feat: Add 'mouse-enter' and 'mouse-leave' Tray events for Windows. (#40072)

docs/api/tray.md

@@ -187,7 +187,7 @@ Returns:
 
 Emitted when the mouse clicks the tray icon.
 
-#### Event: 'mouse-enter' _macOS_
+#### Event: 'mouse-enter' _macOS_ _Windows_
 
 Returns:
 
@@ -196,7 +196,7 @@ Returns:
 
 Emitted when the mouse enters the tray icon.
 
-#### Event: 'mouse-leave' _macOS_
+#### Event: 'mouse-leave' _macOS_ _Windows_
 
 Returns:
 

shell/browser/ui/win/notify_icon.cc

@@ -102,6 +102,16 @@ void NotifyIcon::HandleMouseMoveEvent(int modifiers) {
     NotifyMouseMoved(cursorPos, modifiers);
 }
 
+void NotifyIcon::HandleMouseEntered(int modifiers) {
+  gfx::Point cursor_pos = display::Screen::GetScreen()->GetCursorScreenPoint();
+  NotifyMouseEntered(cursor_pos, modifiers);
+}
+
+void NotifyIcon::HandleMouseExited(int modifiers) {
+  gfx::Point cursor_pos = display::Screen::GetScreen()->GetCursorScreenPoint();
+  NotifyMouseExited(cursor_pos, modifiers);
+}
+
 void NotifyIcon::ResetIcon() {
   NOTIFYICONDATA icon_data;
   InitIconData(&icon_data);

shell/browser/ui/win/notify_icon.h

@@ -50,6 +50,8 @@ class NotifyIcon : public TrayIcon {
 
   // Handles a mouse move event from the user.
   void HandleMouseMoveEvent(int modifiers);
+  void HandleMouseEntered(int modifiers);
+  void HandleMouseExited(int modifiers);
 
   // Re-creates the status tray icon now after the taskbar has been created.
   void ResetIcon();

shell/browser/ui/win/notify_icon_host.cc

@@ -11,11 +11,13 @@
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 #include "base/stl_util.h"
+#include "base/timer/timer.h"
 #include "base/win/win_util.h"
 #include "base/win/windows_types.h"
 #include "base/win/wrapped_window_proc.h"
 #include "content/public/browser/browser_thread.h"
 #include "shell/browser/ui/win/notify_icon.h"
+#include "ui/display/screen.h"
 #include "ui/events/event_constants.h"
 #include "ui/events/win/system_event_state_lookup.h"
 #include "ui/gfx/win/hwnd_util.h"
@@ -31,6 +33,8 @@ const UINT kBaseIconId = 2;
 
 const wchar_t kNotifyIconHostWindowClass[] = L"Electron_NotifyIconHostWindow";
 
+constexpr unsigned int kMouseLeaveCheckFrequency = 250;
+
 bool IsWinPressed() {
   return ((::GetKeyState(VK_LWIN) & 0x8000) == 0x8000) ||
          ((::GetKeyState(VK_RWIN) & 0x8000) == 0x8000);
@@ -51,6 +55,103 @@ int GetKeyboardModifiers() {
 
 }  // namespace
 
+// Helper class used to detect mouse entered and mouse exited events based on
+// mouse move event.
+class NotifyIconHost::MouseEnteredExitedDetector {
+ public:
+  MouseEnteredExitedDetector() = default;
+  ~MouseEnteredExitedDetector() = default;
+
+  // disallow copy
+  MouseEnteredExitedDetector(const MouseEnteredExitedDetector&) = delete;
+  MouseEnteredExitedDetector& operator=(const MouseEnteredExitedDetector&) =
+      delete;
+
+  // disallow move
+  MouseEnteredExitedDetector(MouseEnteredExitedDetector&&) = delete;
+  MouseEnteredExitedDetector& operator=(MouseEnteredExitedDetector&&) = delete;
+
+  void MouseMoveEvent(raw_ptr<NotifyIcon> icon) {
+    if (!icon)
+      return;
+
+    // If cursor is out of icon then skip this move event.
+    if (!IsCursorOverIcon(icon))
+      return;
+
+    // If user moved cursor to other icon then send mouse exited event for
+    // old icon.
+    if (current_mouse_entered_ &&
+        current_mouse_entered_->icon_id() != icon->icon_id()) {
+      SendExitedEvent();
+    }
+
+    // If timer is runnig then cursor is arelady over icon and
+    // CheckCursorPositionOverIcon will be repeadly checking when to send
+    // mouse exited event.
+    if (mouse_exit_timer_.IsRunning())
+      return;
+
+    SendEnteredEvent(icon);
+
+    // Start repeadly checking when to send mouse exited event.
+    StartObservingIcon(icon);
+  }
+
+  void IconRemoved(raw_ptr<NotifyIcon> icon) {
+    if (current_mouse_entered_ &&
+        current_mouse_entered_->icon_id() == icon->icon_id()) {
+      SendExitedEvent();
+    }
+  }
+
+ private:
+  void SendEnteredEvent(raw_ptr<NotifyIcon> icon) {
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&NotifyIcon::HandleMouseEntered,
+                                  icon->GetWeakPtr(), GetKeyboardModifiers()));
+  }
+
+  void SendExitedEvent() {
+    mouse_exit_timer_.Stop();
+    content::GetUIThreadTaskRunner({})->PostTask(
+        FROM_HERE, base::BindOnce(&NotifyIcon::HandleMouseExited,
+                                  std::move(current_mouse_entered_),
+                                  GetKeyboardModifiers()));
+  }
+
+  bool IsCursorOverIcon(raw_ptr<NotifyIcon> icon) {
+    gfx::Point cursor_pos =
+        display::Screen::GetScreen()->GetCursorScreenPoint();
+    return icon->GetBounds().Contains(cursor_pos);
+  }
+
+  void CheckCursorPositionOverIcon() {
+    if (!current_mouse_entered_ ||
+        IsCursorOverIcon(current_mouse_entered_.get()))
+      return;
+
+    SendExitedEvent();
+  }
+
+  void StartObservingIcon(raw_ptr<NotifyIcon> icon) {
+    current_mouse_entered_ = icon->GetWeakPtr();
+    mouse_exit_timer_.Start(
+        FROM_HERE, base::Milliseconds(kMouseLeaveCheckFrequency),
+        base::BindRepeating(
+            &MouseEnteredExitedDetector::CheckCursorPositionOverIcon,
+            weak_factory_.GetWeakPtr()));
+  }
+
+  // Timer used to check if cursor is still over the icon.
+  base::MetronomeTimer mouse_exit_timer_;
+
+  // Weak pointer to icon over which cursor is hovering.
+  base::WeakPtr<NotifyIcon> current_mouse_entered_;
+
+  base::WeakPtrFactory<MouseEnteredExitedDetector> weak_factory_{this};
+};
+
 NotifyIconHost::NotifyIconHost() {
   // Register our window class
   WNDCLASSEX window_class;
@@ -74,6 +175,9 @@ NotifyIconHost::NotifyIconHost() {
                          instance_, 0);
   gfx::CheckWindowCreated(window_, ::GetLastError());
   gfx::SetWindowUserData(window_, this);
+
+  mouse_entered_exited_detector_ =
+      std::make_unique<MouseEnteredExitedDetector>();
 }
 
 NotifyIconHost::~NotifyIconHost() {
@@ -116,6 +220,8 @@ void NotifyIconHost::Remove(NotifyIcon* icon) {
     return;
   }
 
+  mouse_entered_exited_detector_->IconRemoved(*i);
+
   notify_icons_.erase(i);
 }
 
@@ -208,6 +314,8 @@ LRESULT CALLBACK NotifyIconHost::WndProc(HWND hwnd,
         return TRUE;
 
       case WM_MOUSEMOVE:
+        mouse_entered_exited_detector_->MouseMoveEvent(win_icon);
+
         content::GetUIThreadTaskRunner({})->PostTask(
             FROM_HERE, base::BindOnce(&NotifyIcon::HandleMouseMoveEvent,
                                       win_icon_weak, GetKeyboardModifiers()));

shell/browser/ui/win/notify_icon_host.h

@@ -64,6 +64,9 @@ class NotifyIconHost {
   // The message ID of the "TaskbarCreated" message, sent to us when we need to
   // reset our status icons.
   UINT taskbar_created_message_ = 0;
+
+  class MouseEnteredExitedDetector;
+  std::unique_ptr<MouseEnteredExitedDetector> mouse_entered_exited_detector_;
 };
 
 }  // namespace electron