[fix] release pressed modifier keys when stream window loses focus

src/gui/render.cpp

@@ -2455,6 +2455,7 @@ void Render::ProcessSdlEvent(const SDL_Event& event) {
     case SDL_EVENT_WINDOW_FOCUS_LOST:
       if (stream_window_ &&
           SDL_GetWindowID(stream_window_) == event.window.windowID) {
+        ForceReleasePressedModifiers();
         focus_on_stream_window_ = false;
       } else if (main_window_ &&
                  SDL_GetWindowID(main_window_) == event.window.windowID) {

src/gui/render.h

@@ -20,6 +20,7 @@
 #include <shared_mutex>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include <vector>
 
 #include "IconsFontAwesome6.h"
@@ -322,6 +323,9 @@ class Render {
 
  private:
   int SendKeyCommand(int key_code, bool is_down);
+  static bool IsModifierVkKey(int key_code);
+  void UpdatePressedModifierState(int key_code, bool is_down);
+  void ForceReleasePressedModifiers();
   int ProcessMouseEvent(const SDL_Event& event);
 
   static void SdlCaptureAudioIn(void* userdata, Uint8* stream, int len);
@@ -506,6 +510,8 @@ class Render {
   std::string controlled_remote_id_ = "";
   std::string focused_remote_id_ = "";
   std::string remote_client_id_ = "";
+  std::unordered_set<int> pressed_modifier_keys_;
+  std::mutex pressed_modifier_keys_mutex_;
   SDL_Event last_mouse_event;
   SDL_AudioStream* output_stream_;
   uint32_t STREAM_REFRESH_EVENT = 0;

src/gui/render_callback.cpp

@@ -81,6 +81,55 @@ void Render::OnSignalMessageCb(const char* message, size_t size,
   }
 }
 
+bool Render::IsModifierVkKey(int key_code) {
+  switch (key_code) {
+    case 0x10:  // VK_SHIFT
+    case 0x11:  // VK_CONTROL
+    case 0x12:  // VK_MENU(ALT)
+    case 0x5B:  // VK_LWIN
+    case 0x5C:  // VK_RWIN
+    case 0xA0:  // VK_LSHIFT
+    case 0xA1:  // VK_RSHIFT
+    case 0xA2:  // VK_LCONTROL
+    case 0xA3:  // VK_RCONTROL
+    case 0xA4:  // VK_LMENU
+    case 0xA5:  // VK_RMENU
+      return true;
+    default:
+      return false;
+  }
+}
+
+void Render::UpdatePressedModifierState(int key_code, bool is_down) {
+  if (!IsModifierVkKey(key_code)) {
+    return;
+  }
+
+  std::lock_guard<std::mutex> lock(pressed_modifier_keys_mutex_);
+  if (is_down) {
+    pressed_modifier_keys_.insert(key_code);
+  } else {
+    pressed_modifier_keys_.erase(key_code);
+  }
+}
+
+void Render::ForceReleasePressedModifiers() {
+  std::vector<int> pressed_keys;
+  {
+    std::lock_guard<std::mutex> lock(pressed_modifier_keys_mutex_);
+    if (pressed_modifier_keys_.empty()) {
+      return;
+    }
+    pressed_keys.assign(pressed_modifier_keys_.begin(),
+                        pressed_modifier_keys_.end());
+    pressed_modifier_keys_.clear();
+  }
+
+  for (int key_code : pressed_keys) {
+    SendKeyCommand(key_code, false);
+  }
+}
+
 int Render::SendKeyCommand(int key_code, bool is_down) {
   RemoteAction remote_action;
   remote_action.type = ControlType::keyboard;
@@ -109,6 +158,8 @@ int Render::SendKeyCommand(int key_code, bool is_down) {
     }
   }
 
+  UpdatePressedModifierState(key_code, is_down);
+
   return 0;
 }