refactor: move used_ids and tooltip_rect from Memory to FrameState

egui/src/containers/popup.rs

@@ -15,7 +15,7 @@ use crate::*;
 /// }
 /// ```
 pub fn show_tooltip(ctx: &CtxRef, add_contents: impl FnOnce(&mut Ui)) {
-    let tooltip_rect = ctx.memory().tooltip_rect;
+    let tooltip_rect = ctx.frame_state().tooltip_rect;
 
     let window_pos = if let Some(tooltip_rect) = tooltip_rect {
         tooltip_rect.left_bottom()
@@ -36,7 +36,7 @@ pub fn show_tooltip(ctx: &CtxRef, add_contents: impl FnOnce(&mut Ui)) {
     let response = show_popup(ctx, id, window_pos, add_contents);
 
     let tooltip_rect = tooltip_rect.unwrap_or_else(Rect::nothing);
-    ctx.memory().tooltip_rect = Some(tooltip_rect.union(response.rect));
+    ctx.frame_state().tooltip_rect = Some(tooltip_rect.union(response.rect));
 }
 
 /// Show some text at the current mouse position (if any).

egui/src/context.rs

@@ -26,9 +26,14 @@ struct Options {
 
 // ----------------------------------------------------------------------------
 
-/// State that is collected during a frame and then cleared
+/// State that is collected during a frame and then cleared.
+/// Short-term (single frame) memory.
 #[derive(Clone)]
 pub(crate) struct FrameState {
+    /// All `Id`s that were used this frame.
+    /// Used to debug `Id` clashes of widgets.
+    pub(crate) used_ids: ahash::AHashMap<Id, Pos2>,
+
     /// Starts off as the screen_rect, shrinks as panels are added.
     /// The `CentralPanel` does not change this.
     /// This is the area available to Window's.
@@ -41,17 +46,24 @@ pub(crate) struct FrameState {
     /// How much space is used by panels.
     used_by_panels: Rect,
 
+    /// If a tooltip has been shown this frame, where was it?
+    /// This is used to prevent multiple tooltips to cover each other.
+    /// Initialized to `None` at the start of each frame.
+    pub(crate) tooltip_rect: Option<Rect>,
+
+    /// Cleared by the first `ScrollArea` that makes use of it.
     pub(crate) scroll_delta: Vec2,
     pub(crate) scroll_target: Option<(f32, Align)>,
-    // TODO: move some things from `Memory` to here
 }
 
 impl Default for FrameState {
     fn default() -> Self {
         Self {
+            used_ids: Default::default(),
             available_rect: Rect::invalid(),
             unused_rect: Rect::invalid(),
             used_by_panels: Rect::invalid(),
+            tooltip_rect: None,
             scroll_delta: Vec2::zero(),
             scroll_target: None,
         }
@@ -60,11 +72,23 @@ impl Default for FrameState {
 
 impl FrameState {
     fn begin_frame(&mut self, input: &InputState) {
-        self.available_rect = input.screen_rect();
-        self.unused_rect = input.screen_rect();
-        self.used_by_panels = Rect::nothing();
-        self.scroll_delta = input.scroll_delta;
-        self.scroll_target = None;
+        let Self {
+            used_ids,
+            available_rect,
+            unused_rect,
+            used_by_panels,
+            tooltip_rect,
+            scroll_delta,
+            scroll_target,
+        } = self;
+
+        used_ids.clear();
+        *available_rect = input.screen_rect();
+        *unused_rect = input.screen_rect();
+        *used_by_panels = Rect::nothing();
+        *tooltip_rect = None;
+        *scroll_delta = input.scroll_delta;
+        *scroll_target = None;
     }
 
     /// How much space is still available after panels has been added.
@@ -166,7 +190,7 @@ impl CtxRef {
     /// If the given [`Id`] is not unique, an error will be printed at the given position.
     /// Call this for [`Id`]:s that need interaction or persistence.
     pub(crate) fn register_interaction_id(&self, id: Id, new_pos: Pos2) {
-        let prev_pos = self.memory().used_ids.insert(id, new_pos);
+        let prev_pos = self.frame_state().used_ids.insert(id, new_pos);
         if let Some(prev_pos) = prev_pos {
             if prev_pos.distance(new_pos) < 0.1 {
                 // Likely same Widget being interacted with twice, which is fine.
@@ -590,7 +614,7 @@ impl Context {
             self.request_repaint();
         }
 
-        self.memory().end_frame();
+        self.memory().end_frame(&self.frame_state().used_ids);
 
         let mut output: Output = std::mem::take(&mut self.output());
         if self.repaint_requests.load(SeqCst) > 0 {

egui/src/memory.rs

@@ -19,11 +19,6 @@ use crate::{
 #[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 #[cfg_attr(feature = "serde", serde(default))]
 pub struct Memory {
-    /// All `Id`s that were used this frame.
-    /// Used to debug `Id` clashes of widgets.
-    #[cfg_attr(feature = "serde", serde(skip))]
-    pub(crate) used_ids: ahash::AHashMap<Id, Pos2>,
-
     #[cfg_attr(feature = "serde", serde(skip))]
     pub(crate) interaction: Interaction,
 
@@ -39,7 +34,7 @@ pub struct Memory {
     pub(crate) window_interaction: Option<window::WindowInteraction>,
 
     /// For temporary edit of e.g. a slider value.
-    /// Couples with `kb_focus_id`.
+    /// Couples with [`Interaction::kb_focus_id`].
     #[cfg_attr(feature = "serde", serde(skip))]
     pub(crate) temp_edit_string: Option<String>,
 
@@ -54,12 +49,6 @@ pub struct Memory {
     #[cfg_attr(feature = "serde", serde(skip))]
     popup: Option<Id>,
 
-    /// If a tooltip has been shown this frame, where was it?
-    /// This is used to prevent multiple tooltips to cover each other.
-    /// Initialized to `None` at the start of each frame.
-    #[cfg_attr(feature = "serde", serde(skip))]
-    pub(crate) tooltip_rect: Option<Rect>,
-
     #[cfg_attr(feature = "serde", serde(skip))]
     everything_is_visible: bool,
 }
@@ -162,16 +151,14 @@ impl Memory {
         prev_input: &crate::input::InputState,
         new_input: &crate::input::RawInput,
     ) {
-        self.used_ids.clear();
         self.interaction.begin_frame(prev_input, new_input);
-        self.tooltip_rect = None;
 
         if !prev_input.mouse.down {
             self.window_interaction = None;
         }
     }
 
-    pub(crate) fn end_frame(&mut self) {
+    pub(crate) fn end_frame(&mut self, used_ids: &ahash::AHashMap<Id, Pos2>) {
         self.areas.end_frame();
 
         if let Some(kb_focus_id) = self.interaction.kb_focus_id {
@@ -179,8 +166,8 @@ impl Memory {
             let recently_gained_kb_focus =
                 self.interaction.kb_focus_id_previous_frame != Some(kb_focus_id);
 
-            if !recently_gained_kb_focus && !self.used_ids.contains_key(&kb_focus_id) {
-                // Dead-mans-switch: the widget with kb focus has dissappeared!
+            if !recently_gained_kb_focus && !used_ids.contains_key(&kb_focus_id) {
+                // Dead-mans-switch: the widget with kb focus has disappeared!
                 self.interaction.kb_focus_id = None;
             }
         }