From fd7166b7b32225cdd3a9ba9d248fd1d6de8bf62f Mon Sep 17 00:00:00 2001
From: Yuqian Yang <crupest@crupest.life>
Date: Tue, 9 Sep 2025 23:24:52 +0800
Subject: xcb window focus event.

---
 include/cru/platform/gui/xcb/Window.h |  3 ++-
 src/platform/gui/xcb/Window.cpp       | 29 +++++++++++++++++++++++++----
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/include/cru/platform/gui/xcb/Window.h b/include/cru/platform/gui/xcb/Window.h
index 9c6b4f43..3f21131c 100644
--- a/include/cru/platform/gui/xcb/Window.h
+++ b/include/cru/platform/gui/xcb/Window.h
@@ -67,7 +67,7 @@ class XcbWindow : public XcbResource, public virtual INativeWindow {
 
   virtual IEvent<WindowVisibilityType>* VisibilityChangeEvent() = 0;
   virtual IEvent<Size>* ResizeEvent() = 0;
-  virtual IEvent<FocusChangeType>* FocusEvent() = 0;
+  IEvent<FocusChangeType>* FocusEvent() override;
 
   IEvent<MouseEnterLeaveType>* MouseEnterLeaveEvent() override;
   IEvent<Point>* MouseMoveEvent() override;
@@ -91,6 +91,7 @@ class XcbWindow : public XcbResource, public virtual INativeWindow {
   XcbUiApplication* application_;
   std::optional<xcb_window_t> xcb_window_;
 
+  Event<FocusChangeType> focus_event_;
   Event<MouseEnterLeaveType> mouse_enter_leave_event_;
   Event<Point> mouse_move_event_;
   Event<NativeMouseButtonEventArgs> mouse_down_event_;
diff --git a/src/platform/gui/xcb/Window.cpp b/src/platform/gui/xcb/Window.cpp
index 7cbbce47..7e4f698e 100644
--- a/src/platform/gui/xcb/Window.cpp
+++ b/src/platform/gui/xcb/Window.cpp
@@ -73,6 +73,8 @@ XcbWindow::XcbWindow(XcbUiApplication *application)
 
 XcbWindow::~XcbWindow() { application_->UnregisterWindow(this); }
 
+IEvent<FocusChangeType> *XcbWindow::FocusEvent() { return &focus_event_; }
+
 IEvent<MouseEnterLeaveType> *XcbWindow::MouseEnterLeaveEvent() {
   return &mouse_enter_leave_event_;
 }
@@ -107,10 +109,11 @@ xcb_window_t XcbWindow::DoCreateWindow() {
 
   uint32_t mask = XCB_CW_EVENT_MASK;
   uint32_t values[1] = {
-      XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_BUTTON_PRESS |
-      XCB_EVENT_MASK_BUTTON_RELEASE | XCB_EVENT_MASK_POINTER_MOTION |
-      XCB_EVENT_MASK_ENTER_WINDOW | XCB_EVENT_MASK_LEAVE_WINDOW |
-      XCB_EVENT_MASK_KEY_PRESS | XCB_EVENT_MASK_KEY_RELEASE};
+      XCB_EVENT_MASK_EXPOSURE | XCB_EVENT_MASK_FOCUS_CHANGE |
+      XCB_EVENT_MASK_BUTTON_PRESS | XCB_EVENT_MASK_BUTTON_RELEASE |
+      XCB_EVENT_MASK_POINTER_MOTION | XCB_EVENT_MASK_ENTER_WINDOW |
+      XCB_EVENT_MASK_LEAVE_WINDOW | XCB_EVENT_MASK_KEY_PRESS |
+      XCB_EVENT_MASK_KEY_RELEASE};
 
   xcb_create_window(connection, XCB_COPY_FROM_PARENT, xcb_window, screen->root,
                     100, 100, 400, 200, 10, XCB_WINDOW_CLASS_INPUT_OUTPUT,
@@ -131,6 +134,16 @@ void XcbWindow::HandleEvent(xcb_generic_event_t *event) {
              expose->height);
       break;
     }
+    case XCB_FOCUS_IN: {
+      xcb_focus_in_event_t *fi = (xcb_focus_in_event_t *)event;
+      focus_event_.Raise(FocusChangeType::Gain);
+      break;
+    }
+    case XCB_FOCUS_OUT: {
+      xcb_focus_out_event_t *fo = (xcb_focus_out_event_t *)event;
+      focus_event_.Raise(FocusChangeType::Lose);
+      break;
+    }
     case XCB_BUTTON_PRESS: {
       xcb_button_press_event_t *bp = (xcb_button_press_event_t *)event;
 
@@ -210,6 +223,14 @@ std::optional<xcb_window_t> XcbWindow::GetEventWindow(
       xcb_expose_event_t *expose = (xcb_expose_event_t *)event;
       return expose->window;
     }
+    case XCB_FOCUS_IN: {
+      xcb_focus_in_event_t *fi = (xcb_focus_in_event_t *)event;
+      return fi->event;
+    }
+    case XCB_FOCUS_OUT: {
+      xcb_focus_out_event_t *fo = (xcb_focus_out_event_t *)event;
+      return fo->event;
+    }
     case XCB_BUTTON_PRESS: {
       xcb_button_press_event_t *bp = (xcb_button_press_event_t *)event;
       return bp->event;
-- 
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