[fix] preserve Linux keypad navigation semantics and Windows scan-code metadata for remote keyboard input

src/device_controller/keyboard/linux/keyboard_capturer.cpp

@@ -6,6 +6,7 @@
 #include "keyboard_converter.h"
 #include "platform.h"
 #include "rd_log.h"
+#include "windows_key_metadata.h"
 
 namespace crossdesk {
 
@@ -35,9 +36,12 @@ static int KeyboardEventHandler(Display* display, XEvent* event) {
 
     int key_code = key_it->second;
     bool is_key_down = (event->xkey.type == KeyPress);
+    uint32_t scan_code = 0;
+    bool extended = false;
+    LookupWindowsKeyMetadataFromVk(key_code, &scan_code, &extended);
 
     if (g_on_key_action) {
-      g_on_key_action(key_code, is_key_down, 0, false, g_user_ptr);
+      g_on_key_action(key_code, is_key_down, scan_code, extended, g_user_ptr);
     }
   }
   return 0;
@@ -157,7 +161,9 @@ int KeyboardCapturer::SendKeyboardCommand(int key_code, bool is_down,
         use_wayland_portal_ = true;
         LOG_INFO("Keyboard controller initialized with Wayland portal backend");
       } else {
-        LOG_WARN("Wayland keyboard control init failed, falling back to X11/XTest backend");
+        LOG_WARN(
+            "Wayland keyboard control init failed, falling back to X11/XTest "
+            "backend");
       }
     }
 

src/device_controller/windows_key_metadata.h

@@ -0,0 +1,89 @@
+/*
+ * @Author: DI JUNKUN
+ * @Date: 2026-05-07
+ * Copyright (c) 2026 by DI JUNKUN, All Rights Reserved.
+ */
+
+#ifndef _WINDOWS_KEY_METADATA_H_
+#define _WINDOWS_KEY_METADATA_H_
+
+#include <cstdint>
+
+namespace crossdesk {
+
+inline bool LookupWindowsKeyMetadataFromVk(int key_code,
+                                           uint32_t* scan_code_out,
+                                           bool* extended_out) {
+  if (scan_code_out == nullptr || extended_out == nullptr) {
+    return false;
+  }
+
+  switch (key_code) {
+    case 0x21:  // Page Up
+      *scan_code_out = 0x49;
+      *extended_out = true;
+      return true;
+    case 0x22:  // Page Down
+      *scan_code_out = 0x51;
+      *extended_out = true;
+      return true;
+    case 0x23:  // End
+      *scan_code_out = 0x4F;
+      *extended_out = true;
+      return true;
+    case 0x24:  // Home
+      *scan_code_out = 0x47;
+      *extended_out = true;
+      return true;
+    case 0x25:  // Left Arrow
+      *scan_code_out = 0x4B;
+      *extended_out = true;
+      return true;
+    case 0x26:  // Up Arrow
+      *scan_code_out = 0x48;
+      *extended_out = true;
+      return true;
+    case 0x27:  // Right Arrow
+      *scan_code_out = 0x4D;
+      *extended_out = true;
+      return true;
+    case 0x28:  // Down Arrow
+      *scan_code_out = 0x50;
+      *extended_out = true;
+      return true;
+    case 0x2D:  // Insert
+      *scan_code_out = 0x52;
+      *extended_out = true;
+      return true;
+    case 0x2E:  // Delete
+      *scan_code_out = 0x53;
+      *extended_out = true;
+      return true;
+    case 0x6F:  // Numpad /
+      *scan_code_out = 0x35;
+      *extended_out = true;
+      return true;
+    case 0xA3:  // Right Ctrl
+      *scan_code_out = 0x1D;
+      *extended_out = true;
+      return true;
+    case 0xA5:  // Right Alt
+      *scan_code_out = 0x38;
+      *extended_out = true;
+      return true;
+    case 0x5B:  // Left Win
+      *scan_code_out = 0x5B;
+      *extended_out = true;
+      return true;
+    case 0x5C:  // Right Win
+      *scan_code_out = 0x5C;
+      *extended_out = true;
+      return true;
+    default:
+      return false;
+  }
+}
+
+}  // namespace crossdesk
+
+#endif

src/gui/render_callback.cpp

@@ -17,6 +17,7 @@
 #include "platform.h"
 #include "rd_log.h"
 #include "render.h"
+#include "windows_key_metadata.h"
 #if _WIN32
 #include "interactive_state.h"
 #include "service_host.h"
@@ -28,34 +29,66 @@ namespace crossdesk {
 
 namespace {
 
-int TranslateSdlKeypadScancodeToVk(SDL_Scancode scancode) {
-  switch (scancode) {
+int TranslateSdlKeypadScancodeToVk(const SDL_KeyboardEvent& event) {
+  const bool numlock_enabled = (event.mod & SDL_KMOD_NUM) != 0;
+
+  switch (event.scancode) {
     case SDL_SCANCODE_NUMLOCKCLEAR:
       return 0x90;
     case SDL_SCANCODE_KP_ENTER:
       return 0x0D;
     case SDL_SCANCODE_KP_0:
+      if (!numlock_enabled) {
+        return 0x2D;
+      }
       return 0x60;
     case SDL_SCANCODE_KP_1:
+      if (!numlock_enabled) {
+        return 0x23;
+      }
       return 0x61;
     case SDL_SCANCODE_KP_2:
+      if (!numlock_enabled) {
+        return 0x28;
+      }
       return 0x62;
     case SDL_SCANCODE_KP_3:
+      if (!numlock_enabled) {
+        return 0x22;
+      }
       return 0x63;
     case SDL_SCANCODE_KP_4:
+      if (!numlock_enabled) {
+        return 0x25;
+      }
       return 0x64;
     case SDL_SCANCODE_KP_5:
       return 0x65;
     case SDL_SCANCODE_KP_6:
+      if (!numlock_enabled) {
+        return 0x27;
+      }
       return 0x66;
     case SDL_SCANCODE_KP_7:
+      if (!numlock_enabled) {
+        return 0x24;
+      }
       return 0x67;
     case SDL_SCANCODE_KP_8:
+      if (!numlock_enabled) {
+        return 0x26;
+      }
       return 0x68;
     case SDL_SCANCODE_KP_9:
+      if (!numlock_enabled) {
+        return 0x21;
+      }
       return 0x69;
     case SDL_SCANCODE_KP_PERIOD:
     case SDL_SCANCODE_KP_COMMA:
+      if (!numlock_enabled) {
+        return 0x2E;
+      }
       return 0x6E;
     case SDL_SCANCODE_KP_DIVIDE:
       return 0x6F;
@@ -73,7 +106,7 @@ int TranslateSdlKeypadScancodeToVk(SDL_Scancode scancode) {
 }
 
 int TranslateSdlKeyboardEventToVk(const SDL_KeyboardEvent& event) {
-  const int keypad_key_code = TranslateSdlKeypadScancodeToVk(event.scancode);
+  const int keypad_key_code = TranslateSdlKeypadScancodeToVk(event);
   if (keypad_key_code >= 0) {
     return keypad_key_code;
   }
@@ -200,9 +233,9 @@ int TranslateSdlKeyboardEventToVk(const SDL_KeyboardEvent& event) {
   }
 }
 
-#if _WIN32
 int NormalizeWindowsModifierVk(int key_code, uint32_t scan_code,
                                bool extended) {
+#if _WIN32
   if (key_code != 0x10 && key_code != 0x11 && key_code != 0x12) {
     return key_code;
   }
@@ -215,6 +248,11 @@ int NormalizeWindowsModifierVk(int key_code, uint32_t scan_code,
   const UINT normalized_vk =
       MapVirtualKeyW(scan_code_with_prefix, MAPVK_VSC_TO_VK_EX);
   return normalized_vk != 0 ? static_cast<int>(normalized_vk) : key_code;
+#else
+  (void)scan_code;
+  (void)extended;
+  return key_code;
+#endif
 }
 
 void PopulateWindowsKeyMetadataFromVk(int key_code, uint32_t* scan_code_out,
@@ -223,16 +261,20 @@ void PopulateWindowsKeyMetadataFromVk(int key_code, uint32_t* scan_code_out,
     return;
   }
 
+#if _WIN32
   const UINT scan_code =
       MapVirtualKeyW(static_cast<UINT>(key_code), MAPVK_VK_TO_VSC_EX);
   if (scan_code == 0) {
+    LookupWindowsKeyMetadataFromVk(key_code, scan_code_out, extended_out);
     return;
   }
 
   *scan_code_out = static_cast<uint32_t>(scan_code & 0xFF);
   *extended_out = (scan_code & 0xFF00) != 0;
-}
+#else
+  LookupWindowsKeyMetadataFromVk(key_code, scan_code_out, extended_out);
 #endif
+}
 
 #if _WIN32
 constexpr uint32_t kSecureDesktopInputLogIntervalMs = 2000;
@@ -397,10 +439,10 @@ int Render::SendKeyCommand(int key_code, bool is_down, uint32_t scan_code,
     remote_action.k.flag = KeyFlag::key_up;
   }
 
-#if _WIN32
   if (scan_code == 0) {
     PopulateWindowsKeyMetadataFromVk(key_code, &scan_code, &extended);
   }
+#if _WIN32
   key_code = NormalizeWindowsModifierVk(key_code, scan_code, extended);
 #endif