Remove String stage 1.

33 files changed, 271 insertions, 309 deletions

diff --git a/src/platform/CMakeLists.txt b/src/platform/CMakeLists.txt
index a917f81f..9122e499 100644
--- a/src/platform/CMakeLists.txt
+++ b/src/platform/CMakeLists.txt
@@ -2,7 +2,6 @@ add_library(CruPlatformBase
 	Color.cpp
 	Exception.cpp
 	GraphicsBase.cpp
-	Resource.cpp
 )
 target_link_libraries(CruPlatformBase PUBLIC CruBase)
 target_compile_definitions(CruPlatformBase PRIVATE CRU_PLATFORM_EXPORT_API)
diff --git a/src/platform/Resource.cpp b/src/platform/Resource.cpp
deleted file mode 100644
index d0dbf53b..00000000
--- a/src/platform/Resource.cpp
+++ /dev/null
@@ -1,7 +0,0 @@
-#include "cru/platform/Resource.h"
-
-namespace cru::platform {
-std::string IPlatformResource::GetPlatformIdUtf8() const {
-  return GetPlatformId().ToUtf8();
-}
-}  // namespace cru::platform
diff --git a/src/platform/graphics/CMakeLists.txt b/src/platform/graphics/CMakeLists.txt
index 43ef80e0..e86e9c89 100644
--- a/src/platform/graphics/CMakeLists.txt
+++ b/src/platform/graphics/CMakeLists.txt
@@ -1,8 +1,6 @@
 add_library(CruPlatformGraphics
-	ForDllExport.cpp
 	Geometry.cpp
 	Image.cpp
-	NullPainter.cpp
 	SvgGeometryBuilderMixin.cpp
 )
 target_compile_definitions(CruPlatformGraphics PRIVATE CRU_PLATFORM_GRAPHICS_EXPORT_API)
diff --git a/src/platform/graphics/Geometry.cpp b/src/platform/graphics/Geometry.cpp
index 2c842a6e..e88577ce 100644
--- a/src/platform/graphics/Geometry.cpp
+++ b/src/platform/graphics/Geometry.cpp
@@ -1,6 +1,7 @@
 #include "cru/platform/graphics/Geometry.h"
 
 #include "cru/base/Exception.h"
+#include "cru/base/String.h"
 #include "cru/platform/Exception.h"
 #include "cru/platform/graphics/Factory.h"
 
@@ -15,7 +16,7 @@ bool IGeometry::StrokeContains(float width, const Point& point) {
 
 std::unique_ptr<IGeometry> IGeometry::CreateStrokeGeometry(
     [[maybe_unused]] float width) {
-  throw PlatformUnsupportedException(GetPlatformIdUtf8(), "CreateStrokeGeometry",
+  throw PlatformUnsupportedException(GetPlatformId(), "CreateStrokeGeometry",
                                      "Create stroke geometry of a geometry is "
                                      "not supported on this platform.");
 }
@@ -207,7 +208,7 @@ const std::unordered_set<char16_t> kSvgPathDataCommands = {
     'S', 's', 'Q', 'q', 'T', 't', 'A', 'a', 'Z', 'z'};
 }
 
-void IGeometryBuilder::ParseAndApplySvgPathData(StringView path_d) {
+void IGeometryBuilder::ParseAndApplySvgPathData(std::string_view path_d) {
   Index position = 0;
   const auto size = path_d.size();
 
@@ -236,8 +237,9 @@ void IGeometryBuilder::ParseAndApplySvgPathData(StringView path_d) {
 
     Index processed_count = 0;
 
-    auto result = path_d.substr(position).ParseToFloat(
-        &processed_count, StringToNumberFlags::kAllowTrailingJunk);
+    auto result = String::FromUtf8(path_d.substr(position))
+                      .ParseToFloat(&processed_count,
+                                    StringToNumberFlags::kAllowTrailingJunk);
 
     if (std::isnan(result)) throw Exception("Invalid svg path data number.");
 
@@ -252,7 +254,7 @@ void IGeometryBuilder::ParseAndApplySvgPathData(StringView path_d) {
     return Point(x, y);
   };
 
-  auto do_command = [&, this](char16_t command) {
+  auto do_command = [&, this](char command) {
     last_command = command;
     last_is_cubic = false;
     last_is_quad = false;
@@ -442,7 +444,7 @@ void IGeometryBuilder::ParseAndApplySvgPathData(StringView path_d) {
 }
 
 std::unique_ptr<IGeometry> CreateGeometryFromSvgPathData(
-    IGraphicsFactory* factory, StringView path_d) {
+    IGraphicsFactory* factory, std::string_view path_d) {
   auto builder = factory->CreateGeometryBuilder();
   builder->ParseAndApplySvgPathData(path_d);
   return builder->Build();
diff --git a/src/platform/graphics/SvgGeometryBuilderMixin.cpp b/src/platform/graphics/SvgGeometryBuilderMixin.cpp
index 73290da5..0863e5eb 100644
--- a/src/platform/graphics/SvgGeometryBuilderMixin.cpp
+++ b/src/platform/graphics/SvgGeometryBuilderMixin.cpp
@@ -1,7 +1,7 @@
 #include "cru/platform/graphics/SvgGeometryBuilderMixin.h"
 #include "cru/platform/Exception.h"
 
-#include "cru/base/Format.h"
+#include <string>
 
 namespace cru::platform::graphics {
 SvgGeometryBuilderMixin::SvgGeometryBuilderMixin() {}
@@ -10,34 +10,34 @@ SvgGeometryBuilderMixin::~SvgGeometryBuilderMixin() {}
 
 Point SvgGeometryBuilderMixin::GetCurrentPosition() {
   throw PlatformUnsupportedException(
-      GetPlatformIdUtf8(), "GetCurrentPosition",
+      GetPlatformId(), "GetCurrentPosition",
       "Svg-based geometry does not support get current position.");
 }
 
 void SvgGeometryBuilderMixin::MoveTo(const Point& point) {
-  AppendCommand(u"M");
+  AppendCommand("M");
   Append(point);
 }
 
 void SvgGeometryBuilderMixin::RelativeMoveTo(const Point& offset) {
-  AppendCommand(u"m");
+  AppendCommand("m");
   Append(offset);
 }
 
 void SvgGeometryBuilderMixin::LineTo(const Point& point) {
-  AppendCommand(u"L");
+  AppendCommand("L");
   Append(point);
 }
 
 void SvgGeometryBuilderMixin::RelativeLineTo(const Point& offset) {
-  AppendCommand(u"l");
+  AppendCommand("l");
   Append(offset);
 }
 
 void SvgGeometryBuilderMixin::CubicBezierTo(const Point& start_control_point,
                                             const Point& end_control_point,
                                             const Point& end_point) {
-  AppendCommand(u"C");
+  AppendCommand("C");
   Append(start_control_point);
   Append(end_control_point);
   Append(end_point);
@@ -46,7 +46,7 @@ void SvgGeometryBuilderMixin::CubicBezierTo(const Point& start_control_point,
 void SvgGeometryBuilderMixin::RelativeCubicBezierTo(
     const Point& start_control_offset, const Point& end_control_offset,
     const Point& end_offset) {
-  AppendCommand(u"c");
+  AppendCommand("c");
   Append(start_control_offset);
   Append(end_control_offset);
   Append(end_offset);
@@ -54,14 +54,14 @@ void SvgGeometryBuilderMixin::RelativeCubicBezierTo(
 
 void SvgGeometryBuilderMixin::QuadraticBezierTo(const Point& control_point,
                                                 const Point& end_point) {
-  AppendCommand(u"Q");
+  AppendCommand("Q");
   Append(control_point);
   Append(end_point);
 }
 
 void SvgGeometryBuilderMixin::RelativeQuadraticBezierTo(
     const Point& control_offset, const Point& end_offset) {
-  AppendCommand(u"q");
+  AppendCommand("q");
   Append(control_offset);
   Append(end_offset);
 }
@@ -69,7 +69,7 @@ void SvgGeometryBuilderMixin::RelativeQuadraticBezierTo(
 void SvgGeometryBuilderMixin::ArcTo(const Point& radius, float angle,
                                     bool is_large_arc, bool is_clockwise,
                                     const Point& end_point) {
-  AppendCommand(u"A");
+  AppendCommand("A");
   Append(radius.x);
   Append(radius.y);
   Append(angle);
@@ -82,7 +82,7 @@ void SvgGeometryBuilderMixin::RelativeArcTo(const Point& radius, float angle,
                                             bool is_large_arc,
                                             bool is_clockwise,
                                             const Point& end_offset) {
-  AppendCommand(u"a");
+  AppendCommand("a");
   Append(radius.x);
   Append(radius.y);
   Append(angle);
@@ -92,14 +92,15 @@ void SvgGeometryBuilderMixin::RelativeArcTo(const Point& radius, float angle,
 }
 
 void SvgGeometryBuilderMixin::CloseFigure(bool close) {
-  if (close) AppendCommand(u"z");
+  if (close) AppendCommand("z");
 }
 
-void SvgGeometryBuilderMixin::ParseAndApplySvgPathData(StringView path_d) {
+void SvgGeometryBuilderMixin::ParseAndApplySvgPathData(
+    std::string_view path_d) {
   AppendCommand(path_d);
 }
 
-void SvgGeometryBuilderMixin::AppendCommand(StringView command) {
+void SvgGeometryBuilderMixin::AppendCommand(std::string_view command) {
   current_ += command;
   current_ += u' ';
 }
@@ -110,14 +111,14 @@ void SvgGeometryBuilderMixin::Append(bool flag) {
 }
 
 void SvgGeometryBuilderMixin::Append(float number) {
-  current_ += cru::ToString(number);
+  current_ += std::to_string(number);
   current_ += u' ';
 }
 
 void SvgGeometryBuilderMixin::Append(const Point& point) {
-  current_ += cru::ToString(point.x);
+  current_ += std::to_string(point.x);
   current_ += u',';
-  current_ += cru::ToString(point.y);
+  current_ += std::to_string(point.y);
   current_ += u' ';
 }
 }  // namespace cru::platform::graphics
diff --git a/src/platform/graphics/cairo/CairoGraphicsFactory.cpp b/src/platform/graphics/cairo/CairoGraphicsFactory.cpp
index 11d2e734..7414e14f 100644
--- a/src/platform/graphics/cairo/CairoGraphicsFactory.cpp
+++ b/src/platform/graphics/cairo/CairoGraphicsFactory.cpp
@@ -32,13 +32,13 @@ CairoGraphicsFactory::CreateGeometryBuilder() {
   return std::make_unique<CairoGeometryBuilder>(this);
 }
 
-std::unique_ptr<IFont> CairoGraphicsFactory::CreateFont(String font_family,
+std::unique_ptr<IFont> CairoGraphicsFactory::CreateFont(std::string font_family,
                                                         float font_size) {
   return std::make_unique<PangoFont>(this, std::move(font_family), font_size);
 }
 
 std::unique_ptr<ITextLayout> CairoGraphicsFactory::CreateTextLayout(
-    std::shared_ptr<IFont> font, String text) {
+    std::shared_ptr<IFont> font, std::string text) {
   auto text_layout = std::make_unique<PangoTextLayout>(this, std::move(font));
   text_layout->SetText(std::move(text));
   return text_layout;
diff --git a/src/platform/graphics/cairo/CairoImageFactory.cpp b/src/platform/graphics/cairo/CairoImageFactory.cpp
index ff922e77..6225247a 100644
--- a/src/platform/graphics/cairo/CairoImageFactory.cpp
+++ b/src/platform/graphics/cairo/CairoImageFactory.cpp
@@ -212,7 +212,7 @@ std::unique_ptr<IImage> CairoImageFactory::DecodeFromStream(
 
 void CairoImageFactory::EncodeToStream(IImage* image, io::Stream* stream,
                                        ImageFormat format, float quality) {
-  auto cairo_image = CheckPlatform<CairoImage>(image, GetPlatformIdUtf8());
+  auto cairo_image = CheckPlatform<CairoImage>(image, GetPlatformId());
 
   if (format == ImageFormat::Png) {
     EncodePng(cairo_image->GetCairoSurface(), stream);
diff --git a/src/platform/graphics/cairo/CairoPainter.cpp b/src/platform/graphics/cairo/CairoPainter.cpp
index 94111098..d043e686 100644
--- a/src/platform/graphics/cairo/CairoPainter.cpp
+++ b/src/platform/graphics/cairo/CairoPainter.cpp
@@ -56,7 +56,7 @@ void CairoPainter::Clear(const Color& color) {
 void CairoPainter::DrawLine(const Point& start, const Point& end, IBrush* brush,
                             float width) {
   CheckValidation();
-  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformIdUtf8());
+  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformId());
   auto cairo_pattern = cairo_brush->GetCairoPattern();
   cairo_save(cairo_);
   cairo_set_source(cairo_, cairo_pattern);
@@ -71,7 +71,7 @@ void CairoPainter::DrawLine(const Point& start, const Point& end, IBrush* brush,
 void CairoPainter::StrokeRectangle(const Rect& rectangle, IBrush* brush,
                                    float width) {
   CheckValidation();
-  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformIdUtf8());
+  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformId());
   auto cairo_pattern = cairo_brush->GetCairoPattern();
   cairo_save(cairo_);
   cairo_set_source(cairo_, cairo_pattern);
@@ -85,7 +85,7 @@ void CairoPainter::StrokeRectangle(const Rect& rectangle, IBrush* brush,
 
 void CairoPainter::FillRectangle(const Rect& rectangle, IBrush* brush) {
   CheckValidation();
-  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformIdUtf8());
+  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformId());
   auto cairo_pattern = cairo_brush->GetCairoPattern();
   cairo_save(cairo_);
   cairo_set_source(cairo_, cairo_pattern);
@@ -99,7 +99,7 @@ void CairoPainter::FillRectangle(const Rect& rectangle, IBrush* brush) {
 void CairoPainter::StrokeEllipse(const Rect& outline_rect, IBrush* brush,
                                  float width) {
   CheckValidation();
-  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformIdUtf8());
+  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformId());
   auto cairo_pattern = cairo_brush->GetCairoPattern();
   cairo_save(cairo_);
   cairo_set_source(cairo_, cairo_pattern);
@@ -122,7 +122,7 @@ void CairoPainter::StrokeEllipse(const Rect& outline_rect, IBrush* brush,
 
 void CairoPainter::FillEllipse(const Rect& outline_rect, IBrush* brush) {
   CheckValidation();
-  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformIdUtf8());
+  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformId());
   auto cairo_pattern = cairo_brush->GetCairoPattern();
   cairo_save(cairo_);
   cairo_set_source(cairo_, cairo_pattern);
@@ -145,8 +145,8 @@ void CairoPainter::FillEllipse(const Rect& outline_rect, IBrush* brush) {
 void CairoPainter::StrokeGeometry(IGeometry* geometry, IBrush* brush,
                                   float width) {
   CheckValidation();
-  auto cairo_geometry = CheckPlatform<CairoGeometry>(geometry, GetPlatformIdUtf8());
-  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformIdUtf8());
+  auto cairo_geometry = CheckPlatform<CairoGeometry>(geometry, GetPlatformId());
+  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformId());
 
   auto cairo_path = cairo_geometry->GetCairoPath();
   auto cairo_pattern = cairo_brush->GetCairoPattern();
@@ -162,8 +162,8 @@ void CairoPainter::StrokeGeometry(IGeometry* geometry, IBrush* brush,
 
 void CairoPainter::FillGeometry(IGeometry* geometry, IBrush* brush) {
   CheckValidation();
-  auto cairo_geometry = CheckPlatform<CairoGeometry>(geometry, GetPlatformIdUtf8());
-  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformIdUtf8());
+  auto cairo_geometry = CheckPlatform<CairoGeometry>(geometry, GetPlatformId());
+  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformId());
 
   auto cairo_path = cairo_geometry->GetCairoPath();
   auto cairo_pattern = cairo_brush->GetCairoPattern();
@@ -181,9 +181,9 @@ void CairoPainter::DrawText(const Point& offset, ITextLayout* text_layout,
   CheckValidation();
 
   auto pango_text_layout =
-      CheckPlatform<PangoTextLayout>(text_layout, GetPlatformIdUtf8());
+      CheckPlatform<PangoTextLayout>(text_layout, GetPlatformId());
 
-  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformIdUtf8());
+  auto cairo_brush = CheckPlatform<CairoBrush>(brush, GetPlatformId());
   auto cairo_pattern = cairo_brush->GetCairoPattern();
 
   cairo_save(cairo_);
@@ -196,7 +196,7 @@ void CairoPainter::DrawText(const Point& offset, ITextLayout* text_layout,
 
 void CairoPainter::DrawImage(const Point& offset, IImage* image) {
   CheckValidation();
-  auto cairo_image = CheckPlatform<CairoImage>(image, GetPlatformIdUtf8());
+  auto cairo_image = CheckPlatform<CairoImage>(image, GetPlatformId());
   cairo_save(cairo_);
   cairo_set_source_surface(cairo_, cairo_image->GetCairoSurface(), 0, 0);
   cairo_new_path(cairo_);
diff --git a/src/platform/graphics/cairo/CairoResource.cpp b/src/platform/graphics/cairo/CairoResource.cpp
index ee371efc..f8ce9666 100644
--- a/src/platform/graphics/cairo/CairoResource.cpp
+++ b/src/platform/graphics/cairo/CairoResource.cpp
@@ -2,14 +2,16 @@
 #include "cru/platform/graphics/cairo/CairoGraphicsFactory.h"
 
 namespace cru::platform::graphics::cairo {
-static const String kCairoGraphicsPlatformId(u"cairo");
+static const std::string kCairoGraphicsPlatformId("cairo");
 
 CairoResource::CairoResource(CairoGraphicsFactory* factory)
     : factory_(factory) {}
 
 CairoResource::~CairoResource() {}
 
-String CairoResource::GetPlatformId() const { return kCairoGraphicsPlatformId; }
+std::string CairoResource::GetPlatformId() const {
+  return kCairoGraphicsPlatformId;
+}
 
 IGraphicsFactory* CairoResource::GetGraphicsFactory() { return factory_; }
 }  // namespace cru::platform::graphics::cairo
diff --git a/src/platform/graphics/cairo/PangoFont.cpp b/src/platform/graphics/cairo/PangoFont.cpp
index d5c1ad0b..e375d674 100644
--- a/src/platform/graphics/cairo/PangoFont.cpp
+++ b/src/platform/graphics/cairo/PangoFont.cpp
@@ -1,23 +1,24 @@
 #include "cru/platform/graphics/cairo/PangoFont.h"
 
 namespace cru::platform::graphics::cairo {
-PangoFont::PangoFont(CairoGraphicsFactory* factory, String font_family,
+PangoFont::PangoFont(CairoGraphicsFactory* factory, std::string font_family,
                      float font_size)
     : CairoResource(factory),
       font_family_(std::move(font_family)),
       font_size_(font_size) {
   pango_font_description_ = pango_font_description_new();
-  auto font_family_str = font_family_.ToUtf8();
+  auto font_family_str = font_family_;
   pango_font_description_set_family(pango_font_description_,
                                     font_family_str.c_str());
-  pango_font_description_set_size(pango_font_description_, font_size * PANGO_SCALE);
+  pango_font_description_set_size(pango_font_description_,
+                                  font_size * PANGO_SCALE);
 }
 
 PangoFont::~PangoFont() {
   pango_font_description_free(pango_font_description_);
 }
 
-String PangoFont::GetFontName() { return font_family_; }
+std::string PangoFont::GetFontName() { return font_family_; }
 
 float PangoFont::GetFontSize() { return font_size_; }
 }  // namespace cru::platform::graphics::cairo
diff --git a/src/platform/graphics/cairo/PangoTextLayout.cpp b/src/platform/graphics/cairo/PangoTextLayout.cpp
index 746056e2..f8ed20c7 100644
--- a/src/platform/graphics/cairo/PangoTextLayout.cpp
+++ b/src/platform/graphics/cairo/PangoTextLayout.cpp
@@ -1,5 +1,4 @@
 #include "cru/platform/graphics/cairo/PangoTextLayout.h"
-#include "cru/base/StringUtil.h"
 #include "cru/platform/Check.h"
 #include "cru/platform/GraphicsBase.h"
 #include "cru/platform/graphics/Base.h"
@@ -24,7 +23,7 @@ PangoTextLayout::PangoTextLayout(CairoGraphicsFactory* factory,
                                  std::shared_ptr<IFont> font)
     : CairoResource(factory) {
   Expects(font);
-  font_ = CheckPlatform<PangoFont>(font, GetPlatformIdUtf8());
+  font_ = CheckPlatform<PangoFont>(font, GetPlatformId());
   pango_layout_ = pango_cairo_create_layout(factory->GetDefaultCairo());
   pango_layout_set_font_description(pango_layout_,
                                     font_->GetPangoFontDescription());
@@ -32,19 +31,18 @@ PangoTextLayout::PangoTextLayout(CairoGraphicsFactory* factory,
 
 PangoTextLayout::~PangoTextLayout() { g_object_unref(pango_layout_); }
 
-String PangoTextLayout::GetText() { return text_; }
+std::string PangoTextLayout::GetText() { return text_; }
 
-void PangoTextLayout::SetText(String new_text) {
+void PangoTextLayout::SetText(std::string new_text) {
   text_ = std::move(new_text);
-  utf8_text_ = text_.ToUtf8();
-  pango_layout_set_text(pango_layout_, utf8_text_.c_str(), utf8_text_.size());
+  pango_layout_set_text(pango_layout_, text_.c_str(), text_.size());
 }
 
 std::shared_ptr<IFont> PangoTextLayout::GetFont() { return font_; }
 
 void PangoTextLayout::SetFont(std::shared_ptr<IFont> font) {
   Expects(font);
-  font_ = CheckPlatform<PangoFont>(font, GetPlatformIdUtf8());
+  font_ = CheckPlatform<PangoFont>(font, GetPlatformId());
   pango_layout_set_font_description(pango_layout_,
                                     font_->GetPangoFontDescription());
 }
@@ -63,9 +61,8 @@ void PangoTextLayout::SetEditMode(bool enable) { edit_mode_ = enable; }
 
 Index PangoTextLayout::GetLineIndexFromCharIndex(Index char_index) {
   int line;
-  pango_layout_index_to_line_x(pango_layout_,
-                               FromUtf16IndexToUtf8Index(char_index), false,
-                               &line, nullptr);
+  pango_layout_index_to_line_x(pango_layout_, char_index, false, &line,
+                               nullptr);
   return line;
 }
 
@@ -80,27 +77,6 @@ float PangoTextLayout::GetLineHeight(Index line_index) {
   return static_cast<float>(height) / PANGO_SCALE;
 }
 
-Index PangoTextLayout::FromUtf8IndexToUtf16Index(Index index) {
-  Utf8CodePointIterator iter(utf8_text_.data(), utf8_text_.size());
-  int cp_count = 0;
-  while ((!iter.IsPastEnd()) && iter.GetPosition() < index) {
-    ++iter;
-    cp_count++;
-  }
-  return text_.IndexFromCodePointToCodeUnit(cp_count);
-}
-
-Index PangoTextLayout::FromUtf16IndexToUtf8Index(Index index) {
-  Index cp_index = text_.IndexFromCodeUnitToCodePoint(index);
-  Utf8CodePointIterator iter(utf8_text_.data(), utf8_text_.size());
-
-  for (Index i = 0; i < cp_index; ++i) {
-    ++iter;
-  }
-
-  return iter.GetPosition();
-}
-
 Rect PangoTextLayout::GetTextBounds(bool includingTrailingSpace) {
   PangoRectangle rectangle;
   pango_layout_get_extents(pango_layout_, nullptr, &rectangle);
@@ -110,17 +86,17 @@ Rect PangoTextLayout::GetTextBounds(bool includingTrailingSpace) {
 
 std::vector<Rect> PangoTextLayout::TextRangeRect(const TextRange& text_range) {
   auto tr = text_range.Normalize();
-  auto utf8_start_index = FromUtf16IndexToUtf8Index(tr.GetStart());
-  auto utf8_end_index = FromUtf16IndexToUtf8Index(tr.GetEnd());
+  auto start_index = tr.GetStart();
+  auto end_index = tr.GetEnd();
   PangoRectangle rectangle;
 
   int start_line_index, end_line_index, start_x_pos, end_x_pos;
-  pango_layout_index_to_line_x(pango_layout_, utf8_start_index, false,
+  pango_layout_index_to_line_x(pango_layout_, start_index, false,
                                &start_line_index, &start_x_pos);
-  pango_layout_index_to_line_x(pango_layout_, utf8_end_index, false,
-                               &end_line_index, &end_x_pos);
+  pango_layout_index_to_line_x(pango_layout_, end_index, false, &end_line_index,
+                               &end_x_pos);
 
-  pango_layout_index_to_pos(pango_layout_, utf8_start_index, &rectangle);
+  pango_layout_index_to_pos(pango_layout_, start_index, &rectangle);
   auto top = rectangle.y;
 
   if (start_line_index == end_line_index) {
@@ -161,9 +137,8 @@ std::vector<Rect> PangoTextLayout::TextRangeRect(const TextRange& text_range) {
 }
 
 Rect PangoTextLayout::TextSinglePoint(Index position, bool trailing) {
-  auto utf8_index = FromUtf16IndexToUtf8Index(position);
   int line_index, x_pos, y_pos = 0;
-  pango_layout_index_to_line_x(pango_layout_, utf8_index, trailing, &line_index,
+  pango_layout_index_to_line_x(pango_layout_, position, trailing, &line_index,
                                &x_pos);
 
   for (int i = 0; i < line_index; i++) {
@@ -186,8 +161,7 @@ TextHitTestResult PangoTextLayout::HitTest(const Point& point) {
   auto inside_text =
       pango_layout_xy_to_index(pango_layout_, point.x * PANGO_SCALE,
                                point.y * PANGO_SCALE, &index, &trailing);
-  return TextHitTestResult{FromUtf8IndexToUtf16Index(index), trailing != 0,
-                           inside_text != 0};
+  return TextHitTestResult{index, trailing != 0, inside_text != 0};
 }
 
 }  // namespace cru::platform::graphics::cairo
diff --git a/src/platform/graphics/direct2d/ImageFactory.cpp b/src/platform/graphics/direct2d/ImageFactory.cpp
index b9e9221a..aff411c4 100644
--- a/src/platform/graphics/direct2d/ImageFactory.cpp
+++ b/src/platform/graphics/direct2d/ImageFactory.cpp
@@ -74,7 +74,7 @@ GUID ConvertImageFormatToGUID(ImageFormat format) {
 
 void WinImageFactory::EncodeToStream(IImage* image, io::Stream* stream,
                                      ImageFormat format, float quality) {
-  auto direct_image = CheckPlatform<Direct2DImage>(image, GetPlatformIdUtf8());
+  auto direct_image = CheckPlatform<Direct2DImage>(image, GetPlatformId());
 
   Microsoft::WRL::ComPtr<IStream> com_stream(
       platform::win::ConvertStreamToComStream(stream));
diff --git a/src/platform/graphics/direct2d/Painter.cpp b/src/platform/graphics/direct2d/Painter.cpp
index 29ddcabb..fabcdafd 100644
--- a/src/platform/graphics/direct2d/Painter.cpp
+++ b/src/platform/graphics/direct2d/Painter.cpp
@@ -55,7 +55,7 @@ void D2DDeviceContextPainter::Clear(const Color& color) {
 void D2DDeviceContextPainter::DrawLine(const Point& start, const Point& end,
                                        IBrush* brush, float width) {
   CheckValidation();
-  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformIdUtf8());
+  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformId());
   device_context_->DrawLine(Convert(start), Convert(end),
                             b->GetD2DBrushInterface(), width);
 }
@@ -63,7 +63,7 @@ void D2DDeviceContextPainter::DrawLine(const Point& start, const Point& end,
 void D2DDeviceContextPainter::StrokeRectangle(const Rect& rectangle,
                                               IBrush* brush, float width) {
   CheckValidation();
-  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformIdUtf8());
+  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformId());
   device_context_->DrawRectangle(Convert(rectangle), b->GetD2DBrushInterface(),
                                  width);
 }
@@ -71,14 +71,14 @@ void D2DDeviceContextPainter::StrokeRectangle(const Rect& rectangle,
 void D2DDeviceContextPainter::FillRectangle(const Rect& rectangle,
                                             IBrush* brush) {
   CheckValidation();
-  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformIdUtf8());
+  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformId());
   device_context_->FillRectangle(Convert(rectangle), b->GetD2DBrushInterface());
 }
 
 void D2DDeviceContextPainter::StrokeEllipse(const Rect& outline_rect,
                                             IBrush* brush, float width) {
   CheckValidation();
-  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformIdUtf8());
+  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformId());
   device_context_->DrawEllipse(
       D2D1::Ellipse(Convert(outline_rect.GetCenter()),
                     outline_rect.width / 2.0f, outline_rect.height / 2.0f),
@@ -87,7 +87,7 @@ void D2DDeviceContextPainter::StrokeEllipse(const Rect& outline_rect,
 void D2DDeviceContextPainter::FillEllipse(const Rect& outline_rect,
                                           IBrush* brush) {
   CheckValidation();
-  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformIdUtf8());
+  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformId());
   device_context_->FillEllipse(
       D2D1::Ellipse(Convert(outline_rect.GetCenter()),
                     outline_rect.width / 2.0f, outline_rect.height / 2.0f),
@@ -97,16 +97,16 @@ void D2DDeviceContextPainter::FillEllipse(const Rect& outline_rect,
 void D2DDeviceContextPainter::StrokeGeometry(IGeometry* geometry, IBrush* brush,
                                              float width) {
   CheckValidation();
-  const auto g = CheckPlatform<D2DGeometry>(geometry, GetPlatformIdUtf8());
-  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformIdUtf8());
+  const auto g = CheckPlatform<D2DGeometry>(geometry, GetPlatformId());
+  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformId());
   device_context_->DrawGeometry(g->GetComInterface(), b->GetD2DBrushInterface(),
                                 width);
 }
 
 void D2DDeviceContextPainter::FillGeometry(IGeometry* geometry, IBrush* brush) {
   CheckValidation();
-  const auto g = CheckPlatform<D2DGeometry>(geometry, GetPlatformIdUtf8());
-  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformIdUtf8());
+  const auto g = CheckPlatform<D2DGeometry>(geometry, GetPlatformId());
+  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformId());
   device_context_->FillGeometry(g->GetComInterface(),
                                 b->GetD2DBrushInterface());
 }
@@ -115,15 +115,15 @@ void D2DDeviceContextPainter::DrawText(const Point& offset,
                                        ITextLayout* text_layout,
                                        IBrush* brush) {
   CheckValidation();
-  const auto t = CheckPlatform<DWriteTextLayout>(text_layout, GetPlatformIdUtf8());
-  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformIdUtf8());
+  const auto t = CheckPlatform<DWriteTextLayout>(text_layout, GetPlatformId());
+  const auto b = CheckPlatform<ID2DBrush>(brush, GetPlatformId());
   device_context_->DrawTextLayout(Convert(offset), t->GetComInterface(),
                                   b->GetD2DBrushInterface());
 }
 
 void D2DDeviceContextPainter::DrawImage(const Point& offset, IImage* image) {
   CheckValidation();
-  const auto i = CheckPlatform<Direct2DImage>(image, GetPlatformIdUtf8());
+  const auto i = CheckPlatform<Direct2DImage>(image, GetPlatformId());
 
   Microsoft::WRL::ComPtr<ID2D1DeviceContext> device_context;
 
diff --git a/src/platform/graphics/direct2d/TextLayout.cpp b/src/platform/graphics/direct2d/TextLayout.cpp
index 7a2074ec..06bbcaa6 100644
--- a/src/platform/graphics/direct2d/TextLayout.cpp
+++ b/src/platform/graphics/direct2d/TextLayout.cpp
@@ -14,7 +14,7 @@ DWriteTextLayout::DWriteTextLayout(DirectGraphicsFactory* factory,
                                    std::shared_ptr<IFont> font, String text)
     : DirectGraphicsResource(factory), text_(std::move(text)) {
   Expects(font);
-  font_ = CheckPlatform<DWriteFont>(font, GetPlatformIdUtf8());
+  font_ = CheckPlatform<DWriteFont>(font, GetPlatformId());
 
   ThrowIfFailed(factory->GetDWriteFactory()->CreateTextLayout(
       reinterpret_cast<const wchar_t*>(text_.c_str()),
@@ -39,7 +39,7 @@ std::shared_ptr<IFont> DWriteTextLayout::GetFont() {
 }
 
 void DWriteTextLayout::SetFont(std::shared_ptr<IFont> font) {
-  font_ = CheckPlatform<DWriteFont>(font, GetPlatformIdUtf8());
+  font_ = CheckPlatform<DWriteFont>(font, GetPlatformId());
   ThrowIfFailed(GetDirectFactory()->GetDWriteFactory()->CreateTextLayout(
       reinterpret_cast<const wchar_t*>(text_.c_str()),
       static_cast<UINT32>(text_.size()), font_->GetComInterface(), max_width_,
diff --git a/src/platform/graphics/quartz/Factory.cpp b/src/platform/graphics/quartz/Factory.cpp
index 5d5b48b5..862c0966 100644
--- a/src/platform/graphics/quartz/Factory.cpp
+++ b/src/platform/graphics/quartz/Factory.cpp
@@ -33,7 +33,7 @@ std::unique_ptr<IFont> QuartzGraphicsFactory::CreateFont(String font_family,
 
 std::unique_ptr<ITextLayout> QuartzGraphicsFactory::CreateTextLayout(
     std::shared_ptr<IFont> font, String text) {
-  auto f = CheckPlatform<OsxCTFont>(font, GetPlatformIdUtf8());
+  auto f = CheckPlatform<OsxCTFont>(font, GetPlatformId());
   return std::make_unique<OsxCTTextLayout>(this, f, text);
 }
 
diff --git a/src/platform/graphics/quartz/ImageFactory.cpp b/src/platform/graphics/quartz/ImageFactory.cpp
index 62229bcb..2090828c 100644
--- a/src/platform/graphics/quartz/ImageFactory.cpp
+++ b/src/platform/graphics/quartz/ImageFactory.cpp
@@ -49,7 +49,7 @@ void QuartzImageFactory::EncodeToStream(IImage* image, io::Stream* stream,
     throw Exception("Invalid quality value.");
   }
 
-  auto quartz_image = CheckPlatform<QuartzImage>(image, GetPlatformIdUtf8());
+  auto quartz_image = CheckPlatform<QuartzImage>(image, GetPlatformId());
   auto cg_image = quartz_image->GetCGImage();
 
   auto uti = ToCFString(GetImageFormatUniformTypeIdentifier(format));
diff --git a/src/platform/graphics/quartz/Painter.cpp b/src/platform/graphics/quartz/Painter.cpp
index fe0f5d43..45dee716 100644
--- a/src/platform/graphics/quartz/Painter.cpp
+++ b/src/platform/graphics/quartz/Painter.cpp
@@ -66,7 +66,7 @@ void QuartzCGContextPainter::DrawLine(const Point& start, const Point& end,
   CGContextMoveToPoint(cg_context_, start.x, start.y);
   CGContextAddLineToPoint(cg_context_, end.x, end.y);
 
-  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformIdUtf8());
+  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformId());
   b->Select(cg_context_);
   SetLineWidth(width);
 
@@ -77,7 +77,7 @@ void QuartzCGContextPainter::StrokeRectangle(const Rect& rectangle,
                                              IBrush* brush, float width) {
   Validate();
 
-  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformIdUtf8());
+  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformId());
   b->Select(cg_context_);
   CGContextStrokeRectWithWidth(cg_context_, Convert(rectangle), width);
 }
@@ -86,7 +86,7 @@ void QuartzCGContextPainter::FillRectangle(const Rect& rectangle,
                                            IBrush* brush) {
   Validate();
 
-  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformIdUtf8());
+  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformId());
   b->Select(cg_context_);
   CGContextFillRect(cg_context_, Convert(rectangle));
 }
@@ -95,7 +95,7 @@ void QuartzCGContextPainter::StrokeEllipse(const Rect& outline_rect,
                                            IBrush* brush, float width) {
   Validate();
 
-  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformIdUtf8());
+  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformId());
   b->Select(cg_context_);
   SetLineWidth(width);
 
@@ -106,7 +106,7 @@ void QuartzCGContextPainter::FillEllipse(const Rect& outline_rect,
                                          IBrush* brush) {
   Validate();
 
-  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformIdUtf8());
+  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformId());
   b->Select(cg_context_);
   CGContextFillEllipseInRect(cg_context_, Convert(outline_rect));
 }
@@ -115,8 +115,8 @@ void QuartzCGContextPainter::StrokeGeometry(IGeometry* geometry, IBrush* brush,
                                             float width) {
   Validate();
 
-  QuartzGeometry* g = CheckPlatform<QuartzGeometry>(geometry, GetPlatformIdUtf8());
-  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformIdUtf8());
+  QuartzGeometry* g = CheckPlatform<QuartzGeometry>(geometry, GetPlatformId());
+  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformId());
 
   b->Select(cg_context_);
   SetLineWidth(width);
@@ -129,8 +129,8 @@ void QuartzCGContextPainter::StrokeGeometry(IGeometry* geometry, IBrush* brush,
 void QuartzCGContextPainter::FillGeometry(IGeometry* geometry, IBrush* brush) {
   Validate();
 
-  QuartzGeometry* g = CheckPlatform<QuartzGeometry>(geometry, GetPlatformIdUtf8());
-  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformIdUtf8());
+  QuartzGeometry* g = CheckPlatform<QuartzGeometry>(geometry, GetPlatformId());
+  QuartzBrush* b = CheckPlatform<QuartzBrush>(brush, GetPlatformId());
 
   b->Select(cg_context_);
   CGContextBeginPath(cg_context_);
@@ -142,7 +142,7 @@ void QuartzCGContextPainter::DrawText(const Point& offset,
                                       ITextLayout* text_layout, IBrush* brush) {
   Validate();
 
-  auto tl = CheckPlatform<OsxCTTextLayout>(text_layout, GetPlatformIdUtf8());
+  auto tl = CheckPlatform<OsxCTTextLayout>(text_layout, GetPlatformId());
 
   Color color;
 
@@ -169,7 +169,7 @@ void QuartzCGContextPainter::DrawText(const Point& offset,
 
 void QuartzCGContextPainter::DrawImage(const Point& offset, IImage* image) {
   Validate();
-  auto i = CheckPlatform<QuartzImage>(image, GetPlatformIdUtf8());
+  auto i = CheckPlatform<QuartzImage>(image, GetPlatformId());
 
   auto cg_image = i->GetCGImage();
 
diff --git a/src/platform/graphics/quartz/TextLayout.cpp b/src/platform/graphics/quartz/TextLayout.cpp
index 41a2f176..8c573c7a 100644
--- a/src/platform/graphics/quartz/TextLayout.cpp
+++ b/src/platform/graphics/quartz/TextLayout.cpp
@@ -31,7 +31,7 @@ OsxCTTextLayout::~OsxCTTextLayout() {
 }
 
 void OsxCTTextLayout::SetFont(std::shared_ptr<IFont> font) {
-  font_ = CheckPlatform<OsxCTFont>(font, GetPlatformIdUtf8());
+  font_ = CheckPlatform<OsxCTFont>(font, GetPlatformId());
   RecreateFrame();
 }
 
diff --git a/src/platform/graphics/web_canvas/Painter.cpp b/src/platform/graphics/web_canvas/Painter.cpp
index f928de35..c9184165 100644
--- a/src/platform/graphics/web_canvas/Painter.cpp
+++ b/src/platform/graphics/web_canvas/Painter.cpp
@@ -94,7 +94,7 @@ void WebCanvasPainter::SetFillStyle(IBrush* brush) {
 }
 
 WebCanvasBrush* WebCanvasPainter::ConvertBrush(IBrush* brush) const {
-  return CheckPlatform<WebCanvasBrush>(brush, GetPlatformIdUtf8());
+  return CheckPlatform<WebCanvasBrush>(brush, GetPlatformId());
 }
 
 WebCanvasRef WebCanvasPainter::GetCanvas() {
diff --git a/src/platform/gui/CMakeLists.txt b/src/platform/gui/CMakeLists.txt
index b541428e..70ae62f9 100644
--- a/src/platform/gui/CMakeLists.txt
+++ b/src/platform/gui/CMakeLists.txt
@@ -1,5 +1,5 @@
 add_library(CruPlatformGui
-	Keyboard.cpp
+	Input.cpp
 	Menu.cpp
 	UiApplication.cpp
 	Window.cpp
diff --git a/src/platform/gui/Input.cpp b/src/platform/gui/Input.cpp
new file mode 100644
index 00000000..a5e25dc8
--- /dev/null
+++ b/src/platform/gui/Input.cpp
@@ -0,0 +1,140 @@
+#include "cru/platform/gui/Input.h"
+
+#include <array>
+#include <string>
+#include <string_view>
+
+namespace cru::platform::gui {
+const std::array<std::string_view, static_cast<int>(KeyCode::NumPad9) + 1>
+    key_code_string_list{"Unknown",
+                         "LeftButton",
+                         "MiddleButton",
+                         "RightButton",
+                         "Escape",
+                         "F1",
+                         "F2",
+                         "F3",
+                         "F4",
+                         "F5",
+                         "F6",
+                         "F7",
+                         "F8",
+                         "F9",
+                         "F10",
+                         "F11",
+                         "F12",
+                         "N0",
+                         "N1",
+                         "N2",
+                         "N3",
+                         "N4",
+                         "N5",
+                         "N6",
+                         "N7",
+                         "N8",
+                         "N9",
+                         "A",
+                         "B",
+                         "C",
+                         "D",
+                         "E",
+                         "F",
+                         "G",
+                         "H",
+                         "I",
+                         "J",
+                         "K",
+                         "L",
+                         "M",
+                         "N",
+                         "O",
+                         "P",
+                         "Q",
+                         "R",
+                         "S",
+                         "T",
+                         "U",
+                         "V",
+                         "W",
+                         "X",
+                         "Y",
+                         "Z",
+                         "GraveAccent",
+                         "Tab",
+                         "CapsLock",
+                         "LeftShift",
+                         "LeftCtrl",
+                         "LeftSuper",
+                         "LeftAlt",
+                         "Minus",
+                         "Equal",
+                         "Backspace",
+                         "LeftSquareBracket",
+                         "RightSquareBracket",
+                         "BackSlash",
+                         "Semicolon",
+                         "Quote",
+                         "Comma",
+                         "Period",
+                         "Slash",
+                         "RightShift",
+                         "RightCtrl",
+                         "RightSuper",
+                         "RightAlt",
+                         "Insert",
+                         "Delete",
+                         "Home",
+                         "End",
+                         "PageUp",
+                         "PageDown",
+                         "Up",
+                         "Left",
+                         "Down",
+                         "Right",
+                         "PrintScreen",
+                         "ScrollLock",
+                         "Pause",
+                         "NumPad0",
+                         "NumPad1",
+                         "NumPad2",
+                         "NumPad3",
+                         "NumPad4",
+                         "NumPad5",
+                         "NumPad6",
+                         "NumPad7",
+                         "NumPad8",
+                         "NumPad9"};
+
+std::string ToString(KeyCode key_code) {
+  if (static_cast<int>(key_code) < 0 ||
+      static_cast<int>(key_code) >=
+          static_cast<int>(key_code_string_list.size()))
+    return "UNKNOWN_KEYCODENAME";
+
+  return std::string(key_code_string_list[static_cast<int>(key_code)]);
+}
+
+std::string ToString(KeyModifier key_modifier, std::string_view separator) {
+  std::vector<std::string> list;
+  if (key_modifier & KeyModifiers::Shift) {
+    list.push_back("Shift");
+  }
+
+  if (key_modifier & KeyModifiers::Ctrl) {
+    list.push_back("Ctrl");
+  }
+
+  if (key_modifier & KeyModifiers::Alt) {
+    list.push_back("Shift");
+  }
+
+  if (list.empty()) return "";
+  std::string result = list.front();
+  for (auto iter = list.cbegin() + 1; iter != list.cend(); ++iter) {
+    result += separator;
+    result += *iter;
+  }
+
+  return result;
+}
+}  // namespace cru::platform::gui
diff --git a/src/platform/gui/Keyboard.cpp b/src/platform/gui/Keyboard.cpp
deleted file mode 100644
index 775995c2..00000000
--- a/src/platform/gui/Keyboard.cpp
+++ /dev/null
@@ -1,140 +0,0 @@
-#include "cru/platform/gui/Keyboard.h"
-
-#include <array>
-#include <string>
-#include <string_view>
-
-namespace cru::platform::gui {
-const std::array<StringView, static_cast<int>(KeyCode::NumPad9) + 1>
-    key_code_string_list{u"Unknown",
-                         u"LeftButton",
-                         u"MiddleButton",
-                         u"RightButton",
-                         u"Escape",
-                         u"F1",
-                         u"F2",
-                         u"F3",
-                         u"F4",
-                         u"F5",
-                         u"F6",
-                         u"F7",
-                         u"F8",
-                         u"F9",
-                         u"F10",
-                         u"F11",
-                         u"F12",
-                         u"N0",
-                         u"N1",
-                         u"N2",
-                         u"N3",
-                         u"N4",
-                         u"N5",
-                         u"N6",
-                         u"N7",
-                         u"N8",
-                         u"N9",
-                         u"A",
-                         u"B",
-                         u"C",
-                         u"D",
-                         u"E",
-                         u"F",
-                         u"G",
-                         u"H",
-                         u"I",
-                         u"J",
-                         u"K",
-                         u"L",
-                         u"M",
-                         u"N",
-                         u"O",
-                         u"P",
-                         u"Q",
-                         u"R",
-                         u"S",
-                         u"T",
-                         u"U",
-                         u"V",
-                         u"W",
-                         u"X",
-                         u"Y",
-                         u"Z",
-                         u"GraveAccent",
-                         u"Tab",
-                         u"CapsLock",
-                         u"LeftShift",
-                         u"LeftCtrl",
-                         u"LeftSuper",
-                         u"LeftAlt",
-                         u"Minus",
-                         u"Equal",
-                         u"Backspace",
-                         u"LeftSquareBracket",
-                         u"RightSquareBracket",
-                         u"BackSlash",
-                         u"Semicolon",
-                         u"Quote",
-                         u"Comma",
-                         u"Period",
-                         u"Slash",
-                         u"RightShift",
-                         u"RightCtrl",
-                         u"RightSuper",
-                         u"RightAlt",
-                         u"Insert",
-                         u"Delete",
-                         u"Home",
-                         u"End",
-                         u"PageUp",
-                         u"PageDown",
-                         u"Up",
-                         u"Left",
-                         u"Down",
-                         u"Right",
-                         u"PrintScreen",
-                         u"ScrollLock",
-                         u"Pause",
-                         u"NumPad0",
-                         u"NumPad1",
-                         u"NumPad2",
-                         u"NumPad3",
-                         u"NumPad4",
-                         u"NumPad5",
-                         u"NumPad6",
-                         u"NumPad7",
-                         u"NumPad8",
-                         u"NumPad9"};
-
-String ToString(KeyCode key_code) {
-  if (static_cast<int>(key_code) < 0 ||
-      static_cast<int>(key_code) >=
-          static_cast<int>(key_code_string_list.size()))
-    return u"UNKNOWN_KEYCODENAME";
-
-  return key_code_string_list[static_cast<int>(key_code)].ToString();
-}
-
-String ToString(KeyModifier key_modifier, StringView separator) {
-  std::vector<String> list;
-  if (key_modifier & KeyModifiers::shift) {
-    list.push_back(u"Shift");
-  }
-
-  if (key_modifier & KeyModifiers::ctrl) {
-    list.push_back(u"Ctrl");
-  }
-
-  if (key_modifier & KeyModifiers::alt) {
-    list.push_back(u"Shift");
-  }
-
-  if (list.empty()) return u"";
-  String result = list.front();
-  for (auto iter = list.cbegin() + 1; iter != list.cend(); ++iter) {
-    result += separator;
-    result += *iter;
-  }
-
-  return result;
-}
-}  // namespace cru::platform::gui
diff --git a/src/platform/gui/UiApplication.cpp b/src/platform/gui/UiApplication.cpp
index ac93a57d..086440c0 100644
--- a/src/platform/gui/UiApplication.cpp
+++ b/src/platform/gui/UiApplication.cpp
@@ -1,5 +1,6 @@
 #include "cru/platform/gui/UiApplication.h"
 
+#include "cru/base/Base.h"
 #include "cru/base/Exception.h"
 
 namespace cru::platform::gui {
@@ -22,13 +23,13 @@ IUiApplication::~IUiApplication() { instance = nullptr; }
 
 IMenu* IUiApplication::GetApplicationMenu() { return nullptr; }
 
-std::optional<String> IUiApplication::ShowSaveDialog(
+std::optional<std::string> IUiApplication::ShowSaveDialog(
     SaveDialogOptions options) {
-  throw Exception("Not implemented.");
+  NotImplemented();
 }
 
-std::optional<std::vector<String>> IUiApplication::ShowOpenDialog(
+std::optional<std::vector<std::string>> IUiApplication::ShowOpenDialog(
     OpenDialogOptions options) {
-  throw Exception("Not implemented.");
+  NotImplemented();
 }
 }  // namespace cru::platform::gui
diff --git a/src/platform/gui/osx/Window.mm b/src/platform/gui/osx/Window.mm
index 7381ca55..6559cf70 100644
--- a/src/platform/gui/osx/Window.mm
+++ b/src/platform/gui/osx/Window.mm
@@ -64,7 +64,7 @@ void OsxWindowPrivate::OnWindowWillClose() {
     bool quit = true;
 
     for (auto window : all_window) {
-      auto w = CheckPlatform<OsxWindow>(window, osx_window_->GetPlatformIdUtf8());
+      auto w = CheckPlatform<OsxWindow>(window, osx_window_->GetPlatformId());
       if (w->p_->window_) {
         quit = false;
         break;
@@ -179,7 +179,7 @@ void OsxWindowPrivate::CreateWindow() {
   [window_ setDelegate:window_delegate_];
 
   if (parent_) {
-    auto parent = CheckPlatform<OsxWindow>(parent_, this->osx_window_->GetPlatformIdUtf8());
+    auto parent = CheckPlatform<OsxWindow>(parent_, this->osx_window_->GetPlatformId());
     [window_ setParentWindow:parent->p_->window_];
   }
 
@@ -231,7 +231,7 @@ void OsxWindow::Close() {
 INativeWindow* OsxWindow::GetParent() { return p_->parent_; }
 
 void OsxWindow::SetParent(INativeWindow* parent) {
-  auto p = CheckPlatform<OsxWindow>(parent, GetPlatformIdUtf8());
+  auto p = CheckPlatform<OsxWindow>(parent, GetPlatformId());
 
   p_->parent_ = parent;
 
@@ -366,7 +366,7 @@ bool OsxWindow::CaptureMouse() { return true; }
 bool OsxWindow::ReleaseMouse() { return true; }
 
 void OsxWindow::SetCursor(std::shared_ptr<ICursor> cursor) {
-  p_->cursor_ = CheckPlatform<OsxCursor>(cursor, GetPlatformIdUtf8());
+  p_->cursor_ = CheckPlatform<OsxCursor>(cursor, GetPlatformId());
   p_->UpdateCursor();
 }
 
diff --git a/src/platform/gui/sdl/Window.cpp b/src/platform/gui/sdl/Window.cpp
index e802b82f..84cf0ad4 100644
--- a/src/platform/gui/sdl/Window.cpp
+++ b/src/platform/gui/sdl/Window.cpp
@@ -35,7 +35,7 @@ void SdlWindow::Close() {
 INativeWindow *SdlWindow::GetParent() { return parent_; }
 
 void SdlWindow::SetParent(INativeWindow *parent) {
-  parent_ = CheckPlatform<SdlWindow>(parent, GetPlatformIdUtf8());
+  parent_ = CheckPlatform<SdlWindow>(parent, GetPlatformId());
   NotImplemented();
 }
 
@@ -46,9 +46,9 @@ void SdlWindow::SetStyleFlag(WindowStyleFlag flag) {
   NotImplemented();
 }
 
-String SdlWindow::GetTitle() { NotImplemented(); }
+std::string SdlWindow::GetTitle() { NotImplemented(); }
 
-void SdlWindow::SetTitle(String title) { NotImplemented(); }
+void SdlWindow::SetTitle(std::string title) { NotImplemented(); }
 
 WindowVisibilityType SdlWindow::GetVisibility() { NotImplemented(); }
 
diff --git a/src/platform/gui/win/Window.cpp b/src/platform/gui/win/Window.cpp
index 5739d0f3..eeb2cde4 100644
--- a/src/platform/gui/win/Window.cpp
+++ b/src/platform/gui/win/Window.cpp
@@ -79,7 +79,7 @@ void WinNativeWindow::Close() {
 }
 
 void WinNativeWindow::SetParent(INativeWindow* parent) {
-  auto p = CheckPlatform<WinNativeWindow>(parent, GetPlatformIdUtf8());
+  auto p = CheckPlatform<WinNativeWindow>(parent, GetPlatformId());
   parent_window_ = p;
 
   if (hwnd_) {
@@ -228,7 +228,7 @@ void WinNativeWindow::SetCursor(std::shared_ptr<ICursor> cursor) {
     throw std::runtime_error("Can't use a nullptr as cursor.");
   }
 
-  cursor_ = CheckPlatform<WinCursor>(cursor, GetPlatformIdUtf8());
+  cursor_ = CheckPlatform<WinCursor>(cursor, GetPlatformId());
 
   if (hwnd_) return;
 
diff --git a/src/platform/gui/xcb/CMakeLists.txt b/src/platform/gui/xcb/CMakeLists.txt
index cafc2e67..676fc7b1 100644
--- a/src/platform/gui/xcb/CMakeLists.txt
+++ b/src/platform/gui/xcb/CMakeLists.txt
@@ -6,8 +6,8 @@ find_library(LIBRARY_XKBCOMMON_X11 xkbcommon-x11 REQUIRED)
 add_library(CruPlatformGuiXcb
 	Clipboard.cpp
 	Cursor.cpp
+	Input.cpp
 	InputMethod.cpp
-	Keyboard.cpp
 	UiApplication.cpp
 	Window.cpp
 )
diff --git a/src/platform/gui/xcb/Clipboard.cpp b/src/platform/gui/xcb/Clipboard.cpp
index d0d9d74f..a42130ab 100644
--- a/src/platform/gui/xcb/Clipboard.cpp
+++ b/src/platform/gui/xcb/Clipboard.cpp
@@ -7,7 +7,7 @@ XcbClipboard::XcbClipboard(XcbUiApplication* application)
 
 XcbClipboard::~XcbClipboard() {}
 
-String XcbClipboard::GetText() { return String{}; }
+std::string XcbClipboard::GetText() { return {}; }
 
-void XcbClipboard::SetText(String text) {}
+void XcbClipboard::SetText(std::string text) {}
 }  // namespace cru::platform::gui::xcb
diff --git a/src/platform/gui/xcb/Cursor.cpp b/src/platform/gui/xcb/Cursor.cpp
index 5582c6a6..69d904df 100644
--- a/src/platform/gui/xcb/Cursor.cpp
+++ b/src/platform/gui/xcb/Cursor.cpp
@@ -1,6 +1,5 @@
 #include "cru/platform/gui/xcb/Cursor.h"
 #include "cru/base/Exception.h"
-#include "cru/platform/gui/Cursor.h"
 #include "cru/platform/gui/xcb/UiApplication.h"
 
 #include <xcb/xcb.h>
diff --git a/src/platform/gui/xcb/Keyboard.cpp b/src/platform/gui/xcb/Input.cpp
index 4bfc448c..9b6d76c2 100644
--- a/src/platform/gui/xcb/Keyboard.cpp
+++ b/src/platform/gui/xcb/Input.cpp
@@ -1,7 +1,6 @@
-#include "cru/platform/gui/xcb/Keyboard.h"
+#include "cru/platform/gui/xcb/Input.h"
 #include "cru/base/Exception.h"
 #include "cru/base/Guard.h"
-#include "cru/platform/gui/Keyboard.h"
 #include "cru/platform/gui/xcb/UiApplication.h"
 
 #include <xcb/xcb.h>
@@ -200,11 +199,11 @@ KeyModifier ConvertModifiersOfEvent(uint32_t mask) {
   //     "Shift", "Lock",    "Ctrl",    "Alt",     "Mod2",    "Mod3",   "Mod4",
   //     "Mod5",  "Button1", "Button2", "Button3", "Button4", "Button5"};
   constexpr KeyModifier MODIFIERS[] = {
-      KeyModifiers::Shift, KeyModifiers::none, KeyModifiers::Ctrl,
-      KeyModifiers::Alt,   KeyModifiers::none, KeyModifiers::none,
-      KeyModifiers::none,  KeyModifiers::none, KeyModifiers::none,
-      KeyModifiers::none,  KeyModifiers::none, KeyModifiers::none,
-      KeyModifiers::none,
+      KeyModifiers::Shift, KeyModifiers::None, KeyModifiers::Ctrl,
+      KeyModifiers::Alt,   KeyModifiers::None, KeyModifiers::None,
+      KeyModifiers::None,  KeyModifiers::None, KeyModifiers::None,
+      KeyModifiers::None,  KeyModifiers::None, KeyModifiers::None,
+      KeyModifiers::None,
   };
 
   KeyModifier result;
diff --git a/src/platform/gui/xcb/InputMethod.cpp b/src/platform/gui/xcb/InputMethod.cpp
index 16d6b4bd..5ee06ab4 100644
--- a/src/platform/gui/xcb/InputMethod.cpp
+++ b/src/platform/gui/xcb/InputMethod.cpp
@@ -1,10 +1,7 @@
 #include "cru/platform/gui/xcb/InputMethod.h"
 #include "cru/base/log/Logger.h"
 #include "cru/platform/Check.h"
-#include "cru/platform/gui/InputMethod.h"
-#include "cru/platform/gui/Keyboard.h"
-#include "cru/platform/gui/Window.h"
-#include "cru/platform/gui/xcb/Keyboard.h"
+#include "cru/platform/gui/xcb/Input.h"
 #include "cru/platform/gui/xcb/UiApplication.h"
 #include "cru/platform/gui/xcb/Window.h"
 
@@ -99,7 +96,7 @@ void XcbXimInputMethodManager::DispatchCommit(xcb_xim_t *im, xcb_xic_t ic,
   if (focus_context_) {
     focus_context_->composition_event_.Raise(nullptr);
     focus_context_->composition_end_event_.Raise(nullptr);
-    focus_context_->text_event_.Raise(String::FromUtf8(text));
+    focus_context_->text_event_.Raise(std::move(text));
   }
 }
 
@@ -135,7 +132,7 @@ XcbXimInputMethodContext::XcbXimInputMethodContext(
 
   window->FocusEvent()->AddHandler([this, window](FocusChangeType type) {
     auto context = CheckPlatform<XcbXimInputMethodContext>(
-        window->GetInputMethodContext(), GetPlatformIdUtf8());
+        window->GetInputMethodContext(), GetPlatformId());
     if (type == FocusChangeType::Gain) {
       SetFocus();
     }
@@ -208,7 +205,7 @@ IEvent<std::nullptr_t> *XcbXimInputMethodContext::CompositionEvent() {
   return &composition_event_;
 }
 
-IEvent<StringView> *XcbXimInputMethodContext::TextEvent() {
+IEvent<std::string> *XcbXimInputMethodContext::TextEvent() {
   return &text_event_;
 }
 
diff --git a/src/platform/gui/xcb/UiApplication.cpp b/src/platform/gui/xcb/UiApplication.cpp
index a0a949b7..436bb335 100644
--- a/src/platform/gui/xcb/UiApplication.cpp
+++ b/src/platform/gui/xcb/UiApplication.cpp
@@ -1,13 +1,12 @@
 #include "cru/platform/gui/xcb/UiApplication.h"
 
-#include "cru/base/Base.h"
 #include "cru/base/Guard.h"
 #include "cru/platform/graphics/cairo/CairoGraphicsFactory.h"
 #include "cru/platform/gui/Window.h"
 #include "cru/platform/gui/xcb/Clipboard.h"
 #include "cru/platform/gui/xcb/Cursor.h"
+#include "cru/platform/gui/xcb/Input.h"
 #include "cru/platform/gui/xcb/InputMethod.h"
-#include "cru/platform/gui/xcb/Keyboard.h"
 #include "cru/platform/gui/xcb/Window.h"
 
 #include <poll.h>
diff --git a/src/platform/gui/xcb/Window.cpp b/src/platform/gui/xcb/Window.cpp
index 6458046b..003afc40 100644
--- a/src/platform/gui/xcb/Window.cpp
+++ b/src/platform/gui/xcb/Window.cpp
@@ -7,12 +7,9 @@
 #include "cru/platform/graphics/NullPainter.h"
 #include "cru/platform/graphics/Painter.h"
 #include "cru/platform/graphics/cairo/CairoPainter.h"
-#include "cru/platform/gui/Base.h"
-#include "cru/platform/gui/Keyboard.h"
-#include "cru/platform/gui/Window.h"
 #include "cru/platform/gui/xcb/Cursor.h"
+#include "cru/platform/gui/xcb/Input.h"
 #include "cru/platform/gui/xcb/InputMethod.h"
-#include "cru/platform/gui/xcb/Keyboard.h"
 #include "cru/platform/gui/xcb/UiApplication.h"
 
 #include <cairo-xcb.h>
@@ -73,7 +70,7 @@ void XcbWindow::Close() {
 INativeWindow *XcbWindow::GetParent() { return parent_; }
 
 void XcbWindow::SetParent(INativeWindow *parent) {
-  parent_ = CheckPlatform<XcbWindow>(parent, GetPlatformIdUtf8());
+  parent_ = CheckPlatform<XcbWindow>(parent, GetPlatformId());
   if (xcb_window_) {
     DoSetParent(*xcb_window_);
   }
@@ -90,10 +87,10 @@ void XcbWindow::SetStyleFlag(WindowStyleFlag flag) {
   application_->XcbFlush();
 }
 
-String XcbWindow::GetTitle() { return String::FromUtf8(title_); }
+std::string XcbWindow::GetTitle() { return title_; }
 
-void XcbWindow::SetTitle(String title) {
-  title_ = title.ToUtf8();
+void XcbWindow::SetTitle(std::string title) {
+  title_ = std::move(title);
   if (xcb_window_) {
     DoSetTitle(*xcb_window_);
   }
@@ -271,7 +268,7 @@ bool XcbWindow::ReleaseMouse() {
 
 void XcbWindow::SetCursor(std::shared_ptr<ICursor> cursor) {
   if (!xcb_window_) return;
-  auto xcb_cursor = CheckPlatform<XcbCursor>(cursor, GetPlatformIdUtf8());
+  auto xcb_cursor = CheckPlatform<XcbCursor>(cursor, GetPlatformId());
   cursor_ = xcb_cursor;
   DoSetCursor(*xcb_window_, xcb_cursor.get());
 }