T14c, T15 review fixes: Tab steps past merges, empty charts lay out nothing, flat domains widen by size, pointed parts let go of shrunk data, signed waterfall totals, sunburst children take their share, today stays on the timeline

src/tables/gridkeys.rs

@@ -69,6 +69,29 @@ pub(crate) fn land(merges: &[Merge], (row, col): (usize, usize)) -> (usize, usiz
         .map_or((row, col), |merge| merge.from)
 }
 
+/// Where a key moves the cursor from a cell: past the far side of a merge it stands on, and onto the first cell of any merge it reaches.
+pub(crate) fn stepped(
+    merges: &[Merge],
+    (row, col): (usize, usize),
+    key: &str,
+    (rows, cols): (usize, usize),
+) -> Option<(usize, usize)> {
+    let far = merges
+        .iter()
+        .find(|merge| merge.from == (row, col))
+        .map_or((row, col), |merge| merge.to);
+    let to = match key {
+        "up" => (row.saturating_sub(1), col),
+        "down" | "enter" => ((far.0 + 1).min(rows - 1), col),
+        "left" => (row, col.saturating_sub(1)),
+        "right" => (row, (far.1 + 1).min(cols - 1)),
+        "home" => (row, 0),
+        "end" => (row, cols - 1),
+        _ => return None,
+    };
+    Some(land(merges, to))
+}
+
 /// Pulls the cursor, its anchor and a fill back inside a grid of `size`; whether anything moved.
 pub(crate) fn fit(sheet: &mut Sheet, size: (usize, usize)) -> bool {
     let last = (size.0.saturating_sub(1), size.1.saturating_sub(1));
@@ -84,26 +107,22 @@ pub(crate) fn fit(sheet: &mut Sheet, size: (usize, usize)) -> bool {
 
 /// Tab and Shift-Tab: keep an open edit, then step across, staying inside the grid.
 pub(crate) fn across(
-    sheet: &Entity<Sheet>,
-    editor: &Entity<Editing>,
-    (cols, back): (usize, bool),
+    (sheet, editor): (&Entity<Sheet>, &Entity<Editing>),
+    (merges, size, back): (&[Merge], (usize, usize), bool),
     (metrics, frozen): (Metrics, (usize, usize)),
     window: &mut Window,
     cx: &mut App,
 ) {
     cx.stop_propagation();
+    if size.0 == 0 || size.1 == 0 {
+        return;
+    }
     let (row, col) = sheet.read(cx).cursor;
     if sheet.read(cx).editing {
         editor.update(cx, |editing, cx| editing.finish(false, window, cx));
     }
-    let to = (
-        row,
-        if back {
-            col.saturating_sub(1)
-        } else {
-            (col + 1).min(cols.saturating_sub(1))
-        },
-    );
+    let key = if back { "left" } else { "right" };
+    let to = stepped(merges, (row, col), key, size).expect("left and right always step");
     sheet.update(cx, |sheet, cx| {
         (sheet.cursor, sheet.anchor) = (to, to);
         reveal(sheet, metrics, frozen);
@@ -221,21 +240,7 @@ pub(crate) fn keys(
         let stroke = &event.keystroke;
         let held = &stroke.modifiers;
         let (row, col) = sheet.read(cx).cursor;
-        let far = face
-            .merges
-            .iter()
-            .find(|merge| merge.from == (row, col))
-            .map_or((row, col), |merge| merge.to);
-        let to = match stroke.key.as_str() {
-            "up" => Some((row.saturating_sub(1), col)),
-            "down" | "enter" => Some(((far.0 + 1).min(rows - 1), col)),
-            "left" => Some((row, col.saturating_sub(1))),
-            "right" => Some((row, (far.1 + 1).min(cols - 1))),
-            "home" => Some((row, 0)),
-            "end" => Some((row, cols - 1)),
-            _ => None,
-        };
-        if let Some(to) = to.map(|to| land(&face.merges, to)) {
+        if let Some(to) = stepped(&face.merges, (row, col), stroke.key.as_str(), (rows, cols)) {
             cx.stop_propagation();
             let stretch = held.shift && stroke.key != "enter";
             sheet.update(cx, |sheet, cx| {