M7: area type vertical alignment

Area Type Options > Align: Top / Center / Bottom / Justify (AreaOptions.verticalAlign,
LayoutOptions.vertical_align). Each row/column cell is aligned on its own; rectangular
cells shift their lines, other frames and text wrap reflow until settled without
losing text. Justify shares the leftover space equally between line gaps. Area Type Options
shows Align and First Baseline as dropdowns (the parameter dialog's choices table).

crates/engine/src/cmd/typecmd.rs

@@ -48,7 +48,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Area Type Options…",
             ["Type"],
             None,
-            "{ids?, width?: pt, height?: pt, rows?, columns?, gutter?: pt, inset?: pt, firstBaseline?: ascent|capHeight|xHeight|leading|fixed, firstBaselineMin?: pt} set the selected area type's options; width and height size the type area from its top-left corner, along the type's own axes, and the text reflows at its size (none given: query) → the first object's options",
+            "{ids?, width?: pt, height?: pt, rows?, columns?, gutter?: pt, inset?: pt, firstBaseline?: ascent|capHeight|xHeight|leading|fixed, firstBaselineMin?: pt, verticalAlign?: top|center|bottom|justify} set the selected area type's options; width and height size the type area from its top-left corner, along the type's own axes, and the text reflows at its size (none given: query) → the first object's options",
             has_selection,
             area_options
         ),

crates/engine/src/tests_typearea.rs

@@ -339,3 +339,38 @@ fn the_type_widget_converts_point_and_area_type() {
     s.execute("edit.undo", &json!({})).unwrap();
     assert_eq!(text(&s, id), before);
 }
+
+#[test]
+fn area_type_options_align_the_lines_vertically() {
+    use vectorcraft_doc::VerticalAlign;
+    let mut s = session();
+    let id = area(&mut s, 40.0, 40.0, 200.0, 300.0, "Short story");
+    sel(&mut s, &[id]);
+    assert_eq!(s.execute("text.areaOptions", &json!({})).unwrap()["verticalAlign"], "top");
+    let top = layout(&s, id).lines[0].baseline;
+    let before = text(&s, id).cached_bounds;
+    let n = undo_len(&s);
+    let r = s.execute("text.areaOptions", &json!({"verticalAlign": "bottom"})).unwrap();
+    assert_eq!(r["verticalAlign"], "bottom");
+    assert_eq!(text(&s, id).area.vertical_align, VerticalAlign::Bottom);
+    let l = layout(&s, id);
+    let last = l.lines.last().unwrap();
+    assert!((last.baseline + last.descent - 300.0).abs() < 1e-6);
+    assert!(l.lines[0].baseline > top + 200.0);
+    assert_ne!(text(&s, id).cached_bounds, before, "the cached bounds follow the text");
+    assert_eq!((undo_len(&s), last_step(&s).as_str()), (n + 1, "Area Type Options"));
+    s.execute("text.areaOptions", &json!({"verticalAlign": "center"})).unwrap();
+    assert_eq!(text(&s, id).area.vertical_align, VerticalAlign::Center);
+    // Unknown values are refused and change nothing.
+    for bad in [json!({"verticalAlign": "middle"}), json!({"verticalAlign": 3}), json!({"verticalAlign": null})] {
+        assert!(s.execute("text.areaOptions", &bad).is_err(), "{bad}");
+    }
+    assert_eq!(undo_len(&s), n + 2);
+    assert_eq!(text(&s, id).area.vertical_align, VerticalAlign::Center);
+    s.execute("edit.undo", &json!({})).unwrap();
+    s.execute("edit.undo", &json!({})).unwrap();
+    assert_eq!(text(&s, id).area.vertical_align, VerticalAlign::Top);
+    assert_eq!(layout(&s, id).lines[0].baseline, top);
+    assert_eq!(text(&s, id).cached_bounds, before);
+    assert!(cmd::find_command("text.areaOptions").unwrap().params.contains("verticalAlign?: top|center|bottom|justify"));
+}