diff --git a/src/main/paste.js b/src/main/paste.js
index 82f19cb..c684d11 100644
--- a/src/main/paste.js
+++ b/src/main/paste.js
@@ -1,5 +1,7 @@
 'use strict';
 
+const { loadWin32 } = require('./win32');
+
 const INPUT_KEYBOARD = 1;
 const KEYEVENTF_KEYUP = 0x0002;
 const VK_CONTROL = 0x11;
@@ -42,58 +44,6 @@ function writeSnapshot(clipboard, snap) {
   clipboard.write(payload);
 }
 
-let win32 = null;
-
-function loadWin32() {
-  if (win32) return win32;
-  if (process.platform !== 'win32') return null;
-  const koffi = require('koffi');
-  const user32 = koffi.load('user32.dll');
-  const kernel32 = koffi.load('kernel32.dll');
-
-  const KEYBDINPUT = koffi.struct('KEYBDINPUT', {
-    wVk: 'uint16_t',
-    wScan: 'uint16_t',
-    dwFlags: 'uint32_t',
-    time: 'uint32_t',
-    dwExtraInfo: 'uintptr_t',
-  });
-  const MOUSEINPUT = koffi.struct('MOUSEINPUT', {
-    dx: 'long',
-    dy: 'long',
-    mouseData: 'uint32_t',
-    dwFlags: 'uint32_t',
-    time: 'uint32_t',
-    dwExtraInfo: 'uintptr_t',
-  });
-  const HARDWAREINPUT = koffi.struct('HARDWAREINPUT', {
-    uMsg: 'uint32_t',
-    wParamL: 'uint16_t',
-    wParamH: 'uint16_t',
-  });
-  const INPUT = koffi.struct('INPUT', {
-    type: 'uint32_t',
-    u: koffi.union({
-      mi: MOUSEINPUT,
-      ki: KEYBDINPUT,
-      hi: HARDWAREINPUT,
-    }),
-  });
-
-  win32 = {
-    koffi,
-    INPUT,
-    GetForegroundWindow: user32.func('void * __stdcall GetForegroundWindow()'),
-    SetForegroundWindow: user32.func('bool __stdcall SetForegroundWindow(void *hWnd)'),
-    AllowSetForegroundWindow: user32.func('bool __stdcall AllowSetForegroundWindow(uint32_t dwProcessId)'),
-    GetWindowThreadProcessId: user32.func('uint32_t __stdcall GetWindowThreadProcessId(void *hWnd, _Out_ uint32_t *lpdwProcessId)'),
-    AttachThreadInput: user32.func('bool __stdcall AttachThreadInput(uint32_t idAttach, uint32_t idAttachTo, bool fAttach)'),
-    GetCurrentThreadId: kernel32.func('uint32_t __stdcall GetCurrentThreadId()'),
-    SendInput: user32.func('unsigned int __stdcall SendInput(unsigned int cInputs, INPUT *pInputs, int cbSize)'),
-  };
-  return win32;
-}
-
 function captureForeground() {
   try {
     const api = loadWin32();
diff --git a/src/main/win32.js b/src/main/win32.js
new file mode 100644
index 0000000..d9e0347
--- /dev/null
+++ b/src/main/win32.js
@@ -0,0 +1,81 @@
+'use strict';
+
+let win32 = null;
+
+function loadWin32() {
+  if (win32) return win32;
+  if (process.platform !== 'win32') return null;
+  const koffi = require('koffi');
+  const user32 = koffi.load('user32.dll');
+  const kernel32 = koffi.load('kernel32.dll');
+
+  const KEYBDINPUT = koffi.struct('KEYBDINPUT', {
+    wVk: 'uint16_t',
+    wScan: 'uint16_t',
+    dwFlags: 'uint32_t',
+    time: 'uint32_t',
+    dwExtraInfo: 'uintptr_t',
+  });
+  const MOUSEINPUT = koffi.struct('MOUSEINPUT', {
+    dx: 'long',
+    dy: 'long',
+    mouseData: 'uint32_t',
+    dwFlags: 'uint32_t',
+    time: 'uint32_t',
+    dwExtraInfo: 'uintptr_t',
+  });
+  const HARDWAREINPUT = koffi.struct('HARDWAREINPUT', {
+    uMsg: 'uint32_t',
+    wParamL: 'uint16_t',
+    wParamH: 'uint16_t',
+  });
+  const INPUT = koffi.struct('INPUT', {
+    type: 'uint32_t',
+    u: koffi.union({
+      mi: MOUSEINPUT,
+      ki: KEYBDINPUT,
+      hi: HARDWAREINPUT,
+    }),
+  });
+
+  // 64 位默认对齐：两个 DWORD 之后 HWND 从偏移 8 开始，末尾 RECT，共 72 字节。
+  const RECT = koffi.struct('RECT', {
+    left: 'long',
+    top: 'long',
+    right: 'long',
+    bottom: 'long',
+  });
+  const POINT = koffi.struct('POINT', {
+    x: 'long',
+    y: 'long',
+  });
+  const GUITHREADINFO = koffi.struct('GUITHREADINFO', {
+    cbSize: 'uint32_t',
+    flags: 'uint32_t',
+    hwndActive: 'void *',
+    hwndFocus: 'void *',
+    hwndCapture: 'void *',
+    hwndMenuOwner: 'void *',
+    hwndMoveSize: 'void *',
+    hwndCaret: 'void *',
+    rcCaret: RECT,
+  });
+
+  win32 = {
+    koffi,
+    INPUT,
+    GUITHREADINFO,
+    GetForegroundWindow: user32.func('void * __stdcall GetForegroundWindow()'),
+    SetForegroundWindow: user32.func('bool __stdcall SetForegroundWindow(void *hWnd)'),
+    AllowSetForegroundWindow: user32.func('bool __stdcall AllowSetForegroundWindow(uint32_t dwProcessId)'),
+    GetWindowThreadProcessId: user32.func('uint32_t __stdcall GetWindowThreadProcessId(void *hWnd, _Out_ uint32_t *lpdwProcessId)'),
+    AttachThreadInput: user32.func('bool __stdcall AttachThreadInput(uint32_t idAttach, uint32_t idAttachTo, bool fAttach)'),
+    GetCurrentThreadId: kernel32.func('uint32_t __stdcall GetCurrentThreadId()'),
+    SendInput: user32.func('unsigned int __stdcall SendInput(unsigned int cInputs, INPUT *pInputs, int cbSize)'),
+    GetGUIThreadInfo: user32.func('bool __stdcall GetGUIThreadInfo(uint32_t idThread, _Inout_ GUITHREADINFO *pgui)'),
+    ClientToScreen: user32.func('bool __stdcall ClientToScreen(void *hWnd, _Inout_ POINT *lpPoint)'),
+  };
+  return win32;
+}
+
+module.exports = { loadWin32 };