[feat] add controller info and file transfer in server window

src/common/window_util_mac.h

@@ -0,0 +1,25 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-01-20
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _WINDOW_UTIL_MAC_H_
+#define _WINDOW_UTIL_MAC_H_
+
+namespace crossdesk {
+
+struct SDL_Window;
+
+// Best-effort: keep an SDL window above normal windows on macOS.
+// No-op on non-macOS builds.
+void MacSetWindowAlwaysOnTop(SDL_Window* window, bool always_on_top);
+
+// Best-effort: exclude an SDL window from the Window menu and window cycling.
+// Note: Cmd-Tab switches apps (not individual windows), so this primarily
+// affects the Window menu and Cmd-` window cycling.
+void MacSetWindowExcludedFromWindowMenu(SDL_Window* window, bool excluded);
+
+}  // namespace crossdesk
+
+#endif

src/common/window_util_mac.mm

@@ -0,0 +1,64 @@
+#include "window_util_mac.h"
+
+#if defined(__APPLE__)
+
+#include <SDL3/SDL.h>
+
+#import <Cocoa/Cocoa.h>
+
+namespace crossdesk {
+
+static NSWindow* GetNSWindowFromSDL(SDL_Window* window) {
+  if (!window) {
+    return nil;
+  }
+
+#if !defined(SDL_PROP_WINDOW_COCOA_WINDOW_POINTER)
+  return nil;
+#else
+  SDL_PropertiesID props = SDL_GetWindowProperties(window);
+  void* cocoa_window_ptr =
+      SDL_GetPointerProperty(props, SDL_PROP_WINDOW_COCOA_WINDOW_POINTER, NULL);
+  if (!cocoa_window_ptr) {
+    return nil;
+  }
+  return (__bridge NSWindow*)cocoa_window_ptr;
+#endif
+}
+
+void MacSetWindowAlwaysOnTop(SDL_Window* window, bool always_on_top) {
+  NSWindow* ns_window = GetNSWindowFromSDL(window);
+  if (!ns_window) {
+    (void)always_on_top;
+    return;
+  }
+
+  // Keep above normal windows.
+  const NSInteger level = always_on_top ? NSFloatingWindowLevel : NSNormalWindowLevel;
+  [ns_window setLevel:level];
+
+  // Optional: keep visible across Spaces/fullscreen. Safe as best-effort.
+  NSWindowCollectionBehavior behavior = [ns_window collectionBehavior];
+  behavior |= NSWindowCollectionBehaviorCanJoinAllSpaces;
+  behavior |= NSWindowCollectionBehaviorFullScreenAuxiliary;
+  [ns_window setCollectionBehavior:behavior];
+}
+
+void MacSetWindowExcludedFromWindowMenu(SDL_Window* window, bool excluded) {
+  NSWindow* ns_window = GetNSWindowFromSDL(window);
+  if (!ns_window) {
+    (void)excluded;
+    return;
+  }
+
+  [ns_window setExcludedFromWindowsMenu:excluded];
+
+  NSWindowCollectionBehavior behavior = [ns_window collectionBehavior];
+  behavior |= NSWindowCollectionBehaviorIgnoresCycle;
+  behavior |= NSWindowCollectionBehaviorTransient;
+  [ns_window setCollectionBehavior:behavior];
+}
+
+}  // namespace crossdesk
+
+#endif  // __APPLE__

src/gui/assets/localization/localization.h

@@ -185,6 +185,23 @@ static std::vector<std::string> enable_daemon = {
 static std::vector<std::string> takes_effect_after_restart = {
     reinterpret_cast<const char*>(u8"重启后生效"),
     "Takes effect after restart"};
+static std::vector<std::string> select_file = {
+    reinterpret_cast<const char*>(u8"选择文件"), "Select File"};
+static std::vector<std::string> file_transfer_progress = {
+    reinterpret_cast<const char*>(u8"文件传输进度"), "File Transfer Progress"};
+static std::vector<std::string> queued = {
+    reinterpret_cast<const char*>(u8"队列中"), "Queued"};
+static std::vector<std::string> sending = {
+    reinterpret_cast<const char*>(u8"正在传输"), "Sending"};
+static std::vector<std::string> completed = {
+    reinterpret_cast<const char*>(u8"已完成"), "Completed"};
+static std::vector<std::string> failed = {
+    reinterpret_cast<const char*>(u8"失败"), "Failed"};
+static std::vector<std::string> controller = {
+    reinterpret_cast<const char*>(u8"控制端:"), "Controller:"};
+static std::vector<std::string> file_transfer = {
+    reinterpret_cast<const char*>(u8"文件传输:"), "File Transfer:"};
+
 #if _WIN32
 static std::vector<std::string> minimize_to_tray = {
     reinterpret_cast<const char*>(u8"退出时最小化到系统托盘:"),

src/gui/panels/local_peer_panel.cpp

@@ -30,6 +30,7 @@ int Render::LocalWindow() {
   ImGui::SetCursorPos(
       ImVec2(io.DisplaySize.x * 0.045f, io.DisplaySize.y * 0.02f));
 
+  ImGui::SetWindowFontScale(0.9f);
   ImGui::TextColored(
       ImVec4(0.0f, 0.0f, 0.0f, 0.5f), "%s",
       localization::local_desktop[localization_language_index_].c_str());

src/gui/panels/recent_connections_panel.cpp

@@ -26,6 +26,7 @@ int Render::RecentConnectionsWindow() {
   ImGui::SetCursorPos(
       ImVec2(io.DisplaySize.x * 0.045f, io.DisplaySize.y * 0.02f));
 
+  ImGui::SetWindowFontScale(0.9f);
   ImGui::TextColored(
       ImVec4(0.0f, 0.0f, 0.0f, 0.5f), "%s",
       localization::recent_connections[localization_language_index_].c_str());

src/gui/panels/remote_peer_panel.cpp

@@ -31,6 +31,7 @@ int Render::RemoteWindow() {
   ImGui::SetCursorPos(
       ImVec2(io.DisplaySize.x * 0.057f, io.DisplaySize.y * 0.02f));
 
+  ImGui::SetWindowFontScale(0.9f);
   ImGui::TextColored(
       ImVec4(0.0f, 0.0f, 0.0f, 0.5f), "%s",
       localization::remote_desktop[localization_language_index_].c_str());
@@ -189,11 +190,11 @@ int Render::ConnectTo(const std::string& remote_id, const char* password,
         props->params_.user_id = props->local_id_.c_str();
         props->peer_ = CreatePeer(&props->params_);
 
-        props->control_window_width_ = title_bar_height_ * 8.0f;
+        props->control_window_width_ = title_bar_height_ * 9.0f;
         props->control_window_height_ = title_bar_height_ * 1.3f;
         props->control_window_min_width_ = title_bar_height_ * 0.65f;
         props->control_window_min_height_ = title_bar_height_ * 1.3f;
-        props->control_window_max_width_ = title_bar_height_ * 8.0f;
+        props->control_window_max_width_ = title_bar_height_ * 9.0f;
         props->control_window_max_height_ = title_bar_height_ * 6.0f;
 
         if (!props->peer_) {
@@ -205,7 +206,11 @@ int Render::ConnectTo(const std::string& remote_id, const char* password,
           AddVideoStream(props->peer_, display_info.name.c_str());
         }
         AddAudioStream(props->peer_, props->audio_label_.c_str());
-        AddDataStream(props->peer_, props->data_label_.c_str());
+        AddDataStream(props->peer_, props->data_label_.c_str(), false);
+        AddDataStream(props->peer_, props->control_data_label_.c_str(), true);
+        AddDataStream(props->peer_, props->file_label_.c_str(), true);
+        AddDataStream(props->peer_, props->file_feedback_label_.c_str(), true);
+        AddDataStream(props->peer_, props->clipboard_label_.c_str(), true);
 
         props->connection_status_ = ConnectionStatus::Connecting;
 

src/gui/render.cpp

@@ -2,6 +2,12 @@
 
 #include <libyuv.h>
 
+#if defined(__linux__) && !defined(__APPLE__)
+#include <X11/Xatom.h>
+#include <X11/Xlib.h>
+#endif
+
+#include <cstring>
 #include <filesystem>
 #include <fstream>
 #include <iostream>
@@ -9,9 +15,11 @@
 #include <thread>
 
 #include "OPPOSans_Regular.h"
+#include "clipboard.h"
 #include "device_controller_factory.h"
 #include "fa_regular_400.h"
 #include "fa_solid_900.h"
+#include "file_transfer.h"
 #include "layout_relative.h"
 #include "localization.h"
 #include "platform.h"
@@ -19,10 +27,123 @@
 #include "screen_capturer_factory.h"
 #include "version_checker.h"
 
+#if defined(__APPLE__)
+#include "window_util_mac.h"
+#endif
+
 #define NV12_BUFFER_SIZE 1280 * 720 * 3 / 2
 
 namespace crossdesk {
 
+namespace {
+#if defined(__linux__) && !defined(__APPLE__)
+inline bool X11GetDisplayAndWindow(SDL_Window* window, Display** display_out,
+                                   ::Window* x11_window_out) {
+  if (!window || !display_out || !x11_window_out) {
+    return false;
+  }
+
+#if !defined(SDL_PROP_WINDOW_X11_DISPLAY_POINTER) || \
+    !defined(SDL_PROP_WINDOW_X11_WINDOW_NUMBER)
+  // SDL build does not expose X11 window properties.
+  return false;
+#else
+  SDL_PropertiesID props = SDL_GetWindowProperties(window);
+  Display* display = (Display*)SDL_GetPointerProperty(
+      props, SDL_PROP_WINDOW_X11_DISPLAY_POINTER, NULL);
+  const Sint64 x11_window_num =
+      SDL_GetNumberProperty(props, SDL_PROP_WINDOW_X11_WINDOW_NUMBER, 0);
+  const ::Window x11_window = (::Window)x11_window_num;
+
+  if (!display || !x11_window) {
+    return false;
+  }
+
+  *display_out = display;
+  *x11_window_out = x11_window;
+  return true;
+#endif
+}
+
+inline void X11SendNetWmState(Display* display, ::Window x11_window,
+                              long action, Atom state1, Atom state2 = 0) {
+  if (!display || !x11_window) {
+    return;
+  }
+
+  const Atom wm_state = XInternAtom(display, "_NET_WM_STATE", False);
+
+  XEvent event;
+  memset(&event, 0, sizeof(event));
+  event.xclient.type = ClientMessage;
+  event.xclient.serial = 0;
+  event.xclient.send_event = True;
+  event.xclient.message_type = wm_state;
+  event.xclient.window = x11_window;
+  event.xclient.format = 32;
+  event.xclient.data.l[0] = action;
+  event.xclient.data.l[1] = (long)state1;
+  event.xclient.data.l[2] = (long)state2;
+  event.xclient.data.l[3] = 1;  // normal source indication
+  event.xclient.data.l[4] = 0;
+
+  XSendEvent(display, DefaultRootWindow(display), False,
+             SubstructureRedirectMask | SubstructureNotifyMask, &event);
+}
+
+inline void X11SetWindowTypeUtility(Display* display, ::Window x11_window) {
+  if (!display || !x11_window) {
+    return;
+  }
+
+  const Atom wm_window_type =
+      XInternAtom(display, "_NET_WM_WINDOW_TYPE", False);
+  const Atom wm_window_type_utility =
+      XInternAtom(display, "_NET_WM_WINDOW_TYPE_UTILITY", False);
+
+  XChangeProperty(display, x11_window, wm_window_type, XA_ATOM, 32,
+                  PropModeReplace, (unsigned char*)&wm_window_type_utility, 1);
+}
+
+inline void X11SetWindowAlwaysOnTop(SDL_Window* window) {
+  Display* display = nullptr;
+  ::Window x11_window = 0;
+  if (!X11GetDisplayAndWindow(window, &display, &x11_window)) {
+    return;
+  }
+
+  const Atom state_above = XInternAtom(display, "_NET_WM_STATE_ABOVE", False);
+  const Atom state_stays_on_top =
+      XInternAtom(display, "_NET_WM_STATE_STAYS_ON_TOP", False);
+
+  // Request _NET_WM_STATE_ADD for ABOVE + STAYS_ON_TOP.
+  X11SendNetWmState(display, x11_window, 1, state_above, state_stays_on_top);
+  XFlush(display);
+}
+
+inline void X11SetWindowSkipTaskbar(SDL_Window* window) {
+  Display* display = nullptr;
+  ::Window x11_window = 0;
+  if (!X11GetDisplayAndWindow(window, &display, &x11_window)) {
+    return;
+  }
+
+  const Atom skip_taskbar =
+      XInternAtom(display, "_NET_WM_STATE_SKIP_TASKBAR", False);
+  const Atom skip_pager =
+      XInternAtom(display, "_NET_WM_STATE_SKIP_PAGER", False);
+
+  // Request _NET_WM_STATE_ADD for SKIP_TASKBAR + SKIP_PAGER.
+  X11SendNetWmState(display, x11_window, 1, skip_taskbar, skip_pager);
+
+  // Hint the WM that this is an auxiliary/utility window.
+  X11SetWindowTypeUtility(display, x11_window);
+
+  XFlush(display);
+}
+#endif
+}  // namespace
+
 std::vector<char> Render::SerializeRemoteAction(const RemoteAction& action) {
   std::vector<char> buffer;
   buffer.push_back(static_cast<char>(action.type));
@@ -129,6 +250,20 @@ SDL_HitTestResult Render::HitTestCallback(SDL_Window* window,
     return SDL_HITTEST_NORMAL;
   }
 
+  // Server window: OS-level dragging for the title bar, but keep the left-side
+  // collapse/expand button clickable.
+  if (render->server_window_ && window == render->server_window_) {
+    const float title_h = render->server_window_title_bar_height_;
+    const float button_w = title_h;
+    if (area->y >= 0 && area->y < title_h) {
+      if (area->x >= 0 && area->x < button_w) {
+        return SDL_HITTEST_NORMAL;
+      }
+      return SDL_HITTEST_DRAGGABLE;
+    }
+    return SDL_HITTEST_NORMAL;
+  }
+
   int window_width, window_height;
   SDL_GetWindowSize(window, &window_width, &window_height);
 
@@ -713,7 +848,11 @@ int Render::CreateConnectionPeer() {
     }
 
     AddAudioStream(peer_, audio_label_.c_str());
-    AddDataStream(peer_, data_label_.c_str());
+    AddDataStream(peer_, data_label_.c_str(), false);
+    AddDataStream(peer_, control_data_label_.c_str(), true);
+    AddDataStream(peer_, file_label_.c_str(), true);
+    AddDataStream(peer_, file_feedback_label_.c_str(), true);
+    AddDataStream(peer_, clipboard_label_.c_str(), true);
     return 0;
   } else {
     return -1;
@@ -805,10 +944,10 @@ int Render::CreateMainWindow() {
   if (std::abs(dpi_scale_ - dpi_scale) > 0.01f) {
     dpi_scale_ = dpi_scale;
 
-    main_window_width_ = (int)(main_window_width_ * dpi_scale_);
-    main_window_height_ = (int)(main_window_height_ * dpi_scale_);
-    stream_window_width_ = (int)(stream_window_width_ * dpi_scale_);
-    stream_window_height_ = (int)(stream_window_height_ * dpi_scale_);
+    main_window_width_ = (int)(main_window_width_default_ * dpi_scale_);
+    main_window_height_ = (int)(main_window_height_default_ * dpi_scale_);
+    stream_window_width_ = (int)(stream_window_width_default_ * dpi_scale_);
+    stream_window_height_ = (int)(stream_window_height_default_ * dpi_scale_);
 
     SDL_SetWindowSize(main_window_, (int)main_window_width_,
                       (int)main_window_height_);
@@ -819,7 +958,7 @@ int Render::CreateMainWindow() {
   // for window region action
   SDL_SetWindowHitTest(main_window_, HitTestCallback, this);
 
-  SetupFontAndStyle(true);
+  SetupFontAndStyle(&main_windows_system_chinese_font_);
 
   ImGuiStyle& style = ImGui::GetStyle();
   style.ScaleAllSizes(dpi_scale_);
@@ -863,6 +1002,9 @@ int Render::CreateStreamWindow() {
     return 0;
   }
 
+  stream_window_width_ = (int)(stream_window_width_default_ * dpi_scale_);
+  stream_window_height_ = (int)(stream_window_height_default_ * dpi_scale_);
+
   stream_ctx_ = ImGui::CreateContext();
   if (!stream_ctx_) {
     LOG_ERROR("Stream context is null");
@@ -888,7 +1030,7 @@ int Render::CreateStreamWindow() {
   // for window region action
   SDL_SetWindowHitTest(stream_window_, HitTestCallback, this);
 
-  SetupFontAndStyle(false);
+  SetupFontAndStyle(&stream_windows_system_chinese_font_);
 
   ImGuiStyle& style = ImGui::GetStyle();
   style.ScaleAllSizes(dpi_scale_);
@@ -933,7 +1075,126 @@ int Render::DestroyStreamWindow() {
   return 0;
 }
 
-int Render::SetupFontAndStyle(bool main_window) {
+int Render::CreateServerWindow() {
+  if (server_window_created_) {
+    return 0;
+  }
+  server_ctx_ = ImGui::CreateContext();
+  if (!server_ctx_) {
+    LOG_ERROR("Server context is null");
+    return -1;
+  }
+  ImGui::SetCurrentContext(server_ctx_);
+  if (!SDL_CreateWindowAndRenderer("Server window", (int)server_window_width_,
+                                   (int)server_window_height_,
+                                   SDL_WINDOW_HIGH_PIXEL_DENSITY |
+                                       SDL_WINDOW_BORDERLESS |
+                                       SDL_WINDOW_TRANSPARENT,
+                                   &server_window_, &server_renderer_)) {
+    LOG_ERROR("Error creating server_window_ and server_renderer_: {}",
+              SDL_GetError());
+    return -1;
+  }
+
+#if _WIN32
+  // Hide server window from the taskbar by making it an owned tool window.
+  {
+    SDL_PropertiesID server_props = SDL_GetWindowProperties(server_window_);
+    HWND server_hwnd = (HWND)SDL_GetPointerProperty(
+        server_props, SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
+
+    HWND owner_hwnd = nullptr;
+    if (main_window_) {
+      SDL_PropertiesID main_props = SDL_GetWindowProperties(main_window_);
+      owner_hwnd = (HWND)SDL_GetPointerProperty(
+          main_props, SDL_PROP_WINDOW_WIN32_HWND_POINTER, NULL);
+    }
+
+    if (server_hwnd) {
+      LONG_PTR ex_style = GetWindowLongPtr(server_hwnd, GWL_EXSTYLE);
+      ex_style |= WS_EX_TOOLWINDOW;
+      ex_style &= ~WS_EX_APPWINDOW;
+      SetWindowLongPtr(server_hwnd, GWL_EXSTYLE, ex_style);
+
+      if (owner_hwnd) {
+        SetWindowLongPtr(server_hwnd, GWLP_HWNDPARENT, (LONG_PTR)owner_hwnd);
+      }
+
+      // Keep the server window above normal windows.
+      SetWindowPos(server_hwnd, HWND_TOPMOST, 0, 0, 0, 0,
+                   SWP_NOMOVE | SWP_NOSIZE | SWP_FRAMECHANGED | SWP_NOACTIVATE);
+    }
+  }
+#endif
+
+#if defined(__linux__) && !defined(__APPLE__)
+  // Best-effort keep above other windows on X11.
+  X11SetWindowAlwaysOnTop(server_window_);
+  // Best-effort hide from taskbar on X11.
+  X11SetWindowSkipTaskbar(server_window_);
+#endif
+
+#if defined(__APPLE__)
+  // Best-effort keep above other windows on macOS.
+  MacSetWindowAlwaysOnTop(server_window_, true);
+  // Best-effort exclude from Window menu / window cycling.
+  MacSetWindowExcludedFromWindowMenu(server_window_, true);
+#endif
+
+  // Set window position to bottom-right corner
+  SDL_Rect display_bounds;
+  if (SDL_GetDisplayUsableBounds(SDL_GetDisplayForWindow(server_window_),
+                                 &display_bounds)) {
+    int window_x =
+        display_bounds.x + display_bounds.w - (int)server_window_width_;
+    int window_y =
+        display_bounds.y + display_bounds.h - (int)server_window_height_;
+    SDL_SetWindowPosition(server_window_, window_x, window_y);
+  }
+
+  SDL_SetWindowResizable(server_window_, false);
+
+  SDL_SetRenderDrawBlendMode(server_renderer_, SDL_BLENDMODE_BLEND);
+
+  // for window region action
+  SDL_SetWindowHitTest(server_window_, HitTestCallback, this);
+
+  SetupFontAndStyle(&server_windows_system_chinese_font_);
+
+  ImGuiStyle& style = ImGui::GetStyle();
+  style.ScaleAllSizes(dpi_scale_);
+  style.FontScaleDpi = dpi_scale_;
+
+  ImGui_ImplSDL3_InitForSDLRenderer(server_window_, server_renderer_);
+  ImGui_ImplSDLRenderer3_Init(server_renderer_);
+
+  server_window_created_ = true;
+  server_window_inited_ = true;
+
+  LOG_INFO("Server window inited");
+
+  return 0;
+}
+
+int Render::DestroyServerWindow() {
+  if (server_ctx_) {
+    ImGui::SetCurrentContext(server_ctx_);
+  }
+
+  if (server_renderer_) {
+    SDL_DestroyRenderer(server_renderer_);
+  }
+
+  if (server_window_) {
+    SDL_DestroyWindow(server_window_);
+  }
+
+  server_window_created_ = false;
+
+  return 0;
+}
+
+int Render::SetupFontAndStyle(ImFont** system_chinese_font_out) {
   float font_size = 32.0f;
 
   // Setup Dear ImGui style
@@ -955,10 +1216,8 @@ int Render::SetupFontAndStyle(bool main_window) {
   // Load system Chinese font as fallback
   config.MergeMode = false;
   config.FontDataOwnedByAtlas = false;
-  if (main_window) {
-    main_windows_system_chinese_font_ = nullptr;
-  } else {
-    stream_windows_system_chinese_font_ = nullptr;
+  if (system_chinese_font_out) {
+    *system_chinese_font_out = nullptr;
   }
 
 #if defined(_WIN32)
@@ -985,37 +1244,36 @@ int Render::SetupFontAndStyle(bool main_window) {
     std::ifstream font_file(font_paths[i], std::ios::binary);
     if (font_file.good()) {
       font_file.close();
-      if (main_window) {
-        main_windows_system_chinese_font_ =
-            io.Fonts->AddFontFromFileTTF(font_paths[i], font_size, &config,
-                                         io.Fonts->GetGlyphRangesChineseFull());
-        if (main_windows_system_chinese_font_ != nullptr) {
-          LOG_INFO("Loaded system Chinese font: {}", font_paths[i]);
-          break;
-        }
-      } else {
-        stream_windows_system_chinese_font_ =
-            io.Fonts->AddFontFromFileTTF(font_paths[i], font_size, &config,
-                                         io.Fonts->GetGlyphRangesChineseFull());
-        if (stream_windows_system_chinese_font_ != nullptr) {
-          LOG_INFO("Loaded system Chinese font: {}", font_paths[i]);
-          break;
-        }
+      if (!system_chinese_font_out) {
+        break;
+      }
+
+      *system_chinese_font_out =
+          io.Fonts->AddFontFromFileTTF(font_paths[i], font_size, &config,
+                                       io.Fonts->GetGlyphRangesChineseFull());
+      if (*system_chinese_font_out != nullptr) {
+        // Merge FontAwesome icons into the Chinese font
+        config.MergeMode = true;
+        static const ImWchar icon_ranges[] = {ICON_MIN_FA, ICON_MAX_FA, 0};
+        io.Fonts->AddFontFromMemoryTTF(fa_solid_900_ttf, fa_solid_900_ttf_len,
+                                       font_size, &config, icon_ranges);
+        config.MergeMode = false;
+        LOG_INFO("Loaded system Chinese font with icons: {}", font_paths[i]);
+        break;
       }
     }
   }
 
   // If no system font found, use default font
-  if (main_window) {
-    if (main_windows_system_chinese_font_ == nullptr) {
-      main_windows_system_chinese_font_ = io.Fonts->AddFontDefault(&config);
-      LOG_WARN("System Chinese font not found, using default font");
-    }
-  } else {
-    if (stream_windows_system_chinese_font_ == nullptr) {
-      stream_windows_system_chinese_font_ = io.Fonts->AddFontDefault(&config);
-      LOG_WARN("System Chinese font not found, using default font");
-    }
+  if (system_chinese_font_out && *system_chinese_font_out == nullptr) {
+    *system_chinese_font_out = io.Fonts->AddFontDefault(&config);
+    // Merge FontAwesome icons into the default font
+    config.MergeMode = true;
+    static const ImWchar icon_ranges[] = {ICON_MIN_FA, ICON_MAX_FA, 0};
+    io.Fonts->AddFontFromMemoryTTF(fa_solid_900_ttf, fa_solid_900_ttf_len,
+                                   font_size, &config, icon_ranges);
+    config.MergeMode = false;
+    LOG_WARN("System Chinese font not found, using default font with icons");
   }
 
   ImGui::StyleColorsLight();
@@ -1153,6 +1411,35 @@ int Render::DrawStreamWindow() {
   return 0;
 }
 
+int Render::DrawServerWindow() {
+  if (!server_ctx_) {
+    LOG_ERROR("Server context is null");
+    return -1;
+  }
+
+  if (server_window_) {
+    int w = 0;
+    int h = 0;
+    SDL_GetWindowSize(server_window_, &w, &h);
+    if (w > 0 && h > 0) {
+      server_window_width_ = (float)w;
+      server_window_height_ = (float)h;
+    }
+  }
+
+  ImGui::SetCurrentContext(server_ctx_);
+  ImGui_ImplSDLRenderer3_NewFrame();
+  ImGui_ImplSDL3_NewFrame();
+  ImGui::NewFrame();
+  ServerWindow();
+  ImGui::Render();
+  SDL_SetRenderDrawColor(server_renderer_, 255, 255, 255, 255);
+  SDL_RenderClear(server_renderer_);
+  ImGui_ImplSDLRenderer3_RenderDrawData(ImGui::GetDrawData(), server_renderer_);
+  SDL_RenderPresent(server_renderer_);
+  return 0;
+}
+
 int Render::Run() {
   latest_version_info_ = CheckUpdate();
   if (!latest_version_info_.empty() &&
@@ -1264,6 +1551,36 @@ void Render::InitializeModules() {
     keyboard_capturer_ = (KeyboardCapturer*)device_controller_factory_->Create(
         DeviceControllerFactory::Device::Keyboard);
     CreateConnectionPeer();
+
+    // start clipboard monitoring with callback to send data to peers
+    Clipboard::StartMonitoring(
+        100, [this](const char* data, size_t size) -> int {
+          // send clipboard data to all connected peers
+          std::shared_lock lock(client_properties_mutex_);
+          int ret = -1;
+          for (const auto& [remote_id, props] : client_properties_) {
+            if (props && props->peer_ && props->connection_established_) {
+              ret = SendReliableDataFrame(props->peer_, data, size,
+                                          props->clipboard_label_.c_str());
+              if (ret != 0) {
+                LOG_WARN("Failed to send clipboard data to peer [{}], ret={}",
+                         remote_id.c_str(), ret);
+                return ret;
+              }
+            }
+          }
+
+          ret = SendReliableDataFrame(peer_, data, size,
+                                      clipboard_label_.c_str());
+          if (ret != 0) {
+            LOG_WARN("Failed to send clipboard data to peer [{}], ret={}",
+                     remote_id_display_, ret);
+            return ret;
+          }
+
+          return 0;
+        });
+
     modules_inited_ = true;
   }
 }
@@ -1297,12 +1614,17 @@ void Render::MainLoop() {
     UpdateLabels();
     HandleRecentConnections();
     HandleStreamWindow();
+    HandleServerWindow();
 
     DrawMainWindow();
     if (stream_window_inited_) {
       DrawStreamWindow();
     }
 
+    if (is_server_mode_) {
+      DrawServerWindow();
+    }
+
     UpdateInteractions();
 
     if (need_to_send_host_info_) {
@@ -1340,8 +1662,8 @@ void Render::MainLoop() {
       remote_action.i.host_name_size = host_name.size();
 
       std::string msg = remote_action.to_json();
-      int ret =
-          SendDataFrame(peer_, msg.data(), msg.size(), data_label_.c_str());
+      int ret = SendReliableDataFrame(peer_, msg.data(), msg.size(),
+                                      control_data_label_.c_str());
       FreeRemoteAction(remote_action);
       if (0 == ret) {
         need_to_send_host_info_ = false;
@@ -1394,7 +1716,21 @@ void Render::HandleStreamWindow() {
   }
 }
 
+void Render::HandleServerWindow() {
+  if (need_to_create_server_window_) {
+    CreateServerWindow();
+    need_to_create_server_window_ = false;
+  }
+
+  if (need_to_destroy_server_window_) {
+    DestroyServerWindow();
+    need_to_destroy_server_window_ = false;
+  }
+}
+
 void Render::Cleanup() {
+  Clipboard::StopMonitoring();
+
   if (screen_capturer_) {
     screen_capturer_->Destroy();
     delete screen_capturer_;
@@ -1542,6 +1878,166 @@ void Render::CleanSubStreamWindowProperties(
   }
 }
 
+void Render::StartFileTransfer(std::shared_ptr<SubStreamWindowProperties> props,
+                               const std::filesystem::path& file_path,
+                               const std::string& file_label) {
+  if (!props || !props->peer_) {
+    LOG_ERROR("StartFileTransfer: invalid props or peer");
+    return;
+  }
+
+  bool expected = false;
+  if (!props->file_sending_.compare_exchange_strong(expected, true)) {
+    // Already sending, this should not happen if called correctly
+    LOG_WARN(
+        "StartFileTransfer called but file_sending_ is already true, "
+        "file should have been queued: {}",
+        file_path.filename().string().c_str());
+    return;
+  }
+
+  auto peer = props->peer_;
+  auto props_weak = std::weak_ptr<SubStreamWindowProperties>(props);
+  Render* render_ptr = this;
+
+  std::thread([peer, file_path, file_label, props_weak, render_ptr]() {
+    auto props_locked = props_weak.lock();
+    if (!props_locked) {
+      return;
+    }
+
+    std::error_code ec;
+    uint64_t total_size = std::filesystem::file_size(file_path, ec);
+    if (ec) {
+      LOG_ERROR("Failed to get file size: {}", ec.message().c_str());
+      props_locked->file_sending_ = false;
+      return;
+    }
+
+    props_locked->file_sent_bytes_ = 0;
+    props_locked->file_total_bytes_ = total_size;
+    props_locked->file_send_rate_bps_ = 0;
+    props_locked->file_transfer_window_visible_ = true;
+    {
+      std::lock_guard<std::mutex> lock(props_locked->file_transfer_mutex_);
+      props_locked->file_send_start_time_ = std::chrono::steady_clock::now();
+      props_locked->file_send_last_update_time_ =
+          props_locked->file_send_start_time_;
+      props_locked->file_send_last_bytes_ = 0;
+    }
+
+    LOG_INFO(
+        "File transfer started: {} ({} bytes), file_sending_={}, "
+        "total_bytes_={}",
+        file_path.filename().string(), total_size,
+        props_locked->file_sending_.load(),
+        props_locked->file_total_bytes_.load());
+
+    FileSender sender;
+    uint32_t file_id = FileSender::NextFileId();
+
+    {
+      std::lock_guard<std::shared_mutex> lock(
+          render_ptr->file_id_to_props_mutex_);
+      render_ptr->file_id_to_props_[file_id] = props_weak;
+    }
+
+    props_locked->current_file_id_ = file_id;
+
+    // Update file transfer list: mark as sending
+    // Find the queued file that matches the exact file path
+    {
+      std::lock_guard<std::mutex> lock(props_locked->file_transfer_list_mutex_);
+      for (auto& info : props_locked->file_transfer_list_) {
+        if (info.file_path == file_path &&
+            info.status ==
+                SubStreamWindowProperties::FileTransferStatus::Queued) {
+          info.status = SubStreamWindowProperties::FileTransferStatus::Sending;
+          info.file_id = file_id;
+          info.file_size = total_size;
+          info.sent_bytes = 0;
+          break;
+        }
+      }
+    }
+
+    props_locked->file_transfer_window_visible_ = true;
+
+    // Progress will be updated via ACK from receiver
+    int ret = sender.SendFile(
+        file_path, file_path.filename().string(),
+        [peer, file_label](const char* buf, size_t sz) -> int {
+          return SendReliableDataFrame(peer, buf, sz, file_label.c_str());
+        },
+        64 * 1024, file_id);
+
+    // file_sending_ should remain true until we receive the final ACK from
+    // receiver
+    auto props_locked_final = props_weak.lock();
+    if (props_locked_final) {
+      // On error, set file_sending_ to false immediately to allow next file
+      if (ret != 0) {
+        props_locked_final->file_sending_ = false;
+        props_locked_final->file_transfer_window_visible_ = false;
+        props_locked_final->file_sent_bytes_ = 0;
+        props_locked_final->file_total_bytes_ = 0;
+        props_locked_final->file_send_rate_bps_ = 0;
+        props_locked_final->current_file_id_ = 0;
+
+        // Unregister file_id mapping on error
+        {
+          std::lock_guard<std::shared_mutex> lock(
+              render_ptr->file_id_to_props_mutex_);
+          render_ptr->file_id_to_props_.erase(file_id);
+        }
+
+        // Update file transfer list: mark as failed
+        {
+          std::lock_guard<std::mutex> lock(
+              props_locked_final->file_transfer_list_mutex_);
+          for (auto& info : props_locked_final->file_transfer_list_) {
+            if (info.file_id == file_id) {
+              info.status =
+                  SubStreamWindowProperties::FileTransferStatus::Failed;
+              break;
+            }
+          }
+        }
+
+        LOG_ERROR("FileSender::SendFile failed for [{}], ret={}",
+                  file_path.string().c_str(), ret);
+
+        render_ptr->ProcessFileQueue(props_locked_final);
+      }
+    }
+  }).detach();
+}
+
+void Render::ProcessFileQueue(
+    std::shared_ptr<SubStreamWindowProperties> props) {
+  if (!props) {
+    return;
+  }
+
+  if (props->file_sending_.load()) {
+    return;
+  }
+
+  SubStreamWindowProperties::QueuedFile queued_file;
+  {
+    std::lock_guard<std::mutex> lock(props->file_queue_mutex_);
+    if (props->file_send_queue_.empty()) {
+      return;
+    }
+    queued_file = props->file_send_queue_.front();
+    props->file_send_queue_.pop();
+  }
+
+  LOG_INFO("Processing next file in queue: {}",
+           queued_file.file_path.string().c_str());
+  StartFileTransfer(props, queued_file.file_path, queued_file.file_label);
+}
+
 void Render::UpdateRenderRect() {
   // std::shared_lock lock(client_properties_mutex_);
   for (auto& [_, props] : client_properties_) {
@@ -1610,6 +2106,16 @@ void Render::ProcessSdlEvent(const SDL_Event& event) {
     }
   }
 
+  if (server_window_inited_) {
+    if (server_ctx_) {
+      ImGui::SetCurrentContext(server_ctx_);
+      ImGui_ImplSDL3_ProcessEvent(&event);
+    } else {
+      LOG_ERROR("Server context is null");
+      return;
+    }
+  }
+
   switch (event.type) {
     case SDL_EVENT_QUIT:
       if (stream_window_inited_) {
@@ -1699,6 +2205,9 @@ void Render::ProcessSdlEvent(const SDL_Event& event) {
         foucs_on_main_window_ = false;
       }
       break;
+    case SDL_EVENT_DROP_FILE:
+      ProcessFileDropEvent(event);
+      break;
 
     case SDL_EVENT_MOUSE_MOTION:
     case SDL_EVENT_MOUSE_BUTTON_DOWN:
@@ -1779,4 +2288,112 @@ void Render::ProcessSdlEvent(const SDL_Event& event) {
       break;
   }
 }
+
+void Render::ProcessFileDropEvent(const SDL_Event& event) {
+  if (!((stream_window_ &&
+         SDL_GetWindowID(stream_window_) == event.window.windowID) ||
+        (server_window_ &&
+         SDL_GetWindowID(server_window_) == event.window.windowID))) {
+    return;
+  }
+
+  if (event.type != SDL_EVENT_DROP_FILE) {
+    return;
+  }
+
+  if (SDL_GetWindowID(stream_window_) == event.window.windowID) {
+    if (!stream_window_inited_) {
+      return;
+    }
+
+    std::shared_lock lock(client_properties_mutex_);
+    for (auto& [_, props] : client_properties_) {
+      if (props->tab_selected_) {
+        if (event.drop.data == nullptr) {
+          LOG_ERROR("ProcessFileDropEvent: drop event data is null");
+          break;
+        }
+
+        if (!props || !props->peer_) {
+          LOG_ERROR("ProcessFileDropEvent: invalid props or peer");
+          break;
+        }
+
+        std::string utf8_path = static_cast<const char*>(event.drop.data);
+        std::filesystem::path file_path = std::filesystem::u8path(utf8_path);
+
+        // Check if file exists
+        std::error_code ec;
+        if (!std::filesystem::exists(file_path, ec)) {
+          LOG_ERROR("ProcessFileDropEvent: file does not exist: {}",
+                    file_path.string().c_str());
+          break;
+        }
+
+        // Check if it's a regular file
+        if (!std::filesystem::is_regular_file(file_path, ec)) {
+          LOG_ERROR("ProcessFileDropEvent: path is not a regular file: {}",
+                    file_path.string().c_str());
+          break;
+        }
+
+        // Get file size
+        uint64_t file_size = std::filesystem::file_size(file_path, ec);
+        if (ec) {
+          LOG_ERROR("ProcessFileDropEvent: failed to get file size: {}",
+                    ec.message().c_str());
+          break;
+        }
+
+        LOG_INFO("Drop file [{}] to send (size: {} bytes)", event.drop.data,
+                 file_size);
+
+        // Use ProcessSelectedFile to handle the file processing
+        ProcessSelectedFile(utf8_path, props, props->file_label_);
+
+        break;
+      }
+    }
+  } else if (SDL_GetWindowID(server_window_) == event.window.windowID) {
+    if (!server_window_inited_) {
+      return;
+    }
+
+    if (event.drop.data == nullptr) {
+      LOG_ERROR("ProcessFileDropEvent: drop event data is null");
+      return;
+    }
+
+    std::string utf8_path = static_cast<const char*>(event.drop.data);
+    std::filesystem::path file_path = std::filesystem::u8path(utf8_path);
+
+    // Check if file exists
+    std::error_code ec;
+    if (!std::filesystem::exists(file_path, ec)) {
+      LOG_ERROR("ProcessFileDropEvent: file does not exist: {}",
+                file_path.string().c_str());
+      return;
+    }
+
+    // Check if it's a regular file
+    if (!std::filesystem::is_regular_file(file_path, ec)) {
+      LOG_ERROR("ProcessFileDropEvent: path is not a regular file: {}",
+                file_path.string().c_str());
+      return;
+    }
+
+    // Get file size
+    uint64_t file_size = std::filesystem::file_size(file_path, ec);
+    if (ec) {
+      LOG_ERROR("ProcessFileDropEvent: failed to get file size: {}",
+                ec.message().c_str());
+      return;
+    }
+
+    LOG_INFO("Drop file [{}] on server window (size: {} bytes)",
+             event.drop.data, file_size);
+
+    // Handle the dropped file on server window as needed
+  }
+}
 }  // namespace crossdesk

src/gui/render.h

@@ -11,10 +11,12 @@
 
 #include <atomic>
 #include <chrono>
+#include <filesystem>
 #include <fstream>
 #include <mutex>
 #include <nlohmann/json.hpp>
 #include <optional>
+#include <queue>
 #include <shared_mutex>
 #include <string>
 #include <unordered_map>
@@ -44,7 +46,11 @@ class Render {
     Params params_;
     PeerPtr* peer_ = nullptr;
     std::string audio_label_ = "control_audio";
-    std::string data_label_ = "control_data";
+    std::string data_label_ = "data";
+    std::string file_label_ = "file";
+    std::string control_data_label_ = "control_data";
+    std::string file_feedback_label_ = "file_feedback";
+    std::string clipboard_label_ = "clipboard";
     std::string local_id_ = "";
     std::string remote_id_ = "";
     bool exit_ = false;
@@ -122,6 +128,39 @@ class Render {
     int frame_count_ = 0;
     std::chrono::steady_clock::time_point last_time_;
     XNetTrafficStats net_traffic_stats_;
+
+    // File transfer progress
+    std::atomic<bool> file_sending_ = false;
+    std::atomic<uint64_t> file_sent_bytes_ = 0;
+    std::atomic<uint64_t> file_total_bytes_ = 0;
+    std::atomic<uint32_t> file_send_rate_bps_ = 0;
+    std::mutex file_transfer_mutex_;
+    std::chrono::steady_clock::time_point file_send_start_time_;
+    std::chrono::steady_clock::time_point file_send_last_update_time_;
+    uint64_t file_send_last_bytes_ = 0;
+    bool file_transfer_window_visible_ = false;
+    std::atomic<uint32_t> current_file_id_{0};
+
+    struct QueuedFile {
+      std::filesystem::path file_path;
+      std::string file_label;
+    };
+    std::queue<QueuedFile> file_send_queue_;
+    std::mutex file_queue_mutex_;
+
+    enum class FileTransferStatus { Queued, Sending, Completed, Failed };
+
+    struct FileTransferInfo {
+      std::string file_name;
+      std::filesystem::path file_path;
+      uint64_t file_size = 0;
+      FileTransferStatus status = FileTransferStatus::Queued;
+      uint64_t sent_bytes = 0;
+      uint32_t file_id = 0;
+      uint32_t rate_bps = 0;
+    };
+    std::vector<FileTransferInfo> file_transfer_list_;
+    std::mutex file_transfer_list_mutex_;
   };
 
  public:
@@ -142,6 +181,7 @@ class Render {
   void UpdateInteractions();
   void HandleRecentConnections();
   void HandleStreamWindow();
+  void HandleServerWindow();
   void Cleanup();
   void CleanupFactories();
   void CleanupPeer(std::shared_ptr<SubStreamWindowProperties> props);
@@ -151,12 +191,20 @@ class Render {
   void UpdateRenderRect();
   void ProcessSdlEvent(const SDL_Event& event);
 
+  void ProcessFileDropEvent(const SDL_Event& event);
+
+  void ProcessSelectedFile(const std::string& path,
+                           std::shared_ptr<SubStreamWindowProperties>& props,
+                           const std::string& file_label);
+
  private:
   int CreateStreamRenderWindow();
   int TitleBar(bool main_window);
   int MainWindow();
   int UpdateNotificationWindow();
   int StreamWindow();
+  int ServerWindow();
+  int RemoteClientInfoWindow();
   int LocalWindow();
   int RemoteWindow();
   int RecentConnectionsWindow();
@@ -172,6 +220,8 @@ class Render {
   int ShowRecentConnections();
   void Hyperlink(const std::string& label, const std::string& url,
                  const float window_width);
+  int FileTransferWindow(std::shared_ptr<SubStreamWindowProperties>& props);
+  std::string OpenFileDialog(std::string title);
 
  private:
   int ConnectTo(const std::string& remote_id, const char* password,
@@ -180,11 +230,15 @@ class Render {
   int DestroyMainWindow();
   int CreateStreamWindow();
   int DestroyStreamWindow();
-  int SetupFontAndStyle(bool main_window);
+  int CreateServerWindow();
+  int DestroyServerWindow();
+  int SetupFontAndStyle(ImFont** system_chinese_font_out);
   int DestroyMainWindowContext();
   int DestroyStreamWindowContext();
+  int DestroyServerWindowContext();
   int DrawMainWindow();
   int DrawStreamWindow();
+  int DrawServerWindow();
   int ConfirmDeleteConnection();
   int NetTrafficStats(std::shared_ptr<SubStreamWindowProperties>& props);
   void DrawConnectionStatusText(
@@ -201,14 +255,17 @@ class Render {
  public:
   static void OnReceiveVideoBufferCb(const XVideoFrame* video_frame,
                                      const char* user_id, size_t user_id_size,
+                                     const char* src_id, size_t src_id_size,
                                      void* user_data);
 
   static void OnReceiveAudioBufferCb(const char* data, size_t size,
                                      const char* user_id, size_t user_id_size,
+                                     const char* src_id, size_t src_id_size,
                                      void* user_data);
 
   static void OnReceiveDataBufferCb(const char* data, size_t size,
                                     const char* user_id, size_t user_id_size,
+                                    const char* src_id, size_t src_id_size,
                                     void* user_data);
 
   static void OnSignalStatusCb(SignalStatus status, const char* user_id,
@@ -259,6 +316,12 @@ class Render {
 
   int CreateConnectionPeer();
 
+  // File transfer helper functions
+  void StartFileTransfer(std::shared_ptr<SubStreamWindowProperties> props,
+                         const std::filesystem::path& file_path,
+                         const std::string& file_label);
+  void ProcessFileQueue(std::shared_ptr<SubStreamWindowProperties> props);
+
   int AudioDeviceInit();
   int AudioDeviceDestroy();
 
@@ -334,6 +397,7 @@ class Render {
   ImGuiContext* main_ctx_ = nullptr;
   ImFont* main_windows_system_chinese_font_ = nullptr;
   ImFont* stream_windows_system_chinese_font_ = nullptr;
+  ImFont* server_windows_system_chinese_font_ = nullptr;
   bool exit_ = false;
   const int sdl_refresh_ms_ = 16;  // ~60 FPS
 #if _WIN32
@@ -406,6 +470,7 @@ class Render {
   std::string controlled_remote_id_ = "";
   std::string focused_remote_id_ = "";
   bool need_to_send_host_info_ = false;
+  std::string remote_client_id_ = "";
   SDL_Event last_mouse_event;
   SDL_AudioStream* output_stream_;
   uint32_t STREAM_REFRESH_EVENT = 0;
@@ -432,6 +497,42 @@ class Render {
   float stream_window_dpi_scaling_w_ = 1.0f;
   float stream_window_dpi_scaling_h_ = 1.0f;
 
+  // server window render
+  SDL_Window* server_window_ = nullptr;
+  SDL_Renderer* server_renderer_ = nullptr;
+  ImGuiContext* server_ctx_ = nullptr;
+
+  // server window properties
+  bool need_to_create_server_window_ = false;
+  bool need_to_destroy_server_window_ = false;
+  bool server_window_created_ = false;
+  bool server_window_inited_ = false;
+  int server_window_width_default_ = 250;
+  int server_window_height_default_ = 150;
+  float server_window_width_ = 250;
+  float server_window_height_ = 150;
+  float server_window_title_bar_height_ = 30.0f;
+  SDL_PixelFormat server_pixformat_ = SDL_PIXELFORMAT_NV12;
+  int server_window_normal_width_ = 250;
+  int server_window_normal_height_ = 150;
+  float server_window_dpi_scaling_w_ = 1.0f;
+  float server_window_dpi_scaling_h_ = 1.0f;
+
+  // server window collapsed mode
+  bool server_window_collapsed_ = false;
+  bool server_window_collapsed_dragging_ = false;
+  float server_window_collapsed_drag_start_mouse_x_ = 0.0f;
+  float server_window_collapsed_drag_start_mouse_y_ = 0.0f;
+  int server_window_collapsed_drag_start_win_x_ = 0;
+  int server_window_collapsed_drag_start_win_y_ = 0;
+
+  // server window drag normal mode
+  bool server_window_dragging_ = false;
+  float server_window_drag_start_mouse_x_ = 0.0f;
+  float server_window_drag_start_mouse_y_ = 0.0f;
+  int server_window_drag_start_win_x_ = 0;
+  int server_window_drag_start_win_y_ = 0;
+
   bool label_inited_ = false;
   bool connect_button_pressed_ = false;
   bool password_validating_ = false;
@@ -448,6 +549,7 @@ class Render {
   bool fullscreen_button_pressed_ = false;
   bool focus_on_input_widget_ = true;
   bool is_client_mode_ = false;
+  bool is_server_mode_ = false;
   bool reload_recent_connections_ = true;
   bool show_confirm_delete_connection_ = false;
   bool delete_connection_ = false;
@@ -464,7 +566,16 @@ class Render {
   std::string video_secondary_label_ = "secondary_display";
   std::string audio_label_ = "audio";
   std::string data_label_ = "data";
+  std::string info_label_ = "info";
+  std::string control_data_label_ = "control_data";
+  std::string file_label_ = "file";
+  std::string file_feedback_label_ = "file_feedback";
+  std::string clipboard_label_ = "clipboard";
   Params params_;
+  // Map file_id to props for tracking file transfer progress via ACK
+  std::unordered_map<uint32_t, std::weak_ptr<SubStreamWindowProperties>>
+      file_id_to_props_;
+  std::shared_mutex file_id_to_props_mutex_;
   SDL_AudioDeviceID input_dev_;
   SDL_AudioDeviceID output_dev_;
   ScreenCapturerFactory* screen_capturer_factory_ = nullptr;

src/gui/render_callback.cpp

@@ -1,8 +1,16 @@
+#include <chrono>
 #include <cmath>
+#include <cstdlib>
+#include <cstring>
+#include <filesystem>
 #include <fstream>
+#include <unordered_map>
 
+#include "clipboard.h"
 #include "device_controller.h"
+#include "file_transfer.h"
 #include "localization.h"
+#include "minirtc.h"
 #include "platform.h"
 #include "rd_log.h"
 #include "render.h"
@@ -212,6 +220,7 @@ void Render::SdlCaptureAudioOut([[maybe_unused]] void* userdata,
 
 void Render::OnReceiveVideoBufferCb(const XVideoFrame* video_frame,
                                     const char* user_id, size_t user_id_size,
+                                    const char* src_id, size_t src_id_size,
                                     void* user_data) {
   Render* render = (Render*)user_data;
   if (!render) {
@@ -279,6 +288,7 @@ void Render::OnReceiveVideoBufferCb(const XVideoFrame* video_frame,
 
 void Render::OnReceiveAudioBufferCb(const char* data, size_t size,
                                     const char* user_id, size_t user_id_size,
+                                    const char* src_id, size_t src_id_size,
                                     void* user_data) {
   Render* render = (Render*)user_data;
   if (!render) {
@@ -298,12 +308,142 @@ void Render::OnReceiveAudioBufferCb(const char* data, size_t size,
 
 void Render::OnReceiveDataBufferCb(const char* data, size_t size,
                                    const char* user_id, size_t user_id_size,
+                                   const char* src_id, size_t src_id_size,
                                    void* user_data) {
   Render* render = (Render*)user_data;
   if (!render) {
     return;
   }
 
+  std::string source_id = std::string(src_id, src_id_size);
+  if (source_id == render->file_label_) {
+    std::string remote_user_id = std::string(user_id, user_id_size);
+
+    static FileReceiver receiver;
+    receiver.SetOnSendAck([render](const FileTransferAck& ack) -> int {
+      return SendReliableDataFrame(
+          render->peer_, reinterpret_cast<const char*>(&ack),
+          sizeof(FileTransferAck), render->file_feedback_label_.c_str());
+    });
+
+    receiver.OnData(data, size);
+    return;
+  } else if (source_id == render->clipboard_label_) {
+    if (size > 0) {
+      std::string clipboard_text(data, size);
+      if (!Clipboard::SetText(clipboard_text)) {
+        LOG_ERROR("Failed to set clipboard content from remote");
+      }
+    }
+    return;
+  } else if (source_id == render->file_feedback_label_) {
+    if (size < sizeof(FileTransferAck)) {
+      LOG_ERROR("FileTransferAck: buffer too small, size={}", size);
+      return;
+    }
+
+    FileTransferAck ack{};
+    memcpy(&ack, data, sizeof(FileTransferAck));
+
+    if (ack.magic != kFileAckMagic) {
+      LOG_ERROR(
+          "FileTransferAck: invalid magic, got 0x{:08X}, expected 0x{:08X}",
+          ack.magic, kFileAckMagic);
+      return;
+    }
+
+    std::shared_ptr<SubStreamWindowProperties> props = nullptr;
+    {
+      std::shared_lock lock(render->file_id_to_props_mutex_);
+      auto it = render->file_id_to_props_.find(ack.file_id);
+      if (it != render->file_id_to_props_.end()) {
+        props = it->second.lock();
+      }
+    }
+
+    if (!props) {
+      LOG_WARN("FileTransferAck: no props found for file_id={}", ack.file_id);
+      return;
+    }
+
+    // Update progress based on ACK
+    props->file_sent_bytes_ = ack.acked_offset;
+    props->file_total_bytes_ = ack.total_size;
+
+    uint32_t rate_bps = 0;
+    {
+      uint32_t data_channel_bitrate =
+          props->net_traffic_stats_.data_outbound_stats.bitrate;
+
+      if (data_channel_bitrate > 0 && props->file_sending_.load()) {
+        rate_bps = static_cast<uint32_t>(data_channel_bitrate * 0.99f);
+
+        uint32_t current_rate = props->file_send_rate_bps_.load();
+        if (current_rate > 0) {
+          // 70% old + 30% new for smoother display
+          rate_bps = static_cast<uint32_t>(current_rate * 0.7 + rate_bps * 0.3);
+        }
+      } else {
+        rate_bps = props->file_send_rate_bps_.load();
+      }
+
+      props->file_send_rate_bps_ = rate_bps;
+      props->file_send_last_bytes_ = ack.acked_offset;
+      auto now = std::chrono::steady_clock::now();
+      props->file_send_last_update_time_ = now;
+    }
+
+    // Update file transfer list: update progress and rate
+    {
+      std::lock_guard<std::mutex> lock(props->file_transfer_list_mutex_);
+      for (auto& info : props->file_transfer_list_) {
+        if (info.file_id == ack.file_id) {
+          info.sent_bytes = ack.acked_offset;
+          info.file_size = ack.total_size;
+          info.rate_bps = rate_bps;
+          break;
+        }
+      }
+    }
+
+    // Check if transfer is completed
+    if ((ack.flags & 0x01) != 0) {
+      // Transfer completed - receiver has finished receiving the file
+      // Reopen window if it was closed by user
+      props->file_transfer_window_visible_ = true;
+      props->file_sending_ = false;  // Mark sending as finished
+      LOG_INFO(
+          "File transfer completed via ACK, file_id={}, total_size={}, "
+          "acked_offset={}",
+          ack.file_id, ack.total_size, ack.acked_offset);
+
+      // Update file transfer list: mark as completed
+      {
+        std::lock_guard<std::mutex> lock(props->file_transfer_list_mutex_);
+        for (auto& info : props->file_transfer_list_) {
+          if (info.file_id == ack.file_id) {
+            info.status =
+                SubStreamWindowProperties::FileTransferStatus::Completed;
+            info.sent_bytes = ack.total_size;
+            break;
+          }
+        }
+      }
+
+      // Unregister file_id mapping after completion
+      {
+        std::lock_guard<std::shared_mutex> lock(
+            render->file_id_to_props_mutex_);
+        render->file_id_to_props_.erase(ack.file_id);
+      }
+
+      // Process next file in queue
+      render->ProcessFileQueue(props);
+    }
+
+    return;
+  }
+
   std::string json_str(data, size);
   RemoteAction remote_action;
 
@@ -428,6 +568,7 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
 
     switch (status) {
       case ConnectionStatus::Connected: {
+        render->need_to_send_host_info_ = true;
         if (!render->need_to_create_stream_window_ &&
             !render->client_properties_.empty()) {
           render->need_to_create_stream_window_ = true;
@@ -482,9 +623,12 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
 
     switch (status) {
       case ConnectionStatus::Connected: {
+        render->need_to_create_server_window_ = true;
         render->need_to_send_host_info_ = true;
+        render->is_server_mode_ = true;
         render->start_screen_capturer_ = true;
         render->start_speaker_capturer_ = true;
+        render->remote_client_id_ = remote_id;
 #ifdef CROSSDESK_DEBUG
         render->start_mouse_controller_ = false;
         render->start_keyboard_capturer_ = false;
@@ -507,11 +651,14 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
                                  kv.second == ConnectionStatus::Failed ||
                                  kv.second == ConnectionStatus::Disconnected;
                         })) {
+          render->need_to_destroy_server_window_ = true;
+          render->is_server_mode_ = false;
           render->start_screen_capturer_ = false;
           render->start_speaker_capturer_ = false;
           render->start_mouse_controller_ = false;
           render->start_keyboard_capturer_ = false;
           render->need_to_send_host_info_ = false;
+          render->remote_client_id_ = "";
           if (props) props->connection_established_ = false;
           if (render->audio_capture_) {
             render->StopSpeakerCapturer();

src/gui/toolbars/control_bar.cpp

@@ -1,7 +1,17 @@
+#include <algorithm>
+#include <atomic>
+#include <chrono>
+#include <filesystem>
+#include <fstream>
+#include <thread>
+#include <vector>
+
+#include "file_transfer.h"
 #include "layout.h"
 #include "localization.h"
 #include "rd_log.h"
 #include "render.h"
+#include "tinyfiledialogs.h"
 
 namespace crossdesk {
 
@@ -31,6 +41,89 @@ int LossRateDisplay(float loss_rate) {
   return 0;
 }
 
+std::string Render::OpenFileDialog(std::string title) {
+  const char* path = tinyfd_openFileDialog(title.c_str(),
+                                           "",       // default path
+                                           0,        // number of filters
+                                           nullptr,  // filters
+                                           nullptr,  // filter description
+                                           0         // no multiple selection
+  );
+
+  return path ? path : "";
+}
+
+void Render::ProcessSelectedFile(
+    const std::string& path, std::shared_ptr<SubStreamWindowProperties>& props,
+    const std::string& file_label) {
+  if (path.empty()) {
+    return;
+  }
+
+  LOG_INFO("Selected file: {}", path.c_str());
+
+  std::filesystem::path file_path = std::filesystem::u8path(path);
+
+  // Get file size
+  std::error_code ec;
+  uint64_t file_size = std::filesystem::file_size(file_path, ec);
+  if (ec) {
+    LOG_ERROR("Failed to get file size: {}", ec.message().c_str());
+    file_size = 0;
+  }
+
+  // Add file to transfer list
+  {
+    std::lock_guard<std::mutex> lock(props->file_transfer_list_mutex_);
+    SubStreamWindowProperties::FileTransferInfo info;
+    info.file_name = file_path.filename().u8string();
+    info.file_path = file_path;  // Store full path for precise matching
+    info.file_size = file_size;
+    info.status = SubStreamWindowProperties::FileTransferStatus::Queued;
+    info.sent_bytes = 0;
+    info.file_id = 0;
+    info.rate_bps = 0;
+    props->file_transfer_list_.push_back(info);
+  }
+  props->file_transfer_window_visible_ = true;
+
+  if (props->file_sending_.load()) {
+    // Add to queue
+    size_t queue_size = 0;
+    {
+      std::lock_guard<std::mutex> lock(props->file_queue_mutex_);
+      SubStreamWindowProperties::QueuedFile queued_file;
+      queued_file.file_path = file_path;
+      queued_file.file_label = file_label;
+      props->file_send_queue_.push(queued_file);
+      queue_size = props->file_send_queue_.size();
+    }
+    LOG_INFO("File added to queue: {} ({} files in queue)",
+             file_path.filename().string().c_str(), queue_size);
+  } else {
+    StartFileTransfer(props, file_path, file_label);
+
+    if (props->file_sending_.load()) {
+    } else {
+      // Failed to start (race condition: another file started between
+      // check and call) Add to queue
+      size_t queue_size = 0;
+      {
+        std::lock_guard<std::mutex> lock(props->file_queue_mutex_);
+        SubStreamWindowProperties::QueuedFile queued_file;
+        queued_file.file_path = file_path;
+        queued_file.file_label = file_label;
+        props->file_send_queue_.push(queued_file);
+        queue_size = props->file_send_queue_.size();
+      }
+      LOG_INFO(
+          "File added to queue after race condition: {} ({} files in "
+          "queue)",
+          file_path.filename().string().c_str(), queue_size);
+    }
+  }
+}
+
 int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
   float button_width = title_bar_height_ * 0.8f;
   float button_height = title_bar_height_ * 0.8f;
@@ -41,14 +134,14 @@ int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
   if (props->control_bar_expand_) {
     ImGui::SetCursorPosX(props->is_control_bar_in_left_
                              ? props->control_window_width_ * 1.03f
-                             : props->control_window_width_ * 0.2f);
+                             : props->control_window_width_ * 0.17f);
 
     ImDrawList* draw_list = ImGui::GetWindowDrawList();
     if (!props->is_control_bar_in_left_) {
       draw_list->AddLine(
-          ImVec2(ImGui::GetCursorScreenPos().x - button_height * 0.56f,
+          ImVec2(ImGui::GetCursorScreenPos().x - button_height * 0.5f,
                  ImGui::GetCursorScreenPos().y + button_height * 0.2f),
-          ImVec2(ImGui::GetCursorScreenPos().x - button_height * 0.56f,
+          ImVec2(ImGui::GetCursorScreenPos().x - button_height * 0.5f,
                  ImGui::GetCursorScreenPos().y + button_height * 0.8f),
           IM_COL32(178, 178, 178, 255), 2.0f);
     }
@@ -73,8 +166,8 @@ int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
           remote_action.d = i;
           if (props->connection_status_ == ConnectionStatus::Connected) {
             std::string msg = remote_action.to_json();
-            SendDataFrame(props->peer_, msg.c_str(), msg.size(),
-                          props->data_label_.c_str());
+            SendReliableDataFrame(props->peer_, msg.c_str(), msg.size(),
+                                  props->control_data_label_.c_str());
           }
         }
         props->display_selectable_hovered_ = ImGui::IsWindowHovered();
@@ -154,8 +247,8 @@ int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
         remote_action.type = ControlType::audio_capture;
         remote_action.a = props->audio_capture_button_pressed_;
         std::string msg = remote_action.to_json();
-        SendDataFrame(props->peer_, msg.c_str(), msg.size(),
-                      props->data_label_.c_str());
+        SendReliableDataFrame(props->peer_, msg.c_str(), msg.size(),
+                              props->control_data_label_.c_str());
       }
     }
 
@@ -175,6 +268,16 @@ int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
           line_thickness);
     }
 
+    ImGui::SameLine();
+    std::string open_folder = ICON_FA_FOLDER_OPEN;
+    if (ImGui::Button(open_folder.c_str(),
+                      ImVec2(button_width, button_height))) {
+      std::string title =
+          localization::select_file[localization_language_index_];
+      std::string path = OpenFileDialog(title);
+      this->ProcessSelectedFile(path, props, file_label_);
+    }
+
     ImGui::SameLine();
     // net traffic stats button
     bool button_color_style_pushed = false;
@@ -238,9 +341,9 @@ int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
 
     if (props->is_control_bar_in_left_) {
       draw_list->AddLine(
-          ImVec2(ImGui::GetCursorScreenPos().x + button_height * 0.2f,
+          ImVec2(ImGui::GetCursorScreenPos().x + button_height * 0.13f,
                  ImGui::GetCursorScreenPos().y + button_height * 0.2f),
-          ImVec2(ImGui::GetCursorScreenPos().x + button_height * 0.2f,
+          ImVec2(ImGui::GetCursorScreenPos().x + button_height * 0.13f,
                  ImGui::GetCursorScreenPos().y + button_height * 0.8f),
           IM_COL32(178, 178, 178, 255), 2.0f);
     }
@@ -250,7 +353,7 @@ int Render::ControlBar(std::shared_ptr<SubStreamWindowProperties>& props) {
 
   float expand_button_pos_x =
       props->control_bar_expand_ ? (props->is_control_bar_in_left_
-                                        ? props->control_window_width_ * 1.91f
+                                        ? props->control_window_width_ * 1.917f
                                         : props->control_window_width_ * 0.03f)
                                  : (props->is_control_bar_in_left_
                                         ? props->control_window_width_ * 1.02f

src/gui/windows/file_transfer_window.cpp

@@ -0,0 +1,242 @@
+#include <algorithm>
+#include <cmath>
+
+#include "IconsFontAwesome6.h"
+#include "layout.h"
+#include "localization.h"
+#include "rd_log.h"
+#include "render.h"
+
+namespace crossdesk {
+
+namespace {
+int CountDigits(int number) {
+  if (number == 0) return 1;
+  return (int)std::floor(std::log10(std::abs(number))) + 1;
+}
+
+int BitrateDisplay(int bitrate) {
+  int num_of_digits = CountDigits(bitrate);
+  if (num_of_digits <= 3) {
+    ImGui::Text("%d bps", bitrate);
+  } else if (num_of_digits > 3 && num_of_digits <= 6) {
+    ImGui::Text("%d kbps", bitrate / 1000);
+  } else {
+    ImGui::Text("%.1f mbps", bitrate / 1000000.0f);
+  }
+  return 0;
+}
+}  // namespace
+
+int Render::FileTransferWindow(
+    std::shared_ptr<SubStreamWindowProperties>& props) {
+  // Only show window if there are files in transfer list or currently
+  // transferring
+  std::vector<SubStreamWindowProperties::FileTransferInfo> file_list;
+  {
+    std::lock_guard<std::mutex> lock(props->file_transfer_list_mutex_);
+    file_list = props->file_transfer_list_;
+  }
+
+  // Sort file list: Sending first, then Completed, then Queued, then Failed
+  std::sort(
+      file_list.begin(), file_list.end(),
+      [](const SubStreamWindowProperties::FileTransferInfo& a,
+         const SubStreamWindowProperties::FileTransferInfo& b) {
+        // Priority: Sending > Completed > Queued > Failed
+        auto get_priority =
+            [](SubStreamWindowProperties::FileTransferStatus status) {
+              switch (status) {
+                case SubStreamWindowProperties::FileTransferStatus::Sending:
+                  return 0;
+                case SubStreamWindowProperties::FileTransferStatus::Completed:
+                  return 1;
+                case SubStreamWindowProperties::FileTransferStatus::Queued:
+                  return 2;
+                case SubStreamWindowProperties::FileTransferStatus::Failed:
+                  return 3;
+              }
+              return 3;
+            };
+        return get_priority(a.status) < get_priority(b.status);
+      });
+
+  // Only show window if file_transfer_window_visible_ is true
+  // Window can be closed by user even during transfer
+  // It will be reopened automatically when:
+  // 1. A file transfer completes (in render_callback.cpp)
+  // 2. A new file starts sending from queue (in render.cpp)
+  if (!props->file_transfer_window_visible_) {
+    return 0;
+  }
+
+  ImGuiIO& io = ImGui::GetIO();
+
+  // Position window at bottom-left of stream window
+  // Adjust window size based on number of files
+  float file_transfer_window_width = main_window_width_ * 0.6f;
+  float file_transfer_window_height =
+      main_window_height_ * 0.3f;  // Dynamic height
+  float pos_x = file_transfer_window_width * 0.05f;
+  float pos_y = stream_window_height_ - file_transfer_window_height -
+                file_transfer_window_width * 0.05;
+  float same_line_width = file_transfer_window_width * 0.1f;
+
+  ImGui::SetNextWindowPos(ImVec2(pos_x, pos_y), ImGuiCond_Always);
+  ImGui::SetNextWindowSize(
+      ImVec2(file_transfer_window_width, file_transfer_window_height),
+      ImGuiCond_Always);
+
+  // Set Chinese font for proper display
+  if (stream_windows_system_chinese_font_) {
+    ImGui::PushFont(stream_windows_system_chinese_font_);
+  }
+
+  ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 3.0f);
+  ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 1.0f);
+  ImGui::PushStyleColor(ImGuiCol_WindowBg, ImVec4(1.0f, 1.0f, 1.0f, 0.9f));
+  ImGui::PushStyleColor(ImGuiCol_Border, ImVec4(1.0f, 1.0f, 1.0f, 1.0f));
+  ImGui::PushStyleColor(ImGuiCol_TitleBg, ImVec4(1.0f, 1.0f, 1.0f, 1.0f));
+  ImGui::PushStyleColor(ImGuiCol_TitleBgActive, ImVec4(1.0f, 1.0f, 1.0f, 1.0f));
+
+  ImGui::SetWindowFontScale(0.5f);
+  bool window_opened = true;
+  if (ImGui::Begin(
+          localization::file_transfer_progress[localization_language_index_]
+              .c_str(),
+          &window_opened,
+          ImGuiWindowFlags_NoCollapse | ImGuiWindowFlags_NoResize |
+              ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoSavedSettings |
+              ImGuiWindowFlags_NoScrollbar)) {
+    ImGui::SetWindowFontScale(1.0f);
+    ImGui::SetWindowFontScale(0.5f);
+    ImGui::PopStyleColor(4);
+    ImGui::PopStyleVar(2);
+
+    // Close button handling
+    if (!window_opened) {
+      props->file_transfer_window_visible_ = false;
+      ImGui::End();
+      return 0;
+    }
+
+    // Display file list
+    if (file_list.empty()) {
+      ImGui::Text("No files in transfer queue");
+    } else {
+      // Use a scrollable child window for the file list
+      ImGui::SetWindowFontScale(0.5f);
+      ImGui::BeginChild(
+          "FileList", ImVec2(0, file_transfer_window_height * 0.75f),
+          ImGuiChildFlags_Border, ImGuiWindowFlags_HorizontalScrollbar);
+      ImGui::SetWindowFontScale(1.0f);
+      ImGui::SetWindowFontScale(0.5f);
+
+      for (size_t i = 0; i < file_list.size(); ++i) {
+        const auto& info = file_list[i];
+        ImGui::PushID(static_cast<int>(i));
+
+        // Status icon and file name
+        const char* status_icon = "";
+        ImVec4 status_color(0.5f, 0.5f, 0.5f, 1.0f);
+        const char* status_text = "";
+
+        switch (info.status) {
+          case SubStreamWindowProperties::FileTransferStatus::Queued:
+            status_icon = ICON_FA_CLOCK;
+            status_color =
+                ImVec4(0.5f, 0.6f, 0.7f, 1.0f);  // Common blue-gray for queued
+            status_text =
+                localization::queued[localization_language_index_].c_str();
+            break;
+          case SubStreamWindowProperties::FileTransferStatus::Sending:
+            status_icon = ICON_FA_ARROW_UP;
+            status_color = ImVec4(0.2f, 0.6f, 1.0f, 1.0f);
+            status_text =
+                localization::sending[localization_language_index_].c_str();
+            break;
+          case SubStreamWindowProperties::FileTransferStatus::Completed:
+            status_icon = ICON_FA_CHECK;
+            status_color = ImVec4(0.0f, 0.8f, 0.0f, 1.0f);
+            status_text =
+                localization::completed[localization_language_index_].c_str();
+            break;
+          case SubStreamWindowProperties::FileTransferStatus::Failed:
+            status_icon = ICON_FA_XMARK;
+            status_color = ImVec4(1.0f, 0.2f, 0.2f, 1.0f);
+            status_text =
+                localization::failed[localization_language_index_].c_str();
+            break;
+        }
+
+        ImGui::TextColored(status_color, "%s", status_icon);
+        ImGui::SameLine();
+        ImGui::Text("%s", info.file_name.c_str());
+        ImGui::SameLine();
+        ImGui::TextColored(status_color, "%s", status_text);
+
+        // Progress bar for sending files
+        if (info.status ==
+                SubStreamWindowProperties::FileTransferStatus::Sending &&
+            info.file_size > 0) {
+          float progress = static_cast<float>(info.sent_bytes) /
+                           static_cast<float>(info.file_size);
+          progress = (std::max)(0.0f, (std::min)(1.0f, progress));
+
+          float text_height = ImGui::GetTextLineHeight();
+          ImGui::ProgressBar(
+              progress, ImVec2(file_transfer_window_width * 0.5f, text_height),
+              "");
+          ImGui::SameLine();
+
+          ImGui::Text("%.1f%%", progress * 100.0f);
+          ImGui::SameLine();
+
+          float speed_x_pos = file_transfer_window_width * 0.65f;
+          ImGui::SetCursorPosX(speed_x_pos);
+          BitrateDisplay(static_cast<int>(info.rate_bps));
+        } else if (info.status ==
+                   SubStreamWindowProperties::FileTransferStatus::Completed) {
+          // Show completed size
+          char size_str[64];
+          if (info.file_size < 1024) {
+            snprintf(size_str, sizeof(size_str), "%llu B",
+                     (unsigned long long)info.file_size);
+          } else if (info.file_size < 1024 * 1024) {
+            snprintf(size_str, sizeof(size_str), "%.2f KB",
+                     info.file_size / 1024.0f);
+          } else {
+            snprintf(size_str, sizeof(size_str), "%.2f MB",
+                     info.file_size / (1024.0f * 1024.0f));
+          }
+          ImGui::Text("Size: %s", size_str);
+        }
+
+        ImGui::PopID();
+        ImGui::Spacing();
+      }
+
+      ImGui::SetWindowFontScale(1.0f);
+      ImGui::SetWindowFontScale(0.5f);
+      ImGui::EndChild();
+      ImGui::SetWindowFontScale(1.0f);
+    }
+    ImGui::SetWindowFontScale(1.0f);
+    ImGui::SetWindowFontScale(0.5f);
+    ImGui::End();
+    ImGui::SetWindowFontScale(1.0f);
+
+    // Pop Chinese font if it was pushed
+    if (stream_windows_system_chinese_font_) {
+      ImGui::PopFont();
+    }
+  } else {
+    ImGui::PopStyleColor(4);
+    ImGui::PopStyleVar(2);
+  }
+  ImGui::SetWindowFontScale(1.0f);
+
+  return 0;
+}
+
+}  // namespace crossdesk

src/gui/windows/server_settings_window.cpp

@@ -230,6 +230,7 @@ int Render::SelfHostedServerWindow() {
 
       //   ShowSimpleFileBrowser();
       // }
+
       {
         ImGui::AlignTextToFramePadding();
         if (ImGui::Button(localization::reset_cert_fingerprint

src/gui/windows/server_window.cpp

@@ -0,0 +1,159 @@
+#include "layout_relative.h"
+#include "localization.h"
+#include "rd_log.h"
+#include "render.h"
+
+namespace crossdesk {
+
+namespace {}  // namespace
+
+int Render::ServerWindow() {
+  ImGui::SetNextWindowSize(ImVec2(server_window_width_, server_window_height_),
+                           ImGuiCond_Always);
+  ImGui::SetNextWindowPos(ImVec2(0, 0), ImGuiCond_Always);
+
+  ImGui::Begin("##server_window", nullptr,
+               ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize |
+                   ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoCollapse |
+                   ImGuiWindowFlags_NoScrollbar |
+                   ImGuiWindowFlags_NoScrollWithMouse);
+
+  ImGui::PushStyleColor(ImGuiCol_ChildBg, ImVec4(1.0f, 1.0f, 1.0f, 1.0f));
+  ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0, 0));
+  ImGui::SetNextWindowPos(ImVec2(0, 0), ImGuiCond_Always);
+  ImGui::BeginChild(
+      "ServerTitleBar",
+      ImVec2(server_window_width_, server_window_title_bar_height_),
+      ImGuiChildFlags_Border,
+      ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoMove |
+          ImGuiWindowFlags_NoBringToFrontOnFocus);
+
+  float server_title_bar_button_width = server_window_title_bar_height_;
+  float server_title_bar_button_height = server_window_title_bar_height_;
+
+  // Collapse/expand toggle button (FontAwesome icon).
+  {
+    ImGui::SetCursorPos(ImVec2(0.0f, 0.0f));
+
+    ImGui::PushStyleColor(ImGuiCol_Button, ImVec4(0, 0, 0, 0));
+    ImGui::PushStyleColor(ImGuiCol_ButtonHovered, ImVec4(0, 0, 0, 0.1f));
+    ImGui::PushStyleColor(ImGuiCol_ButtonActive,
+                          ImVec4(1.0f, 1.0f, 1.0f, 1.0f));
+
+    ImGui::SetWindowFontScale(0.5f);
+    const char* icon =
+        server_window_collapsed_ ? ICON_FA_ANGLE_DOWN : ICON_FA_ANGLE_UP;
+    std::string toggle_label = std::string(icon) + "##server_toggle";
+    if (ImGui::Button(toggle_label.c_str(),
+                      ImVec2(server_title_bar_button_width,
+                             server_title_bar_button_height))) {
+      if (server_window_) {
+        int w = 0;
+        int h = 0;
+        int x = 0;
+        int y = 0;
+        SDL_GetWindowSize(server_window_, &w, &h);
+        SDL_GetWindowPosition(server_window_, &x, &y);
+
+        if (server_window_collapsed_) {
+          const int normal_h = server_window_normal_height_;
+          SDL_SetWindowSize(server_window_, w, normal_h);
+          SDL_SetWindowPosition(server_window_, x, y);
+          server_window_collapsed_ = false;
+        } else {
+          const int collapsed_h = (int)server_window_title_bar_height_;
+          // Collapse upward: keep top edge stable.
+          SDL_SetWindowSize(server_window_, w, collapsed_h);
+          SDL_SetWindowPosition(server_window_, x, y);
+          server_window_collapsed_ = true;
+        }
+      }
+    }
+    ImGui::SetWindowFontScale(1.0f);
+
+    ImGui::PopStyleColor(3);
+  }
+
+  ImGui::EndChild();
+  ImGui::PopStyleVar();
+  ImGui::PopStyleColor();
+
+  RemoteClientInfoWindow();
+
+  ImGui::End();
+  return 0;
+}
+
+int Render::RemoteClientInfoWindow() {
+  float remote_client_info_window_width = server_window_width_ * 0.75f;
+  float remote_client_info_window_height =
+      (server_window_height_ - server_window_title_bar_height_) * 0.3f;
+
+  ImGui::PushStyleColor(ImGuiCol_ChildBg, ImVec4(1.0f, 1.0f, 1.0f, 1.0f));
+  ImGui::PushStyleVar(ImGuiStyleVar_ChildRounding, 5.0f);
+  ImGui::BeginChild(
+      "RemoteClientInfoWindow",
+      ImVec2(remote_client_info_window_width, remote_client_info_window_height),
+      ImGuiChildFlags_Border,
+      ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoMove |
+          ImGuiWindowFlags_NoBringToFrontOnFocus);
+  ImGui::PopStyleVar();
+  ImGui::PopStyleColor();
+
+  ImGui::SetWindowFontScale(0.7f);
+  ImGui::Text("%s",
+              localization::controller[localization_language_index_].c_str());
+  ImGui::SameLine();
+  ImGui::Text("%s", remote_client_id_.c_str());
+
+  ImGui::SetWindowFontScale(1.0f);
+
+  ImGui::EndChild();
+
+  ImGui::SameLine();
+
+  float close_connection_button_width = server_window_width_ * 0.15f;
+  float close_connection_button_height = remote_client_info_window_height;
+
+  ImGui::PushStyleColor(ImGuiCol_Button, ImVec4(1.0f, 0.0f, 0.0f, 1.0f));
+  ImGui::PushStyleColor(ImGuiCol_ButtonHovered, ImVec4(1.0f, 0.3f, 0.3f, 1.0f));
+  ImGui::PushStyleColor(ImGuiCol_ButtonActive, ImVec4(1.0f, 0.5f, 0.5f, 1.0f));
+  ImGui::PushStyleVar(ImGuiStyleVar_FrameRounding, 5.0f);
+  ImGui::SetWindowFontScale(0.7f);
+  if (ImGui::Button(ICON_FA_XMARK, ImVec2(close_connection_button_width,
+                                          close_connection_button_height))) {
+    LeaveConnection(peer_, self_hosted_id_);
+  }
+  ImGui::SetWindowFontScale(1.0f);
+  ImGui::PopStyleColor(3);
+  ImGui::PopStyleVar();
+
+  ImGui::PushStyleColor(ImGuiCol_Border, ImVec4(1.0f, 1.0f, 1.0f, 0.0f));
+  ImGui::BeginChild(
+      "RemoteClientInfoFileTransferWindow",
+      ImVec2(remote_client_info_window_width, remote_client_info_window_height),
+      ImGuiChildFlags_Border,
+      ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoMove |
+          ImGuiWindowFlags_NoBringToFrontOnFocus);
+  ImGui::PopStyleColor();
+
+  ImGui::SetWindowFontScale(0.7f);
+  ImGui::AlignTextToFramePadding();
+  ImGui::Text(
+      "%s", localization::file_transfer[localization_language_index_].c_str());
+
+  ImGui::SameLine();
+
+  if (ImGui::Button(
+          localization::select_file[localization_language_index_].c_str())) {
+    std::string title = localization::select_file[localization_language_index_];
+    std::string path = OpenFileDialog(title);
+    LOG_INFO("Selected file path: {}", path.c_str());
+  }
+  ImGui::SetWindowFontScale(1.0f);
+
+  ImGui::EndChild();
+
+  return 0;
+}
+}  // namespace crossdesk

src/gui/windows/stream_window.cpp

@@ -138,6 +138,9 @@ int Render::StreamWindow() {
           UpdateRenderRect();
 
           ControlWindow(props);
+          
+          // Show file transfer window if needed
+          FileTransferWindow(props);
 
           focused_remote_id_ = props->remote_id_;
 
@@ -233,6 +236,10 @@ int Render::StreamWindow() {
         UpdateRenderRect();
 
         ControlWindow(props);
+        
+        // Show file transfer window if needed
+        FileTransferWindow(props);
+        
         ImGui::End();
 
         if (!props->peer_) {

src/tools/clipboard.cpp

@@ -0,0 +1,534 @@
+
+#include "clipboard.h"
+
+#include <atomic>
+#include <chrono>
+#include <mutex>
+#include <string>
+#include <thread>
+
+#include "rd_log.h"
+
+#ifdef _WIN32
+#include <windows.h>
+#elif __linux__
+#include <X11/Xatom.h>
+#include <X11/Xlib.h>
+#include <X11/extensions/Xfixes.h>
+
+#include <cstring>
+#include <memory>
+#endif
+
+namespace crossdesk {
+
+std::atomic<bool> g_monitoring{false};
+std::thread g_monitor_thread;
+std::mutex g_monitor_mutex;
+std::string g_last_clipboard_text;
+int g_check_interval_ms = 100;
+Clipboard::OnClipboardChanged g_on_clipboard_changed;
+
+#ifdef _WIN32
+HWND g_clipboard_wnd = nullptr;
+const char* g_clipboard_class_name = "CrossDeskClipboardMonitor";
+#endif
+
+#ifdef __linux__
+Display* g_x11_display = nullptr;
+Atom g_clipboard_atom = None;
+Atom g_xfixes_selection_notify = None;
+#endif
+}  // namespace crossdesk
+
+namespace crossdesk {
+
+#ifdef _WIN32
+std::string Clipboard::GetText() {
+  if (!OpenClipboard(nullptr)) {
+    LOG_ERROR("Clipboard::GetText: failed to open clipboard");
+    return "";
+  }
+
+  std::string result;
+  HANDLE hData = GetClipboardData(CF_UNICODETEXT);
+  if (hData != nullptr) {
+    wchar_t* pszText = static_cast<wchar_t*>(GlobalLock(hData));
+    if (pszText != nullptr) {
+      int size_needed = WideCharToMultiByte(CP_UTF8, 0, pszText, -1, nullptr, 0,
+                                            nullptr, nullptr);
+      if (size_needed > 0) {
+        // -1 because WideCharToMultiByte contains '\0'
+        result.resize(size_needed - 1);
+        WideCharToMultiByte(CP_UTF8, 0, pszText, -1, &result[0], size_needed,
+                            nullptr, nullptr);
+      }
+      GlobalUnlock(hData);
+    }
+  }
+
+  CloseClipboard();
+  return result;
+}
+
+bool Clipboard::SetText(const std::string& text) {
+  if (!OpenClipboard(nullptr)) {
+    LOG_ERROR("Clipboard::SetText: failed to open clipboard");
+    return false;
+  }
+
+  if (!EmptyClipboard()) {
+    LOG_ERROR("Clipboard::SetText: failed to empty clipboard");
+    CloseClipboard();
+    return false;
+  }
+
+  // Convert UTF-8 string to wide char
+  int size_needed =
+      MultiByteToWideChar(CP_UTF8, 0, text.c_str(), -1, nullptr, 0);
+  if (size_needed <= 0) {
+    LOG_ERROR("Clipboard::SetText: failed to convert to wide char");
+    CloseClipboard();
+    return false;
+  }
+
+  HGLOBAL hMem = GlobalAlloc(GMEM_MOVEABLE, size_needed * sizeof(wchar_t));
+  if (hMem == nullptr) {
+    LOG_ERROR("Clipboard::SetText: failed to allocate memory");
+    CloseClipboard();
+    return false;
+  }
+
+  wchar_t* pszText = static_cast<wchar_t*>(GlobalLock(hMem));
+  if (pszText == nullptr) {
+    LOG_ERROR("Clipboard::SetText: failed to lock memory");
+    GlobalFree(hMem);
+    CloseClipboard();
+    return false;
+  }
+
+  MultiByteToWideChar(CP_UTF8, 0, text.c_str(), -1, pszText, size_needed);
+  GlobalUnlock(hMem);
+
+  if (SetClipboardData(CF_UNICODETEXT, hMem) == nullptr) {
+    LOG_ERROR("Clipboard::SetText: failed to set clipboard data");
+    GlobalFree(hMem);
+    CloseClipboard();
+    return false;
+  }
+
+  CloseClipboard();
+  return true;
+}
+
+bool Clipboard::HasText() {
+  if (!OpenClipboard(nullptr)) {
+    return false;
+  }
+
+  bool has_text = IsClipboardFormatAvailable(CF_UNICODETEXT) ||
+                  IsClipboardFormatAvailable(CF_TEXT);
+  CloseClipboard();
+  return has_text;
+}
+
+#elif __APPLE__
+// macOS implementation is in clipboard_mac.mm
+#elif __linux__
+
+std::string Clipboard::GetText() {
+  Display* display = XOpenDisplay(nullptr);
+  if (display == nullptr) {
+    LOG_ERROR("Clipboard::GetText: failed to open X display");
+    return "";
+  }
+
+  std::string result;
+  Window owner = XGetSelectionOwner(display, XA_PRIMARY);
+  if (owner == None) {
+    // Try using CLIPBOARD
+    owner =
+        XGetSelectionOwner(display, XInternAtom(display, "CLIPBOARD", False));
+    if (owner == None) {
+      XCloseDisplay(display);
+      return "";
+    }
+  }
+
+  Atom selection = XA_PRIMARY;
+  Atom target = XInternAtom(display, "UTF8_STRING", False);
+  if (target == None) {
+    target = XA_STRING;
+  }
+
+  XEvent event;
+  Window window = XCreateSimpleWindow(display, DefaultRootWindow(display), 0, 0,
+                                      1, 1, 0, 0, 0);
+  XSelectInput(display, window, PropertyChangeMask);
+
+  XConvertSelection(display, selection, target, XA_PRIMARY, window,
+                    CurrentTime);
+
+  // Wait for selection conversion to complete
+  bool done = false;
+  while (!done) {
+    XNextEvent(display, &event);
+    if (event.type == SelectionNotify) {
+      if (event.xselection.property == None) {
+        // Try using CLIPBOARD
+        if (selection == XA_PRIMARY) {
+          selection = XInternAtom(display, "CLIPBOARD", False);
+          XConvertSelection(display, selection, target, XA_PRIMARY, window,
+                            CurrentTime);
+          continue;
+        }
+        break;
+      }
+
+      Atom actual_type;
+      int actual_format;
+      unsigned long nitems;
+      unsigned long bytes_after;
+      unsigned char* data = nullptr;
+
+      if (XGetWindowProperty(display, window, XA_PRIMARY, 0, LONG_MAX / 4,
+                             False, AnyPropertyType, &actual_type,
+                             &actual_format, &nitems, &bytes_after,
+                             &data) == Success) {
+        if (data != nullptr) {
+          result = std::string(reinterpret_cast<char*>(data), nitems);
+          XFree(data);
+        }
+        done = true;
+      }
+    }
+  }
+
+  XDestroyWindow(display, window);
+  XCloseDisplay(display);
+  return result;
+}
+
+bool Clipboard::SetText(const std::string& text) {
+  Display* display = XOpenDisplay(nullptr);
+  if (display == nullptr) {
+    LOG_ERROR("Clipboard::SetText: failed to open X display");
+    return false;
+  }
+
+  Window window = XCreateSimpleWindow(display, DefaultRootWindow(display), 0, 0,
+                                      1, 1, 0, 0, 0);
+  Atom clipboard = XInternAtom(display, "CLIPBOARD", False);
+  Atom utf8_string = XInternAtom(display, "UTF8_STRING", False);
+  Atom targets = XInternAtom(display, "TARGETS", False);
+  Atom xa_string = XA_STRING;
+
+  XSetSelectionOwner(display, clipboard, window, CurrentTime);
+  if (XGetSelectionOwner(display, clipboard) != window) {
+    LOG_ERROR("Clipboard::SetText: failed to set selection owner");
+    XDestroyWindow(display, window);
+    XCloseDisplay(display);
+    return false;
+  }
+
+  XChangeProperty(display, window, XA_PRIMARY, utf8_string, 8, PropModeReplace,
+                  reinterpret_cast<const unsigned char*>(text.c_str()),
+                  static_cast<int>(text.length()));
+
+  XEvent event;
+  while (true) {
+    XNextEvent(display, &event);
+    if (event.type == SelectionRequest) {
+      XSelectionRequestEvent* req = &event.xselectionrequest;
+      XSelectionEvent se;
+      se.type = SelectionNotify;
+      se.display = req->display;
+      se.requestor = req->requestor;
+      se.selection = req->selection;
+      se.time = req->time;
+      se.target = req->target;
+      se.property = req->property;
+
+      if (req->target == targets) {
+        // Return supported formats
+        Atom supported[] = {utf8_string, xa_string, targets};
+        XChangeProperty(display, req->requestor, req->property, XA_ATOM, 32,
+                        PropModeReplace,
+                        reinterpret_cast<unsigned char*>(supported), 3);
+        se.property = req->property;
+      } else if (req->target == utf8_string || req->target == xa_string) {
+        // Return text data
+        XChangeProperty(display, req->requestor, req->property, req->target, 8,
+                        PropModeReplace,
+                        reinterpret_cast<const unsigned char*>(text.c_str()),
+                        static_cast<int>(text.length()));
+        se.property = req->property;
+      } else {
+        se.property = None;
+      }
+
+      XSendEvent(display, req->requestor, False, 0,
+                 reinterpret_cast<XEvent*>(&se));
+      XSync(display, False);
+    } else if (event.type == SelectionClear) {
+      break;
+    }
+  }
+
+  XDestroyWindow(display, window);
+  XCloseDisplay(display);
+  return true;
+}
+
+bool Clipboard::HasText() {
+  Display* display = XOpenDisplay(nullptr);
+  if (display == nullptr) {
+    return false;
+  }
+
+  Atom clipboard = XInternAtom(display, "CLIPBOARD", False);
+  Window owner = XGetSelectionOwner(display, clipboard);
+  if (owner == None) {
+    owner = XGetSelectionOwner(display, XA_PRIMARY);
+  }
+
+  XCloseDisplay(display);
+  return owner != None;
+}
+
+#else
+
+std::string Clipboard::GetText() {
+  LOG_ERROR("Clipboard::GetText: unsupported platform");
+  return "";
+}
+
+bool Clipboard::SetText(const std::string& text) {
+  LOG_ERROR("Clipboard::SetText: unsupported platform");
+  return false;
+}
+
+bool Clipboard::HasText() {
+  LOG_ERROR("Clipboard::HasText: unsupported platform");
+  return false;
+}
+
+#endif
+
+void HandleClipboardChange() {
+  if (!Clipboard::HasText()) {
+    std::lock_guard<std::mutex> lock(g_monitor_mutex);
+    if (!g_last_clipboard_text.empty()) {
+      g_last_clipboard_text.clear();
+      LOG_INFO("Clipboard content cleared");
+    }
+    return;
+  }
+
+  std::string current_text = Clipboard::GetText();
+
+  // Check if the content has changed
+  {
+    std::lock_guard<std::mutex> lock(g_monitor_mutex);
+    if (current_text != g_last_clipboard_text) {
+      g_last_clipboard_text = current_text;
+      if (!current_text.empty()) {
+        if (g_on_clipboard_changed) {
+          int ret = g_on_clipboard_changed(current_text.c_str(),
+                                           current_text.length());
+          if (ret != 0) {
+            LOG_WARN("Clipboard callback returned error: {}", ret);
+          }
+        }
+      }
+    }
+  }
+}
+
+#ifdef _WIN32
+LRESULT CALLBACK ClipboardWndProc(HWND hwnd, UINT uMsg, WPARAM wParam,
+                                  LPARAM lParam) {
+  if (uMsg == WM_CLIPBOARDUPDATE) {
+    HandleClipboardChange();
+    return 0;
+  }
+  return DefWindowProc(hwnd, uMsg, wParam, lParam);
+}
+
+static void MonitorThreadFunc() {
+  // Create a hidden window to receive clipboard messages
+  WNDCLASSA wc = {0};
+  wc.lpfnWndProc = ClipboardWndProc;
+  wc.hInstance = GetModuleHandle(nullptr);
+  wc.lpszClassName = g_clipboard_class_name;
+  RegisterClassA(&wc);
+
+  g_clipboard_wnd = CreateWindowA(g_clipboard_class_name, nullptr, 0, 0, 0, 0,
+                                  0, HWND_MESSAGE, nullptr, nullptr, nullptr);
+  if (!g_clipboard_wnd) {
+    LOG_ERROR("Failed to create clipboard monitor window");
+    g_monitoring.store(false);
+    return;
+  }
+
+  // Register clipboard format listener
+  if (!AddClipboardFormatListener(g_clipboard_wnd)) {
+    LOG_ERROR("Failed to add clipboard format listener");
+    DestroyWindow(g_clipboard_wnd);
+    g_clipboard_wnd = nullptr;
+    g_monitoring.store(false);
+    return;
+  }
+
+  LOG_INFO("Clipboard event monitoring started (Windows)");
+
+  MSG msg;
+  while (g_monitoring.load()) {
+    BOOL ret = GetMessage(&msg, nullptr, 0, 0);
+    if (ret == 0 || ret == -1) {
+      break;
+    }
+    TranslateMessage(&msg);
+    DispatchMessage(&msg);
+  }
+
+  RemoveClipboardFormatListener(g_clipboard_wnd);
+  if (g_clipboard_wnd) {
+    DestroyWindow(g_clipboard_wnd);
+    g_clipboard_wnd = nullptr;
+  }
+  UnregisterClassA(g_clipboard_class_name, GetModuleHandle(nullptr));
+}
+
+#elif __APPLE__
+// macOS use notification mechanism, need external functions
+extern void StartMacOSClipboardMonitoring();
+extern void StopMacOSClipboardMonitoring();
+
+static void MonitorThreadFunc() { StartMacOSClipboardMonitoring(); }
+
+#elif __linux__
+static void MonitorThreadFunc() {
+  g_x11_display = XOpenDisplay(nullptr);
+  if (!g_x11_display) {
+    LOG_ERROR("Failed to open X display for clipboard monitoring");
+    g_monitoring.store(false);
+    return;
+  }
+
+  // Check if XFixes extension is available
+  int event_base, error_base;
+  if (!XFixesQueryExtension(g_x11_display, &event_base, &error_base)) {
+    LOG_WARN("XFixes extension not available, falling back to polling");
+    XCloseDisplay(g_x11_display);
+    g_x11_display = nullptr;
+    // fallback to polling mode
+    while (g_monitoring.load()) {
+      std::this_thread::sleep_for(
+          std::chrono::milliseconds(g_check_interval_ms));
+      if (!g_monitoring.load()) {
+        break;
+      }
+      HandleClipboardChange();
+    }
+    return;
+  }
+
+  g_clipboard_atom = XInternAtom(g_x11_display, "CLIPBOARD", False);
+  g_xfixes_selection_notify =
+      XInternAtom(g_x11_display, "XFIXES_SELECTION_NOTIFY", False);
+
+  // Create event window
+  Window root = DefaultRootWindow(g_x11_display);
+  Window event_window =
+      XCreateSimpleWindow(g_x11_display, root, 0, 0, 1, 1, 0, 0, 0);
+
+  // Select events to monitor
+  XFixesSelectSelectionInput(g_x11_display, event_window, g_clipboard_atom,
+                             XFixesSetSelectionOwnerNotifyMask |
+                                 XFixesSelectionWindowDestroyNotifyMask |
+                                 XFixesSelectionClientCloseNotifyMask);
+
+  LOG_INFO("Clipboard event monitoring started (Linux XFixes)");
+
+  XEvent event;
+  while (g_monitoring.load()) {
+    XNextEvent(g_x11_display, &event);
+    if (event.type == event_base + XFixesSelectionNotify) {
+      HandleClipboardChange();
+    }
+  }
+
+  XFixesSelectSelectionInput(g_x11_display, event_window, g_clipboard_atom, 0);
+  XDestroyWindow(g_x11_display, event_window);
+  XCloseDisplay(g_x11_display);
+  g_x11_display = nullptr;
+}
+
+#else
+// Fallback to polling mode for other platforms
+static void MonitorThreadFunc() {
+  while (g_monitoring.load()) {
+    std::this_thread::sleep_for(std::chrono::milliseconds(g_check_interval_ms));
+    if (!g_monitoring.load()) {
+      break;
+    }
+    HandleClipboardChange();
+  }
+}
+#endif
+
+void Clipboard::StartMonitoring(int check_interval_ms,
+                                OnClipboardChanged on_changed) {
+  if (g_monitoring.load()) {
+    LOG_WARN("Clipboard monitoring is already running");
+    return;
+  }
+
+  g_check_interval_ms = check_interval_ms > 0 ? check_interval_ms : 100;
+  {
+    std::lock_guard<std::mutex> lock(g_monitor_mutex);
+    g_on_clipboard_changed = on_changed;
+    if (HasText()) {
+      g_last_clipboard_text = GetText();
+    } else {
+      g_last_clipboard_text.clear();
+    }
+  }
+  g_monitoring.store(true);
+
+  g_monitor_thread = std::thread(MonitorThreadFunc);
+  LOG_INFO("Clipboard event monitoring started");
+}
+
+void Clipboard::StopMonitoring() {
+  if (!g_monitoring.load()) {
+    return;
+  }
+
+  g_monitoring.store(false);
+
+#ifdef _WIN32
+  if (g_clipboard_wnd) {
+    PostMessage(g_clipboard_wnd, WM_QUIT, 0, 0);
+  }
+#elif __APPLE__
+  StopMacOSClipboardMonitoring();
+#endif
+
+  if (g_monitor_thread.joinable()) {
+    g_monitor_thread.join();
+  }
+
+  {
+    std::lock_guard<std::mutex> lock(g_monitor_mutex);
+    g_last_clipboard_text.clear();
+    g_on_clipboard_changed = nullptr;
+  }
+
+  LOG_INFO("Clipboard monitoring stopped");
+}
+
+bool Clipboard::IsMonitoring() { return g_monitoring.load(); }
+
+}  // namespace crossdesk

src/tools/clipboard.h

@@ -0,0 +1,38 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2025-12-28
+ * Copyright (c) 2025 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _CLIPBOARD_H_
+#define _CLIPBOARD_H_
+
+#include <functional>
+#include <string>
+
+namespace crossdesk {
+
+class Clipboard {
+ public:
+  using OnClipboardChanged = std::function<int(const char* data, size_t size)>;
+
+  Clipboard() = default;
+  ~Clipboard() = default;
+
+  static std::string GetText();
+
+  static bool SetText(const std::string& text);
+
+  static bool HasText();
+
+  static void StartMonitoring(int check_interval_ms = 100,
+                              OnClipboardChanged on_changed = nullptr);
+
+  static void StopMonitoring();
+
+  static bool IsMonitoring();
+};
+
+}  // namespace crossdesk
+
+#endif

src/tools/clipboard_mac.mm

@@ -0,0 +1,120 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2025-12-18
+ * Copyright (c) 2025 by DI JUNKUN, All Rights Reserved.
+ */
+
+#include "clipboard.h"
+
+#include <AppKit/AppKit.h>
+#include <CoreFoundation/CoreFoundation.h>
+#include <atomic>
+#include <mutex>
+#include <string>
+#include <thread>
+
+#include "rd_log.h"
+
+namespace crossdesk {
+
+extern std::atomic<bool> g_monitoring;
+extern std::mutex g_monitor_mutex;
+extern std::string g_last_clipboard_text;
+extern Clipboard::OnClipboardChanged g_on_clipboard_changed;
+
+static CFRunLoopRef g_monitor_runloop = nullptr;
+
+std::string Clipboard::GetText() {
+  @autoreleasepool {
+    NSPasteboard* pasteboard = [NSPasteboard generalPasteboard];
+    NSString* string = [pasteboard stringForType:NSPasteboardTypeString];
+    if (string == nil) {
+      return "";
+    }
+    return std::string([string UTF8String]);
+  }
+}
+
+bool Clipboard::SetText(const std::string& text) {
+  @autoreleasepool {
+    NSPasteboard* pasteboard = [NSPasteboard generalPasteboard];
+    [pasteboard clearContents];
+    NSString* string = [NSString stringWithUTF8String:text.c_str()];
+    if (string == nil) {
+      LOG_ERROR("Clipboard::SetText: failed to create NSString");
+      return false;
+    }
+    BOOL success = [pasteboard setString:string forType:NSPasteboardTypeString];
+    return success == YES;
+  }
+}
+
+bool Clipboard::HasText() {
+  @autoreleasepool {
+    NSPasteboard* pasteboard = [NSPasteboard generalPasteboard];
+    NSArray* types = [pasteboard types];
+    return [types containsObject:NSPasteboardTypeString];
+  }
+}
+
+extern void HandleClipboardChange();
+
+void StartMacOSClipboardMonitoring() {
+  @autoreleasepool {
+    NSPasteboard* pasteboard = [NSPasteboard generalPasteboard];
+
+    // Store RunLoop reference for waking up
+    NSRunLoop* runLoop = [NSRunLoop currentRunLoop];
+    g_monitor_runloop = [runLoop getCFRunLoop];
+    if (g_monitor_runloop) {
+      CFRetain(g_monitor_runloop);
+    }
+
+    // Track changeCount to detect clipboard changes
+    // Use __block to allow modification inside the block
+    __block NSInteger lastChangeCount = [pasteboard changeCount];
+
+    LOG_INFO("Clipboard event monitoring started (macOS)");
+
+    // Use a timer to periodically check changeCount
+    // This is more reliable than NSPasteboardDidChangeNotification which may not be available
+    NSTimer* timer =
+        [NSTimer scheduledTimerWithTimeInterval:0.1
+                                        repeats:YES
+                                          block:^(NSTimer* timer) {
+                                            if (!g_monitoring.load()) {
+                                              [timer invalidate];
+                                              return;
+                                            }
+                                            NSInteger currentChangeCount = [pasteboard changeCount];
+                                            if (currentChangeCount != lastChangeCount) {
+                                              lastChangeCount = currentChangeCount;
+                                              HandleClipboardChange();
+                                            }
+                                          }];
+
+    while (g_monitoring.load()) {
+      @autoreleasepool {
+        NSDate* date = [NSDate dateWithTimeIntervalSinceNow:0.1];
+        [runLoop runMode:NSDefaultRunLoopMode beforeDate:date];
+      }
+    }
+
+    // Cleanup
+    [timer invalidate];
+    if (g_monitor_runloop) {
+      CFRelease(g_monitor_runloop);
+      g_monitor_runloop = nullptr;
+    }
+  }
+}
+
+void StopMacOSClipboardMonitoring() {
+  // Wake up the RunLoop immediately so it can check g_monitoring and exit
+  // This ensures the RunLoop exits promptly instead of waiting up to 0.1 seconds
+  if (g_monitor_runloop) {
+    CFRunLoopWakeUp(g_monitor_runloop);
+  }
+}
+
+}  // namespace crossdesk

src/tools/file_transfer.cpp

@@ -0,0 +1,307 @@
+#include "file_transfer.h"
+
+#include <atomic>
+#include <chrono>
+
+#include "rd_log.h"
+
+namespace crossdesk {
+
+namespace {
+std::atomic<uint32_t> g_next_file_id{1};
+}  // namespace
+
+uint32_t FileSender::NextFileId() { return g_next_file_id.fetch_add(1); }
+
+int FileSender::SendFile(const std::filesystem::path& path,
+                         const std::string& label, const SendFunc& send,
+                         std::size_t chunk_size, uint32_t file_id) {
+  if (!send) {
+    LOG_ERROR("FileSender::SendFile: send function is empty");
+    return -1;
+  }
+
+  std::error_code ec;
+  if (!std::filesystem::exists(path, ec) ||
+      !std::filesystem::is_regular_file(path, ec)) {
+    LOG_ERROR("FileSender::SendFile: file [{}] not found or not regular",
+              path.string().c_str());
+    return -1;
+  }
+
+  uint64_t total_size = std::filesystem::file_size(path, ec);
+  if (ec) {
+    LOG_ERROR("FileSender::SendFile: failed to get size of [{}]: {}",
+              path.string().c_str(), ec.message().c_str());
+    return -1;
+  }
+
+  std::ifstream ifs(path, std::ios::binary);
+  if (!ifs.is_open()) {
+    LOG_ERROR("FileSender::SendFile: failed to open [{}]",
+              path.string().c_str());
+    return -1;
+  }
+  LOG_INFO("FileSender send file {}, total size {}, file_id={}",
+           path.string().c_str(), total_size, file_id);
+
+  if (file_id == 0) {
+    file_id = NextFileId();
+  }
+  const uint32_t final_file_id = file_id;
+  uint64_t offset = 0;
+  bool is_first = true;
+  std::string file_name = label.empty() ? path.filename().string() : label;
+
+  std::vector<char> buffer;
+  buffer.resize(chunk_size);
+
+  while (ifs && offset < total_size) {
+    uint64_t remaining = total_size - offset;
+    uint32_t to_read =
+        static_cast<uint32_t>(std::min<uint64_t>(remaining, chunk_size));
+
+    ifs.read(buffer.data(), static_cast<std::streamsize>(to_read));
+    std::streamsize bytes_read = ifs.gcount();
+    if (bytes_read <= 0) {
+      break;
+    }
+
+    bool is_last = (offset + static_cast<uint64_t>(bytes_read) >= total_size);
+    const std::string* name_ptr = is_first ? &file_name : nullptr;
+
+    std::vector<char> chunk = BuildChunk(
+        final_file_id, offset, total_size, buffer.data(),
+        static_cast<uint32_t>(bytes_read), name_ptr, is_first, is_last);
+
+    int ret = send(chunk.data(), chunk.size());
+    if (ret != 0) {
+      LOG_ERROR("FileSender::SendFile: send failed for [{}], ret={}",
+                path.string().c_str(), ret);
+      return ret;
+    }
+
+    offset += static_cast<uint64_t>(bytes_read);
+    is_first = false;
+  }
+
+  return 0;
+}
+
+std::vector<char> FileSender::BuildChunk(uint32_t file_id, uint64_t offset,
+                                         uint64_t total_size, const char* data,
+                                         uint32_t data_size,
+                                         const std::string* file_name,
+                                         bool is_first, bool is_last) {
+  FileChunkHeader header{};
+  header.magic = kFileChunkMagic;
+  header.file_id = file_id;
+  header.offset = offset;
+  header.total_size = total_size;
+  header.chunk_size = data_size;
+  header.name_len =
+      (file_name && is_first) ? static_cast<uint16_t>(file_name->size()) : 0;
+  header.flags = 0;
+  if (is_first) header.flags |= 0x01;
+  if (is_last) header.flags |= 0x02;
+
+  std::size_t total_size_bytes =
+      sizeof(FileChunkHeader) + header.name_len + header.chunk_size;
+
+  std::vector<char> buffer;
+  buffer.resize(total_size_bytes);
+
+  std::size_t offset_bytes = 0;
+  memcpy(buffer.data() + offset_bytes, &header, sizeof(FileChunkHeader));
+  offset_bytes += sizeof(FileChunkHeader);
+
+  if (header.name_len > 0 && file_name) {
+    memcpy(buffer.data() + offset_bytes, file_name->data(), header.name_len);
+    offset_bytes += header.name_len;
+  }
+
+  if (header.chunk_size > 0 && data) {
+    memcpy(buffer.data() + offset_bytes, data, header.chunk_size);
+  }
+
+  return buffer;
+}
+
+// ---------- FileReceiver ----------
+
+FileReceiver::FileReceiver() : output_dir_(GetDefaultDesktopPath()) {}
+
+FileReceiver::FileReceiver(const std::filesystem::path& output_dir)
+    : output_dir_(output_dir) {
+  std::error_code ec;
+  if (!output_dir_.empty()) {
+    std::filesystem::create_directories(output_dir_, ec);
+    if (ec) {
+      LOG_ERROR("FileReceiver: failed to create output dir [{}]: {}",
+                output_dir_.string().c_str(), ec.message().c_str());
+    }
+  }
+}
+
+std::filesystem::path FileReceiver::GetDefaultDesktopPath() {
+#ifdef _WIN32
+  const char* home_env = std::getenv("USERPROFILE");
+#else
+  const char* home_env = std::getenv("HOME");
+#endif
+  if (!home_env) {
+    return std::filesystem::path{};
+  }
+
+  std::filesystem::path desktop_path =
+      std::filesystem::path(home_env) / "Desktop";
+
+  std::error_code ec;
+  std::filesystem::create_directories(desktop_path, ec);
+  if (ec) {
+    LOG_ERROR("FileReceiver: failed to create desktop directory [{}]: {}",
+              desktop_path.string().c_str(), ec.message().c_str());
+  }
+
+  return desktop_path;
+}
+
+bool FileReceiver::OnData(const char* data, size_t size) {
+  if (!data || size < sizeof(FileChunkHeader)) {
+    LOG_ERROR("FileReceiver::OnData: invalid buffer");
+    return false;
+  }
+
+  FileChunkHeader header{};
+  memcpy(&header, data, sizeof(FileChunkHeader));
+
+  if (header.magic != kFileChunkMagic) {
+    return false;
+  }
+
+  std::size_t header_and_name =
+      sizeof(FileChunkHeader) + static_cast<std::size_t>(header.name_len);
+  if (size < header_and_name ||
+      size < header_and_name + static_cast<std::size_t>(header.chunk_size)) {
+    LOG_ERROR("FileReceiver::OnData: buffer too small for header + payload");
+    return false;
+  }
+
+  const char* name_ptr = data + sizeof(FileChunkHeader);
+  std::string file_name;
+  const std::string* file_name_ptr = nullptr;
+  if (header.name_len > 0) {
+    file_name.assign(name_ptr,
+                     name_ptr + static_cast<std::size_t>(header.name_len));
+    file_name_ptr = &file_name;
+  }
+
+  const char* payload = data + header_and_name;
+  std::size_t payload_size =
+      static_cast<std::size_t>(header.chunk_size);  // may be 0
+
+  return HandleChunk(header, payload, payload_size, file_name_ptr);
+}
+
+bool FileReceiver::HandleChunk(const FileChunkHeader& header,
+                               const char* payload, size_t payload_size,
+                               const std::string* file_name) {
+  auto it = contexts_.find(header.file_id);
+  if (it == contexts_.end()) {
+    // new file context must start with first chunk.
+    if ((header.flags & 0x01) == 0) {
+      LOG_ERROR("FileReceiver: received non-first chunk for unknown file_id={}",
+                header.file_id);
+      return false;
+    }
+
+    FileContext ctx;
+    ctx.total_size = header.total_size;
+
+    std::string filename;
+    if (file_name && !file_name->empty()) {
+      filename = *file_name;
+    } else {
+      filename = "received_" + std::to_string(header.file_id);
+    }
+
+    ctx.file_name = filename;
+
+    std::filesystem::path save_path = output_dir_.empty()
+                                          ? std::filesystem::path(filename)
+                                          : output_dir_ / filename;
+
+    // if file exists, append timestamp.
+    std::error_code ec;
+    if (std::filesystem::exists(save_path, ec)) {
+      auto now = std::chrono::system_clock::now();
+      auto ts = std::chrono::duration_cast<std::chrono::milliseconds>(
+                    now.time_since_epoch())
+                    .count();
+      save_path = save_path.parent_path() /
+                  (save_path.stem().string() + "_" + std::to_string(ts) +
+                   save_path.extension().string());
+    }
+
+    ctx.ofs.open(save_path, std::ios::binary | std::ios::trunc);
+    if (!ctx.ofs.is_open()) {
+      LOG_ERROR("FileReceiver: failed to open [{}] for writing",
+                save_path.string().c_str());
+      return false;
+    }
+
+    contexts_.emplace(header.file_id, std::move(ctx));
+    it = contexts_.find(header.file_id);
+  }
+
+  FileContext& ctx = it->second;
+
+  if (payload_size > 0 && payload) {
+    ctx.ofs.seekp(static_cast<std::streamoff>(header.offset), std::ios::beg);
+    ctx.ofs.write(payload, static_cast<std::streamsize>(payload_size));
+    if (!ctx.ofs.good()) {
+      LOG_ERROR("FileReceiver: write failed for file_id={}", header.file_id);
+      return false;
+    }
+    ctx.received += static_cast<uint64_t>(payload_size);
+  }
+
+  // Send ACK after processing chunk
+  if (on_send_ack_) {
+    FileTransferAck ack{};
+    ack.magic = kFileAckMagic;
+    ack.file_id = header.file_id;
+    ack.acked_offset = header.offset + static_cast<uint64_t>(payload_size);
+    ack.total_size = header.total_size;
+    ack.flags = 0;
+
+    bool is_last = (header.flags & 0x02) != 0;
+    if (is_last || ctx.received >= ctx.total_size) {
+      ack.flags |= 0x01;  // completed
+    }
+
+    int ret = on_send_ack_(ack);
+    if (ret != 0) {
+      LOG_ERROR("FileReceiver: failed to send ACK for file_id={}, ret={}",
+                header.file_id, ret);
+    }
+  }
+
+  bool is_last = (header.flags & 0x02) != 0;
+  if (is_last || ctx.received >= ctx.total_size) {
+    ctx.ofs.close();
+
+    std::filesystem::path saved_path =
+        output_dir_.empty() ? std::filesystem::path(ctx.file_name)
+                            : output_dir_ / ctx.file_name;
+
+    LOG_INFO("FileReceiver: file received complete, file_id={}, size={}",
+             header.file_id, ctx.received);
+
+    contexts_.erase(header.file_id);
+  }
+
+  return true;
+}
+
+}  // namespace crossdesk

src/tools/file_transfer.h

@@ -0,0 +1,114 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2025-12-18
+ * Copyright (c) 2025 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _FILE_TRANSFER_H_
+#define _FILE_TRANSFER_H_
+
+#include <cstdint>
+#include <filesystem>
+#include <fstream>
+#include <functional>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace crossdesk {
+
+// Magic constants for file transfer protocol
+constexpr uint32_t kFileChunkMagic = 0x4A4E544D;  // 'JNTM'
+constexpr uint32_t kFileAckMagic = 0x4A4E5443;    // 'JNTC'
+
+#pragma pack(push, 1)
+struct FileChunkHeader {
+  uint32_t magic;       // magic to identify file-transfer chunks
+  uint32_t file_id;     // unique id per file transfer
+  uint64_t offset;      // offset in file
+  uint64_t total_size;  // total file size
+  uint32_t chunk_size;  // payload size in this chunk
+  uint16_t name_len;    // filename length (bytes), only set on first chunk
+  uint8_t flags;        // bit0: is_first, bit1: is_last, others reserved
+};
+
+struct FileTransferAck {
+  uint32_t magic;         // magic to identify file-transfer ack
+  uint32_t file_id;       // must match FileChunkHeader.file_id
+  uint64_t acked_offset;  // received offset
+  uint64_t total_size;    // total file size
+  uint32_t flags;         // bit0: completed, bit1: error
+};
+#pragma pack(pop)
+
+class FileSender {
+ public:
+  using SendFunc = std::function<int(const char* data, size_t size)>;
+
+ public:
+  FileSender() = default;
+
+  // generate a new file id
+  static uint32_t NextFileId();
+
+  // synchronously send a file using the provided send function.
+  // `path`  : full path to the local file.
+  // `label` : logical filename to send (usually path.filename()).
+  // `send`  : callback that pushes one encoded chunk into the data channel.
+  // `file_id` : file id to use (0 means auto-generate).
+  // Return 0 on success, <0 on error.
+  int SendFile(const std::filesystem::path& path, const std::string& label,
+               const SendFunc& send, std::size_t chunk_size = 64 * 1024,
+               uint32_t file_id = 0);
+
+  // build a single encoded chunk buffer according to FileChunkHeader protocol.
+  static std::vector<char> BuildChunk(uint32_t file_id, uint64_t offset,
+                                      uint64_t total_size, const char* data,
+                                      uint32_t data_size,
+                                      const std::string* file_name,
+                                      bool is_first, bool is_last);
+};
+
+class FileReceiver {
+ public:
+  struct FileContext {
+    std::string file_name;
+    uint64_t total_size = 0;
+    uint64_t received = 0;
+    std::ofstream ofs;
+  };
+
+  using OnFileComplete =
+      std::function<void(const std::filesystem::path& saved_path)>;
+  using OnSendAck = std::function<int(const FileTransferAck& ack)>;
+
+ public:
+  // save to default desktop directory.
+  FileReceiver();
+
+  // save to a specified directory.
+  explicit FileReceiver(const std::filesystem::path& output_dir);
+
+  // process one received data buffer (one chunk).
+  // return true if parsed and processed successfully, false otherwise.
+  bool OnData(const char* data, size_t size);
+
+  void SetOnSendAck(OnSendAck cb) { on_send_ack_ = cb; }
+
+  const std::filesystem::path& OutputDir() const { return output_dir_; }
+
+ private:
+  static std::filesystem::path GetDefaultDesktopPath();
+
+  bool HandleChunk(const FileChunkHeader& header, const char* payload,
+                   size_t payload_size, const std::string* file_name);
+
+ private:
+  std::filesystem::path output_dir_;
+  std::unordered_map<uint32_t, FileContext> contexts_;
+  OnSendAck on_send_ack_ = nullptr;
+};
+
+}  // namespace crossdesk
+
+#endif

xmake.lua

@@ -33,6 +33,7 @@ add_requires("imgui v1.92.1-docking", {configs = {sdl3 = true, sdl3_renderer = t
 add_requires("openssl3 3.3.2", {system = false})
 add_requires("nlohmann_json 3.11.3")
 add_requires("cpp-httplib v0.26.0", {configs = {ssl = true}})
+add_requires("tinyfiledialogs 3.15.1")
 
 if is_os("windows") then
     add_requires("libyuv", "miniaudio 0.11.21")
@@ -69,6 +70,9 @@ target("common")
     set_kind("object")
     add_deps("rd_log")
     add_files("src/common/*.cpp")
+    if is_os("macosx") then
+        add_files("src/common/*.mm")
+    end
     add_includedirs("src/common", {public = true})
 
 target("path_manager")
@@ -168,13 +172,22 @@ target("version_checker")
     add_files("src/version_checker/*.cpp")
     add_includedirs("src/version_checker", {public = true})
 
+target("tools")
+    set_kind("object")
+    add_deps("rd_log")
+    add_files("src/tools/*.cpp")
+    if is_os("macosx") then
+        add_files("src/tools/*.mm")
+    end
+    add_includedirs("src/tools", {public = true})
+
 target("gui")
     set_kind("object")
-    add_packages("libyuv")
+    add_packages("libyuv", "tinyfiledialogs")
     add_defines("CROSSDESK_VERSION=\"" .. (get_config("CROSSDESK_VERSION") or "Unknown") .. "\"")
     add_deps("rd_log", "common", "assets", "config_center", "minirtc", 
         "path_manager", "screen_capturer", "speaker_capturer", 
-        "device_controller", "thumbnail", "version_checker")
+        "device_controller", "thumbnail", "version_checker", "tools")
     add_files("src/gui/*.cpp", "src/gui/panels/*.cpp", "src/gui/toolbars/*.cpp",
         "src/gui/windows/*.cpp")
     add_includedirs("src/gui", "src/gui/panels", "src/gui/toolbars",