4 files changed, 88 insertions, 4 deletions
diff --git a/src/win/native/CMakeLists.txt b/src/win/native/CMakeLists.txt
index 82994d67..521b32cf 100644
--- a/src/win/native/CMakeLists.txt
+++ b/src/win/native/CMakeLists.txt
@@ -9,6 +9,7 @@ add_library(cru_win_native STATIC
 
 	cursor.cpp
 	god_window.cpp
+	input_method.cpp
 	keyboard.cpp
 	timer.cpp
 	ui_application.cpp
@@ -22,6 +23,7 @@ target_sources(cru_win_native PUBLIC
 	${CRU_WIN_NATIVE_INCLUDE_DIR}/cursor.hpp
 	${CRU_WIN_NATIVE_INCLUDE_DIR}/exception.hpp
 	${CRU_WIN_NATIVE_INCLUDE_DIR}/god_window.hpp
+	${CRU_WIN_NATIVE_INCLUDE_DIR}/input_method.hpp
 	${CRU_WIN_NATIVE_INCLUDE_DIR}/keyboard.hpp
 	${CRU_WIN_NATIVE_INCLUDE_DIR}/resource.hpp
 	${CRU_WIN_NATIVE_INCLUDE_DIR}/ui_application.hpp
diff --git a/src/win/native/dpi_util.hpp b/src/win/native/dpi_util.hpp
index d8c5610c..07b89a95 100644
--- a/src/win/native/dpi_util.hpp
+++ b/src/win/native/dpi_util.hpp
@@ -32,4 +32,15 @@ inline float PixelToDipX(const int pixel_x) {
 inline float PixelToDipY(const int pixel_y) {
   return DipToPixelInternal(pixel_y, GetDpi().y);
 }
+
+inline Point PiToDip(const POINT& pi_point) {
+  return Point(PixelToDipX(pi_point.x), PixelToDipY(pi_point.y));
+}
+
+inline POINT DipToPi(const Point& dip_point) {
+  POINT result;
+  result.x = DipToPixelX(dip_point.x);
+  result.y = DipToPixelY(dip_point.y);
+  return result;
+}
 }  // namespace cru::platform::native::win
diff --git a/src/win/native/input_method.cpp b/src/win/native/input_method.cpp
new file mode 100644
index 00000000..4edfdc5f
--- /dev/null
+++ b/src/win/native/input_method.cpp
@@ -0,0 +1,75 @@
+#include "cru/win/native/input_method.hpp"
+
+#include "cru/common/logger.hpp"
+#include "cru/win/exception.hpp"
+#include "cru/win/native/window.hpp"
+#include "cru/win/string.hpp"
+#include "dpi_util.hpp"
+
+#include <vector>
+
+namespace cru::platform::native::win {
+WinInputMethodContextRef::WinInputMethodContextRef(WinNativeWindow* window)
+    : window_(window) {
+  Expects(window);
+
+  window_handle_ = window->GetWindowHandle();
+  handle_ = ::ImmGetContext(window_handle_);
+
+  // TODO: Events
+}
+
+WinInputMethodContextRef::~WinInputMethodContextRef() {
+  ::ImmReleaseContext(window_handle_, handle_);
+}
+
+void WinInputMethodContextRef::Reset() {
+  wchar_t s[1] = {L'\0'};
+
+  if (!::ImmSetCompositionStringW(handle_, SCS_SETSTR, static_cast<LPVOID>(s),
+                                  sizeof(s), static_cast<LPVOID>(s),
+                                  sizeof(s))) {
+    log::Warn(
+        "WinInputMethodContextRef: Failed to reset input method context.");
+  }
+}
+
+std::string WinInputMethodContextRef::GetCompositionString() {
+  const auto length =
+      ::ImmGetCompositionStringW(handle_, GCS_RESULTREADSTR, NULL, 0) +
+      sizeof(wchar_t);
+  std::vector<std::byte> data(length);
+  const auto result = ::ImmGetCompositionStringW(
+      handle_, GCS_RESULTREADSTR, static_cast<LPVOID>(data.data()), length);
+
+  if (result == IMM_ERROR_NODATA) {
+    return std::string{};
+  } else if (result == IMM_ERROR_GENERAL) {
+    throw new platform::win::Win32Error(::GetLastError(),
+                                        "Failed to get composition string.");
+  }
+
+  return platform::win::ToUtf8String(
+      std::wstring_view(reinterpret_cast<wchar_t*>(data.data())));
+}
+
+void WinInputMethodContextRef::SetCandidateWindowPosition(const Point& point) {
+  ::CANDIDATEFORM form;
+  form.dwIndex = 1;
+  form.dwStyle = CFS_CANDIDATEPOS;
+  form.ptCurrentPos = DipToPi(point);
+
+  if (!::ImmSetCandidateWindow(handle_, &form))
+    log::Debug(
+        "WinInputMethodContextRef: Failed to set input method candidate window "
+        "position.");
+}
+
+IEvent<std::string>* WinInputMethodContextRef::CompositionTextChangeEvent() {
+  return &composition_text_change_event_;
+}
+
+IEvent<std::string>* WinInputMethodContextRef::CharEvent() {
+  return &char_event_;
+}
+}  // namespace cru::platform::native::win
diff --git a/src/win/native/window.cpp b/src/win/native/window.cpp
index 1b590026..6f66cb57 100644
--- a/src/win/native/window.cpp
+++ b/src/win/native/window.cpp
@@ -17,10 +17,6 @@
 #include <windowsx.h>
 
 namespace cru::platform::native::win {
-inline Point PiToDip(const POINT& pi_point) {
-  return Point(PixelToDipX(pi_point.x), PixelToDipY(pi_point.y));
-}
-
 WinNativeWindow::WinNativeWindow(WinUiApplication* application,
                                  WindowClass* window_class, DWORD window_style,
                                  WinNativeWindow* parent)