Fix wrong cursor advancement for `allocate_ui`

egui/src/demos/demo_window.rs

@@ -342,12 +342,12 @@ impl LayoutDemo {
             .show(ui, |ui| {
                 if self.main_wrap {
                     if self.main_dir.is_horizontal() {
-                        ui.allocate_ui_min(
+                        ui.allocate_ui(
                             vec2(ui.available_finite().width(), self.wrap_row_height),
                             |ui| ui.with_layout(self.layout(), |ui| self.demo_ui(ui)),
                         );
                     } else {
-                        ui.allocate_ui_min(
+                        ui.allocate_ui(
                             vec2(self.wrap_column_width, ui.available_finite().height()),
                             |ui| ui.with_layout(self.layout(), |ui| self.demo_ui(ui)),
                         );

egui/src/layout.rs

@@ -462,12 +462,20 @@ impl Layout {
     }
 
     /// Advance cursor after a widget was added to a specific rectangle.
-    pub fn advance_after_outer_rect(self, region: &mut Region, rect: Rect, item_spacing: Vec2) {
+    /// `outer_rect` is a hack needed because the Vec2 cursor is not quite sufficient to keep track
+    /// of what is happening when we are doing wrapping layouts.
+    pub fn advance_after_outer_rect(
+        self,
+        region: &mut Region,
+        outer_rect: Rect,
+        inner_rect: Rect,
+        item_spacing: Vec2,
+    ) {
         region.cursor = match self.main_dir {
-            Direction::LeftToRight => pos2(rect.right() + item_spacing.x, rect.top()),
-            Direction::RightToLeft => pos2(rect.left() - item_spacing.x, rect.top()),
-            Direction::TopDown => pos2(rect.left(), rect.bottom() + item_spacing.y),
-            Direction::BottomUp => pos2(rect.left(), rect.top() - item_spacing.y),
+            Direction::LeftToRight => pos2(inner_rect.right() + item_spacing.x, outer_rect.top()),
+            Direction::RightToLeft => pos2(inner_rect.left() - item_spacing.x, outer_rect.top()),
+            Direction::TopDown => pos2(outer_rect.left(), inner_rect.bottom() + item_spacing.y),
+            Direction::BottomUp => pos2(outer_rect.left(), inner_rect.top() - item_spacing.y),
         };
     }
 }

egui/src/ui.rs

@@ -452,49 +452,23 @@ impl Ui {
             .next_space(&self.region, desired_size, item_spacing);
         let inner_child_rect = self.layout.justify_or_align(outer_child_rect, desired_size);
 
-        self.layout
-            .advance_after_outer_rect(&mut self.region, outer_child_rect, item_spacing);
-        self.region.expand_to_include_rect(inner_child_rect);
-
-        self.next_auto_id = self.next_auto_id.wrapping_add(1);
-        inner_child_rect
-    }
-
-    /// Allocated the given space and then adds content to that space.
-    /// If the contents overflow, more space will be allocated.
-    /// At least the amount of space requested will always be allocated.
-    /// Thus you can ask for a little and use more, but you cannot ask for a lot and use less.
-    pub fn allocate_ui_max<R>(
-        &mut self,
-        desired_size: Vec2,
-        add_contents: impl FnOnce(&mut Ui) -> R,
-    ) -> (R, Response) {
-        let item_spacing = self.style().spacing.item_spacing;
-        let outer_child_rect = self
-            .layout
-            .next_space(&self.region, desired_size, item_spacing);
-        let inner_child_rect = self.layout.justify_or_align(outer_child_rect, desired_size);
-
-        let mut child_ui = self.child_ui(inner_child_rect, self.layout);
-        let ret = add_contents(&mut child_ui);
-        let final_child_rect = child_ui.region.max_rect;
-
         self.layout.advance_after_outer_rect(
             &mut self.region,
-            outer_child_rect.union(final_child_rect),
+            outer_child_rect,
+            inner_child_rect,
             item_spacing,
         );
-        self.region.expand_to_include_rect(final_child_rect);
+        self.region.expand_to_include_rect(inner_child_rect);
 
-        let response = self.interact_hover(final_child_rect);
-        (ret, response)
+        self.next_auto_id = self.next_auto_id.wrapping_add(1);
+        inner_child_rect
     }
 
     /// Allocated the given space and then adds content to that space.
     /// If the contents overflow, more space will be allocated.
     /// When finished, the amount of space actually used (`min_rect`) will be allocated.
     /// So you can request a lot of space and then use less.
-    pub fn allocate_ui_min<R>(
+    pub fn allocate_ui<R>(
         &mut self,
         desired_size: Vec2,
         add_contents: impl FnOnce(&mut Self) -> R,
@@ -512,6 +486,7 @@ impl Ui {
         self.layout.advance_after_outer_rect(
             &mut self.region,
             outer_child_rect.union(final_child_rect),
+            final_child_rect,
             item_spacing,
         );
         self.region.expand_to_include_rect(final_child_rect);
@@ -731,13 +706,13 @@ impl Ui {
         })
     }
 
-    #[deprecated = "Use `ui.allocate_ui_max` or `ui.allocate_ui_min` instead"]
+    #[deprecated = "Use `ui.allocate_ui` instead"]
     pub fn add_custom_contents(
         &mut self,
         desired_size: Vec2,
         add_contents: impl FnOnce(&mut Ui),
     ) -> Rect {
-        self.allocate_ui_max(desired_size, add_contents).1.rect
+        self.allocate_ui(desired_size, add_contents).1.rect
     }
 
     /// A `CollapsingHeader` that starts out collapsed.
@@ -888,7 +863,7 @@ impl Ui {
         }
         .with_main_wrap(main_wrap);
 
-        self.allocate_ui_min(initial_size, |ui| ui.with_layout(layout, add_contents).0)
+        self.allocate_ui(initial_size, |ui| ui.with_layout(layout, add_contents).0)
     }
 
     /// Start a ui with vertical layout.
@@ -907,7 +882,7 @@ impl Ui {
         let rect = child_ui.min_rect();
         let item_spacing = self.style().spacing.item_spacing;
         self.layout
-            .advance_after_outer_rect(&mut self.region, rect, item_spacing);
+            .advance_after_outer_rect(&mut self.region, rect, rect, item_spacing);
         self.region.expand_to_include_rect(rect);
         (ret, self.interact_hover(rect))
     }