Remove String stage 1.

33 files changed, 133 insertions, 148 deletions

diff --git a/include/cru/platform/Check.h b/include/cru/platform/Check.h
index b36b7fc1..6b002c0c 100644
--- a/include/cru/platform/Check.h
+++ b/include/cru/platform/Check.h
@@ -13,7 +13,7 @@ TTarget* CheckPlatform(IPlatformResource* resource,
   const auto result = dynamic_cast<TTarget*>(resource);
   if (result == nullptr) {
     throw PlatformNotMatchException(
-        resource->GetPlatformIdUtf8(), target_platform,
+        resource->GetPlatformId(), target_platform,
         "Try to convert resource to target platform failed.");
   }
   return result;
@@ -28,7 +28,7 @@ std::shared_ptr<TTarget> CheckPlatform(const std::shared_ptr<TSource>& resource,
   const auto result = std::dynamic_pointer_cast<TTarget>(resource);
   if (result == nullptr) {
     throw PlatformNotMatchException(
-        resource->GetPlatformIdUtf8(), target_platform,
+        resource->GetPlatformId(), target_platform,
         "Try to convert resource to target platform failed.");
   }
   return result;
diff --git a/include/cru/platform/Resource.h b/include/cru/platform/Resource.h
index a16a9dbd..35a401be 100644
--- a/include/cru/platform/Resource.h
+++ b/include/cru/platform/Resource.h
@@ -1,17 +1,13 @@
 #pragma once
 #include "Base.h"
 
-#include "cru/base/Base.h"
-#include "cru/base/String.h"
+#include <cru/base/Base.h>
+
+#include <string>
 
 namespace cru::platform {
 struct CRU_PLATFORM_API IPlatformResource : virtual Interface {
-  CRU_DEFAULT_CONSTRUCTOR_DESTRUCTOR(IPlatformResource)
-
-  virtual String GetPlatformId() const = 0;
-
-  virtual String GetDebugString() { return String(); }
-
-  virtual std::string GetPlatformIdUtf8() const;
+  virtual std::string GetPlatformId() const = 0;
+  virtual std::string GetDebugString() { return {}; }
 };
 }  // namespace cru::platform
diff --git a/include/cru/platform/graphics/Base.h b/include/cru/platform/graphics/Base.h
index a61eb2a7..c3381394 100644
--- a/include/cru/platform/graphics/Base.h
+++ b/include/cru/platform/graphics/Base.h
@@ -1,8 +1,8 @@
 #pragma once
-#include "../Color.h"
-#include "../GraphicsBase.h"
-#include "../Matrix.h"
-#include "../Resource.h"
+#include <cru/platform/Base.h>          // IWYU pragma: export
+#include <cru/platform/Color.h>         // IWYU pragma: export
+#include <cru/platform/GraphicsBase.h>  // IWYU pragma: export
+#include <cru/platform/Matrix.h>        // IWYU pragma: export
 
 #ifdef CRU_IS_DLL
 #ifdef CRU_PLATFORM_GRAPHICS_EXPORT_API
diff --git a/include/cru/platform/graphics/Factory.h b/include/cru/platform/graphics/Factory.h
index d197d821..fa9a3a95 100644
--- a/include/cru/platform/graphics/Factory.h
+++ b/include/cru/platform/graphics/Factory.h
@@ -1,10 +1,9 @@
 #pragma once
-#include "Resource.h"
+#include "Base.h"
 
 #include "Brush.h"
 #include "Font.h"
 #include "Geometry.h"
-#include "Image.h"
 #include "ImageFactory.h"
 #include "TextLayout.h"
 
@@ -15,11 +14,11 @@ struct CRU_PLATFORM_GRAPHICS_API IGraphicsFactory : virtual IPlatformResource {
 
   virtual std::unique_ptr<IGeometryBuilder> CreateGeometryBuilder() = 0;
 
-  virtual std::unique_ptr<IFont> CreateFont(String font_family,
+  virtual std::unique_ptr<IFont> CreateFont(std::string font_family,
                                             float font_size) = 0;
 
   virtual std::unique_ptr<ITextLayout> CreateTextLayout(
-      std::shared_ptr<IFont> font, String text) = 0;
+      std::shared_ptr<IFont> font, std::string text) = 0;
 
   std::unique_ptr<ISolidColorBrush> CreateSolidColorBrush(const Color& color) {
     std::unique_ptr<ISolidColorBrush> brush = CreateSolidColorBrush();
diff --git a/include/cru/platform/graphics/Font.h b/include/cru/platform/graphics/Font.h
index 7144fdc2..de24222c 100644
--- a/include/cru/platform/graphics/Font.h
+++ b/include/cru/platform/graphics/Font.h
@@ -1,9 +1,11 @@
 #pragma once
 #include "Resource.h"
 
+#include <string>
+
 namespace cru::platform::graphics {
 struct CRU_PLATFORM_GRAPHICS_API IFont : virtual IGraphicsResource {
-  virtual String GetFontName() = 0;
+  virtual std::string GetFontName() = 0;
   virtual float GetFontSize() = 0;
 };
 }  // namespace cru::platform::graphics
diff --git a/include/cru/platform/graphics/Geometry.h b/include/cru/platform/graphics/Geometry.h
index b4b05194..2b251495 100644
--- a/include/cru/platform/graphics/Geometry.h
+++ b/include/cru/platform/graphics/Geometry.h
@@ -95,9 +95,10 @@ struct CRU_PLATFORM_GRAPHICS_API IGeometryBuilder : virtual IGraphicsResource {
 
   virtual std::unique_ptr<IGeometry> Build() = 0;
 
-  virtual void ParseAndApplySvgPathData(StringView path_d);
+  virtual void ParseAndApplySvgPathData(std::string_view path_d);
 };
 
 std::unique_ptr<IGeometry> CRU_PLATFORM_GRAPHICS_API
-CreateGeometryFromSvgPathData(IGraphicsFactory* factory, StringView path_d);
+CreateGeometryFromSvgPathData(IGraphicsFactory* factory,
+                              std::string_view path_d);
 }  // namespace cru::platform::graphics
diff --git a/include/cru/platform/graphics/NullPainter.h b/include/cru/platform/graphics/NullPainter.h
index 27cb6393..74d71c16 100644
--- a/include/cru/platform/graphics/NullPainter.h
+++ b/include/cru/platform/graphics/NullPainter.h
@@ -14,9 +14,9 @@ class CRU_PLATFORM_GRAPHICS_API NullPainter : public Object,
   ~NullPainter() override = default;
 
  public:
-  String GetPlatformId() const override { return u"NULL"; }
+  std::string GetPlatformId() const override { return "NULL"; }
 
-  String GetDebugString() override { return u"NullPainter"; }
+  std::string GetDebugString() override { return "NullPainter"; }
 
   Matrix GetTransform() override { return Matrix(); }
   void SetTransform(const Matrix& matrix) override { CRU_UNUSED(matrix) }
diff --git a/include/cru/platform/graphics/Resource.h b/include/cru/platform/graphics/Resource.h
index ab1b8de6..f910ca8a 100644
--- a/include/cru/platform/graphics/Resource.h
+++ b/include/cru/platform/graphics/Resource.h
@@ -1,6 +1,8 @@
 #pragma once
 #include "Base.h"
 
+#include <cru/platform/Resource.h>
+
 namespace cru::platform::graphics {
 struct IGraphicsFactory;
 
diff --git a/include/cru/platform/graphics/SvgGeometryBuilderMixin.h b/include/cru/platform/graphics/SvgGeometryBuilderMixin.h
index 32b665a5..586872b0 100644
--- a/include/cru/platform/graphics/SvgGeometryBuilderMixin.h
+++ b/include/cru/platform/graphics/SvgGeometryBuilderMixin.h
@@ -45,25 +45,24 @@ class CRU_PLATFORM_GRAPHICS_API SvgGeometryBuilderMixin
 
   void CloseFigure(bool close) override;
 
-  void ParseAndApplySvgPathData(StringView path_d) override;
+  void ParseAndApplySvgPathData(std::string_view path_d) override;
 
  protected:
-  String GetPathData() const { return current_; }
+  std::string GetPathData() const { return current_; }
 
  private:
   template <typename... Args>
-  void Append(StringView format, Args&&... args) {
-    current_ += String::FromUtf8(
-        std::format(format.ToUtf8(), std::forward<Args>(args)...));
-    current_ += u' ';
+  void Append(std::string_view format, Args&&... args) {
+    current_ += std::format(format, std::forward<Args>(args)...);
+    current_ += ' ';
   }
 
-  void AppendCommand(StringView command);
+  void AppendCommand(std::string_view command);
   void Append(bool flag);
   void Append(float number);
   void Append(const Point& point);
 
  private:
-  String current_;
+  std::string current_;
 };
 }  // namespace cru::platform::graphics
diff --git a/include/cru/platform/graphics/TextLayout.h b/include/cru/platform/graphics/TextLayout.h
index e060186b..4c5302eb 100644
--- a/include/cru/platform/graphics/TextLayout.h
+++ b/include/cru/platform/graphics/TextLayout.h
@@ -8,8 +8,8 @@ namespace cru::platform::graphics {
 // Requirement:
 // All text must be left-top aligned.
 struct CRU_PLATFORM_GRAPHICS_API ITextLayout : virtual IGraphicsResource {
-  virtual String GetText() = 0;
-  virtual void SetText(String new_text) = 0;
+  virtual std::string GetText() = 0;
+  virtual void SetText(std::string new_text) = 0;
 
   virtual std::shared_ptr<IFont> GetFont() = 0;
   virtual void SetFont(std::shared_ptr<IFont> font) = 0;
diff --git a/include/cru/platform/graphics/cairo/CairoGraphicsFactory.h b/include/cru/platform/graphics/cairo/CairoGraphicsFactory.h
index f0f7ecc5..563c6b40 100644
--- a/include/cru/platform/graphics/cairo/CairoGraphicsFactory.h
+++ b/include/cru/platform/graphics/cairo/CairoGraphicsFactory.h
@@ -26,11 +26,11 @@ class CRU_PLATFORM_GRAPHICS_CAIRO_API CairoGraphicsFactory
 
   std::unique_ptr<IGeometryBuilder> CreateGeometryBuilder() override;
 
-  std::unique_ptr<IFont> CreateFont(String font_family,
+  std::unique_ptr<IFont> CreateFont(std::string font_family,
                                     float font_size) override;
 
   std::unique_ptr<ITextLayout> CreateTextLayout(std::shared_ptr<IFont> font,
-                                                String text) override;
+                                                std::string text) override;
 
   IImageFactory* GetImageFactory() override;
 
diff --git a/include/cru/platform/graphics/cairo/CairoResource.h b/include/cru/platform/graphics/cairo/CairoResource.h
index bf35ab26..14730e8a 100644
--- a/include/cru/platform/graphics/cairo/CairoResource.h
+++ b/include/cru/platform/graphics/cairo/CairoResource.h
@@ -17,7 +17,7 @@ class CRU_PLATFORM_GRAPHICS_CAIRO_API CairoResource
 
   ~CairoResource() override;
 
-  String GetPlatformId() const override;
+  std::string GetPlatformId() const override;
   IGraphicsFactory* GetGraphicsFactory() override;
   CairoGraphicsFactory* GetCairoGraphicsFactory() const { return factory_; }
 
diff --git a/include/cru/platform/graphics/cairo/PangoFont.h b/include/cru/platform/graphics/cairo/PangoFont.h
index 3014739d..e8dbf3ec 100644
--- a/include/cru/platform/graphics/cairo/PangoFont.h
+++ b/include/cru/platform/graphics/cairo/PangoFont.h
@@ -9,12 +9,12 @@ namespace cru::platform::graphics::cairo {
 class CRU_PLATFORM_GRAPHICS_CAIRO_API PangoFont : public CairoResource,
                                                   public virtual IFont {
  public:
-  PangoFont(CairoGraphicsFactory* factory, String font_family, float font_size);
+  PangoFont(CairoGraphicsFactory* factory, std::string font_family, float font_size);
 
   ~PangoFont() override;
 
  public:
-  String GetFontName() override;
+  std::string GetFontName() override;
   float GetFontSize() override;
 
   PangoFontDescription* GetPangoFontDescription() {
@@ -22,7 +22,7 @@ class CRU_PLATFORM_GRAPHICS_CAIRO_API PangoFont : public CairoResource,
   }
 
  private:
-  String font_family_;
+  std::string font_family_;
   float font_size_;
   PangoFontDescription* pango_font_description_;
 };
diff --git a/include/cru/platform/graphics/cairo/PangoTextLayout.h b/include/cru/platform/graphics/cairo/PangoTextLayout.h
index cdc54e8d..270022ee 100644
--- a/include/cru/platform/graphics/cairo/PangoTextLayout.h
+++ b/include/cru/platform/graphics/cairo/PangoTextLayout.h
@@ -15,8 +15,8 @@ class CRU_PLATFORM_GRAPHICS_CAIRO_API PangoTextLayout
   ~PangoTextLayout() override;
 
  public:
-  String GetText() override;
-  void SetText(String new_text) override;
+  std::string GetText() override;
+  void SetText(std::string new_text) override;
 
   std::shared_ptr<IFont> GetFont() override;
   void SetFont(std::shared_ptr<IFont> font) override;
@@ -40,12 +40,7 @@ class CRU_PLATFORM_GRAPHICS_CAIRO_API PangoTextLayout
   PangoLayout* GetPangoLayout() { return pango_layout_; }
 
  private:
-  Index FromUtf8IndexToUtf16Index(Index index);
-  Index FromUtf16IndexToUtf8Index(Index index);
-
- private:
-  String text_;
-  std::string utf8_text_;
+  std::string text_;
 
   bool edit_mode_ = false;
 
diff --git a/include/cru/platform/gui/Base.h b/include/cru/platform/gui/Base.h
index affce4cd..f8ffbc51 100644
--- a/include/cru/platform/gui/Base.h
+++ b/include/cru/platform/gui/Base.h
@@ -1,9 +1,6 @@
 #pragma once
-#include "cru/base/Base.h"
-#include "cru/base/Bitmask.h"
-#include "cru/platform/graphics/Base.h"
-
-#include "../Resource.h"
+#include <cru/platform/Base.h>      // IWYU pragma: export
+#include <cru/platform/Resource.h>  // IWYU pragma: export
 
 #ifdef CRU_IS_DLL
 #ifdef CRU_PLATFORM_GUI_EXPORT_API
@@ -14,30 +11,3 @@
 #else
 #define CRU_PLATFORM_GUI_API
 #endif
-
-namespace cru::platform::gui {
-struct ICursor;
-struct ICursorManager;
-struct IUiApplication;
-struct INativeWindow;
-struct IInputMethodContext;
-struct IClipboard;
-
-namespace details {
-struct TagMouseButton {};
-}  // namespace details
-
-using MouseButton = Bitmask<details::TagMouseButton>;
-struct MouseButtons {
-  constexpr static MouseButton None = MouseButton::FromOffset(0);
-  constexpr static MouseButton Left = MouseButton::FromOffset(1);
-  constexpr static MouseButton Middle = MouseButton::FromOffset(2);
-  constexpr static MouseButton Right = MouseButton::FromOffset(3);
-};
-
-namespace mouse_buttons {
-constexpr MouseButton left{MouseButtons::Left};
-constexpr MouseButton middle{MouseButtons::Middle};
-constexpr MouseButton right{MouseButtons::Right};
-}  // namespace mouse_buttons
-}  // namespace cru::platform::gui
diff --git a/include/cru/platform/gui/Clipboard.h b/include/cru/platform/gui/Clipboard.h
index 47267895..63932683 100644
--- a/include/cru/platform/gui/Clipboard.h
+++ b/include/cru/platform/gui/Clipboard.h
@@ -3,7 +3,7 @@
 
 namespace cru::platform::gui {
 struct IClipboard : virtual IPlatformResource {
-  virtual String GetText() = 0;
-  virtual void SetText(String text) = 0;
+  virtual std::string GetText() = 0;
+  virtual void SetText(std::string text) = 0;
 };
 }  // namespace cru::platform::gui
diff --git a/include/cru/platform/gui/Keyboard.h b/include/cru/platform/gui/Input.h
index 97665e41..dca064d4 100644
--- a/include/cru/platform/gui/Keyboard.h
+++ b/include/cru/platform/gui/Input.h
@@ -1,8 +1,23 @@
 #pragma once
-#include "cru/base/Bitmask.h"
-#include "cru/platform/gui/Base.h"
+#include "Base.h"
+
+#include <cru/base/Bitmask.h>
+
+#include <string>
 
 namespace cru::platform::gui {
+namespace details {
+struct TagMouseButton {};
+}  // namespace details
+
+using MouseButton = Bitmask<details::TagMouseButton>;
+struct MouseButtons {
+  constexpr static MouseButton None = MouseButton::FromOffset(0);
+  constexpr static MouseButton Left = MouseButton::FromOffset(1);
+  constexpr static MouseButton Middle = MouseButton::FromOffset(2);
+  constexpr static MouseButton Right = MouseButton::FromOffset(3);
+};
+
 // Because of the complexity of keyboard layout, I only add code in US keyboard
 // layout, the most widely used layout in China. We should try to make it easy
 // to add new keyboard layout.
@@ -123,20 +138,15 @@ struct KeyModifiers {
   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
-constexpr KeyModifier kKeyModifierCommand = KeyModifiers::command;
+constexpr KeyModifier kKeyModifierCommand = KeyModifiers::Command;
 #else
-constexpr KeyModifier kKeyModifierCommand = KeyModifiers::ctrl;
+constexpr KeyModifier kKeyModifierCommand = KeyModifiers::Ctrl;
 #endif
 
-CRU_PLATFORM_GUI_API String ToString(KeyCode key_code);
-CRU_PLATFORM_GUI_API String ToString(KeyModifier key_modifier,
-                                     StringView separator = u"+");
+CRU_PLATFORM_GUI_API std::string ToString(KeyCode key_code);
+CRU_PLATFORM_GUI_API std::string ToString(KeyModifier key_modifier,
+                                          std::string_view separator = "+");
 }  // namespace cru::platform::gui
diff --git a/include/cru/platform/gui/InputMethod.h b/include/cru/platform/gui/InputMethod.h
index b4a1e9d9..d178cb8a 100644
--- a/include/cru/platform/gui/InputMethod.h
+++ b/include/cru/platform/gui/InputMethod.h
@@ -1,9 +1,9 @@
 #pragma once
 #include "Base.h"
 
-#include "cru/base/Event.h"
+#include <cru/base/Event.h>
+#include <cru/platform/GraphicsBase.h>
 
-#include <memory>
 #include <vector>
 
 namespace cru::platform::gui {
@@ -16,7 +16,7 @@ struct CompositionClause {
 using CompositionClauses = std::vector<CompositionClause>;
 
 struct CompositionText {
-  String text;
+  std::string text;
   CompositionClauses clauses;
   TextRange selection;
 };
@@ -61,6 +61,6 @@ struct IInputMethodContext : virtual IPlatformResource {
   virtual IEvent<std::nullptr_t>* CompositionStartEvent() = 0;
   virtual IEvent<std::nullptr_t>* CompositionEndEvent() = 0;
   virtual IEvent<std::nullptr_t>* CompositionEvent() = 0;
-  virtual IEvent<StringView>* TextEvent() = 0;
+  virtual IEvent<std::string>* TextEvent() = 0;
 };
 }  // namespace cru::platform::gui
diff --git a/include/cru/platform/gui/Menu.h b/include/cru/platform/gui/Menu.h
index 6e2a8902..d076ca69 100644
--- a/include/cru/platform/gui/Menu.h
+++ b/include/cru/platform/gui/Menu.h
@@ -1,7 +1,6 @@
 #pragma once
 #include "Base.h"
-
-#include "Keyboard.h"
+#include "Input.h"
 
 #include <functional>
 
@@ -9,8 +8,8 @@ namespace cru::platform::gui {
 struct IMenu;
 
 struct CRU_PLATFORM_GUI_API IMenuItem : virtual IPlatformResource {
-  virtual String GetTitle() = 0;
-  virtual void SetTitle(String title) = 0;
+  virtual std::string GetTitle() = 0;
+  virtual void SetTitle(std::string title) = 0;
   virtual bool IsEnabled() = 0;
   virtual void SetEnabled(bool enabled) = 0;
   virtual IMenu* GetParentMenu() = 0;
diff --git a/include/cru/platform/gui/SaveOpenDialogOptions.h b/include/cru/platform/gui/SaveOpenDialogOptions.h
index cff4a44f..484a1552 100644
--- a/include/cru/platform/gui/SaveOpenDialogOptions.h
+++ b/include/cru/platform/gui/SaveOpenDialogOptions.h
@@ -1,12 +1,15 @@
 #pragma once
 #include "Base.h"
 
+#include <string>
+#include <vector>
+
 namespace cru::platform::gui {
 struct CRU_PLATFORM_GUI_API SaveDialogOptions {
-  String title;
-  String prompt;
-  String message;
-  std::vector<String> allowed_file_types;
+  std::string title;
+  std::string prompt;
+  std::string message;
+  std::vector<std::string> allowed_file_types;
   bool allow_all_file_types = false;
 };
 
@@ -20,29 +23,29 @@ template <typename T>
 struct CRU_PLATFORM_GUI_API SaveDialogOptionsBuilderTemplate {
   T options;
 
-  SaveDialogOptionsBuilderTemplate& SetTitle(String title) {
+  SaveDialogOptionsBuilderTemplate& SetTitle(std::string title) {
     options.title = std::move(title);
     return *this;
   }
 
-  SaveDialogOptionsBuilderTemplate& SetPrompt(String prompt) {
+  SaveDialogOptionsBuilderTemplate& SetPrompt(std::string prompt) {
     options.prompt = std::move(prompt);
     return *this;
   }
 
-  SaveDialogOptionsBuilderTemplate& SetMessage(String message) {
+  SaveDialogOptionsBuilderTemplate& SetMessage(std::string message) {
     options.message = std::move(message);
     return *this;
   }
 
   SaveDialogOptionsBuilderTemplate& SetAllowedFileTypes(
-      std::vector<String> allowed_file_types) {
+      std::vector<std::string> allowed_file_types) {
     options.allowed_file_types = std::move(allowed_file_types);
     return *this;
   }
 
   SaveDialogOptionsBuilderTemplate& AddAllowedFileType(
-      String allowed_file_type) {
+      std::string allowed_file_type) {
     options.allowed_file_types.push_back(allowed_file_type);
     return *this;
   }
diff --git a/include/cru/platform/gui/UiApplication.h b/include/cru/platform/gui/UiApplication.h
index b44a450f..d15a3c72 100644
--- a/include/cru/platform/gui/UiApplication.h
+++ b/include/cru/platform/gui/UiApplication.h
@@ -1,17 +1,20 @@
 #pragma once
 #include "Base.h"
-
-#include "cru/base/Bitmask.h"
-#include "cru/platform/gui/Menu.h"
-
+#include "Menu.h"
 #include "SaveOpenDialogOptions.h"
 
+#include <cru/platform/graphics/Factory.h>
+
 #include <chrono>
 #include <functional>
-#include <memory>
 #include <vector>
 
 namespace cru::platform::gui {
+struct ICursorManager;
+struct INativeWindow;
+struct IInputMethodContext;
+struct IClipboard;
+
 // The entry point of a ui application.
 struct CRU_PLATFORM_GUI_API IUiApplication : public virtual IPlatformResource {
  public:
@@ -63,12 +66,12 @@ struct CRU_PLATFORM_GUI_API IUiApplication : public virtual IPlatformResource {
   /**
    * \todo Implement on Windows/X11.
    */
-  virtual std::optional<String> ShowSaveDialog(SaveDialogOptions options);
+  virtual std::optional<std::string> ShowSaveDialog(SaveDialogOptions options);
 
   /**
    * \todo Implement on Windows/X11.
    */
-  virtual std::optional<std::vector<String>> ShowOpenDialog(
+  virtual std::optional<std::vector<std::string>> ShowOpenDialog(
       OpenDialogOptions options);
 };
 }  // namespace cru::platform::gui
diff --git a/include/cru/platform/gui/Window.h b/include/cru/platform/gui/Window.h
index 06fbdb65..3be5b21b 100644
--- a/include/cru/platform/gui/Window.h
+++ b/include/cru/platform/gui/Window.h
@@ -1,11 +1,16 @@
 #pragma once
 #include "Base.h"
 
-#include "Keyboard.h"
+#include "Input.h"
 
-#include "cru/base/Event.h"
+#include <cru/base/Event.h>
+#include <cru/platform/GraphicsBase.h>
+#include <cru/platform/graphics/Painter.h>
 
 namespace cru::platform::gui {
+class ICursor;
+class IInputMethodContext;
+
 namespace details {
 struct WindowStyleFlagTag;
 }
@@ -53,8 +58,8 @@ struct CRU_PLATFORM_GUI_API INativeWindow : virtual IPlatformResource {
   virtual WindowStyleFlag GetStyleFlag() = 0;
   virtual void SetStyleFlag(WindowStyleFlag flag) = 0;
 
-  virtual String GetTitle() = 0;
-  virtual void SetTitle(String title) = 0;
+  virtual std::string GetTitle() = 0;
+  virtual void SetTitle(std::string title) = 0;
 
   virtual WindowVisibilityType GetVisibility() = 0;
   virtual void SetVisibility(WindowVisibilityType visibility) = 0;
diff --git a/include/cru/platform/gui/osx/Keyboard.h b/include/cru/platform/gui/osx/Keyboard.h
index 89e0fa05..619fdd1f 100644
--- a/include/cru/platform/gui/osx/Keyboard.h
+++ b/include/cru/platform/gui/osx/Keyboard.h
@@ -1,5 +1,5 @@
 #pragma once
-#include "cru/platform/gui/Keyboard.h"
+#include <cru/platform/gui/Input.h>
 
 namespace cru::platform::gui::osx {
 KeyCode KeyCodeFromOsxToCru(unsigned short n);
diff --git a/include/cru/platform/gui/sdl/Base.h b/include/cru/platform/gui/sdl/Base.h
index 9dd2eff6..0de2fd1f 100644
--- a/include/cru/platform/gui/sdl/Base.h
+++ b/include/cru/platform/gui/sdl/Base.h
@@ -8,13 +8,13 @@
 namespace cru::platform::gui::sdl {
 class SdlResource : public Object, public virtual IPlatformResource {
  public:
-  static constexpr const char16_t* kPlatformId = u"SDL";
+  static constexpr const char* kPlatformId = "SDL";
 
  protected:
   SdlResource() = default;
 
  public:
-  String GetPlatformId() const final { return String(kPlatformId); }
+  std::string GetPlatformId() const final { return kPlatformId; }
 };
 
 class SdlException : public PlatformException {
diff --git a/include/cru/platform/gui/sdl/Window.h b/include/cru/platform/gui/sdl/Window.h
index 1bcd42bf..4eb0a11d 100644
--- a/include/cru/platform/gui/sdl/Window.h
+++ b/include/cru/platform/gui/sdl/Window.h
@@ -29,8 +29,8 @@ class SdlWindow : public SdlResource, public virtual INativeWindow {
   WindowStyleFlag GetStyleFlag() override;
   void SetStyleFlag(WindowStyleFlag flag) override;
 
-  String GetTitle() override;
-  void SetTitle(String title) override;
+  std::string GetTitle() override;
+  void SetTitle(std::string title) override;
 
   WindowVisibilityType GetVisibility() override;
   void SetVisibility(WindowVisibilityType visibility) override;
diff --git a/include/cru/platform/gui/win/Keyboard.h b/include/cru/platform/gui/win/Keyboard.h
index 18b37b60..c98c49a3 100644
--- a/include/cru/platform/gui/win/Keyboard.h
+++ b/include/cru/platform/gui/win/Keyboard.h
@@ -1,7 +1,7 @@
 #pragma once
 #include "Base.h"
 
-#include "cru/platform/gui/Keyboard.h"
+#include <cru/platform/gui/Input.h>
 
 namespace cru::platform::gui::win {
 KeyCode CRU_WIN_GUI_API VirtualKeyToKeyCode(int virtual_key);
diff --git a/include/cru/platform/gui/xcb/Base.h b/include/cru/platform/gui/xcb/Base.h
index ad571a40..71007f87 100644
--- a/include/cru/platform/gui/xcb/Base.h
+++ b/include/cru/platform/gui/xcb/Base.h
@@ -1,19 +1,19 @@
 #pragma once
 
 #include <cru/base/Exception.h>
-
-#include "../../Resource.h"
+#include <cru/platform/Resource.h>
+#include <cru/platform/gui/Base.h>
 
 namespace cru::platform::gui::xcb {
 class XcbResource : public Object, public virtual IPlatformResource {
  public:
-  static constexpr const char16_t* kPlatformId = u"XCB";
+  static constexpr const char* kPlatformId = "XCB";
 
  protected:
   XcbResource() = default;
 
  public:
-  String GetPlatformId() const final { return String(kPlatformId); }
+  std::string GetPlatformId() const final { return std::string(kPlatformId); }
 };
 
 class XcbException : public PlatformException {
diff --git a/include/cru/platform/gui/xcb/Clipboard.h b/include/cru/platform/gui/xcb/Clipboard.h
index 44294cbc..690cd2b1 100644
--- a/include/cru/platform/gui/xcb/Clipboard.h
+++ b/include/cru/platform/gui/xcb/Clipboard.h
@@ -10,8 +10,8 @@ class XcbClipboard : public XcbResource, public virtual IClipboard {
   explicit XcbClipboard(XcbUiApplication* application);
   ~XcbClipboard() override;
 
-  String GetText() override;
-  void SetText(String text) override;
+  std::string GetText() override;
+  void SetText(std::string text) override;
 
  private:
   XcbUiApplication* application_;
diff --git a/include/cru/platform/gui/xcb/Cursor.h b/include/cru/platform/gui/xcb/Cursor.h
index 02ede7dd..03399333 100644
--- a/include/cru/platform/gui/xcb/Cursor.h
+++ b/include/cru/platform/gui/xcb/Cursor.h
@@ -1,9 +1,10 @@
 #pragma once
 
-#include <cru/base/io/Stream.h>
-#include "../Cursor.h"
 #include "Base.h"
 
+#include <cru/base/io/Stream.h>
+#include <cru/platform/gui/Cursor.h>
+
 #include <xcb/xcb.h>
 #include <xcb/xcb_cursor.h>
 #include <memory>
diff --git a/include/cru/platform/gui/xcb/Keyboard.h b/include/cru/platform/gui/xcb/Input.h
index adff95c1..77e213de 100644
--- a/include/cru/platform/gui/xcb/Keyboard.h
+++ b/include/cru/platform/gui/xcb/Input.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <cru/platform/gui/Keyboard.h>
+#include <cru/platform/gui/Input.h>
 
 #include <xcb/xcb.h>
 #include <xkbcommon/xkbcommon.h>
diff --git a/include/cru/platform/gui/xcb/InputMethod.h b/include/cru/platform/gui/xcb/InputMethod.h
index c5ffd416..e32ed63e 100644
--- a/include/cru/platform/gui/xcb/InputMethod.h
+++ b/include/cru/platform/gui/xcb/InputMethod.h
@@ -1,9 +1,10 @@
 #pragma once
 
-#include <cru/base/Base.h>
-#include "../InputMethod.h"
 #include "Base.h"
 
+#include <cru/base/Base.h>
+#include <cru/platform/gui/InputMethod.h>
+
 #include <xcb-imdkit/imclient.h>
 #include <xcb/xcb.h>
 #include <optional>
@@ -66,7 +67,7 @@ class XcbXimInputMethodContext : public XcbResource,
   IEvent<std::nullptr_t>* CompositionStartEvent() override;
   IEvent<std::nullptr_t>* CompositionEndEvent() override;
   IEvent<std::nullptr_t>* CompositionEvent() override;
-  IEvent<StringView>* TextEvent() override;
+  IEvent<std::string>* TextEvent() override;
 
  private:
   void CreateIc(xcb_window_t window);
@@ -83,6 +84,6 @@ class XcbXimInputMethodContext : public XcbResource,
   Event<std::nullptr_t> composition_start_event_;
   Event<std::nullptr_t> composition_end_event_;
   Event<std::nullptr_t> composition_event_;
-  Event<StringView> text_event_;
+  Event<std::string> 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 ab481c79..55138fd3 100644
--- a/include/cru/platform/gui/xcb/UiApplication.h
+++ b/include/cru/platform/gui/xcb/UiApplication.h
@@ -1,9 +1,9 @@
 #pragma once
-#include "../UiApplication.h"
 #include "Base.h"
 
 #include <cru/base/platform/unix/EventLoop.h>
 #include <cru/platform/graphics/cairo/CairoGraphicsFactory.h>
+#include <cru/platform/gui/UiApplication.h>
 
 #include <xcb/xcb.h>
 #include <functional>
diff --git a/include/cru/platform/gui/xcb/Window.h b/include/cru/platform/gui/xcb/Window.h
index 5f1fd66e..bfd86297 100644
--- a/include/cru/platform/gui/xcb/Window.h
+++ b/include/cru/platform/gui/xcb/Window.h
@@ -1,11 +1,10 @@
 
 #pragma once
-#include <cru/base/Base.h>
-#include "../../GraphicsBase.h"
-#include "../TimerHelper.h"
-#include "../Window.h"
 #include "Base.h"
 
+#include <cru/platform/gui/TimerHelper.h>
+#include <cru/platform/gui/Window.h>
+
 #include <cairo.h>
 #include <xcb/xcb.h>
 #include <cstddef>
@@ -34,8 +33,8 @@ class XcbWindow : public XcbResource, public virtual INativeWindow {
   WindowStyleFlag GetStyleFlag() override;
   void SetStyleFlag(WindowStyleFlag flag) override;
 
-  String GetTitle() override;
-  void SetTitle(String title) override;
+  std::string GetTitle() override;
+  void SetTitle(std::string title) override;
 
   WindowVisibilityType GetVisibility() override;
   void SetVisibility(WindowVisibilityType visibility) override;