Graph Data: Transpose and Switch x/y; | line breaks in labels; pie Legend, Position and Sort

Graph Data's Transpose row/column and Switch x/y, as
https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/visualize-data/add-graph-data.html
describes, a `|` in a label as a line break, as
https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/visualize-data/add-graph-labels-and-data-sets.html
describes, and the pie graph options of
https://helpx.adobe.com/illustrator/desktop/automate-visualize-data/visualize-data/format-pie-graphs.html

- graph.setData {transpose: true} swaps rows and columns (after any new
  data in the same call); a graph with more categories than a graph can
  have series (256) is refused rather than cut. {switchXY: true} swaps
  each scatter series' y and x columns, labels included.
- A `|` in a category or series label starts a new line: legend rows
  grow with their lines, labels beside an axis or in a wedge centre
  theirs. A label of only `|` is blank.
- Pie graphs: pieLegend none|standard|wedges (Legends in Wedges puts the
  series labels inside their wedges, in white on dark wedges, drawn over
  the pies), piePosition ratio|even|stacked and pieSort all|first|none,
  as dropdowns in the Graph Type dialog, which lists them for pie graphs
  only.

Own choices, as the page doesn't say: Position and Sort keep today's
drawing by default (Even, None); Ratio sizes pies by area, the biggest
keeping the full size; Stacked pies share a centre, each drawn as the
ring outside the next smaller one so none covers another, with their
names over them.

New fields are written only when set. Graphs with default options draw
the same art as before.

crates/engine/src/cmd/graph.rs

@@ -34,7 +34,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Data…",
             ["Object", "Graph"],
             None,
-            "{id?, series?, categories?, rows?, csv?: first row = series labels (first cell empty), then one row per category: label, values…; an empty cell or a null is a blank value, a quoted number a label} replace the graph's data; no data → the current {csv, series, categories, rows}",
+            "{id?, series?, categories?, rows?, csv?: first row = series labels (first cell empty), then one row per category: label, values…; an empty cell or a null is a blank value, a quoted number a label, a `|` in a label a line break; transpose?: true swaps rows and columns (Transpose row/column), switchXY?: true swaps each scatter series' y and x columns (Switch x/y)} replace the graph's data; no data → the current {csv, series, categories, rows}",
             has_selection,
             set_data
         ),
@@ -43,7 +43,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Type…",
             ["Object", "Graph"],
             None,
-            "{id?, type?, seriesIndexes?: [index], columnWidth?: %, clusterWidth?: %, legend?: bool, markPoints?: bool, connectPoints?: bool, edgeToEdge?: bool (line graphs: true runs the lines across the whole plot, false puts the points at the centres of their categories), ticks?: n, axisMin?, axisMax?, valueAxis?: left|right|both (the bar graphs' value axis stays along the bottom), separateScales?: bool, rightTicks?: n, rightAxisMin?, rightAxisMax?, tickLength?: none|short|full, tickMarks?: n per division, rightTickLength?, rightTickMarks?, categoryTickLength?: none|short|full, categoryTickMarks?: n, ticksBetweenLabels?: bool, prefix?, suffix?, rightPrefix?, rightSuffix?: text around the value axis numbers} change the graph type and options; with `seriesIndexes`, or (no `id`) with only series selected with Group Selection, `type` goes to those series only and `valueAxis` (left|right; both is refused) puts them on that value axis, while the other options still apply to the whole graph (Combine different graph types: column, stacked column, line and area mix, and so do bar and stacked bar; a series given the graph's type follows the graph again) (axisMin and axisMax together override the calculated value axis: exactly that range in `ticks` divisions, 5 when 0; with the value axis on both sides, separateScales gives the series on the right axis a scale of their own, set the same way with rightTicks, rightAxisMin and rightAxisMax); no options → the current ones",
+            "{id?, type?, seriesIndexes?: [index], columnWidth?: %, clusterWidth?: %, legend?: bool, markPoints?: bool, connectPoints?: bool, edgeToEdge?: bool (line graphs: true runs the lines across the whole plot, false puts the points at the centres of their categories), ticks?: n, axisMin?, axisMax?, valueAxis?: left|right|both (the bar graphs' value axis stays along the bottom), separateScales?: bool, rightTicks?: n, rightAxisMin?, rightAxisMax?, tickLength?: none|short|full, tickMarks?: n per division, rightTickLength?, rightTickMarks?, categoryTickLength?: none|short|full, categoryTickMarks?: n, ticksBetweenLabels?: bool, prefix?, suffix?, rightPrefix?, rightSuffix?: text around the value axis numbers, pieLegend?: none|standard|wedges (Legends in Wedges: the series labels inside their wedges), piePosition?: ratio|even|stacked (several pies sized by their totals, at one size (the default), or stacked), pieSort?: all|first|none (wedges largest first in each pie, in the first pie's order, or in data order (the default)); the query lists the pie options for pie graphs} change the graph type and options; with `seriesIndexes`, or (no `id`) with only series selected with Group Selection, `type` goes to those series only and `valueAxis` (left|right; both is refused) puts them on that value axis, while the other options still apply to the whole graph (Combine different graph types: column, stacked column, line and area mix, and so do bar and stacked bar; a series given the graph's type follows the graph again) (axisMin and axisMax together override the calculated value axis: exactly that range in `ticks` divisions, 5 when 0; with the value axis on both sides, separateScales gives the series on the right axis a scale of their own, set the same way with rightTicks, rightAxisMin and rightAxisMax); no options → the current ones",
             has_selection,
             set_type
         ),
@@ -178,7 +178,12 @@ fn apply_data(g: &mut GraphSpec, p: &Value) -> bool {
         );
         changed = true;
     }
-    // Drop rows with neither a value nor a label; a label-only row stays, its values blank.
+    drop_empty_rows(g);
+    changed
+}
+
+/// Drop rows with neither a value nor a label; a label-only row stays, its values blank.
+fn drop_empty_rows(g: &mut GraphSpec) {
     let mut cells = g.cells();
     let keep: Vec<bool> = (0..cells.len())
         .map(|c| cells.get(c).is_some_and(|r| r.iter().any(Option::is_some)) || g.categories.get(c).is_some_and(|l| !l.is_empty()))
@@ -190,7 +195,6 @@ fn apply_data(g: &mut GraphSpec, p: &Value) -> bool {
         g.categories.retain(|_| k.next().copied().unwrap_or(true));
         g.set_cells(cells);
     }
-    changed
 }
 
 fn fmt_value(v: f64) -> String {
@@ -307,6 +311,13 @@ impl Gen<'_> {
         refresh_bounds(&mut t);
         Arc::new(Node::new(self.d.alloc_id(), NodeKind::Text(Box::new(t))))
     }
+    /// A category or series label: a `|` in it starts a new line (Add graph labels). `middle`: the lines are centred
+    /// on `at` (labels beside an axis or in a wedge) instead of running down from it.
+    fn label(&mut self, at: Point, s: &str, justify: Justify, middle: bool) -> Arc<Node> {
+        let lines = s.split('|').count();
+        let at = if middle { Point::new(at.x, at.y - (lines - 1) as f64 * LABEL_SIZE * 1.2 / 2.0) } else { at };
+        self.text(at, &s.replace('|', "\n"), justify)
+    }
     fn group(&mut self, name: &str, children: Vec<Arc<Node>>) -> Arc<Node> {
         let mut g = Node::group(self.d.alloc_id(), children);
         g.name = Some(name.into());
@@ -329,6 +340,22 @@ impl Gen<'_> {
     }
 }
 
+/// A label with nothing to show (empty, or only `|` line breaks).
+fn blank_label(s: &str) -> bool {
+    s.chars().all(|c| c == '|')
+}
+
+/// Text node `t` with its characters painted `colour`.
+fn recolour_text(t: &Arc<Node>, colour: Color) -> Arc<Node> {
+    let mut n = (**t).clone();
+    if let NodeKind::Text(text) = &mut n.kind {
+        for run in &mut text.runs {
+            run.style.fill = Paint::solid(colour);
+        }
+    }
+    Arc::new(n)
+}
+
 /// The stretches of two or more points between blank cells, which a line connects.
 fn runs(pts: &[Option<Point>]) -> Vec<Vec<Point>> {
     pts.split(Option::is_none).map(|r| r.iter().flatten().copied().collect::<Vec<_>>()).filter(|r| r.len() > 1).collect()
@@ -413,35 +440,110 @@ fn generate(d: &mut Document, g: &GraphSpec) -> Vec<Arc<Node>> {
     // Where the art right of the plot ends (the right value axis' labels), so the legend starts after it.
     let mut right_edge = r.x1;
 
+    // Labels drawn over the series: a pie's Legends in Wedges (in the Legend group) and stacked pies' names.
+    let mut wedge_labels = vec![];
+    let mut on_top = vec![];
     match g.kind {
         GraphKind::Pie => {
-            // One pie per row, side by side; a wedge per series, clockwise from 12 o'clock.
-            let w = r.width() / ncat as f64;
-            let rad = (w.min(r.height()) / 2.0 * 0.9).max(1.0);
-            for c in 0..ncat {
-                let centre = Point::new(r.x0 + w * (c as f64 + 0.5), r.y0 + r.height() / 2.0);
-                let total: f64 = (0..nser).map(|s| val(c, s).max(0.0)).sum();
+            // One pie per row, a wedge per series, clockwise from 12 o'clock. Position: side by side at one size
+            // (Even) or sized by their totals (Ratio, by area), or stacked on one centre, the largest at the back.
+            let totals: Vec<f64> = (0..ncat).map(|c| (0..nser).map(|s| val(c, s).max(0.0)).sum()).collect();
+            let biggest = totals.iter().copied().fold(0.0, f64::max);
+            let stacked = g.pie_position == vectorcraft_doc::PiePosition::Stacked;
+            let w = if stacked { r.width() } else { r.width() / ncat as f64 };
+            let full = (w.min(r.height()) / 2.0 * 0.9).max(1.0);
+            let radius = |total: f64| match g.pie_position {
+                vectorcraft_doc::PiePosition::Even => full,
+                _ if biggest > 0.0 && biggest.is_finite() => (full * (total / biggest).sqrt()).max(1.0),
+                _ => full,
+            };
+            // Sort: data order, largest first in each pie, or the first pie's largest-first order everywhere.
+            let order = |c: usize| {
+                let mut o: Vec<usize> = (0..nser).collect();
+                let by = match g.pie_sort {
+                    vectorcraft_doc::PieSort::None => return o,
+                    vectorcraft_doc::PieSort::All => c,
+                    vectorcraft_doc::PieSort::First => 0,
+                };
+                o.sort_by(|a, b| val(by, *b).max(0.0).total_cmp(&val(by, *a).max(0.0)));
+                o
+            };
+            let mut pies: Vec<usize> = (0..ncat).collect();
+            if stacked {
+                pies.sort_by(|a, b| totals.get(*b).copied().unwrap_or(0.0).total_cmp(&totals.get(*a).copied().unwrap_or(0.0)));
+            }
+            // Stacked pies share a centre: each one but the smallest is drawn as the ring outside the next smaller
+            // one, so a pie never covers another (a pie as big as the next one has no ring and is left out).
+            let inner: Vec<f64> = if stacked {
+                (0..pies.len()).map(|k| pies.get(k + 1).map_or(0.0, |c| radius(totals.get(*c).copied().unwrap_or(0.0)))).collect()
+            } else {
+                vec![0.0; pies.len()]
+            };
+            for (k, c) in pies.into_iter().enumerate() {
+                let total = totals.get(c).copied().unwrap_or(0.0);
+                let rad = radius(total);
+                let hole = inner.get(k).copied().unwrap_or(0.0);
+                if hole >= rad - 1e-9 {
+                    continue;
+                }
+                let centre = if stacked { r.center() } else { Point::new(r.x0 + w * (c as f64 + 0.5), r.y0 + r.height() / 2.0) };
                 let mut a0 = -std::f64::consts::FRAC_PI_2;
-                for (s, items) in series.iter_mut().enumerate() {
+                for s in order(c) {
                     let v = val(c, s).max(0.0);
                     if total <= 0.0 || v <= 0.0 {
                         continue;
                     }
                     let sweep = v / total * std::f64::consts::TAU;
                     let mut bp = BezPath::new();
-                    bp.move_to(centre);
+                    let dir = |a: f64| vectorcraft_geom::Vec2::new(a.cos(), a.sin());
                     let arc = vectorcraft_geom::kurbo::Arc::new(centre, (rad, rad), a0, sweep, 0.0);
-                    bp.line_to(centre + vectorcraft_geom::Vec2::new(a0.cos(), a0.sin()) * rad);
-                    arc.to_cubic_beziers(0.1, |p1, p2, p| bp.curve_to(p1, p2, p));
+                    if hole > 0.0 {
+                        // A ring segment: out along the outer arc, back along the inner one.
+                        bp.move_to(centre + dir(a0) * rad);
+                        arc.to_cubic_beziers(0.1, |p1, p2, p| bp.curve_to(p1, p2, p));
+                        bp.line_to(centre + dir(a0 + sweep) * hole);
+                        let back = vectorcraft_geom::kurbo::Arc::new(centre, (hole, hole), a0 + sweep, -sweep, 0.0);
+                        back.to_cubic_beziers(0.1, |p1, p2, p| bp.curve_to(p1, p2, p));
+                    } else {
+                        bp.move_to(centre);
+                        bp.line_to(centre + dir(a0) * rad);
+                        arc.to_cubic_beziers(0.1, |p1, p2, p| bp.curve_to(p1, p2, p));
+                    }
                     bp.close_path();
-                    let (fill, stroke, w) = mark(s, true, Paint::solid(Color::WHITE), 0.5);
-                    let n = b.path(PathData::from_bezpath(&bp), fill, stroke, w);
-                    items.push(n);
+                    let (fill, stroke, sw) = mark(s, true, Paint::solid(Color::WHITE), 0.5);
+                    // White text on a dark wedge.
+                    let dark = fill.color().is_some_and(|c| {
+                        let [r, g, b] = c.to_rgb();
+                        0.2126 * r + 0.7152 * g + 0.0722 * b < 0.5
+                    });
+                    let n = b.path(PathData::from_bezpath(&bp), fill, stroke, sw);
+                    if let Some(items) = series.get_mut(s) {
+                        items.push(n);
+                    }
+                    // Legends in Wedges: the series label inside its wedge, centred two thirds of the way out.
+                    if g.legend && g.pie_legend_in_wedges {
+                        let label = series_label(s);
+                        if !blank_label(&label) {
+                            // Two thirds of the way out (of the ring, for a stacked pie).
+                            let mid = a0 + sweep / 2.0;
+                            let at = centre + dir(mid) * (hole + (rad - hole) * 0.62);
+                            let t = b.label(Point::new(at.x, at.y + LABEL_SIZE * 0.35), &label, Justify::Center, true);
+                            wedge_labels.push(if dark { recolour_text(&t, Color::WHITE) } else { t });
+                        }
+                    }
                     a0 += sweep;
                 }
                 if let Some(cat) = g.categories.get(c).filter(|c| !c.is_empty()) {
-                    let t = b.text(Point::new(centre.x, centre.y + rad + LABEL_SIZE * 1.6), cat, Justify::Center);
-                    b.out.push(t);
+                    if stacked {
+                        // Just above its own outline, all its lines, and drawn over the pies.
+                        let lines = cat.split('|').count() as f64;
+                        let at = Point::new(centre.x, centre.y - rad - LABEL_SIZE * 0.4 - (lines - 1.0) * LABEL_SIZE * 1.2);
+                        let t = b.label(at, cat, Justify::Center, false);
+                        on_top.push(t);
+                    } else {
+                        let t = b.label(Point::new(centre.x, centre.y + rad + LABEL_SIZE * 1.6), cat, Justify::Center, false);
+                        b.out.push(t);
+                    }
                 }
             }
         }
@@ -458,7 +560,7 @@ fn generate(d: &mut Document, g: &GraphSpec) -> Vec<Arc<Node>> {
                 axes.push(b.line(centre, at(c, hi)));
                 if let Some(cat) = g.categories.get(c).filter(|c| !c.is_empty()) {
                     let p = at(c, hi) + (at(c, hi) - centre).normalize() * (LABEL_SIZE * 1.2);
-                    axes.push(b.text(Point::new(p.x, p.y + LABEL_SIZE * 0.35), cat, Justify::Center));
+                    axes.push(b.label(Point::new(p.x, p.y + LABEL_SIZE * 0.35), cat, Justify::Center, true));
                 }
             }
             for v in tick_values(lo, hi, step).into_iter().skip(1) {
@@ -646,9 +748,9 @@ fn generate(d: &mut Document, g: &GraphSpec) -> Vec<Arc<Node>> {
                 for c in 0..ncat {
                     if let Some(cat) = g.categories.get(c).filter(|c| !c.is_empty()) {
                         let t = if horizontal {
-                            b.text(Point::new(r.x0 - 6.0, cat_mid(c) + LABEL_SIZE * 0.35), cat, Justify::Right)
+                            b.label(Point::new(r.x0 - 6.0, cat_mid(c) + LABEL_SIZE * 0.35), cat, Justify::Right, true)
                         } else {
-                            b.text(Point::new(cat_mid(c), r.y1 + LABEL_SIZE * 1.4), cat, Justify::Center)
+                            b.label(Point::new(cat_mid(c), r.y1 + LABEL_SIZE * 1.4), cat, Justify::Center, false)
                         };
                         axes.push(t);
                     }
@@ -819,19 +921,24 @@ fn generate(d: &mut Document, g: &GraphSpec) -> Vec<Arc<Node>> {
     // Legend: a swatch + label per series, right of the plot; the swatch joins its series group.
     let legend_series = if g.kind == GraphKind::Scatter { nser.div_ceil(2) } else { nser };
     let mut labels = vec![];
-    if g.legend && !g.series.is_empty() {
+    if g.legend && !g.series.is_empty() && !(g.kind == GraphKind::Pie && g.pie_legend_in_wedges) {
         let x = right_edge + 14.0;
+        // Each row as tall as its label's lines (a `|` in a label starts a new line).
+        let mut y = r.y0;
         for (s, items) in series.iter_mut().enumerate().take(legend_series) {
             let label = if g.kind == GraphKind::Scatter { series_label(s * 2) } else { series_label(s) };
-            if label.is_empty() {
+            let row_y = y;
+            if blank_label(&label) {
+                y += LABEL_SIZE * 1.8;
                 continue;
             }
-            let y = r.y0 + s as f64 * (LABEL_SIZE * 1.8);
+            y += LABEL_SIZE * 1.8 * label.split('|').count() as f64;
+            let y = row_y;
             // Series drawn with markers show their marker design in the legend.
             let marked = matches!(g.kind, GraphKind::Scatter | GraphKind::Radar) || kind(s) == GraphKind::Line;
             let paint = mark(s, true, Paint::None, 0.0);
             items.push(b.marker(design(s).filter(|_| marked), Rect::new(x, y, x + 8.0, y + 8.0), paint));
-            labels.push(b.text(Point::new(x + 12.0, y + 7.5), &label, Justify::Left));
+            labels.push(b.label(Point::new(x + 12.0, y + 7.5), &label, Justify::Left, false));
         }
     }
     // Areas at the back, lines and points in front of columns; one graph type keeps the series order.
@@ -850,6 +957,8 @@ fn generate(d: &mut Document, g: &GraphSpec) -> Vec<Arc<Node>> {
         let grp = b.series(&name, s, items);
         b.out.push(grp);
     }
+    b.out.append(&mut on_top);
+    labels.append(&mut wedge_labels);
     if !labels.is_empty() {
         let grp = b.group("Legend", labels);
         b.out.push(grp);
@@ -1020,10 +1129,61 @@ pub(crate) fn capture_series_paints(doc: &mut Document, ids: &[NodeId], fill: bo
     }
 }
 
+/// Graph Data › Transpose row/column: categories become series and series categories.
+fn transpose(g: &mut GraphSpec) {
+    let cells = g.cells();
+    let width = cells.iter().map(Vec::len).max().unwrap_or(0);
+    let flipped: Vec<Vec<Option<f64>>> = (0..width).map(|s| cells.iter().map(|row| row.get(s).copied().flatten()).collect()).collect();
+    std::mem::swap(&mut g.series, &mut g.categories);
+    g.set_cells(flipped);
+}
+
+/// Graph Data › Switch x/y (scatter graphs): each series' y and x columns trade places, with their labels.
+fn switch_xy(g: &mut GraphSpec) {
+    let mut cells = g.cells();
+    // Labels for every column, so each pair's labels trade places with its data.
+    let width = cells.iter().map(Vec::len).max().unwrap_or(0).max(g.series.len());
+    g.series.resize(width, String::new());
+    for row in &mut cells {
+        for pair in row.as_chunks_mut::<2>().0 {
+            pair.swap(0, 1);
+        }
+    }
+    for pair in g.series.as_chunks_mut::<2>().0 {
+        pair.swap(0, 1);
+    }
+    while g.series.last().is_some_and(String::is_empty) {
+        g.series.pop();
+    }
+    g.set_cells(cells);
+}
+
 fn set_data(s: &mut Session, p: &Value) -> Result<Value> {
-    let id = target(s, p, "graph.setData")?;
+    const C: &str = "graph.setData";
+    let id = target(s, p, C)?;
     let mut spec = spec_of(s, id)?;
-    if !apply_data(&mut spec, p) {
+    let flip = bool_or(p, "transpose", false);
+    let swap = bool_or(p, "switchXY", false);
+    if swap && spec.kind != GraphKind::Scatter {
+        return Err(bad(C, "Switch x/y is for scatter graphs"));
+    }
+    // Transpose and Switch x/y act after any new data in the same call.
+    let changed = apply_data(&mut spec, p);
+    if flip {
+        // The categories become series: at most as many as a graph has series.
+        if spec.cells().len() > vectorcraft_doc::MAX_GRAPH_SERIES {
+            return Err(bad(
+                C,
+                format!("a graph has at most {} series, so it transposes with at most that many categories", vectorcraft_doc::MAX_GRAPH_SERIES),
+            ));
+        }
+        transpose(&mut spec);
+        drop_empty_rows(&mut spec);
+    }
+    if swap {
+        switch_xy(&mut spec);
+    }
+    if !(changed || flip || swap) {
         // Blank cells come back as null, so the rows can be edited and sent back as they are.
         return Ok(json!({ "csv": to_csv(&spec), "series": spec.series, "categories": spec.categories, "rows": spec.cells() }));
     }
@@ -1313,6 +1473,9 @@ fn set_type(s: &mut Session, p: &Value) -> Result<Value> {
         "suffix",
         "rightPrefix",
         "rightSuffix",
+        "pieLegend",
+        "piePosition",
+        "pieSort",
     ];
     if !keys.iter().any(|k| p.get(*k).is_some()) {
         // With series picked, the type and value axis they share, so the dialog's OK keeps them.
@@ -1325,7 +1488,7 @@ fn set_type(s: &mut Session, p: &Value) -> Result<Value> {
             Some(r) if sides.iter().all(|x| x == r) => Some(if *r { "right" } else { "left" }),
             Some(_) => None,
         };
-        return Ok(json!({
+        let mut fields = json!({
             "type": kind.id(), "columnWidth": spec.column_width, "clusterWidth": spec.cluster_width, "legend": spec.legend,
             "markPoints": spec.mark_points, "connectPoints": spec.connect_points, "edgeToEdge": spec.edge_to_edge, "ticks": spec.ticks,
             "axisMin": spec.axis_min, "axisMax": spec.axis_max, "valueAxis": value_axis, "separateScales": spec.separate_scales,
@@ -1335,7 +1498,24 @@ fn set_type(s: &mut Session, p: &Value) -> Result<Value> {
             "categoryTickMarks": spec.category_tick_marks.clamp(1, MAX_TICK_MARKS), "ticksBetweenLabels": spec.ticks_between_labels,
             "prefix": one_line(&spec.prefix), "suffix": one_line(&spec.suffix), "rightPrefix": one_line(&spec.right_prefix),
             "rightSuffix": one_line(&spec.right_suffix),
-        }));
+        });
+        // Pie graphs: Legend, Position and Sort (their Legend stands for the legend checkbox).
+        if let Some(o) = fields.as_object_mut().filter(|_| spec.kind == GraphKind::Pie) {
+            o.remove("legend");
+            o.insert(
+                "pieLegend".into(),
+                json!(if !spec.legend {
+                    "none"
+                } else if spec.pie_legend_in_wedges {
+                    "wedges"
+                } else {
+                    "standard"
+                }),
+            );
+            o.insert("piePosition".into(), json!(spec.pie_position.id()));
+            o.insert("pieSort".into(), json!(spec.pie_sort.id()));
+        }
+        return Ok(fields);
     }
     // Series picked with Group Selection stay selected through the regeneration (their groups are new nodes).
     let reselect: Vec<u32> = if p.get("seriesIndexes").is_none() { picked.iter().filter_map(|i| u32::try_from(*i).ok()).collect() } else { vec![] };
@@ -1390,6 +1570,13 @@ fn set_type(s: &mut Session, p: &Value) -> Result<Value> {
         *slot = count_param(p, key, MAX_TICK_MARKS as u64).map_or(*slot, |n| n.max(1));
     }
     spec.ticks_between_labels = bool_or(p, "ticksBetweenLabels", spec.ticks_between_labels);
+    if let Some(v) = str_param(p, "piePosition") {
+        spec.pie_position =
+            vectorcraft_doc::PiePosition::parse(v).ok_or_else(|| bad(C, format!("unknown piePosition `{v}` (even, ratio or stacked)")))?;
+    }
+    if let Some(v) = str_param(p, "pieSort") {
+        spec.pie_sort = vectorcraft_doc::PieSort::parse(v).ok_or_else(|| bad(C, format!("unknown pieSort `{v}` (none, all or first)")))?;
+    }
     for (key, slot) in
         [("prefix", &mut spec.prefix), ("suffix", &mut spec.suffix), ("rightPrefix", &mut spec.right_prefix), ("rightSuffix", &mut spec.right_suffix)]
     {
@@ -1408,6 +1595,15 @@ fn set_type(s: &mut Session, p: &Value) -> Result<Value> {
     spec.column_width = f64_or(p, "columnWidth", spec.column_width).clamp(1.0, 1000.0);
     spec.cluster_width = f64_or(p, "clusterWidth", spec.cluster_width).clamp(1.0, 100.0);
     spec.legend = bool_or(p, "legend", spec.legend);
+    // After `legend`, which the Graph Type dialog sends too.
+    if let Some(v) = str_param(p, "pieLegend") {
+        (spec.legend, spec.pie_legend_in_wedges) = match v.to_ascii_lowercase().as_str() {
+            "none" => (false, false),
+            "standard" => (true, false),
+            "wedges" => (true, true),
+            _ => return Err(bad(C, format!("unknown pieLegend `{v}` (none, standard or wedges)"))),
+        };
+    }
     spec.mark_points = bool_or(p, "markPoints", spec.mark_points);
     spec.connect_points = bool_or(p, "connectPoints", spec.connect_points);
     spec.edge_to_edge = bool_or(p, "edgeToEdge", spec.edge_to_edge);
@@ -2827,4 +3023,245 @@ mod tests {
         assert_eq!(s.execute("graph.design", &json!({})).unwrap()["designs"], json!([]));
         assert!(s.execute("graph.design", &json!({"delete": ["Nope"]})).is_err());
     }
+
+    fn make(s: &mut Session, ty: &str, csv: &str) -> NodeId {
+        NodeId(
+            s.execute("graph.create", &json!({"type": ty, "x": 100, "y": 100, "width": 300, "height": 200, "csv": csv})).unwrap()["id"]
+                .as_u64()
+                .unwrap(),
+        )
+    }
+
+    /// Where each wedge of series `index` starts: its angle from 12 o'clock, clockwise, in degrees (the legend
+    /// swatch, last, left out).
+    fn wedge_starts(s: &Session, id: NodeId, index: u32) -> Vec<f64> {
+        let parts = series_parts(s, id, index);
+        parts[..parts.len() - 1]
+            .iter()
+            .filter_map(|n| match &n.kind {
+                NodeKind::Path { path, .. } => {
+                    let bp = path.to_bezpath();
+                    let pts: Vec<_> = bp.elements().iter().filter_map(|e| e.end_point()).collect();
+                    let (c, p) = (pts.first()?, pts.get(1)?);
+                    let deg = (p.x - c.x).atan2(-(p.y - c.y)).to_degrees();
+                    Some(if deg < -1e-6 { deg + 360.0 } else { deg })
+                }
+                _ => None,
+            })
+            .collect()
+    }
+
+    #[test]
+    fn a_bar_in_a_label_breaks_the_line() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let id = make(&mut s, "column", ",Total|Sales|2023,b\nQ1|first,3,2\nQ2,5,4");
+        let texts = axis_texts(&s, id);
+        assert!(texts.contains(&"Q1\nfirst".to_string()), "{texts:?}");
+        // The legend: a label of three lines, and the next row below all three.
+        let n = s.doc().unwrap().doc.node(id).unwrap().clone();
+        let legend: Vec<_> = group(&n, "Legend").children().unwrap().iter().map(|c| (**c).clone()).collect();
+        let NodeKind::Text(t) = &legend[0].kind else { panic!() };
+        assert_eq!(t.plain_text(), "Total\nSales\n2023");
+        let (a, b) = (
+            series_parts(&s, id, 0).last().unwrap().geometric_bounds().unwrap(),
+            series_parts(&s, id, 1).last().unwrap().geometric_bounds().unwrap(),
+        );
+        assert!((b.y0 - a.y0 - 3.0 * 9.0 * 1.8).abs() < 1e-6, "{a:?} {b:?}");
+    }
+
+    #[test]
+    fn transpose_swaps_rows_and_columns_and_switch_xy_swaps_scatter_pairs() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let id = make(&mut s, "column", ",a,b\nQ1,1,2\nQ2,3,");
+        let before = spec(&s, id);
+        s.execute("graph.setData", &json!({"transpose": true})).unwrap();
+        let g = spec(&s, id);
+        assert_eq!((g.series.clone(), g.categories.clone()), (vec!["Q1".to_string(), "Q2".into()], vec!["a".to_string(), "b".into()]));
+        assert_eq!(g.cells(), [[Some(1.0), Some(3.0)], [Some(2.0), None]]);
+        s.execute("graph.setData", &json!({"transpose": true})).unwrap();
+        assert_eq!(spec(&s, id).cells(), before.cells());
+        s.execute("edit.undo", &json!({})).unwrap();
+        assert_eq!(spec(&s, id).cells(), g.cells());
+        assert!(s.execute("graph.setData", &json!({"switchXY": true})).is_err(), "scatter graphs only");
+        let sc = make(&mut s, "scatter", ",y1,x1,y2,x2\nP,1,10,2,20");
+        s.execute("graph.setData", &json!({"switchXY": true})).unwrap();
+        let g = spec(&s, sc);
+        assert_eq!(g.cells(), [[Some(10.0), Some(1.0), Some(20.0), Some(2.0)]]);
+        assert_eq!(g.series, ["x1", "y1", "x2", "y2"]);
+    }
+
+    #[test]
+    fn pie_wedges_sort_largest_first_in_each_pie_or_in_the_first_pies_order() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let id = make(&mut s, "pie", ",a,b,c\nP1,1,3,2\nP2,3,1,2");
+        // None (data order): a starts at 12 o'clock in both pies.
+        assert_eq!(wedge_starts(&s, id, 0).iter().map(|d| d.round()).collect::<Vec<_>>(), [0.0, 0.0]);
+        s.execute("graph.setType", &json!({"pieSort": "all"})).unwrap();
+        // P1: b (3) first; P2: a (3) first.
+        let (a, b) = (wedge_starts(&s, id, 0), wedge_starts(&s, id, 1));
+        assert!(b[0].abs() < 1e-6 && a[1].abs() < 1e-6, "{a:?} {b:?}");
+        s.execute("graph.setType", &json!({"pieSort": "first"})).unwrap();
+        // P1's order (b, c, a) in both: b first in P2 too.
+        let b = wedge_starts(&s, id, 1);
+        assert!(b.iter().all(|d| d.abs() < 1e-6), "{b:?}");
+        assert_eq!(s.execute("graph.setType", &json!({})).unwrap()["pieSort"], "first");
+        assert!(s.execute("graph.setType", &json!({"pieSort": "random"})).is_err());
+    }
+
+    #[test]
+    fn pies_sized_by_their_totals_side_by_side_or_stacked() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let id = make(&mut s, "pie", ",a,b\nSmall,5,5\nBig,20,20");
+        let pie = |s: &Session, c: usize| {
+            let wedges = |i: u32| {
+                let parts = series_parts(s, id, i);
+                parts[..parts.len() - 1].to_vec()
+            };
+            let rects: Vec<_> = (0..2).flat_map(wedges).filter_map(|n| n.geometric_bounds()).collect();
+            rects.into_iter().skip(c).step_by(2).reduce(|a, b| a.union(b)).unwrap()
+        };
+        let even = (pie(&s, 0), pie(&s, 1));
+        assert!((even.0.width() - even.1.width()).abs() < 1e-6);
+        s.execute("graph.setType", &json!({"piePosition": "ratio"})).unwrap();
+        let (small, big) = (pie(&s, 0), pie(&s, 1));
+        // Areas in proportion to the totals: 10 and 40, so radii 1 : 2.
+        assert!((big.width() / small.width() - 2.0).abs() < 1e-6, "{small:?} {big:?}");
+        assert!((big.width() - even.1.width()).abs() < 1e-6, "the biggest keeps the full size");
+        s.execute("graph.setType", &json!({"piePosition": "stacked"})).unwrap();
+        // Drawn largest first, so the big pie's wedges come first in each series.
+        let (big, small) = (pie(&s, 0), pie(&s, 1));
+        assert!((small.center() - big.center()).hypot() < 1e-6 && (big.width() / small.width() - 2.0).abs() < 1e-6);
+        // The big pie is drawn first, under the small one.
+        let n = s.doc().unwrap().doc.node(id).unwrap().clone();
+        let wedges: Vec<f64> = series(&n, 0).children().unwrap().iter().filter_map(|c| c.geometric_bounds()).map(|b| b.width()).collect();
+        assert!(wedges[0] > wedges[1], "{wedges:?}");
+    }
+
+    #[test]
+    fn legends_in_wedges_put_the_series_labels_inside_the_pie() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let id = make(&mut s, "pie", ",North,South|East\nP,1,1");
+        s.execute("graph.setType", &json!({"pieLegend": "wedges"})).unwrap();
+        let n = s.doc().unwrap().doc.node(id).unwrap().clone();
+        let pie =
+            series(&n, 0).children().unwrap()[0].geometric_bounds().unwrap().union(series(&n, 1).children().unwrap()[0].geometric_bounds().unwrap());
+        let labels: Vec<_> = group(&n, "Legend").children().unwrap().iter().map(|c| (**c).clone()).collect();
+        assert_eq!(labels.len(), 2);
+        for l in &labels {
+            let b = l.geometric_bounds().unwrap();
+            assert!(pie.contains(b.center()), "{b:?} inside {pie:?}");
+        }
+        // No swatches beside the pie: each series group holds only its wedge.
+        assert_eq!((series(&n, 0).children().unwrap().len(), series(&n, 1).children().unwrap().len()), (1, 1));
+        let v = s.execute("graph.setType", &json!({})).unwrap();
+        assert_eq!((v["pieLegend"].clone(), v["piePosition"].clone()), (json!("wedges"), json!("even")));
+        assert!(v.get("legend").is_none(), "a pie's Legend stands for the checkbox");
+        // The labels are drawn over the wedges, and on the black first wedge in white.
+        let order: Vec<_> = n.children().unwrap().iter().map(|c| c.name.clone().unwrap_or_default()).collect();
+        assert_eq!(order.last().map(String::as_str), Some("Legend"), "{order:?}");
+        let colour = |l: &vectorcraft_doc::Node| match &l.kind {
+            NodeKind::Text(t) => t.runs[0].style.fill.color().unwrap().to_hex(),
+            _ => panic!(),
+        };
+        assert_eq!((colour(&labels[0]), colour(&labels[1])), ("#ffffff".to_string(), "#000000".to_string()));
+        // No Legend wins over a legend checkbox sent along (as the dialog does), and Standard comes back without wedges.
+        s.execute("graph.setType", &json!({"pieLegend": "none", "legend": true})).unwrap();
+        assert!(!spec(&s, id).legend);
+        s.execute("graph.setType", &json!({"legend": true})).unwrap();
+        assert!(!spec(&s, id).pie_legend_in_wedges);
+        assert!(s.execute("graph.setType", &json!({"pieLegend": "inside"})).is_err());
+        let path = vectorcraft_testkit::temp_dir("graph-pie").join("pie.vectorcraft");
+        s.execute("graph.setType", &json!({"pieLegend": "wedges", "piePosition": "stacked", "pieSort": "all"})).unwrap();
+        s.execute("document.save", &json!({"path": path})).unwrap();
+        s.execute("document.open", &json!({"path": path})).unwrap();
+        let g = spec(&s, id);
+        assert_eq!(
+            (g.pie_legend_in_wedges, g.pie_position, g.pie_sort),
+            (true, vectorcraft_doc::PiePosition::Stacked, vectorcraft_doc::PieSort::All)
+        );
+        let v = serde_json::to_value(GraphSpec::default()).unwrap();
+        for k in ["pieLegendInWedges", "piePosition", "pieSort"] {
+            assert!(v.get(k).is_none(), "{k}");
+        }
+    }
+
+    #[test]
+    fn stacked_pies_are_rings_so_none_covers_another() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let id = make(&mut s, "pie", ",a,b\nSmall,5,5\nBig,20,20\nSame,20,20");
+        s.execute("graph.setType", &json!({"piePosition": "stacked"})).unwrap();
+        let n = s.doc().unwrap().doc.node(id).unwrap().clone();
+        // Series b's wedges: of the two equal big pies one is left out, the other a ring outside the small pie
+        // (clear of the centre), and the small pie's whole.
+        let b: Vec<_> = series(&n, 1).children().unwrap().iter().map(|c| (**c).clone()).collect();
+        assert_eq!(b.len(), 3, "two wedges and the swatch");
+        let small = b[1].geometric_bounds().unwrap();
+        let NodeKind::Path { path, .. } = &b[0].kind else { panic!() };
+        let c = small.center();
+        let near: Vec<f64> = path.to_bezpath().elements().iter().filter_map(|e| e.end_point()).map(|p| (p - c).hypot()).collect();
+        let min = near.iter().copied().fold(f64::MAX, f64::min);
+        assert!(min > 1.0, "the ring keeps clear of the centre: {near:?}");
+        // The names are drawn over the pies: after every series group.
+        let kids = n.children().unwrap();
+        let last_series = kids.iter().rposition(|c| c.series_index.is_some()).unwrap();
+        let names: Vec<usize> = kids.iter().enumerate().filter(|(_, c)| matches!(c.kind, NodeKind::Text(_))).map(|(i, _)| i).collect();
+        assert_eq!(names.len(), 2, "of two equal pies, one has no ring and no name");
+        assert!(names.iter().all(|i| *i > last_series), "{names:?} after {last_series}");
+    }
+
+    #[test]
+    fn transpose_keeps_within_the_series_cap_and_drops_stale_axis_series() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let rows: Vec<Vec<f64>> = (0..300).map(|i| vec![i as f64]).collect();
+        let id = NodeId(
+            s.execute("graph.create", &json!({"type": "column", "x": 0, "y": 0, "width": 300, "height": 200, "rows": rows})).unwrap()["id"]
+                .as_u64()
+                .unwrap(),
+        );
+        assert!(s.execute("graph.setData", &json!({"transpose": true})).is_err(), "300 categories can't become series");
+        assert_eq!(spec(&s, id).cells().len(), 300);
+        let g = make(&mut s, "column", ",a,b,c\nQ1,1,2,3");
+        s.execute("graph.setType", &json!({"seriesIndexes": [2], "valueAxis": "right"})).unwrap();
+        s.execute("graph.setData", &json!({"transpose": true})).unwrap();
+        assert!(spec(&s, g).right_series.is_empty(), "one series left");
+        // An all-blank series becomes no category.
+        let h = make(&mut s, "column", ",a,b\nQ1,1,\nQ2,2,");
+        s.execute("graph.setData", &json!({"transpose": true})).unwrap();
+        assert_eq!(spec(&s, h).categories, ["a", "b"], "b keeps its label");
+        assert!(s.execute("graph.setData", &json!({"id": h.0, "transpose": false})).unwrap().get("csv").is_some(), "no change: the query");
+    }
+
+    #[test]
+    fn switch_xy_moves_the_labels_with_their_columns() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let id = make(&mut s, "scatter", ",y1,x1,y2\nP,1,10,2,20");
+        s.execute("graph.setData", &json!({"switchXY": true})).unwrap();
+        let g = spec(&s, id);
+        assert_eq!(g.series, ["x1", "y1", "", "y2"]);
+        assert_eq!(g.cells(), [[Some(10.0), Some(1.0), Some(20.0), Some(2.0)]]);
+    }
+
+    #[test]
+    fn a_label_of_only_bars_is_blank_and_non_pie_graphs_list_no_pie_options() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"width": 800, "height": 800})).unwrap();
+        let id = make(&mut s, "column", ",||,b\nQ1,1,2");
+        let n = s.doc().unwrap().doc.node(id).unwrap().clone();
+        assert_eq!(group(&n, "Legend").children().unwrap().len(), 1, "only b");
+        let v = s.execute("graph.setType", &json!({})).unwrap();
+        assert!(v.get("pieLegend").is_none() && v.get("legend").is_some());
+        // Bar and radar labels with a `|` centre their lines on the category.
+        for ty in ["bar", "radar"] {
+            let g = make(&mut s, ty, ",a\nOne|Two|Three,1\nQ2,2\nQ3,3");
+            assert!(axis_texts(&s, g).contains(&"One\nTwo\nThree".to_string()), "{ty}");
+        }
+    }
 }