[refactor] Simplify how ui calls placer after adding a widget

egui/src/layout.rs

@@ -446,12 +446,12 @@ impl Layout {
     }
 
     /// Advance the cursor by this many points.
-    pub(crate) fn advance_cursor(&self, region: &mut Region, amount: f32) {
+    pub(crate) fn advance_cursor(&self, cursor: &mut Pos2, amount: f32) {
         match self.main_dir {
-            Direction::LeftToRight => region.cursor.x += amount,
-            Direction::RightToLeft => region.cursor.x -= amount,
-            Direction::TopDown => region.cursor.y += amount,
-            Direction::BottomUp => region.cursor.y -= amount,
+            Direction::LeftToRight => cursor.x += amount,
+            Direction::RightToLeft => cursor.x -= amount,
+            Direction::TopDown => cursor.y += amount,
+            Direction::BottomUp => cursor.y -= amount,
         }
     }
 
@@ -461,12 +461,12 @@ impl Layout {
     /// * `widget_rect`: the actual rect used by the widget
     pub(crate) fn advance_after_rects(
         &self,
-        region: &mut Region,
+        cursor: &mut Pos2,
         frame_rect: Rect,
         widget_rect: Rect,
         item_spacing: Vec2,
     ) {
-        region.cursor = match self.main_dir {
+        *cursor = match self.main_dir {
             Direction::LeftToRight => pos2(widget_rect.right() + item_spacing.x, frame_rect.top()),
             Direction::RightToLeft => pos2(widget_rect.left() - item_spacing.x, frame_rect.top()),
             Direction::TopDown => pos2(frame_rect.left(), widget_rect.bottom() + item_spacing.y),

egui/src/placer.rs

@@ -111,10 +111,11 @@ impl Placer {
             self.grid.is_none(),
             "You cannot advance the cursor when in a grid layout"
         );
-        self.layout.advance_cursor(&mut self.region, amount)
+        self.layout.advance_cursor(&mut self.region.cursor, amount)
     }
 
-    /// Advance cursor after a widget was added to a specific rectangle.
+    /// Advance cursor after a widget was added to a specific rectangle
+    /// and expand the region min_rect.
     ///
     /// * `frame_rect`: the frame inside which a widget was e.g. centered
     /// * `widget_rect`: the actual rect used by the widget
@@ -127,9 +128,14 @@ impl Placer {
         if let Some(grid) = &mut self.grid {
             grid.advance(&mut self.region.cursor, frame_rect, widget_rect)
         } else {
-            self.layout
-                .advance_after_rects(&mut self.region, frame_rect, widget_rect, item_spacing)
+            self.layout.advance_after_rects(
+                &mut self.region.cursor,
+                frame_rect,
+                widget_rect,
+                item_spacing,
+            )
         }
+        self.region.expand_to_include_rect(widget_rect);
     }
 
     /// Move to the next row in a grid layout or wrapping layout.

egui/src/ui.rs

@@ -512,7 +512,6 @@ impl Ui {
 
         self.placer
             .advance_after_rects(frame_rect, widget_rect, item_spacing);
-        self.expand_to_include_rect(widget_rect);
 
         widget_rect
     }
@@ -520,7 +519,6 @@ impl Ui {
     pub(crate) fn advance_cursor_after_rect(&mut self, rect: Rect) -> Id {
         let item_spacing = self.style().spacing.item_spacing;
         self.placer.advance_after_rects(rect, rect, item_spacing);
-        self.expand_to_include_rect(rect);
 
         self.next_auto_id = self.next_auto_id.wrapping_add(1);
         Id::new(self.next_auto_id)
@@ -552,7 +550,6 @@ impl Ui {
             final_child_rect,
             item_spacing,
         );
-        self.expand_to_include_rect(final_child_rect);
 
         let response = self.interact(final_child_rect, child_ui.id, Sense::hover());
         (ret, response)
@@ -1104,7 +1101,6 @@ impl Ui {
         let rect = child_ui.min_rect();
         let item_spacing = self.style().spacing.item_spacing;
         self.placer.advance_after_rects(rect, rect, item_spacing);
-        self.expand_to_include_rect(rect);
         (ret, self.interact(rect, child_ui.id, Sense::hover()))
     }