WindowServer: Support Alt+Character menu shortcuts :^)

This patch adds support for opening menus via keyboard shortcuts.
Use an ampersand in a menu name to automatically create a keyboard
shortcut (Alt + the character following the ampersand.)

Menus with an Alt shortcut have a small underline under the shortcut
character for discoverability.

Userland/Services/WindowServer/Menu.cpp

@@ -43,12 +43,26 @@
 
 namespace WindowServer {
 
-Menu::Menu(ClientConnection* client, int menu_id, const String& name)
+static u32 find_ampersand_shortcut_character(const String& string)
+{
+    Utf8View utf8_view { string };
+    for (auto it = utf8_view.begin(); it != utf8_view.end(); ++it) {
+        if (*it == '&') {
+            ++it;
+            if (it != utf8_view.end() && *it != '&')
+                return *it;
+        }
+    }
+    return 0;
+}
+
+Menu::Menu(ClientConnection* client, int menu_id, String name)
     : Core::Object(client)
     , m_client(client)
     , m_menu_id(menu_id)
     , m_name(move(name))
 {
+    m_alt_shortcut_character = find_ampersand_shortcut_character(m_name);
 }
 
 Menu::~Menu()

Userland/Services/WindowServer/Menu.h

@@ -47,13 +47,15 @@ class Event;
 class Menu final : public Core::Object {
     C_OBJECT(Menu)
 public:
-    Menu(ClientConnection*, int menu_id, const String& name);
+    Menu(ClientConnection*, int menu_id, String name);
     virtual ~Menu() override;
 
     ClientConnection* client() { return m_client; }
     const ClientConnection* client() const { return m_client; }
     int menu_id() const { return m_menu_id; }
 
+    u32 alt_shortcut_character() const { return m_alt_shortcut_character; }
+
     bool is_empty() const { return m_items.is_empty(); }
     int item_count() const { return m_items.size(); }
     const MenuItem& item(int index) const { return m_items.at(index); }
@@ -142,6 +144,7 @@ private:
     ClientConnection* m_client { nullptr };
     int m_menu_id { 0 };
     String m_name;
+    u32 m_alt_shortcut_character { 0 };
     Gfx::IntRect m_rect_in_window_menubar;
     NonnullOwnPtrVector<MenuItem> m_items;
     RefPtr<Window> m_menu_window;

Userland/Services/WindowServer/Window.cpp

@@ -34,6 +34,7 @@
 #include "WindowManager.h"
 #include <AK/Badge.h>
 #include <WindowServer/WindowClientEndpoint.h>
+#include <ctype.h>
 
 namespace WindowServer {
 
@@ -445,12 +446,7 @@ void Window::event(Core::Event& event)
         m_client->post_message(Messages::WindowClient::WindowLeft(m_window_id));
         break;
     case Event::KeyDown:
-        m_client->post_message(
-            Messages::WindowClient::KeyDown(m_window_id,
-                (u32) static_cast<const KeyEvent&>(event).code_point(),
-                (u32) static_cast<const KeyEvent&>(event).key(),
-                static_cast<const KeyEvent&>(event).modifiers(),
-                (u32) static_cast<const KeyEvent&>(event).scancode()));
+        handle_keydown_event(static_cast<const KeyEvent&>(event));
         break;
     case Event::KeyUp:
         m_client->post_message(
@@ -483,6 +479,25 @@ void Window::event(Core::Event& event)
     }
 }
 
+void Window::handle_keydown_event(const KeyEvent& event)
+{
+    if (event.modifiers() == Mod_Alt && event.code_point() && menubar()) {
+        Menu* menu_to_open = nullptr;
+        menubar()->for_each_menu([&](Menu& menu) {
+            if (tolower(menu.alt_shortcut_character()) == tolower(event.code_point())) {
+                menu_to_open = &menu;
+                return IterationDecision::Break;
+            }
+            return IterationDecision::Continue;
+        });
+        if (menu_to_open) {
+            frame().open_menubar_menu(*menu_to_open);
+            return;
+        }
+    }
+    m_client->post_message(Messages::WindowClient::KeyDown(m_window_id, (u32)event.code_point(), (u32)event.key(), event.modifiers(), (u32)event.scancode()));
+}
+
 void Window::set_global_cursor_tracking_enabled(bool enabled)
 {
     m_global_cursor_tracking_enabled = enabled;

Userland/Services/WindowServer/Window.h

@@ -41,6 +41,7 @@ namespace WindowServer {
 
 class ClientConnection;
 class Cursor;
+class KeyEvent;
 class Menu;
 class MenuBar;
 class MenuItem;
@@ -339,6 +340,7 @@ public:
 private:
     virtual void event(Core::Event&) override;
     void handle_mouse_event(const MouseEvent&);
+    void handle_keydown_event(const KeyEvent&);
     void update_menu_item_text(PopupMenuItem item);
     void update_menu_item_enabled(PopupMenuItem item);
     void add_child_window(Window&);

Userland/Services/WindowServer/WindowFrame.cpp

@@ -317,12 +317,7 @@ void WindowFrame::paint_menubar(Gfx::Painter& painter)
         if (paint_as_pressed || paint_as_hovered) {
             Gfx::StylePainter::paint_button(painter, menu.rect_in_window_menubar(), palette, Gfx::ButtonStyle::CoolBar, paint_as_pressed, paint_as_hovered);
         }
-        painter.draw_text(
-            text_rect,
-            menu.name(),
-            font,
-            Gfx::TextAlignment::Center,
-            text_color);
+        painter.draw_ui_text(menu.name(), text_rect, font, text_color);
         return IterationDecision::Continue;
     });
 }
@@ -749,6 +744,16 @@ void WindowFrame::handle_menubar_mouse_event(const MouseEvent& event)
     }
 }
 
+void WindowFrame::open_menubar_menu(Menu& menu)
+{
+    auto menubar_rect = this->menubar_rect();
+    MenuManager::the().close_everyone();
+    menu.ensure_menu_window().move_to(menu.rect_in_window_menubar().bottom_left().translated(rect().location()).translated(menubar_rect.location()));
+    MenuManager::the().open_menu(menu);
+    WindowManager::the().set_window_with_active_menu(&m_window);
+    invalidate(menubar_rect);
+}
+
 void WindowFrame::handle_menu_mouse_event(Menu& menu, const MouseEvent& event)
 {
     auto menubar_rect = this->menubar_rect();
@@ -758,11 +763,7 @@ void WindowFrame::handle_menu_mouse_event(Menu& menu, const MouseEvent& event)
     bool should_close_menu = &menu == MenuManager::the().current_menu() && is_mousedown_with_left_button;
 
     if (should_open_menu) {
-        MenuManager::the().close_everyone();
-        menu.ensure_menu_window().move_to(menu.rect_in_window_menubar().bottom_left().translated(rect().location()).translated(menubar_rect.location()));
-        MenuManager::the().open_menu(menu);
-        WindowManager::the().set_window_with_active_menu(&m_window);
-        invalidate(menubar_rect);
+        open_menubar_menu(menu);
         return;
     }
 

Userland/Services/WindowServer/WindowFrame.h

@@ -97,6 +97,8 @@ public:
 
     bool hit_test(const Gfx::IntPoint&) const;
 
+    void open_menubar_menu(Menu&);
+
 private:
     void paint_simple_rect_shadow(Gfx::Painter&, const Gfx::IntRect&, const Gfx::Bitmap&) const;
     void paint_notification_frame(Gfx::Painter&);