6 files changed, 98 insertions, 11 deletions
diff --git a/include/cru/base/Bitmask.h b/include/cru/base/Bitmask.h
index 9b6b8957..7606f784 100644
--- a/include/cru/base/Bitmask.h
+++ b/include/cru/base/Bitmask.h
@@ -10,8 +10,10 @@ struct Bitmask final {
   constexpr Bitmask() : value(0) {}
   constexpr explicit Bitmask(TUnderlying value) : value(value) {}
 
+  // Start from 1.
   static constexpr Bitmask FromOffset(int offset) {
-    return Bitmask(static_cast<TUnderlying>(1u << offset));
+    if (offset == 0) return {};
+    return Bitmask(static_cast<TUnderlying>(1u << (offset - 1)));
   }
 
   constexpr bool Has(Bitmask rhs) const { return (value & rhs.value) != 0; }
diff --git a/include/cru/base/StringToNumberConverter.h b/include/cru/base/StringToNumberConverter.h
index 051f44d0..64c29971 100644
--- a/include/cru/base/StringToNumberConverter.h
+++ b/include/cru/base/StringToNumberConverter.h
@@ -14,15 +14,15 @@ using StringToNumberFlag = Bitmask<details::StringToNumberFlagTag>;
 
 struct StringToNumberFlags {
   constexpr static StringToNumberFlag kAllowLeadingSpaces =
-      StringToNumberFlag::FromOffset(0);
-  constexpr static StringToNumberFlag kAllowTrailingSpaces =
       StringToNumberFlag::FromOffset(1);
-  constexpr static StringToNumberFlag kAllowTrailingJunk =
+  constexpr static StringToNumberFlag kAllowTrailingSpaces =
       StringToNumberFlag::FromOffset(2);
-  constexpr static StringToNumberFlag kAllowLeadingZeroForInteger =
+  constexpr static StringToNumberFlag kAllowTrailingJunk =
       StringToNumberFlag::FromOffset(3);
-  constexpr static StringToNumberFlag kThrowOnError =
+  constexpr static StringToNumberFlag kAllowLeadingZeroForInteger =
       StringToNumberFlag::FromOffset(4);
+  constexpr static StringToNumberFlag kThrowOnError =
+      StringToNumberFlag::FromOffset(5);
 };
 
 template <typename TResult>
diff --git a/include/cru/platform/gui/Keyboard.h b/include/cru/platform/gui/Keyboard.h
index eb1cc76e..97665e41 100644
--- a/include/cru/platform/gui/Keyboard.h
+++ b/include/cru/platform/gui/Keyboard.h
@@ -118,16 +118,16 @@ struct TagKeyModifier {};
 using KeyModifier = Bitmask<details::TagKeyModifier>;
 
 struct KeyModifiers {
-  static constexpr KeyModifier none{0};
-  static constexpr KeyModifier shift{0b1};
-  static constexpr KeyModifier ctrl{0b10};
-  static constexpr KeyModifier alt{0b100};
-  static constexpr KeyModifier command{0b1000};
   static constexpr KeyModifier None = KeyModifier::FromOffset(0);
   static constexpr KeyModifier Shift = KeyModifier::FromOffset(1);
   static constexpr KeyModifier Ctrl = KeyModifier::FromOffset(2);
   static constexpr KeyModifier Alt = KeyModifier::FromOffset(3);
   static constexpr KeyModifier Command = KeyModifier::FromOffset(4);
+  static constexpr KeyModifier none = None;
+  static constexpr KeyModifier shift = Shift;
+  static constexpr KeyModifier ctrl = Ctrl;
+  static constexpr KeyModifier alt = Alt;
+  static constexpr KeyModifier command = Command;
 };
 
 #ifdef CRU_PLATFORM_OSX
diff --git a/include/cru/platform/gui/xcb/InputMethod.h b/include/cru/platform/gui/xcb/InputMethod.h
new file mode 100644
index 00000000..286f3158
--- /dev/null
+++ b/include/cru/platform/gui/xcb/InputMethod.h
@@ -0,0 +1,77 @@
+#pragma once
+
+#include "../InputMethod.h"
+#include "Base.h"
+
+#include <xcb-imdkit/imclient.h>
+#include <xcb/xcb.h>
+#include <optional>
+
+namespace cru::platform::gui::xcb {
+class XcbUiApplication;
+class XcbWindow;
+
+class XcbXimInputMethodManager : public XcbResource {
+  friend XcbUiApplication;
+
+ public:
+  XcbXimInputMethodManager(XcbUiApplication* application);
+  ~XcbXimInputMethodManager() override;
+
+  xcb_xim_t* GetXcbXim();
+
+ private:
+  void DispatchCommit(xcb_xim_t* im, xcb_xic_t ic, std::string text);
+  void DispatchComposition(xcb_xim_t* im, xcb_xic_t ic, CompositionText text);
+
+  bool HandleXEvent(xcb_generic_event_t* event);
+
+ private:
+  XcbUiApplication* application_;
+  xcb_xim_t* im_;
+};
+
+class XcbXimInputMethodContext : public XcbResource,
+                                 public virtual IInputMethodContext {
+  friend XcbXimInputMethodManager;
+
+ public:
+  XcbXimInputMethodContext(XcbXimInputMethodManager* manager,
+                           XcbWindow* window);
+  ~XcbXimInputMethodContext() override;
+
+  bool ShouldManuallyDrawCompositionText() override;
+
+  void EnableIME() override;
+  void DisableIME() override;
+
+  void CompleteComposition() override;
+  void CancelComposition() override;
+  CompositionText GetCompositionText() override;
+
+  // Set the candidate window left-top. Relative to window left-top. Use this
+  // method to prepare typing.
+  void SetCandidateWindowPosition(const Point& point) override;
+
+  IEvent<std::nullptr_t>* CompositionStartEvent() override;
+  IEvent<std::nullptr_t>* CompositionEndEvent() override;
+  IEvent<std::nullptr_t>* CompositionEvent() override;
+  IEvent<StringView>* TextEvent() override;
+
+ private:
+  void CreateIc(xcb_window_t window);
+  void DestroyIc();
+
+ private:
+  XcbXimInputMethodManager* manager_;
+  XcbWindow* window_;
+  bool enabled_;
+  std::optional<xcb_xic_t> ic_;
+  CompositionText composition_text_;
+
+  Event<std::nullptr_t> composition_start_event_;
+  Event<std::nullptr_t> composition_end_event_;
+  Event<std::nullptr_t> composition_event_;
+  Event<StringView> text_event_;
+};
+}  // namespace cru::platform::gui::xcb
diff --git a/include/cru/platform/gui/xcb/UiApplication.h b/include/cru/platform/gui/xcb/UiApplication.h
index b8de86f2..d6971099 100644
--- a/include/cru/platform/gui/xcb/UiApplication.h
+++ b/include/cru/platform/gui/xcb/UiApplication.h
@@ -13,6 +13,7 @@
 namespace cru::platform::gui::xcb {
 class XcbWindow;
 class XcbCursorManager;
+class XcbXimInputMethodManager;
 
 class XcbUiApplication : public XcbResource, public virtual IUiApplication {
   friend XcbWindow;
@@ -49,6 +50,8 @@ class XcbUiApplication : public XcbResource, public virtual IUiApplication {
 
 #undef CRU_XCB_UI_APPLICATION_DEFINE_XCB_ATOM
 
+  XcbXimInputMethodManager* GetXcbXimInputMethodManager();
+
  public:
   int Run() override;
 
@@ -100,5 +103,6 @@ class XcbUiApplication : public XcbResource, public virtual IUiApplication {
   std::vector<XcbWindow*> windows_;
 
   XcbCursorManager* cursor_manager_;
+  XcbXimInputMethodManager* input_method_manager_;
 };
 }  // namespace cru::platform::gui::xcb
diff --git a/include/cru/platform/gui/xcb/Window.h b/include/cru/platform/gui/xcb/Window.h
index 61e4b616..e330ba7c 100644
--- a/include/cru/platform/gui/xcb/Window.h
+++ b/include/cru/platform/gui/xcb/Window.h
@@ -12,6 +12,7 @@
 namespace cru::platform::gui::xcb {
 class XcbUiApplication;
 class XcbCursor;
+class XcbXimInputMethodContext;
 
 class XcbWindow : public XcbResource, public virtual INativeWindow {
   friend XcbUiApplication;
@@ -79,6 +80,8 @@ class XcbWindow : public XcbResource, public virtual INativeWindow {
 
  public:
   std::optional<xcb_window_t> GetXcbWindow();
+  XcbUiApplication* GetXcbUiApplication();
+  bool HasFocus();
 
  private:
   xcb_window_t DoCreateWindow();
@@ -112,6 +115,7 @@ class XcbWindow : public XcbResource, public virtual INativeWindow {
   std::shared_ptr<XcbCursor> cursor_;
 
   XcbWindow* parent_;
+  XcbXimInputMethodContext* input_method_;
 
   Event<std::nullptr_t> create_event_;
   Event<std::nullptr_t> destroy_event_;