From 2861bc956a01b4aa1f21e03f0525f09931d43fc5 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emilernerfeldt@gmail.com>
Date: Wed, 5 Aug 2020 13:32:40 +0200
Subject: [PATCH] [menu] click outside a menu to close it

---
 egui/src/containers.rs            |  1 -
 egui/src/input.rs                 | 26 +++++++++++
 egui/src/lib.rs                   |  1 +
 egui/src/memory.rs                |  5 +--
 egui/src/{containers => }/menu.rs | 73 +++++++++++++++++++++----------
 5 files changed, 79 insertions(+), 27 deletions(-)
 rename egui/src/{containers => }/menu.rs (77%)

diff --git a/egui/src/containers.rs b/egui/src/containers.rs
index d42f2994..8ce7ddfb 100644
--- a/egui/src/containers.rs
+++ b/egui/src/containers.rs
@@ -1,7 +1,6 @@
 pub(crate) mod area;
 pub(crate) mod collapsing_header;
 pub(crate) mod frame;
-pub mod menu;
 pub(crate) mod popup;
 pub(crate) mod resize;
 pub(crate) mod scroll_area;
diff --git a/egui/src/input.rs b/egui/src/input.rs
index e541251b..060f2c8b 100644
--- a/egui/src/input.rs
+++ b/egui/src/input.rs
@@ -215,6 +215,32 @@ impl InputState {
             || self.scroll_delta != Vec2::zero()
             || !self.events.is_empty()
     }
+
+    /// Was the given key pressed this frame?
+    pub fn key_pressed(&self, desired_key: Key) -> bool {
+        self.events.iter().any(|event| {
+            matches!(
+                event,
+                Event::Key {
+                    key,
+                    pressed: true
+                } if *key == desired_key
+            )
+        })
+    }
+
+    /// Was the given key released this frame?
+    pub fn key_released(&self, desired_key: Key) -> bool {
+        self.events.iter().any(|event| {
+            matches!(
+                event,
+                Event::Key {
+                    key,
+                    pressed: false
+                } if *key == desired_key
+            )
+        })
+    }
 }
 
 impl MouseInput {
diff --git a/egui/src/lib.rs b/egui/src/lib.rs
index fba6d0db..956edc05 100644
--- a/egui/src/lib.rs
+++ b/egui/src/lib.rs
@@ -33,6 +33,7 @@ mod layers;
 mod layout;
 pub mod math;
 mod memory;
+pub mod menu;
 mod movement_tracker;
 pub mod paint;
 mod painter;
diff --git a/egui/src/memory.rs b/egui/src/memory.rs
index b3f9f142..dd1cb8e5 100644
--- a/egui/src/memory.rs
+++ b/egui/src/memory.rs
@@ -1,9 +1,8 @@
 use std::collections::{HashMap, HashSet};
 
 use crate::{
-    containers::{area, collapsing_header, menu, resize, scroll_area, window},
-    widgets::text_edit,
-    Id, Layer, Pos2, Rect,
+    area, collapsing_header, menu, resize, scroll_area, widgets::text_edit, window, Id, Layer,
+    Pos2, Rect,
 };
 
 /// The data that Egui persists between frames.
diff --git a/egui/src/containers/menu.rs b/egui/src/menu.rs
similarity index 77%
rename from egui/src/containers/menu.rs
rename to egui/src/menu.rs
index a6ec78de..0c0bf919 100644
--- a/egui/src/containers/menu.rs
+++ b/egui/src/menu.rs
@@ -1,6 +1,21 @@
-use crate::{widgets::*, *};
+//! Menu bar functionality.
+//!
+//! Usage:
+//! ``` rust
+//! fn show_menu(ui: &mut egui::Ui) {
+//!     use egui::{menu, Button};
+//!
+//!     menu::bar(ui, |ui| {
+//!         menu::menu(ui, "File", |ui| {
+//!             if ui.add(Button::new("Open")).clicked {
+//!                 // ...
+//!             }
+//!         });
+//!     });
+//! }
+//! ```
 
-use super::*;
+use crate::{widgets::*, *};
 
 #[derive(Clone, Copy, Debug)]
 #[cfg_attr(feature = "with_serde", derive(serde::Deserialize, serde::Serialize))]
@@ -21,6 +36,26 @@ impl Default for BarState {
     }
 }
 
+impl BarState {
+    fn load(ctx: &Context, bar_id: &Id) -> Self {
+        ctx.memory()
+            .menu_bar
+            .get(bar_id)
+            .cloned()
+            .unwrap_or_default()
+    }
+
+    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) {
     ui.inner_layout(Layout::horizontal(Align::Center), |ui| {
         Frame::menu_bar(ui.style()).show(ui, |ui| {
@@ -38,7 +73,17 @@ pub fn bar<R>(ui: &mut Ui, add_contents: impl FnOnce(&mut Ui) -> R) -> (R, Rect)
             let height = ui.style().menu_bar.height;
             ui.set_desired_height(height);
             ui.expand_to_size(vec2(ui.available().width(), height));
-            add_contents(ui)
+
+            let ret = add_contents(ui);
+
+            let clicked_outside = !ui.hovered(ui.rect()) && ui.input().mouse.released;
+            if clicked_outside || ui.input().key_pressed(Key::Escape) {
+                // TODO: this prevent sub-menus in menus. We should fix that.
+                let bar_id = ui.id();
+                BarState::close_menus(ui.ctx(), bar_id);
+            }
+
+            ret
         })
     })
 }
@@ -57,12 +102,7 @@ fn menu_impl<'c>(
     let bar_id = ui.id();
     let menu_id = bar_id.with(&title);
 
-    let mut bar_state = ui
-        .memory()
-        .menu_bar
-        .get(&bar_id)
-        .cloned()
-        .unwrap_or_default();
+    let mut bar_state = BarState::load(ui.ctx(), &bar_id);
 
     let mut button = Button::new(title);
 
@@ -105,7 +145,7 @@ fn menu_impl<'c>(
         }
     }
 
-    ui.memory().menu_bar.insert(bar_id, bar_state);
+    bar_state.save(ui.ctx(), bar_id);
 }
 
 fn interact_with_menu_button(
@@ -138,17 +178,4 @@ fn interact_with_menu_button(
     if button_interact.hovered && bar_state.open_menu.is_some() {
         bar_state.open_menu = Some(menu_id);
     }
-
-    let pressed_escape = input.events.iter().any(|event| {
-        matches!(
-            event,
-            Event::Key {
-                key: Key::Escape,
-                pressed: true
-            }
-        )
-    });
-    if pressed_escape {
-        bar_state.open_menu = None;
-    }
 }