From d8021843f8be81967f02fba866fcaa1ce86ce7d8 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emilernerfeldt@gmail.com>
Date: Fri, 25 Sep 2020 15:31:27 +0200
Subject: [PATCH] [menu] simplify menu interactions, fixing an annoying bug

---
 egui/src/memory.rs |  1 +
 egui/src/menu.rs   | 83 +++++++++-------------------------------------
 2 files changed, 17 insertions(+), 67 deletions(-)

diff --git a/egui/src/memory.rs b/egui/src/memory.rs
index 1cc170f0..017120ba 100644
--- a/egui/src/memory.rs
+++ b/egui/src/memory.rs
@@ -25,6 +25,7 @@ pub struct Memory {
 
     // states of various types of widgets
     pub(crate) collapsing_headers: HashMap<Id, collapsing_header::State>,
+    #[cfg_attr(feature = "serde", serde(skip))]
     pub(crate) menu_bar: HashMap<Id, menu::BarState>,
     pub(crate) resize: HashMap<Id, resize::State>,
     pub(crate) scroll_areas: HashMap<Id, scroll_area::State>,
diff --git a/egui/src/menu.rs b/egui/src/menu.rs
index f93e1a89..9be946d8 100644
--- a/egui/src/menu.rs
+++ b/egui/src/menu.rs
@@ -18,23 +18,9 @@
 use crate::{color::TRANSPARENT, paint::Stroke, widgets::*, *};
 
 /// What is saved between frames.
-#[derive(Clone, Copy, Debug)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[derive(Clone, Copy, Debug, Default)]
 pub(crate) struct BarState {
-    #[cfg_attr(feature = "serde", serde(skip))]
     open_menu: Option<Id>,
-    #[cfg_attr(feature = "serde", serde(skip))]
-    /// When did we open a menu?
-    open_time: f64,
-}
-
-impl Default for BarState {
-    fn default() -> Self {
-        Self {
-            open_menu: None,
-            open_time: f64::NEG_INFINITY,
-        }
-    }
 }
 
 impl BarState {
@@ -49,12 +35,6 @@ impl BarState {
     fn save(self, ctx: &Context, bar_id: Id) {
         ctx.memory().menu_bar.insert(bar_id, self);
     }
-
-    fn close_menus(ctx: &Context, bar_id: Id) {
-        let mut bar_state = BarState::load(ctx, &bar_id);
-        bar_state.open_menu = None;
-        bar_state.save(ctx, bar_id);
-    }
 }
 
 pub fn bar<R>(ui: &mut Ui, add_contents: impl FnOnce(&mut Ui) -> R) -> (R, Rect) {
@@ -75,16 +55,7 @@ pub fn bar<R>(ui: &mut Ui, add_contents: impl FnOnce(&mut Ui) -> R) -> (R, Rect)
             ui.set_desired_height(height);
             ui.expand_to_size(vec2(ui.available().width(), height));
 
-            let ret = add_contents(ui);
-
-            let clicked_outside = !ui.hovered(ui.rect()) && ui.input().mouse.click;
-            if clicked_outside || ui.input().key_pressed(Key::Escape) {
-                // TODO: this prevents sub-menus in menus. We should fix that.
-                let bar_id = ui.id();
-                BarState::close_menus(ui.ctx(), bar_id);
-            }
-
-            ret
+            add_contents(ui)
         })
     })
 }
@@ -112,8 +83,16 @@ fn menu_impl<'c>(
     }
 
     let button_response = ui.add(button);
-
-    interact_with_menu_button(&mut bar_state, ui.input(), menu_id, &button_response);
+    if button_response.clicked {
+        // Toggle
+        if bar_state.open_menu == Some(menu_id) {
+            bar_state.open_menu = None;
+        } else {
+            bar_state.open_menu = Some(menu_id);
+        }
+    } else if button_response.hovered && bar_state.open_menu.is_some() {
+        bar_state.open_menu = Some(menu_id);
+    }
 
     if bar_state.open_menu == Some(menu_id) {
         let area = Area::new(menu_id)
@@ -121,7 +100,7 @@ fn menu_impl<'c>(
             .fixed_pos(button_response.rect.left_bottom());
         let frame = Frame::menu(ui.style());
 
-        let menu_response = area.show(ui.ctx(), |ui| {
+        area.show(ui.ctx(), |ui| {
             frame.show(ui, |ui| {
                 let mut style = ui.style().clone();
                 style.spacing.button_padding = vec2(2.0, 0.0);
@@ -137,42 +116,12 @@ fn menu_impl<'c>(
             })
         });
 
-        if menu_response.hovered && ui.input().mouse.released {
+        // TODO: this prevents sub-menus in menus. We should fix that.
+        if ui.input().key_pressed(Key::Escape) || ui.input().mouse.click && !button_response.clicked
+        {
             bar_state.open_menu = None;
         }
     }
 
     bar_state.save(ui.ctx(), bar_id);
 }
-
-fn interact_with_menu_button(
-    bar_state: &mut BarState,
-    input: &InputState,
-    menu_id: Id,
-    button_response: &Response,
-) {
-    if button_response.hovered && input.mouse.pressed {
-        if bar_state.open_menu.is_some() {
-            bar_state.open_menu = None;
-        } else {
-            bar_state.open_menu = Some(menu_id);
-            bar_state.open_time = input.time;
-        }
-    }
-
-    if button_response.hovered && input.mouse.released && bar_state.open_menu.is_some() {
-        let time_since_open = input.time - bar_state.open_time;
-        if time_since_open < 0.4 {
-            // A quick click
-            bar_state.open_menu = Some(menu_id);
-            bar_state.open_time = input.time;
-        } else {
-            // A long hold, then release
-            bar_state.open_menu = None;
-        }
-    }
-
-    if button_response.hovered && bar_state.open_menu.is_some() {
-        bar_state.open_menu = Some(menu_id);
-    }
-}