When completions menu is displayed above cursor, reverse order (#23446)

Considered doing this when previously working on completions menu
layout, as it brings the default selection position next to the cursor
position, and is generally more symmetrical. With #23445 there is now a
more compelling reason, as the "translucent, cropped bottom" display
doesn't make sense when displayed above.

Release Notes:

- N/A

crates/editor/src/code_context_menus.rs

@@ -125,11 +125,16 @@ impl CodeContextMenu {
         &self,
         style: &EditorStyle,
         max_height_in_lines: u32,
+        y_flipped: bool,
         cx: &mut ViewContext<Editor>,
     ) -> AnyElement {
         match self {
-            CodeContextMenu::Completions(menu) => menu.render(style, max_height_in_lines, cx),
-            CodeContextMenu::CodeActions(menu) => menu.render(style, max_height_in_lines, cx),
+            CodeContextMenu::Completions(menu) => {
+                menu.render(style, max_height_in_lines, y_flipped, cx)
+            }
+            CodeContextMenu::CodeActions(menu) => {
+                menu.render(style, max_height_in_lines, y_flipped, cx)
+            }
         }
     }
 
@@ -268,23 +273,12 @@ impl CompletionsMenu {
         provider: Option<&dyn CompletionProvider>,
         cx: &mut ViewContext<Editor>,
     ) {
-        self.update_selection_index(0, provider, cx);
-    }
-
-    fn select_prev(
-        &mut self,
-        provider: Option<&dyn CompletionProvider>,
-        cx: &mut ViewContext<Editor>,
-    ) {
-        self.update_selection_index(self.prev_match_index(), provider, cx);
-    }
-
-    fn select_next(
-        &mut self,
-        provider: Option<&dyn CompletionProvider>,
-        cx: &mut ViewContext<Editor>,
-    ) {
-        self.update_selection_index(self.next_match_index(), provider, cx);
+        let index = if self.scroll_handle.y_flipped() {
+            self.entries.borrow().len() - 1
+        } else {
+            0
+        };
+        self.update_selection_index(index, provider, cx);
     }
 
     fn select_last(
@@ -292,7 +286,37 @@ impl CompletionsMenu {
         provider: Option<&dyn CompletionProvider>,
         cx: &mut ViewContext<Editor>,
     ) {
-        let index = self.entries.borrow().len() - 1;
+        let index = if self.scroll_handle.y_flipped() {
+            0
+        } else {
+            self.entries.borrow().len() - 1
+        };
+        self.update_selection_index(index, provider, cx);
+    }
+
+    fn select_prev(
+        &mut self,
+        provider: Option<&dyn CompletionProvider>,
+        cx: &mut ViewContext<Editor>,
+    ) {
+        let index = if self.scroll_handle.y_flipped() {
+            self.next_match_index()
+        } else {
+            self.prev_match_index()
+        };
+        self.update_selection_index(index, provider, cx);
+    }
+
+    fn select_next(
+        &mut self,
+        provider: Option<&dyn CompletionProvider>,
+        cx: &mut ViewContext<Editor>,
+    ) {
+        let index = if self.scroll_handle.y_flipped() {
+            self.prev_match_index()
+        } else {
+            self.next_match_index()
+        };
         self.update_selection_index(index, provider, cx);
     }
 
@@ -336,6 +360,11 @@ impl CompletionsMenu {
             }
             _ => {
                 entries.insert(0, hint);
+                // When `y_flipped`, need to scroll to bring it into view.
+                if self.selected_item == 0 {
+                    self.scroll_handle
+                        .scroll_to_item(self.selected_item, ScrollStrategy::Top);
+                }
             }
         }
     }
@@ -439,6 +468,7 @@ impl CompletionsMenu {
         &self,
         style: &EditorStyle,
         max_height_in_lines: u32,
+        y_flipped: bool,
         cx: &mut ViewContext<Editor>,
     ) -> AnyElement {
         let completions = self.completions.borrow_mut();
@@ -664,6 +694,7 @@ impl CompletionsMenu {
         .occlude()
         .max_h(max_height_in_lines as f32 * cx.line_height())
         .track_scroll(self.scroll_handle.clone())
+        .y_flipped(y_flipped)
         .with_width_from_item(widest_completion_ix)
         .with_sizing_behavior(ListSizingBehavior::Infer);
 
@@ -981,39 +1012,63 @@ pub struct CodeActionsMenu {
 
 impl CodeActionsMenu {
     fn select_first(&mut self, cx: &mut ViewContext<Editor>) {
-        self.selected_item = 0;
+        self.selected_item = if self.scroll_handle.y_flipped() {
+            self.actions.len() - 1
+        } else {
+            0
+        };
+        self.scroll_handle
+            .scroll_to_item(self.selected_item, ScrollStrategy::Top);
+        cx.notify()
+    }
+
+    fn select_last(&mut self, cx: &mut ViewContext<Editor>) {
+        self.selected_item = if self.scroll_handle.y_flipped() {
+            0
+        } else {
+            self.actions.len() - 1
+        };
         self.scroll_handle
             .scroll_to_item(self.selected_item, ScrollStrategy::Top);
         cx.notify()
     }
 
     fn select_prev(&mut self, cx: &mut ViewContext<Editor>) {
-        if self.selected_item > 0 {
-            self.selected_item -= 1;
+        self.selected_item = if self.scroll_handle.y_flipped() {
+            self.next_match_index()
         } else {
-            self.selected_item = self.actions.len() - 1;
-        }
+            self.prev_match_index()
+        };
         self.scroll_handle
             .scroll_to_item(self.selected_item, ScrollStrategy::Top);
         cx.notify();
     }
 
     fn select_next(&mut self, cx: &mut ViewContext<Editor>) {
-        if self.selected_item + 1 < self.actions.len() {
-            self.selected_item += 1;
+        self.selected_item = if self.scroll_handle.y_flipped() {
+            self.prev_match_index()
         } else {
-            self.selected_item = 0;
-        }
+            self.next_match_index()
+        };
         self.scroll_handle
             .scroll_to_item(self.selected_item, ScrollStrategy::Top);
         cx.notify();
     }
 
-    fn select_last(&mut self, cx: &mut ViewContext<Editor>) {
-        self.selected_item = self.actions.len() - 1;
-        self.scroll_handle
-            .scroll_to_item(self.selected_item, ScrollStrategy::Top);
-        cx.notify()
+    fn prev_match_index(&self) -> usize {
+        if self.selected_item > 0 {
+            self.selected_item - 1
+        } else {
+            self.actions.len() - 1
+        }
+    }
+
+    fn next_match_index(&self) -> usize {
+        if self.selected_item + 1 < self.actions.len() {
+            self.selected_item + 1
+        } else {
+            0
+        }
     }
 
     fn visible(&self) -> bool {
@@ -1032,6 +1087,7 @@ impl CodeActionsMenu {
         &self,
         _style: &EditorStyle,
         max_height_in_lines: u32,
+        y_flipped: bool,
         cx: &mut ViewContext<Editor>,
     ) -> AnyElement {
         let actions = self.actions.clone();
@@ -1107,6 +1163,7 @@ impl CodeActionsMenu {
         .occlude()
         .max_h(max_height_in_lines as f32 * cx.line_height())
         .track_scroll(self.scroll_handle.clone())
+        .y_flipped(y_flipped)
         .with_width_from_item(
             self.actions
                 .iter()

crates/editor/src/editor.rs

@@ -5246,11 +5246,12 @@ impl Editor {
         &self,
         style: &EditorStyle,
         max_height_in_lines: u32,
+        y_flipped: bool,
         cx: &mut ViewContext<Editor>,
     ) -> Option<AnyElement> {
         self.context_menu.borrow().as_ref().and_then(|menu| {
             if menu.visible() {
-                Some(menu.render(style, max_height_in_lines, cx))
+                Some(menu.render(style, max_height_in_lines, y_flipped, cx))
             } else {
                 None
             }

crates/editor/src/element.rs

@@ -3136,10 +3136,10 @@ impl EditorElement {
         let available_above = bottom_y_when_flipped - text_hitbox.top();
         let available_below = text_hitbox.bottom() - target_position.y;
         let y_overflows_below = unconstrained_max_height > available_below;
-        let mut y_is_flipped = y_overflows_below && available_above > available_below;
+        let mut y_flipped = y_overflows_below && available_above > available_below;
         let mut height = cmp::min(
             unconstrained_max_height,
-            if y_is_flipped {
+            if y_flipped {
                 available_above
             } else {
                 available_below
@@ -3151,16 +3151,16 @@ impl EditorElement {
             let available_above = bottom_y_when_flipped;
             let available_below = viewport_bounds.bottom() - target_position.y;
             if available_below > 3. * line_height {
-                y_is_flipped = false;
+                y_flipped = false;
                 height = min_height;
             } else if available_above > 3. * line_height {
-                y_is_flipped = true;
+                y_flipped = true;
                 height = min_height;
             } else if available_above > available_below {
-                y_is_flipped = true;
+                y_flipped = true;
                 height = available_above;
             } else {
-                y_is_flipped = false;
+                y_flipped = false;
                 height = available_below;
             }
         }
@@ -3169,7 +3169,7 @@ impl EditorElement {
 
         // TODO(mgsloan): use viewport_bounds.width as a max width when rendering menu.
         let Some(mut menu_element) = self.editor.update(cx, |editor, cx| {
-            editor.render_context_menu(&self.style, max_height_in_lines, cx)
+            editor.render_context_menu(&self.style, max_height_in_lines, y_flipped, cx)
         }) else {
             return;
         };
@@ -3181,7 +3181,7 @@ impl EditorElement {
             x: target_position
                 .x
                 .min((viewport_bounds.right() - menu_size.width).max(Pixels::ZERO)),
-            y: if y_is_flipped {
+            y: if y_flipped {
                 bottom_y_when_flipped - menu_size.height
             } else {
                 target_position.y
@@ -3192,7 +3192,7 @@ impl EditorElement {
         // Layout documentation aside
         let menu_bounds = Bounds::new(menu_position, menu_size);
         let max_menu_size = size(menu_size.width, unconstrained_max_height);
-        let max_menu_bounds = if y_is_flipped {
+        let max_menu_bounds = if y_flipped {
             Bounds::new(
                 point(
                     menu_position.x,
@@ -3205,7 +3205,7 @@ impl EditorElement {
         };
         self.layout_context_menu_aside(
             text_hitbox,
-            y_is_flipped,
+            y_flipped,
             menu_position,
             menu_bounds,
             max_menu_bounds,
@@ -3220,7 +3220,7 @@ impl EditorElement {
     fn layout_context_menu_aside(
         &self,
         text_hitbox: &Hitbox,
-        y_is_flipped: bool,
+        y_flipped: bool,
         menu_position: gpui::Point<Pixels>,
         menu_bounds: Bounds<Pixels>,
         max_menu_bounds: Bounds<Pixels>,
@@ -3231,7 +3231,7 @@ impl EditorElement {
     ) {
         let mut extend_amount = Edges::all(MENU_GAP);
         // Extend to include the cursored line to avoid overlapping it.
-        if y_is_flipped {
+        if y_flipped {
             extend_amount.bottom = line_height;
         } else {
             extend_amount.top = line_height;
@@ -3280,13 +3280,13 @@ impl EditorElement {
             let fit_within = |available: Edges<Pixels>, wanted: Size<Pixels>| {
                 // Prefer to fit on the same side of the line as the menu, then on the other side of
                 // the line.
-                if !y_is_flipped && wanted.height < available.bottom {
+                if !y_flipped && wanted.height < available.bottom {
                     Some(bottom_position)
-                } else if !y_is_flipped && wanted.height < available.top {
+                } else if !y_flipped && wanted.height < available.top {
                     Some(top_position)
-                } else if y_is_flipped && wanted.height < available.top {
+                } else if y_flipped && wanted.height < available.top {
                     Some(top_position)
-                } else if y_is_flipped && wanted.height < available.bottom {
+                } else if y_flipped && wanted.height < available.bottom {
                     Some(bottom_position)
                 } else {
                     None

crates/gpui/src/elements/uniform_list.rs

@@ -106,6 +106,8 @@ pub struct UniformListScrollState {
     pub deferred_scroll_to_item: Option<(usize, ScrollStrategy)>,
     /// Size of the item, captured during last layout.
     pub last_item_size: Option<ItemSize>,
+    /// Whether the list was vertically flipped during last layout.
+    pub y_flipped: bool,
 }
 
 #[derive(Copy, Clone, Debug, Default)]
@@ -125,6 +127,7 @@ impl UniformListScrollHandle {
             base_handle: ScrollHandle::new(),
             deferred_scroll_to_item: None,
             last_item_size: None,
+            y_flipped: false,
         })))
     }
 
@@ -133,6 +136,11 @@ impl UniformListScrollHandle {
         self.0.borrow_mut().deferred_scroll_to_item = Some((ix, strategy));
     }
 
+    /// Check if the list is flipped vertically.
+    pub fn y_flipped(&self) -> bool {
+        self.0.borrow().y_flipped
+    }
+
     /// Get the index of the topmost visible child.
     #[cfg(any(test, feature = "test-support"))]
     pub fn logical_scroll_top_index(&self) -> usize {
@@ -264,9 +272,13 @@ impl Element for UniformList {
                     bounds.bottom_right() - point(border.right + padding.right, border.bottom),
                 );
 
-                if let Some(handle) = self.scroll_handle.as_mut() {
-                    handle.0.borrow_mut().base_handle.set_bounds(bounds);
-                }
+                let y_flipped = if let Some(scroll_handle) = self.scroll_handle.as_mut() {
+                    let mut scroll_state = scroll_handle.0.borrow_mut();
+                    scroll_state.base_handle.set_bounds(bounds);
+                    scroll_state.y_flipped
+                } else {
+                    false
+                };
 
                 if self.item_count > 0 {
                     let content_height =
@@ -286,7 +298,10 @@ impl Element for UniformList {
                         scroll_offset.x = Pixels::ZERO;
                     }
 
-                    if let Some((ix, scroll_strategy)) = shared_scroll_to_item {
+                    if let Some((mut ix, scroll_strategy)) = shared_scroll_to_item {
+                        if y_flipped {
+                            ix = self.item_count.saturating_sub(ix + 1);
+                        }
                         let list_height = padded_bounds.size.height;
                         let mut updated_scroll_offset = shared_scroll_offset.borrow_mut();
                         let item_top = item_height * ix + padding.top;
@@ -330,7 +345,15 @@ impl Element for UniformList {
                     let visible_range = first_visible_element_ix
                         ..cmp::min(last_visible_element_ix, self.item_count);
 
-                    let mut items = (self.render_items)(visible_range.clone(), cx);
+                    let items = if y_flipped {
+                        let flipped_range = self.item_count.saturating_sub(visible_range.end)
+                            ..self.item_count.saturating_sub(visible_range.start);
+                        let mut items = (self.render_items)(flipped_range, cx);
+                        items.reverse();
+                        items
+                    } else {
+                        (self.render_items)(visible_range.clone(), cx)
+                    };
 
                     let content_mask = ContentMask { bounds };
                     cx.with_content_mask(Some(content_mask), |cx| {
@@ -500,6 +523,30 @@ impl UniformList {
         self.scroll_handle = Some(handle);
         self
     }
+
+    /// Sets whether the list is flipped vertically, such that item 0 appears at the bottom.
+    pub fn y_flipped(mut self, y_flipped: bool) -> Self {
+        if let Some(ref scroll_handle) = self.scroll_handle {
+            let mut scroll_state = scroll_handle.0.borrow_mut();
+            let mut base_handle = &scroll_state.base_handle;
+            let offset = base_handle.offset();
+            match scroll_state.last_item_size {
+                Some(last_size) if scroll_state.y_flipped != y_flipped => {
+                    let new_y_offset =
+                        -(offset.y + last_size.contents.height - last_size.item.height);
+                    base_handle.set_offset(point(offset.x, new_y_offset));
+                    scroll_state.y_flipped = y_flipped;
+                }
+                // Handle case where list is initially flipped.
+                None if y_flipped => {
+                    base_handle.set_offset(point(offset.x, Pixels::MIN));
+                    scroll_state.y_flipped = y_flipped;
+                }
+                _ => {}
+            }
+        }
+        self
+    }
 }
 
 impl InteractiveElement for UniformList {

crates/gpui/src/geometry.rs

@@ -2500,6 +2500,8 @@ impl Pixels {
     pub const ZERO: Pixels = Pixels(0.0);
     /// The maximum value that can be represented by `Pixels`.
     pub const MAX: Pixels = Pixels(f32::MAX);
+    /// The minimum value that can be represented by `Pixels`.
+    pub const MIN: Pixels = Pixels(f32::MIN);
 
     /// Floors the `Pixels` value to the nearest whole number.
     ///