Make alignment a widget property

core/src/ui/active.rs

@@ -1,5 +1,6 @@
 use crate::{
-    Holds, LayerId, Len, MaskIdx, MoveIdx, PrimitiveHandle, Size, TextureHandle, UiRegion, WidgetId,
+    Holds, LayerId, Len, MaskIdx, MoveIdx, PrimitiveHandle, RegionAlign, Size, TextureHandle,
+    UiRegion, WidgetId,
 };
 
 /// What is kept of a widget its parent has asked about. `drawn` says whether
@@ -8,6 +9,7 @@ use crate::{
 #[derive(Debug)]
 pub struct ActiveData {
     pub id: WidgetId,
+    /// The box its drawing is in, in `parent_move`'s coordinates.
     pub region: UiRegion,
     /// The box its parent first asked about it in, as a part of the box the
     /// parent was itself asked in. Any later box it was given was decided
@@ -18,7 +20,7 @@ pub struct ActiveData {
     pub answer: (Size, [Holds; 2]),
     /// What the widget said it used of its box, the last time it drew.
     pub size: Size,
-    /// The pixel lengths of its box, per axis, that its drawing and `size`
+    /// The pixel lengths of `region`, per axis, that its drawing and `size`
     /// hold for.
     pub holds: [Holds; 2],
     pub drawn: bool,
@@ -39,6 +41,15 @@ pub struct ActiveData {
     /// A change to one moves a box this widget cannot fix by drawing again,
     /// and comparing them is what says so.
     pub declared: [Option<Len>; 2],
+    /// The alignment its parent asked it with. A local redraw repeats that
+    /// question, including an override chosen by a container.
+    pub align: RegionAlign,
+    /// Whether that alignment was the parent's override rather than the
+    /// widget's own property.
+    pub align_override: bool,
+    /// Its own alignment when it was last drawn. A change to the property is
+    /// found against this even when its parent overrode the alignment.
+    pub own_align: RegionAlign,
     /// The movable region whose coordinates `region` uses.
     pub parent_move: MoveIdx,
     pub mask: MaskIdx,