[feat] update MiniRTC to resolve websocket reconnection and post task issues

README.md

@@ -181,7 +181,7 @@ sudo docker run -d \
   -e MAX_PORT=xxxxx \
   -v /var/lib/crossdesk:/var/lib/crossdesk \
   -v /var/log/crossdesk:/var/log/crossdesk \
-  crossdesk/crossdesk-server:v1.1.2
+  crossdesk/crossdesk-server:v1.1.3
 ```
 
 上述命令中，用户需注意的参数如下：
@@ -229,21 +229,19 @@ sudo mkdir -p /var/lib/crossdesk /var/log/crossdesk
 sudo chown -R $(id -u):$(id -g) /var/lib/crossdesk /var/log/crossdesk
 ```
 
-## 证书文件
-在宿主机的 `/var/lib/crossdesk/certs` 路径下可找到证书文件 `crossdesk.cn_root.crt`，下载到你的客户端主机，并在客户端的**自托管服务器设置**中选择相应的**证书文件路径**。
 
 ### 客户端
-1. 点击右上角设置进入设置页面。<br>
+1. 点击右上角设置进入设置页面。<br><br>
 <img width="600" height="210" alt="image" src="https://github.com/user-attachments/assets/6431131d-b32a-4726-8783-6788f47baa3b" /><br><br>
 
-3. 点击点击**自托管服务器配置**。<br><br>
-<img width="600" height="160" alt="image" src="https://github.com/user-attachments/assets/24c761a3-1985-4d7e-84be-787383c2afb8" /><br><br>
+2. 点击点击`自托管服务器配置`按钮。<br><br>
+<img width="600" height="140" alt="image" src="https://github.com/user-attachments/assets/24c761a3-1985-4d7e-84be-787383c2afb8" /><br><br>
 
-5. 在**证书文件路径**选择框中找到 **crossdesk.cn_root.crt** 的存放路径，选中 **crossdesk.cn_root.crt**，点击确认。<br><br>
-<img width="600" height="220" alt="image" src="https://github.com/user-attachments/assets/4af7cd3a-c72e-44fb-b032-30e050019c2a" /><br><br>
+3. 输入`服务器地址`(**EXTERNAL_IP**)、`信令服务端口`(**CROSSDESK_SERVER_PORT**)、`中继服务端口`(**COTURN_PORT**)。<br><br>
+<img width="600" height="200" alt="image" src="https://github.com/user-attachments/assets/9a32ddd5-37f8-4bee-9a51-eae295820f9a" /><br><br>
 
-7. 勾选使用**自托管服务器配置**，点击确认配置生效。<br><br>
-<img width="600" height="160" alt="image" src="https://github.com/user-attachments/assets/1e455dc3-4087-4f37-a544-1ff9f8789383" /><br><br>
+4. 后续如果自托管服务器被重置或因其他原因导致证书更换，可以点击`重置证书指纹`按钮重置客户端保存的证书指纹。<br><br>
+<img width="600" height="200" alt="image" src="https://github.com/user-attachments/assets/d9e423ab-0c2b-4fab-b132-4dc27462d704" /><br><br>
 
 ### Web 客户端
 详情见项目 [CrossDesk Web Client](https://github.com/kunkundi/crossdesk-web-client)。

README_EN.md

@@ -189,7 +189,7 @@ sudo docker run -d \
   -e MAX_PORT=xxxxx \
   -v /var/lib/crossdesk:/var/lib/crossdesk \
   -v /var/log/crossdesk:/var/log/crossdesk \
-  crossdesk/crossdesk-server:v1.1.2
+  crossdesk/crossdesk-server:v1.1.3
 ```
 
 The parameters you need to pay attention to are as follows:
@@ -238,25 +238,21 @@ sudo mkdir -p /var/lib/crossdesk /var/log/crossdesk
 sudo chown -R $(id -u):$(id -g) /var/lib/crossdesk /var/log/crossdesk
 ```
 
-### Certificate Files
-You can find the certificate file `crossdesk.cn_root.crt` at `/var/lib/crossdesk/certs` on the host machine.
-Download it to your client device and select it in the **Certificate File Path** field under the CrossDesk client’s **Self-Hosted Server Settings**.
-
 ### Server Side
 Place **crossdesk.cn.key** and **crossdesk.cn_bundle.crt** into the **/path/to/your/certs** directory.
 
 ### Client Side
-1. Click the settings icon in the top-right corner to enter the settings page.<br>
+1. Click the settings icon in the top-right corner to enter the settings page.<br><br>
 <img width="600" height="210" alt="image" src="https://github.com/user-attachments/assets/6431131d-b32a-4726-8783-6788f47baa3b" /><br><br>
 
-2. Click **Self-Hosted Server Configuration**.<br><br>
+2. Click `Self-Hosted Server Configuration` button.<br><br>
 <img width="600" height="160" alt="image" src="https://github.com/user-attachments/assets/24c761a3-1985-4d7e-84be-787383c2afb8" /><br><br>
 
-3. In the **Certificate File Path** selection, locate and select the **crossdesk.cn_root.crt** file.<br><br>
-<img width="600" height="220" alt="image" src="https://github.com/user-attachments/assets/4af7cd3a-c72e-44fb-b032-30e050019c2a" /><br><br>
+3. Enter the `Server Address` (**EXTERNAL_IP**), `Signaling Service Port` (**CROSSDESK_SERVER_PORT**), and `Relay Service Port` (**COTURN_PORT**).<br><br>
+<img width="600" height="200" alt="image" src="https://github.com/user-attachments/assets/9a32ddd5-37f8-4bee-9a51-eae295820f9a" /><br><br>
 
-4. Check the option to use **Self-Hosted Server Configuration**.<br><br>
-<img width="600" height="160" alt="image" src="https://github.com/user-attachments/assets/1e455dc3-4087-4f37-a544-1ff9f8789383" /><br><br>
+4. If the self-hosted server is later reset or the certificate is replaced for any reason, you can click the `Reset Certificate Fingerprint` button to clear the certificate fingerprint saved on the client.<br><br>
+<img width="600" height="200" alt="image" src="https://github.com/user-attachments/assets/d9e423ab-0c2b-4fab-b132-4dc27462d704" /><br><br>
 
 ### Web Client
 See [CrossDesk Web Client](https://github.com/kunkundi/crossdesk-web-client)。

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_
+
+struct SDL_Window;
+
+namespace crossdesk {
+
+// 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/config_center/config_center.cpp

@@ -77,6 +77,64 @@ int ConfigCenter::Load() {
   } else {
     cert_file_path_ = "";
   }
+  const char* cert_fingerprint_value =
+      ini_.GetValue(section_, "cert_fingerprint", nullptr);
+  if (cert_fingerprint_value != nullptr && strlen(cert_fingerprint_value) > 0) {
+    cert_fingerprint_ = cert_fingerprint_value;
+  } else {
+    cert_fingerprint_ = "";
+  }
+  const char* cert_fingerprint_server_host_value =
+      ini_.GetValue(section_, "cert_fingerprint_server_host", nullptr);
+  if (cert_fingerprint_server_host_value != nullptr &&
+      strlen(cert_fingerprint_server_host_value) > 0) {
+    cert_fingerprint_server_host_ = cert_fingerprint_server_host_value;
+  } else {
+    cert_fingerprint_server_host_ = "";
+  }
+
+  const char* default_cert_fingerprint_value =
+      ini_.GetValue(section_, "default_cert_fingerprint", nullptr);
+  if (default_cert_fingerprint_value != nullptr &&
+      strlen(default_cert_fingerprint_value) > 0) {
+    default_cert_fingerprint_ = default_cert_fingerprint_value;
+  } else {
+    default_cert_fingerprint_ = "";
+  }
+  const char* default_cert_fingerprint_server_host_value =
+      ini_.GetValue(section_, "default_cert_fingerprint_server_host", nullptr);
+  if (default_cert_fingerprint_server_host_value != nullptr &&
+      strlen(default_cert_fingerprint_server_host_value) > 0) {
+    default_cert_fingerprint_server_host_ =
+        default_cert_fingerprint_server_host_value;
+  } else {
+    default_cert_fingerprint_server_host_ = "";
+  }
+
+  if (enable_self_hosted_ && !cert_fingerprint_.empty() &&
+      !cert_fingerprint_server_host_.empty() &&
+      signal_server_host_ != cert_fingerprint_server_host_) {
+    LOG_INFO("Server IP changed from {} to {}, clearing old fingerprint",
+             cert_fingerprint_server_host_, signal_server_host_);
+    cert_fingerprint_.clear();
+    cert_fingerprint_server_host_.clear();
+    ini_.Delete(section_, "cert_fingerprint", false);
+    ini_.Delete(section_, "cert_fingerprint_server_host", false);
+    ini_.SaveFile(config_path_.c_str());
+  }
+
+  if (!enable_self_hosted_ && !default_cert_fingerprint_.empty() &&
+      !default_cert_fingerprint_server_host_.empty() &&
+      signal_server_host_default_ != default_cert_fingerprint_server_host_) {
+    LOG_INFO(
+        "Default server IP changed from {} to {}, clearing old fingerprint",
+        default_cert_fingerprint_server_host_, signal_server_host_default_);
+    default_cert_fingerprint_.clear();
+    default_cert_fingerprint_server_host_.clear();
+    ini_.Delete(section_, "default_cert_fingerprint", false);
+    ini_.Delete(section_, "default_cert_fingerprint_server_host", false);
+    ini_.SaveFile(config_path_.c_str());
+  }
 
   enable_autostart_ =
       ini_.GetBoolValue(section_, "enable_autostart", enable_autostart_);
@@ -108,6 +166,18 @@ int ConfigCenter::Save() {
     ini_.SetLongValue(section_, "coturn_server_port",
                       static_cast<long>(coturn_server_port_));
     ini_.SetValue(section_, "cert_file_path", cert_file_path_.c_str());
+    if (!cert_fingerprint_.empty()) {
+      ini_.SetValue(section_, "cert_fingerprint", cert_fingerprint_.c_str());
+      ini_.SetValue(section_, "cert_fingerprint_server_host",
+                    cert_fingerprint_server_host_.c_str());
+    }
+  }
+
+  if (!default_cert_fingerprint_.empty()) {
+    ini_.SetValue(section_, "default_cert_fingerprint",
+                  default_cert_fingerprint_.c_str());
+    ini_.SetValue(section_, "default_cert_fingerprint_server_host",
+                  default_cert_fingerprint_server_host_.c_str());
   }
 
   ini_.SetBoolValue(section_, "enable_autostart", enable_autostart_);
@@ -200,6 +270,15 @@ int ConfigCenter::SetSrtp(bool enable_srtp) {
 }
 
 int ConfigCenter::SetServerHost(const std::string& signal_server_host) {
+  if (enable_self_hosted_ && !cert_fingerprint_.empty() &&
+      signal_server_host != signal_server_host_) {
+    LOG_INFO("Server IP changed from {} to {}, clearing old fingerprint",
+             signal_server_host_, signal_server_host);
+    cert_fingerprint_.clear();
+    cert_fingerprint_server_host_.clear();
+    ini_.Delete(section_, "cert_fingerprint", false);
+    ini_.Delete(section_, "cert_fingerprint_server_host", false);
+  }
   signal_server_host_ = signal_server_host;
   ini_.SetValue(section_, "signal_server_host", signal_server_host_.c_str());
   SI_Error rc = ini_.SaveFile(config_path_.c_str());
@@ -241,6 +320,57 @@ int ConfigCenter::SetCertFilePath(const std::string& cert_file_path) {
   return 0;
 }
 
+int ConfigCenter::SetCertFingerprint(const std::string& fingerprint) {
+  cert_fingerprint_ = fingerprint;
+  cert_fingerprint_server_host_ = signal_server_host_;
+  ini_.SetValue(section_, "cert_fingerprint", cert_fingerprint_.c_str());
+  ini_.SetValue(section_, "cert_fingerprint_server_host",
+                cert_fingerprint_server_host_.c_str());
+  SI_Error rc = ini_.SaveFile(config_path_.c_str());
+  if (rc < 0) {
+    return -1;
+  }
+  return 0;
+}
+
+int ConfigCenter::SetDefaultCertFingerprint(const std::string& fingerprint) {
+  default_cert_fingerprint_ = fingerprint;
+  default_cert_fingerprint_server_host_ = signal_server_host_default_;
+  ini_.SetValue(section_, "default_cert_fingerprint",
+                default_cert_fingerprint_.c_str());
+  ini_.SetValue(section_, "default_cert_fingerprint_server_host",
+                default_cert_fingerprint_server_host_.c_str());
+  SI_Error rc = ini_.SaveFile(config_path_.c_str());
+  if (rc < 0) {
+    return -1;
+  }
+  return 0;
+}
+
+int ConfigCenter::ClearCertFingerprint() {
+  cert_fingerprint_.clear();
+  cert_fingerprint_server_host_.clear();
+  ini_.Delete(section_, "cert_fingerprint", false);
+  ini_.Delete(section_, "cert_fingerprint_server_host", false);
+  SI_Error rc = ini_.SaveFile(config_path_.c_str());
+  if (rc < 0) {
+    return -1;
+  }
+  return 0;
+}
+
+int ConfigCenter::ClearDefaultCertFingerprint() {
+  default_cert_fingerprint_.clear();
+  default_cert_fingerprint_server_host_.clear();
+  ini_.Delete(section_, "default_cert_fingerprint", false);
+  ini_.Delete(section_, "default_cert_fingerprint_server_host", false);
+  SI_Error rc = ini_.SaveFile(config_path_.c_str());
+  if (rc < 0) {
+    return -1;
+  }
+  return 0;
+}
+
 int ConfigCenter::SetSelfHosted(bool enable_self_hosted) {
   enable_self_hosted_ = enable_self_hosted;
   ini_.SetBoolValue(section_, "enable_self_hosted", enable_self_hosted_);
@@ -272,6 +402,28 @@ int ConfigCenter::SetSelfHosted(bool enable_self_hosted) {
     if (cert_file_path_value != nullptr && strlen(cert_file_path_value) > 0) {
       cert_file_path_ = cert_file_path_value;
     }
+    const char* cert_fingerprint_value =
+        ini_.GetValue(section_, "cert_fingerprint", nullptr);
+    if (cert_fingerprint_value != nullptr &&
+        strlen(cert_fingerprint_value) > 0) {
+      cert_fingerprint_ = cert_fingerprint_value;
+    }
+    const char* cert_fingerprint_server_host_value =
+        ini_.GetValue(section_, "cert_fingerprint_server_host", nullptr);
+    if (cert_fingerprint_server_host_value != nullptr &&
+        strlen(cert_fingerprint_server_host_value) > 0) {
+      cert_fingerprint_server_host_ = cert_fingerprint_server_host_value;
+    }
+
+    if (!cert_fingerprint_.empty() && !cert_fingerprint_server_host_.empty() &&
+        signal_server_host_ != cert_fingerprint_server_host_) {
+      LOG_INFO("Server IP changed from {} to {}, clearing old fingerprint",
+               cert_fingerprint_server_host_, signal_server_host_);
+      cert_fingerprint_.clear();
+      cert_fingerprint_server_host_.clear();
+      ini_.Delete(section_, "cert_fingerprint", false);
+      ini_.Delete(section_, "cert_fingerprint_server_host", false);
+    }
 
     ini_.SetValue(section_, "signal_server_host", signal_server_host_.c_str());
     ini_.SetLongValue(section_, "signal_server_port",
@@ -279,6 +431,11 @@ int ConfigCenter::SetSelfHosted(bool enable_self_hosted) {
     ini_.SetLongValue(section_, "coturn_server_port",
                       static_cast<long>(coturn_server_port_));
     ini_.SetValue(section_, "cert_file_path", cert_file_path_.c_str());
+    if (!cert_fingerprint_.empty()) {
+      ini_.SetValue(section_, "cert_fingerprint", cert_fingerprint_.c_str());
+      ini_.SetValue(section_, "cert_fingerprint_server_host",
+                    cert_fingerprint_server_host_.c_str());
+    }
   }
 
   SI_Error rc = ini_.SaveFile(config_path_.c_str());
@@ -368,6 +525,14 @@ int ConfigCenter::GetCoturnServerPort() const { return coturn_server_port_; }
 
 std::string ConfigCenter::GetCertFilePath() const { return cert_file_path_; }
 
+std::string ConfigCenter::GetCertFingerprint() const {
+  return cert_fingerprint_;
+}
+
+std::string ConfigCenter::GetDefaultCertFingerprint() const {
+  return default_cert_fingerprint_;
+}
+
 std::string ConfigCenter::GetDefaultServerHost() const {
   return signal_server_host_default_;
 }

src/config_center/config_center.h

@@ -38,6 +38,10 @@ class ConfigCenter {
   int SetServerPort(int signal_server_port);
   int SetCoturnServerPort(int coturn_server_port);
   int SetCertFilePath(const std::string& cert_file_path);
+  int SetCertFingerprint(const std::string& fingerprint);
+  int SetDefaultCertFingerprint(const std::string& fingerprint);
+  int ClearCertFingerprint();
+  int ClearDefaultCertFingerprint();
   int SetSelfHosted(bool enable_self_hosted);
   int SetMinimizeToTray(bool enable_minimize_to_tray);
   int SetAutostart(bool enable_autostart);
@@ -56,6 +60,8 @@ class ConfigCenter {
   int GetSignalServerPort() const;
   int GetCoturnServerPort() const;
   std::string GetCertFilePath() const;
+  std::string GetCertFingerprint() const;
+  std::string GetDefaultCertFingerprint() const;
   std::string GetDefaultServerHost() const;
   int GetDefaultSignalServerPort() const;
   int GetDefaultCoturnServerPort() const;
@@ -88,6 +94,10 @@ class ConfigCenter {
   int coturn_server_port_default_ = 3478;
   std::string cert_file_path_ = "";
   std::string cert_file_path_default_ = "";
+  std::string cert_fingerprint_ = "";
+  std::string cert_fingerprint_server_host_ = "";
+  std::string default_cert_fingerprint_ = "";
+  std::string default_cert_fingerprint_server_host_ = "";
   bool enable_self_hosted_ = false;
   bool enable_minimize_to_tray_ = false;
   bool enable_autostart_ = false;

src/gui/assets/localization/localization.h

@@ -116,6 +116,9 @@ static std::vector<std::string> self_hosted_server_certificate_path = {
     reinterpret_cast<const char*>(u8"证书文件路径:"), "Certificate File Path:"};
 static std::vector<std::string> select_a_file = {
     reinterpret_cast<const char*>(u8"请选择文件"), "Please select a file"};
+static std::vector<std::string> reset_cert_fingerprint = {
+    reinterpret_cast<const char*>(u8"重置证书指纹"),
+    "Reset Certificate Fingerprint"};
 static std::vector<std::string> ok = {reinterpret_cast<const char*>(u8"确认"),
                                       "OK"};
 static std::vector<std::string> cancel = {
@@ -182,6 +185,25 @@ 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:"};
+static std::vector<std::string> connection_status = {
+    reinterpret_cast<const char*>(u8"连接状态:"), "Connection Status:"};
+
 #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.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>
@@ -40,11 +42,50 @@
 namespace crossdesk {
 class Render {
  public:
+  struct FileTransferState {
+    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::string remote_id;
+    };
+    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_;
+  };
+
   struct SubStreamWindowProperties {
     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;
@@ -82,8 +123,13 @@ class Render {
     float mouse_diff_control_bar_pos_y_ = 0;
     double control_bar_button_pressed_time_ = 0;
     double net_traffic_stats_button_pressed_time_ = 0;
-    unsigned char* dst_buffer_ = nullptr;
-    size_t dst_buffer_capacity_ = 0;
+    // Double-buffered NV12 frame storage. Written by decode callback thread,
+    // consumed by SDL main thread.
+    std::mutex video_frame_mutex_;
+    std::shared_ptr<std::vector<unsigned char>> front_frame_;
+    std::shared_ptr<std::vector<unsigned char>> back_frame_;
+    bool render_rect_dirty_ = false;
+    bool stream_cleanup_pending_ = false;
     float mouse_pos_x_ = 0;
     float mouse_pos_y_ = 0;
     float mouse_pos_x_last_ = 0;
@@ -122,6 +168,11 @@ class Render {
     int frame_count_ = 0;
     std::chrono::steady_clock::time_point last_time_;
     XNetTrafficStats net_traffic_stats_;
+
+    using QueuedFile = FileTransferState::QueuedFile;
+    using FileTransferStatus = FileTransferState::FileTransferStatus;
+    using FileTransferInfo = FileTransferState::FileTransferInfo;
+    FileTransferState file_transfer_;
   };
 
  public:
@@ -142,6 +193,7 @@ class Render {
   void UpdateInteractions();
   void HandleRecentConnections();
   void HandleStreamWindow();
+  void HandleServerWindow();
   void Cleanup();
   void CleanupFactories();
   void CleanupPeer(std::shared_ptr<SubStreamWindowProperties> props);
@@ -151,12 +203,24 @@ class Render {
   void UpdateRenderRect();
   void ProcessSdlEvent(const SDL_Event& event);
 
+  void ProcessFileDropEvent(const SDL_Event& event);
+
+  void ProcessSelectedFile(
+      const std::string& path,
+      const std::shared_ptr<SubStreamWindowProperties>& props,
+      const std::string& file_label, const std::string& remote_id = "");
+
+  std::shared_ptr<SubStreamWindowProperties>
+  GetSubStreamWindowPropertiesByRemoteId(const std::string& remote_id);
+
  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 +236,8 @@ 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 +246,15 @@ 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 +271,17 @@ 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,
@@ -217,11 +290,11 @@ class Render {
   static void OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
                                    size_t user_id_size, void* user_data);
 
-  static void NetStatusReport(const char* client_id, size_t client_id_size,
-                              TraversalMode mode,
-                              const XNetTrafficStats* net_traffic_stats,
-                              const char* user_id, const size_t user_id_size,
-                              void* user_data);
+  static void OnNetStatusReport(const char* client_id, size_t client_id_size,
+                                TraversalMode mode,
+                                const XNetTrafficStats* net_traffic_stats,
+                                const char* user_id, const size_t user_id_size,
+                                void* user_data);
 
   static SDL_HitTestResult HitTestCallback(SDL_Window* window,
                                            const SDL_Point* area, void* data);
@@ -259,6 +332,13 @@ 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,
+                         const std::string& remote_id = "");
+  void ProcessFileQueue(std::shared_ptr<SubStreamWindowProperties> props);
+
   int AudioDeviceInit();
   int AudioDeviceDestroy();
 
@@ -334,6 +414,7 @@ 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
@@ -356,6 +437,9 @@ class Render {
   bool keyboard_capturer_is_started_ = false;
   bool foucs_on_main_window_ = false;
   bool foucs_on_stream_window_ = false;
+  bool main_window_minimized_ = false;
+  uint32_t last_main_minimize_request_tick_ = 0;
+  uint32_t last_stream_minimize_request_tick_ = 0;
   bool audio_capture_ = false;
   int main_window_width_real_ = 720;
   int main_window_height_real_ = 540;
@@ -405,7 +489,7 @@ class Render {
   bool just_created_ = false;
   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 +516,42 @@ 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 +568,7 @@ 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 +585,20 @@ 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_;
+
+  // Map file_id to FileTransferState for global file transfer (props == null)
+  std::unordered_map<uint32_t, FileTransferState*> file_id_to_transfer_state_;
+  std::shared_mutex file_id_to_transfer_state_mutex_;
   SDL_AudioDeviceID input_dev_;
   SDL_AudioDeviceID output_dev_;
   ScreenCapturerFactory* screen_capturer_factory_ = nullptr;
@@ -478,8 +612,8 @@ class Render {
   uint64_t last_frame_time_;
   bool show_new_version_icon_ = false;
   bool show_new_version_icon_in_menu_ = true;
-  uint64_t new_version_icon_last_trigger_time_ = 0;
-  uint64_t new_version_icon_render_start_time_ = 0;
+  double new_version_icon_last_trigger_time_ = 0.0;
+  double new_version_icon_render_start_time_ = 0.0;
 #ifdef __APPLE__
   bool show_request_permission_window_ = true;
 #endif
@@ -539,6 +673,10 @@ class Render {
 
   /* ------ server mode ------ */
   std::unordered_map<std::string, ConnectionStatus> connection_status_;
+  std::unordered_map<std::string, std::string> connection_host_names_;
+  std::string selected_server_remote_id_ = "";
+  std::string selected_server_remote_hostname_ = "";
+  FileTransferState file_transfer_;
 };
 }  // namespace crossdesk
 #endif

src/gui/render_callback.cpp

@@ -1,8 +1,17 @@
+#include <chrono>
 #include <cmath>
+#include <cstdlib>
+#include <cstring>
+#include <filesystem>
 #include <fstream>
+#include <limits>
+#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 +221,7 @@ 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) {
@@ -228,31 +238,31 @@ void Render::OnReceiveVideoBufferCb(const XVideoFrame* video_frame,
       render->client_properties_.find(remote_id)->second.get();
 
   if (props->connection_established_) {
-    if (!props->dst_buffer_) {
-      props->dst_buffer_capacity_ = video_frame->size;
-      props->dst_buffer_ = new unsigned char[video_frame->size];
-    }
+    {
+      std::lock_guard<std::mutex> lock(props->video_frame_mutex_);
 
-    if (props->dst_buffer_capacity_ < video_frame->size) {
-      delete props->dst_buffer_;
-      props->dst_buffer_capacity_ = video_frame->size;
-      props->dst_buffer_ = new unsigned char[video_frame->size];
-    }
+      if (!props->back_frame_) {
+        props->back_frame_ =
+            std::make_shared<std::vector<unsigned char>>(video_frame->size);
+      }
+      if (props->back_frame_->size() != video_frame->size) {
+        props->back_frame_->resize(video_frame->size);
+      }
 
-    memcpy(props->dst_buffer_, video_frame->data, video_frame->size);
-    bool need_to_update_render_rect = false;
-    if (props->video_width_ != props->video_width_last_ ||
-        props->video_height_ != props->video_height_last_) {
-      need_to_update_render_rect = true;
-      props->video_width_last_ = props->video_width_;
-      props->video_height_last_ = props->video_height_;
-    }
-    props->video_width_ = video_frame->width;
-    props->video_height_ = video_frame->height;
-    props->video_size_ = video_frame->size;
+      std::memcpy(props->back_frame_->data(), video_frame->data,
+                  video_frame->size);
 
-    if (need_to_update_render_rect) {
-      render->UpdateRenderRect();
+      const bool size_changed = (props->video_width_ != video_frame->width) ||
+                                (props->video_height_ != video_frame->height);
+      if (size_changed) {
+        props->render_rect_dirty_ = true;
+      }
+
+      props->video_width_ = video_frame->width;
+      props->video_height_ = video_frame->height;
+      props->video_size_ = video_frame->size;
+
+      props->front_frame_.swap(props->back_frame_);
     }
 
     SDL_Event event;
@@ -279,6 +289,7 @@ 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 +309,219 @@ 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,
+                           remote_user_id](const FileTransferAck& ack) -> int {
+      bool is_server_sending = remote_user_id.rfind("C-", 0) != 0;
+      if (is_server_sending) {
+        auto props =
+            render->GetSubStreamWindowPropertiesByRemoteId(remote_user_id);
+        if (props) {
+          PeerPtr* peer = props->peer_;
+          return SendReliableDataFrame(
+              peer, reinterpret_cast<const char*>(&ack),
+              sizeof(FileTransferAck), render->file_feedback_label_.c_str());
+        }
+      }
+
+      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();
+      }
+    }
+
+    Render::FileTransferState* state = nullptr;
+    if (!props) {
+      {
+        std::shared_lock lock(render->file_id_to_transfer_state_mutex_);
+        auto it = render->file_id_to_transfer_state_.find(ack.file_id);
+        if (it != render->file_id_to_transfer_state_.end()) {
+          state = it->second;
+        }
+      }
+
+      if (!state) {
+        LOG_WARN("FileTransferAck: no props/state found for file_id={}",
+                 ack.file_id);
+        return;
+      }
+    } else {
+      state = &props->file_transfer_;
+    }
+
+    // Update progress based on ACK
+    state->file_sent_bytes_ = ack.acked_offset;
+    state->file_total_bytes_ = ack.total_size;
+
+    uint32_t rate_bps = 0;
+    {
+      if (props) {
+        uint32_t data_channel_bitrate =
+            props->net_traffic_stats_.data_outbound_stats.bitrate;
+
+        if (data_channel_bitrate > 0 && state->file_sending_.load()) {
+          rate_bps = static_cast<uint32_t>(data_channel_bitrate * 0.99f);
+
+          uint32_t current_rate = state->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 = state->file_send_rate_bps_.load();
+        }
+      } else {
+        // Global transfer: no per-connection bitrate available.
+        // Estimate send rate from ACKed bytes delta over time.
+        const uint32_t current_rate = state->file_send_rate_bps_.load();
+        uint32_t estimated_rate_bps = 0;
+        const auto now = std::chrono::steady_clock::now();
+
+        uint64_t last_bytes = 0;
+        std::chrono::steady_clock::time_point last_time;
+        {
+          std::lock_guard<std::mutex> lock(state->file_transfer_mutex_);
+          last_bytes = state->file_send_last_bytes_;
+          last_time = state->file_send_last_update_time_;
+        }
+
+        if (state->file_sending_.load() && ack.acked_offset >= last_bytes) {
+          const uint64_t delta_bytes = ack.acked_offset - last_bytes;
+          const double delta_seconds =
+              std::chrono::duration<double>(now - last_time).count();
+
+          if (delta_seconds > 0.0 && delta_bytes > 0) {
+            const double bps =
+                (static_cast<double>(delta_bytes) * 8.0) / delta_seconds;
+            if (bps > 0.0) {
+              const double capped = (std::min)(
+                  bps,
+                  static_cast<double>((std::numeric_limits<uint32_t>::max)()));
+              estimated_rate_bps = static_cast<uint32_t>(capped);
+            }
+          }
+        }
+
+        if (estimated_rate_bps > 0 && current_rate > 0) {
+          // 70% old + 30% new for smoother display
+          rate_bps = static_cast<uint32_t>(current_rate * 0.7 +
+                                           estimated_rate_bps * 0.3);
+        } else if (estimated_rate_bps > 0) {
+          rate_bps = estimated_rate_bps;
+        } else {
+          rate_bps = current_rate;
+        }
+      }
+
+      state->file_send_rate_bps_ = rate_bps;
+      state->file_send_last_bytes_ = ack.acked_offset;
+      auto now = std::chrono::steady_clock::now();
+      state->file_send_last_update_time_ = now;
+    }
+
+    // Update file transfer list: update progress and rate
+    {
+      std::lock_guard<std::mutex> lock(state->file_transfer_list_mutex_);
+      for (auto& info : state->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
+      state->file_transfer_window_visible_ = true;
+      state->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(state->file_transfer_list_mutex_);
+        for (auto& info : state->file_transfer_list_) {
+          if (info.file_id == ack.file_id) {
+            info.status =
+                Render::FileTransferState::FileTransferStatus::Completed;
+            info.sent_bytes = ack.total_size;
+            break;
+          }
+        }
+      }
+
+      // Unregister file_id mapping after completion
+      {
+        if (props) {
+          std::lock_guard<std::shared_mutex> lock(
+              render->file_id_to_props_mutex_);
+          render->file_id_to_props_.erase(ack.file_id);
+        } else {
+          std::lock_guard<std::shared_mutex> lock(
+              render->file_id_to_transfer_state_mutex_);
+          render->file_id_to_transfer_state_.erase(ack.file_id);
+        }
+      }
+
+      // Process next file in queue
+      render->ProcessFileQueue(props);
+    }
+
+    return;
+  }
+
   std::string json_str(data, size);
   RemoteAction remote_action;
 
@@ -316,24 +534,39 @@ void Render::OnReceiveDataBufferCb(const char* data, size_t size,
 
   std::string remote_id(user_id, user_id_size);
   // std::shared_lock lock(render->client_properties_mutex_);
-  if (render->client_properties_.find(remote_id) !=
-      render->client_properties_.end()) {
-    // local
-    auto props = render->client_properties_.find(remote_id)->second;
-    if (remote_action.type == ControlType::host_infomation &&
-        props->remote_host_name_.empty()) {
-      props->remote_host_name_ = std::string(remote_action.i.host_name,
-                                             remote_action.i.host_name_size);
-      LOG_INFO("Remote hostname: [{}]", props->remote_host_name_);
+  if (remote_action.type == ControlType::host_infomation) {
+    if (render->client_properties_.find(remote_id) !=
+        render->client_properties_.end()) {
+      // client mode
+      auto props = render->client_properties_.find(remote_id)->second;
+      if (props && props->remote_host_name_.empty()) {
+        props->remote_host_name_ = std::string(remote_action.i.host_name,
+                                               remote_action.i.host_name_size);
+        LOG_INFO("Remote hostname: [{}]", props->remote_host_name_);
+
+        for (int i = 0; i < remote_action.i.display_num; i++) {
+          props->display_info_list_.push_back(
+              DisplayInfo(remote_action.i.display_list[i],
+                          remote_action.i.left[i], remote_action.i.top[i],
+                          remote_action.i.right[i], remote_action.i.bottom[i]));
+        }
+      }
+      FreeRemoteAction(remote_action);
+    } else {
+      // server mode
+      render->connection_host_names_[remote_id] = std::string(
+          remote_action.i.host_name, remote_action.i.host_name_size);
+      LOG_INFO("Remote hostname: [{}]",
+               render->connection_host_names_[remote_id]);
 
       for (int i = 0; i < remote_action.i.display_num; i++) {
-        props->display_info_list_.push_back(
+        render->display_info_list_.push_back(
             DisplayInfo(remote_action.i.display_list[i],
                         remote_action.i.left[i], remote_action.i.top[i],
                         remote_action.i.right[i], remote_action.i.bottom[i]));
       }
+      FreeRemoteAction(remote_action);
     }
-    FreeRemoteAction(remote_action);
   } else {
     // remote
     if (remote_action.type == ControlType::mouse && render->mouse_controller_) {
@@ -428,6 +661,49 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
 
     switch (status) {
       case ConnectionStatus::Connected: {
+        {
+          RemoteAction remote_action;
+          remote_action.i.display_num = render->display_info_list_.size();
+          remote_action.i.display_list =
+              (char**)malloc(remote_action.i.display_num * sizeof(char*));
+          remote_action.i.left =
+              (int*)malloc(remote_action.i.display_num * sizeof(int));
+          remote_action.i.top =
+              (int*)malloc(remote_action.i.display_num * sizeof(int));
+          remote_action.i.right =
+              (int*)malloc(remote_action.i.display_num * sizeof(int));
+          remote_action.i.bottom =
+              (int*)malloc(remote_action.i.display_num * sizeof(int));
+          for (int i = 0; i < remote_action.i.display_num; i++) {
+            LOG_INFO("Local display [{}:{}]", i + 1,
+                     render->display_info_list_[i].name);
+            remote_action.i.display_list[i] =
+                (char*)malloc(render->display_info_list_[i].name.length() + 1);
+            strncpy(remote_action.i.display_list[i],
+                    render->display_info_list_[i].name.c_str(),
+                    render->display_info_list_[i].name.length());
+            remote_action.i
+                .display_list[i][render->display_info_list_[i].name.length()] =
+                '\0';
+            remote_action.i.left[i] = render->display_info_list_[i].left;
+            remote_action.i.top[i] = render->display_info_list_[i].top;
+            remote_action.i.right[i] = render->display_info_list_[i].right;
+            remote_action.i.bottom[i] = render->display_info_list_[i].bottom;
+          }
+
+          std::string host_name = GetHostName();
+          remote_action.type = ControlType::host_infomation;
+          memcpy(&remote_action.i.host_name, host_name.data(),
+                 host_name.size());
+          remote_action.i.host_name[host_name.size()] = '\0';
+          remote_action.i.host_name_size = host_name.size();
+
+          std::string msg = remote_action.to_json();
+          int ret = SendReliableDataFrame(props->peer_, msg.data(), msg.size(),
+                                          render->control_data_label_.c_str());
+          FreeRemoteAction(remote_action);
+        }
+
         if (!render->need_to_create_stream_window_ &&
             !render->client_properties_.empty()) {
           render->need_to_create_stream_window_ = true;
@@ -444,12 +720,22 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
       case ConnectionStatus::Closed: {
         props->connection_established_ = false;
         props->mouse_control_button_pressed_ = false;
-        if (props->dst_buffer_ && props->stream_texture_) {
-          memset(props->dst_buffer_, 0, props->dst_buffer_capacity_);
-          SDL_UpdateTexture(props->stream_texture_, NULL, props->dst_buffer_,
-                            props->texture_width_);
+
+        {
+          std::lock_guard<std::mutex> lock(props->video_frame_mutex_);
+          props->front_frame_.reset();
+          props->back_frame_.reset();
+          props->video_width_ = 0;
+          props->video_height_ = 0;
+          props->video_size_ = 0;
+          props->render_rect_dirty_ = true;
+          props->stream_cleanup_pending_ = true;
         }
-        render->CleanSubStreamWindowProperties(props);
+
+        SDL_Event event;
+        event.type = render->STREAM_REFRESH_EVENT;
+        event.user.data1 = props;
+        SDL_PushEvent(&event);
 
         break;
       }
@@ -482,9 +768,54 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
 
     switch (status) {
       case ConnectionStatus::Connected: {
-        render->need_to_send_host_info_ = true;
+        {
+          RemoteAction remote_action;
+          remote_action.i.display_num = render->display_info_list_.size();
+          remote_action.i.display_list =
+              (char**)malloc(remote_action.i.display_num * sizeof(char*));
+          remote_action.i.left =
+              (int*)malloc(remote_action.i.display_num * sizeof(int));
+          remote_action.i.top =
+              (int*)malloc(remote_action.i.display_num * sizeof(int));
+          remote_action.i.right =
+              (int*)malloc(remote_action.i.display_num * sizeof(int));
+          remote_action.i.bottom =
+              (int*)malloc(remote_action.i.display_num * sizeof(int));
+          for (int i = 0; i < remote_action.i.display_num; i++) {
+            LOG_INFO("Local display [{}:{}]", i + 1,
+                     render->display_info_list_[i].name);
+            remote_action.i.display_list[i] =
+                (char*)malloc(render->display_info_list_[i].name.length() + 1);
+            strncpy(remote_action.i.display_list[i],
+                    render->display_info_list_[i].name.c_str(),
+                    render->display_info_list_[i].name.length());
+            remote_action.i
+                .display_list[i][render->display_info_list_[i].name.length()] =
+                '\0';
+            remote_action.i.left[i] = render->display_info_list_[i].left;
+            remote_action.i.top[i] = render->display_info_list_[i].top;
+            remote_action.i.right[i] = render->display_info_list_[i].right;
+            remote_action.i.bottom[i] = render->display_info_list_[i].bottom;
+          }
+
+          std::string host_name = GetHostName();
+          remote_action.type = ControlType::host_infomation;
+          memcpy(&remote_action.i.host_name, host_name.data(),
+                 host_name.size());
+          remote_action.i.host_name[host_name.size()] = '\0';
+          remote_action.i.host_name_size = host_name.size();
+
+          std::string msg = remote_action.to_json();
+          int ret = SendReliableDataFrame(render->peer_, msg.data(), msg.size(),
+                                          render->control_data_label_.c_str());
+          FreeRemoteAction(remote_action);
+        }
+
+        render->need_to_create_server_window_ = 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 +838,13 @@ 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();
@@ -536,11 +869,11 @@ void Render::OnConnectionStatusCb(ConnectionStatus status, const char* user_id,
   }
 }
 
-void Render::NetStatusReport(const char* client_id, size_t client_id_size,
-                             TraversalMode mode,
-                             const XNetTrafficStats* net_traffic_stats,
-                             const char* user_id, const size_t user_id_size,
-                             void* user_data) {
+void Render::OnNetStatusReport(const char* client_id, size_t client_id_size,
+                               TraversalMode mode,
+                               const XNetTrafficStats* net_traffic_stats,
+                               const char* user_id, const size_t user_id_size,
+                               void* user_data) {
   Render* render = (Render*)user_data;
   if (!render) {
     return;

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 +41,97 @@ 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,
+    const std::shared_ptr<SubStreamWindowProperties>& props,
+    const std::string& file_label, const std::string& remote_id) {
+  if (path.empty()) {
+    return;
+  }
+
+  FileTransferState* file_transfer_state =
+      props ? &props->file_transfer_ : &file_transfer_;
+
+  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(
+        file_transfer_state->file_transfer_list_mutex_);
+    FileTransferState::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 = FileTransferState::FileTransferStatus::Queued;
+    info.sent_bytes = 0;
+    info.file_id = 0;
+    info.rate_bps = 0;
+    file_transfer_state->file_transfer_list_.push_back(info);
+  }
+  file_transfer_state->file_transfer_window_visible_ = true;
+
+  if (file_transfer_state->file_sending_.load()) {
+    // Add to queue
+    size_t queue_size = 0;
+    {
+      std::lock_guard<std::mutex> lock(file_transfer_state->file_queue_mutex_);
+      FileTransferState::QueuedFile queued_file;
+      queued_file.file_path = file_path;
+      queued_file.file_label = file_label;
+      queued_file.remote_id = remote_id;
+      file_transfer_state->file_send_queue_.push(queued_file);
+      queue_size = file_transfer_state->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, remote_id);
+
+    if (file_transfer_state->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(
+            file_transfer_state->file_queue_mutex_);
+        FileTransferState::QueuedFile queued_file;
+        queued_file.file_path = file_path;
+        queued_file.file_label = file_label;
+        queued_file.remote_id = remote_id;
+        file_transfer_state->file_send_queue_.push(queued_file);
+        queue_size = file_transfer_state->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 +142,14 @@ 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 +174,8 @@ 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 +255,8 @@ 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 +276,16 @@ 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);
+      ProcessSelectedFile(path, props, file_label_);
+    }
+
     ImGui::SameLine();
     // net traffic stats button
     bool button_color_style_pushed = false;
@@ -238,9 +349,9 @@ 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 +361,7 @@ 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/toolbars/title_bar.cpp

@@ -3,7 +3,8 @@
 #include "rd_log.h"
 #include "render.h"
 
-#define NEW_VERSION_ICON_RENDER_TIME_INTERVAL 2000
+constexpr double kNewVersionIconBlinkIntervalSec = 2.0;
+constexpr double kNewVersionIconBlinkOnTimeSec = 1.0;
 
 namespace crossdesk {
 
@@ -15,14 +16,28 @@ int Render::TitleBar(bool main_window) {
   float title_bar_button_width = title_bar_button_width_;
   float title_bar_button_height = title_bar_button_height_;
   if (main_window) {
-    title_bar_width = io.DisplaySize.x;
-    title_bar_height = io.DisplaySize.y * TITLE_BAR_HEIGHT;
-    title_bar_height_padding = io.DisplaySize.y * (TITLE_BAR_HEIGHT + 0.01f);
-    title_bar_button_width = io.DisplaySize.x * TITLE_BAR_BUTTON_WIDTH;
-    title_bar_button_height = io.DisplaySize.y * TITLE_BAR_BUTTON_HEIGHT;
-    title_bar_height_ = title_bar_height;
-    title_bar_button_width_ = title_bar_button_width;
-    title_bar_button_height_ = title_bar_button_height;
+    // When the main window is minimized, Dear ImGui may report DisplaySize as
+    // (0, 0). Do not overwrite shared title-bar metrics with zeros, otherwise
+    // stream/server windows (which reuse these metrics) will lose their title
+    // bars and appear collapsed.
+    if (io.DisplaySize.x > 0.0f && io.DisplaySize.y > 0.0f) {
+      title_bar_width = io.DisplaySize.x;
+      title_bar_height = io.DisplaySize.y * TITLE_BAR_HEIGHT;
+      title_bar_height_padding = io.DisplaySize.y * (TITLE_BAR_HEIGHT + 0.01f);
+      title_bar_button_width = io.DisplaySize.x * TITLE_BAR_BUTTON_WIDTH;
+      title_bar_button_height = io.DisplaySize.y * TITLE_BAR_BUTTON_HEIGHT;
+
+      title_bar_height_ = title_bar_height;
+      title_bar_button_width_ = title_bar_button_width;
+      title_bar_button_height_ = title_bar_button_height;
+    } else {
+      // Keep using last known good values.
+      title_bar_width = title_bar_width_;
+      title_bar_height = title_bar_height_;
+      title_bar_height_padding = title_bar_height_;
+      title_bar_button_width = title_bar_button_width_;
+      title_bar_button_height = title_bar_button_height_;
+    }
   } else {
     title_bar_width = io.DisplaySize.x;
     title_bar_height = title_bar_button_height_;
@@ -92,13 +107,11 @@ int Render::TitleBar(bool main_window) {
 
       std::string about_str = localization::about[localization_language_index_];
       if (update_available_) {
-        auto now_time = std::chrono::duration_cast<std::chrono::milliseconds>(
-                            std::chrono::steady_clock::now().time_since_epoch())
-                            .count();
+        const double now_time = ImGui::GetTime();
 
         // every 2 seconds
         if (now_time - new_version_icon_last_trigger_time_ >=
-            NEW_VERSION_ICON_RENDER_TIME_INTERVAL) {
+            kNewVersionIconBlinkIntervalSec) {
           show_new_version_icon_ = true;
           new_version_icon_render_start_time_ = now_time;
           new_version_icon_last_trigger_time_ = now_time;
@@ -106,9 +119,9 @@ int Render::TitleBar(bool main_window) {
 
         // render for 1 second
         if (show_new_version_icon_) {
-          about_str = about_str + " " + ICON_FA_TRIANGLE_EXCLAMATION;
+          about_str = about_str + " " + ICON_FA_CIRCLE_ARROW_UP;
           if (now_time - new_version_icon_render_start_time_ >=
-              NEW_VERSION_ICON_RENDER_TIME_INTERVAL / 2) {
+              kNewVersionIconBlinkOnTimeSec) {
             show_new_version_icon_ = false;
           }
         } else {
@@ -137,13 +150,11 @@ int Render::TitleBar(bool main_window) {
     }
 
     if (update_available_ && show_new_version_icon_in_menu_) {
-      auto now_time = std::chrono::duration_cast<std::chrono::milliseconds>(
-                          std::chrono::steady_clock::now().time_since_epoch())
-                          .count();
+      const double now_time = ImGui::GetTime();
 
       // every 2 seconds
       if (now_time - new_version_icon_last_trigger_time_ >=
-          NEW_VERSION_ICON_RENDER_TIME_INTERVAL) {
+          kNewVersionIconBlinkIntervalSec) {
         show_new_version_icon_ = true;
         new_version_icon_render_start_time_ = now_time;
         new_version_icon_last_trigger_time_ = now_time;
@@ -152,14 +163,13 @@ int Render::TitleBar(bool main_window) {
       // render for 1 second
       if (show_new_version_icon_) {
         ImGui::SetWindowFontScale(0.6f);
-        ImGui::SetCursorPos(
-            ImVec2(bar_pos_x + title_bar_button_width * 0.15f,
-                   bar_pos_y - title_bar_button_width * 0.325f));
-        ImGui::Text(ICON_FA_TRIANGLE_EXCLAMATION);
+        ImGui::SetCursorPos(ImVec2(bar_pos_x + title_bar_button_width * 0.21f,
+                                   bar_pos_y - title_bar_button_width * 0.24f));
+        ImGui::Text(ICON_FA_CIRCLE_ARROW_UP);
         ImGui::SetWindowFontScale(1.0f);
 
         if (now_time - new_version_icon_render_start_time_ >=
-            NEW_VERSION_ICON_RENDER_TIME_INTERVAL / 2) {
+            kNewVersionIconBlinkOnTimeSec) {
           show_new_version_icon_ = false;
         }
       }
@@ -187,6 +197,11 @@ int Render::TitleBar(bool main_window) {
   std::string window_minimize_button = "##minimize";  // ICON_FA_MINUS;
   if (ImGui::Button(window_minimize_button.c_str(),
                     ImVec2(title_bar_button_width, title_bar_button_height))) {
+    if (main_window) {
+      last_main_minimize_request_tick_ = SDL_GetTicks();
+    } else {
+      last_stream_minimize_request_tick_ = SDL_GetTicks();
+    }
     SDL_MinimizeWindow(main_window ? main_window_ : stream_window_);
   }
   draw_list->AddLine(

src/gui/windows/file_transfer_window.cpp

@@ -0,0 +1,244 @@
+#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) {
+  FileTransferState* state = props ? &props->file_transfer_ : &file_transfer_;
+
+  // 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(state->file_transfer_list_mutex_);
+    file_list = state->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 (!state->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) {
+      state->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

@@ -214,20 +214,31 @@ int Render::SelfHostedServerWindow() {
 
       ImGui::Separator();
 
+      // {
+      //   ImGui::AlignTextToFramePadding();
+      //   ImGui::Text(
+      //       "%s",
+      //       localization::reset_cert_fingerprint[localization_language_index_]
+      //           .c_str());
+      //   ImGui::SameLine();
+      //   if (ConfigCenter::LANGUAGE::CHINESE == localization_language_) {
+      //     ImGui::SetCursorPosX(title_bar_button_width_ * 2.5f);
+      //   } else {
+      //     ImGui::SetCursorPosX(title_bar_button_width_ * 3.43f);
+      //   }
+      //   ImGui::SetNextItemWidth(title_bar_button_width_ * 3.8f);
+
+      //   ShowSimpleFileBrowser();
+      // }
+
       {
         ImGui::AlignTextToFramePadding();
-        ImGui::Text("%s", localization::self_hosted_server_certificate_path
+        if (ImGui::Button(localization::reset_cert_fingerprint
                               [localization_language_index_]
-                                  .c_str());
-        ImGui::SameLine();
-        if (ConfigCenter::LANGUAGE::CHINESE == localization_language_) {
-          ImGui::SetCursorPosX(title_bar_button_width_ * 2.5f);
-        } else {
-          ImGui::SetCursorPosX(title_bar_button_width_ * 3.43f);
+                                  .c_str())) {
+          config_center_->ClearCertFingerprint();
+          LOG_INFO("Certificate fingerprint cleared by user");
         }
-        ImGui::SetNextItemWidth(title_bar_button_width_ * 3.8f);
-
-        ShowSimpleFileBrowser();
       }
 
       if (stream_window_inited_) {

src/gui/windows/server_window.cpp

@@ -0,0 +1,368 @@
+#include <algorithm>
+#include <cmath>
+#include <cstdio>
+#include <string>
+#include <vector>
+
+#include "layout_relative.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;
+}
+
+void BitrateDisplay(uint32_t bitrate) {
+  const int num_of_digits = CountDigits(static_cast<int>(bitrate));
+  if (num_of_digits <= 3) {
+    ImGui::Text("%u bps", bitrate);
+  } else if (num_of_digits > 3 && num_of_digits <= 6) {
+    ImGui::Text("%u kbps", bitrate / 1000);
+  } else {
+    ImGui::Text("%.1f mbps", bitrate / 1000000.0f);
+  }
+}
+
+std::string FormatBytes(uint64_t bytes) {
+  char buf[64];
+  if (bytes < 1024ULL) {
+    std::snprintf(buf, sizeof(buf), "%llu B", (unsigned long long)bytes);
+  } else if (bytes < 1024ULL * 1024ULL) {
+    std::snprintf(buf, sizeof(buf), "%.2f KB", bytes / 1024.0);
+  } else if (bytes < 1024ULL * 1024ULL * 1024ULL) {
+    std::snprintf(buf, sizeof(buf), "%.2f MB", bytes / (1024.0 * 1024.0));
+  } else {
+    std::snprintf(buf, sizeof(buf), "%.2f GB",
+                  bytes / (1024.0 * 1024.0 * 1024.0));
+  }
+  return std::string(buf);
+}
+}  // 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);
+
+  server_window_title_bar_height_ = title_bar_height_;
+
+  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_ * 0.8f;
+  float remote_client_info_window_height =
+      (server_window_height_ - server_window_title_bar_height_) * 0.9f;
+
+  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();
+
+  float font_scale = localization_language_index_ == 0 ? 0.5f : 0.45f;
+
+  std::vector<std::string> remote_hostnames;
+  remote_hostnames.reserve(connection_host_names_.size());
+  for (const auto& kv : connection_host_names_) {
+    remote_hostnames.push_back(kv.second);
+  }
+
+  auto find_remote_id_by_hostname =
+      [this](const std::string& hostname) -> std::string {
+    for (const auto& kv : connection_host_names_) {
+      if (kv.second == hostname) {
+        return kv.first;
+      }
+    }
+    return {};
+  };
+
+  if (!selected_server_remote_hostname_.empty()) {
+    if (std::find(remote_hostnames.begin(), remote_hostnames.end(),
+                  selected_server_remote_hostname_) == remote_hostnames.end()) {
+      selected_server_remote_hostname_.clear();
+      selected_server_remote_id_.clear();
+    }
+  }
+  if (selected_server_remote_hostname_.empty() && !remote_hostnames.empty()) {
+    selected_server_remote_hostname_ = remote_hostnames.front();
+    selected_server_remote_id_ =
+        find_remote_id_by_hostname(selected_server_remote_hostname_);
+  }
+
+  ImGui::SetWindowFontScale(font_scale);
+  ImGui::AlignTextToFramePadding();
+  ImGui::Text("%s",
+              localization::controller[localization_language_index_].c_str());
+  ImGui::SameLine();
+
+  const char* selected_preview = "-";
+  if (!selected_server_remote_hostname_.empty()) {
+    selected_preview = selected_server_remote_hostname_.c_str();
+  } else if (!remote_client_id_.empty()) {
+    selected_preview = remote_client_id_.c_str();
+  }
+
+  ImGui::SetNextItemWidth(remote_client_info_window_width *
+                          (localization_language_index_ == 0 ? 0.68f : 0.62f));
+  ImGui::SetWindowFontScale(localization_language_index_ == 0 ? 0.45f : 0.4f);
+  ImGui::AlignTextToFramePadding();
+  if (ImGui::BeginCombo("##server_remote_id", selected_preview)) {
+    ImGui::SetWindowFontScale(localization_language_index_ == 0 ? 0.45f : 0.4f);
+    for (int i = 0; i < static_cast<int>(remote_hostnames.size()); i++) {
+      const bool selected =
+          (remote_hostnames[i] == selected_server_remote_hostname_);
+      if (ImGui::Selectable(remote_hostnames[i].c_str(), selected)) {
+        selected_server_remote_hostname_ = remote_hostnames[i];
+        selected_server_remote_id_ =
+            find_remote_id_by_hostname(selected_server_remote_hostname_);
+      }
+      if (selected) {
+        ImGui::SetItemDefaultFocus();
+      }
+    }
+    ImGui::EndCombo();
+  }
+
+  ImGui::Separator();
+
+  ImGui::SetWindowFontScale(font_scale);
+
+  if (!selected_server_remote_id_.empty()) {
+    auto it = connection_status_.find(selected_server_remote_id_);
+    const ConnectionStatus status = (it == connection_status_.end())
+                                        ? ConnectionStatus::Closed
+                                        : it->second;
+
+    ImGui::Text(
+        "%s",
+        localization::connection_status[localization_language_index_].c_str());
+    ImGui::SameLine();
+
+    switch (status) {
+      case ConnectionStatus::Connected:
+        ImGui::Text(
+            "%s",
+            localization::p2p_connected[localization_language_index_].c_str());
+        break;
+      case ConnectionStatus::Connecting:
+        ImGui::Text(
+            "%s",
+            localization::p2p_connecting[localization_language_index_].c_str());
+        break;
+      case ConnectionStatus::Disconnected:
+        ImGui::Text("%s",
+                    localization::p2p_disconnected[localization_language_index_]
+                        .c_str());
+        break;
+      case ConnectionStatus::Failed:
+        ImGui::Text(
+            "%s",
+            localization::p2p_failed[localization_language_index_].c_str());
+        break;
+      case ConnectionStatus::Closed:
+        ImGui::Text(
+            "%s",
+            localization::p2p_closed[localization_language_index_].c_str());
+        break;
+      default:
+        ImGui::Text(
+            "%s",
+            localization::p2p_failed[localization_language_index_].c_str());
+        break;
+    }
+  }
+
+  ImGui::Separator();
+
+  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());
+
+    ProcessSelectedFile(path, nullptr, file_label_, selected_server_remote_id_);
+  }
+
+  if (file_transfer_.file_transfer_window_visible_) {
+    ImGui::SameLine();
+    const bool is_sending = file_transfer_.file_sending_.load();
+
+    if (is_sending) {
+      // Simple animation: cycle icon every 0.5s while sending.
+      static const char* kFileTransferIcons[] = {ICON_FA_ANGLE_UP,
+                                                 ICON_FA_ANGLES_UP};
+      const int icon_index = static_cast<int>(ImGui::GetTime() / 0.5) %
+                             (static_cast<int>(sizeof(kFileTransferIcons) /
+                                               sizeof(kFileTransferIcons[0])));
+      ImGui::Text("%s", kFileTransferIcons[icon_index]);
+    } else {
+      // Completed.
+      ImGui::Text("%s", ICON_FA_CHECK);
+    }
+
+    if (ImGui::IsItemHovered()) {
+      const uint64_t sent_bytes = file_transfer_.file_sent_bytes_.load();
+      const uint64_t total_bytes = file_transfer_.file_total_bytes_.load();
+      const uint32_t rate_bps = file_transfer_.file_send_rate_bps_.load();
+
+      float progress = 0.0f;
+      if (total_bytes > 0) {
+        progress =
+            static_cast<float>(sent_bytes) / static_cast<float>(total_bytes);
+        progress = (std::max)(0.0f, (std::min)(1.0f, progress));
+      }
+
+      std::string current_file_name;
+      const uint32_t current_file_id = file_transfer_.current_file_id_.load();
+      if (current_file_id != 0) {
+        std::lock_guard<std::mutex> lock(
+            file_transfer_.file_transfer_list_mutex_);
+        for (const auto& info : file_transfer_.file_transfer_list_) {
+          if (info.file_id == current_file_id) {
+            current_file_name = info.file_name;
+            break;
+          }
+        }
+      }
+
+      ImGui::BeginTooltip();
+      if (server_windows_system_chinese_font_) {
+        ImGui::PushFont(server_windows_system_chinese_font_);
+      }
+      ImGui::SetWindowFontScale(0.5f);
+      if (!current_file_name.empty()) {
+        ImGui::Text("%s", current_file_name.c_str());
+      }
+      if (total_bytes > 0) {
+        const std::string sent_str = FormatBytes(sent_bytes);
+        const std::string total_str = FormatBytes(total_bytes);
+        ImGui::Text("%s / %s", sent_str.c_str(), total_str.c_str());
+      }
+
+      const float text_height = ImGui::GetTextLineHeight();
+      char overlay[32];
+      std::snprintf(overlay, sizeof(overlay), "%.1f%%", progress * 100.0f);
+      ImGui::ProgressBar(progress, ImVec2(180.0f, text_height), overlay);
+      BitrateDisplay(rate_bps);
+      ImGui::SetWindowFontScale(1.0f);
+      if (server_windows_system_chinese_font_) {
+        ImGui::PopFont();
+      }
+      ImGui::EndTooltip();
+    }
+  }
+
+  ImGui::SetWindowFontScale(1.0f);
+
+  ImGui::EndChild();
+
+  ImGui::SameLine();
+
+  float close_connection_button_width = server_window_width_ * 0.1f;
+  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(font_scale);
+  if (ImGui::Button(ICON_FA_XMARK, ImVec2(close_connection_button_width,
+                                          close_connection_button_height))) {
+    if (peer_ && !selected_server_remote_id_.empty()) {
+      LeaveConnection(peer_, selected_server_remote_id_.c_str());
+    }
+  }
+  ImGui::SetWindowFontScale(1.0f);
+  ImGui::PopStyleColor(3);
+  ImGui::PopStyleVar();
+
+  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",