, WorkbookView};
+use sha2::Digest as _;
 
 use crate::package::ZipOut;
 use crate::xml::{esc, esc_attr};
@@ -112,6 +113,9 @@ pub struct Out {
     pub dxfs: Vec<Style>,
     pub sst: Sst,
     pub images: u32,
+    /// Media parts written so far, by extension and SHA-256 of their bytes: a picture used again
+    /// is found here instead of being compared byte by byte with every earlier one.
+    media: HashMap<(String, [u8; 32]), String>,
     pub charts: u32,
     /// The workbook's file name, which a PivotChart's link to its PivotTable names in brackets.
     pub book_name: String,
@@ -142,15 +146,14 @@ impl Out {
     /// The `xl/media` file name (`imageN.ext`) holding `data`. A picture used on several sheets,
     /// or twice on one, is written once and every drawing points to that part, as in Excel.
     pub fn image_part(&mut self, ext: &str, data: &[u8]) -> String {
-        let existing = self.parts.iter().find(|(name, bytes)| {
-            name.strip_prefix("xl/media/image").is_some_and(|rest| rest.ends_with(&format!(".{ext}"))) && bytes.as_slice() == data
-        });
-        if let Some((name, _)) = existing {
-            return name.trim_start_matches("xl/media/").to_string();
+        let key = (ext.to_string(), sha2::Sha256::digest(data).into());
+        if let Some(file) = self.media.get(&key) {
+            return file.clone();
         }
         self.images += 1;
         let file = format!("image{}.{ext}", self.images);
         self.part(&format!("xl/media/{file}"), None, data.to_vec());
+        self.media.insert(key, file.clone());
         file
     }
     pub fn default_type(&mut self, ext: &str, ct: &str) {
@@ -249,6 +252,7 @@ pub fn write_xlsx_named(wb: &Workbook, kind: XlsxKind, book_name: Option<&str>)
         dxfs: vec![],
         sst: Sst::default(),
         images: 0,
+        media: HashMap::new(),
         charts: 0,
         book_name: book_name.filter(|n| !n.is_empty() && !n.contains(['[', ']'])).unwrap_or(DEFAULT_BOOK_NAME).to_string(),
         chart_names: vec![],