Add explicit orthogonal span sizing

tests/generated.rs

@@ -190,9 +190,10 @@ fn describe(id: WidgetId, h: &Harness) -> String {
     if let Some(w) = any.downcast_ref::<Span>() {
         let sign = if w.dir.sign == Sign::Neg { "-" } else { "+" };
         return format!(
-            "Span{{dir:{:?}{sign},gap:{},n:{}}}",
+            "Span{{dir:{:?}{sign},gap:{},ortho:{:?},n:{}}}",
             w.dir.axis,
             w.gap,
+            w.ortho,
             w.children.len()
         );
     }

tests/layout.rs

@@ -20,6 +20,33 @@ fn a_span_gives_each_child_the_width_it_asked_for() {
     assert_corners!(h, right, (100, 0), (400, 200));
 }
 
+#[test]
+fn a_full_ortho_span_reports_relative_full() {
+    let mut h = Harness::new((400, 200));
+    let child = rect(Color::RED).height(40).add(&mut h.rsc);
+    let span = (child,)
+        .span(Dir::RIGHT)
+        .ortho(OrthoSize::Full)
+        .add(&mut h.rsc);
+    h.set_root(span);
+
+    assert_eq!(h.render.active[&span.id()].size.y, Len::rel(1.0));
+}
+
+#[test]
+fn a_children_ortho_span_reports_its_tallest_fixed_child() {
+    let mut h = Harness::new((400, 200));
+    let short = rect(Color::RED).height(40).add(&mut h.rsc);
+    let tall = rect(Color::BLUE).height(70).add(&mut h.rsc);
+    let span = (short, tall)
+        .span(Dir::RIGHT)
+        .ortho(OrthoSize::Children)
+        .add(&mut h.rsc);
+    h.set_root(span);
+
+    assert_eq!(h.render.active[&span.id()].size.y, Len::px(70.0));
+}
+
 #[test]
 fn resizing_relays_out_against_the_new_output() {
     let mut h = Harness::new((400, 200));
@@ -158,7 +185,12 @@ fn a_box_with_a_fixed_length_can_be_stretched_on_its_other_axis() {
     let inner = rect(Color::BLUE).add(&mut h.rsc);
     let row = inner.pad(10).height(40).add(&mut h.rsc);
     let filler = rect(Color::GREEN).add(&mut h.rsc);
-    let column = (row, filler).span(Dir::DOWN).add(&mut h.rsc);
+    // This column is an item in a row, so it takes the width left for it
+    // rather than asking for a full row-width in addition to the bar.
+    let column = (row, filler)
+        .span(Dir::DOWN)
+        .ortho(OrthoSize::Children)
+        .add(&mut h.rsc);
     let bar = rect(Color::RED).width(100).add(&mut h.rsc);
     h.set_root((bar, column).span(Dir::RIGHT));
     assert_corners!(h, inner, (110, 10), (390, 30));

tests/retained.rs

@@ -264,6 +264,25 @@ fn a_resize_does_not_redraw_what_the_shader_can_move() {
     assert_corners!(h, leaf, (0, 0), (800, 100));
 }
 
+#[test]
+fn a_full_ortho_span_moves_its_child_without_redrawing_it() {
+    let mut h = Harness::new((400, 200));
+    let (leaf, draws) = counted(&mut h, Size::LEFTOVER, false);
+    let span = (leaf,)
+        .span(Dir::RIGHT)
+        .ortho(OrthoSize::Full)
+        .add(&mut h.rsc);
+    h.set_root(span);
+    let settled = draws.get();
+
+    h.resize((400, 100));
+    h.frame();
+
+    assert_eq!(draws.get(), settled);
+    assert_corners!(h, leaf, (0, 0), (400, 100));
+    assert_eq!(h.render.active[&span.id()].size.y, Len::rel(1.0));
+}
+
 /// The output is the root of the box chain, so a resize is a box that changed
 /// length like any other -- there is not a second rule for the window. A
 /// drawing that holds for one length is drawn again whichever box moved.

tests/shrink.rs

@@ -116,6 +116,10 @@ impl Node {
                     children,
                     dir: dir(*down),
                     gap: *gap,
+                    ortho: match down {
+                        true => OrthoSize::Children,
+                        false => OrthoSize::Full,
+                    },
                 }
                 .add(&mut h.rsc);
                 spans.push(handle);

tests/unsettled.rs

@@ -173,6 +173,7 @@ fn plant_pair(h: &mut Harness, swapped: bool) -> (Vec<WidgetId>, WeakWidget<Span
         children,
         dir: Dir::RIGHT,
         gap: 0.0,
+        ortho: OrthoSize::Children,
     }
     .add(&mut h.rsc);
     let span_handle = span;
@@ -230,6 +231,7 @@ fn plant_scrolled(h: &mut Harness, swapped: bool) -> (Vec<WidgetId>, [WeakWidget
         children: inner_children,
         dir: Dir::RIGHT,
         gap: 0.0,
+        ortho: OrthoSize::Children,
     }
     .add(&mut h.rsc);
     let block = rect(Color::RED).add(&mut h.rsc);
@@ -248,6 +250,7 @@ fn plant_scrolled(h: &mut Harness, swapped: bool) -> (Vec<WidgetId>, [WeakWidget
         children: outer_children,
         dir: Dir::RIGHT,
         gap: 0.0,
+        ortho: OrthoSize::Children,
     }
     .add(&mut h.rsc);
     let through = SetSize {