...

14 files changed, 193 insertions, 155 deletions

diff --git a/demos/input_method/main.cpp b/demos/input_method/main.cpp
index a3ac1b96..74654a2d 100644
--- a/demos/input_method/main.cpp
+++ b/demos/input_method/main.cpp
@@ -92,7 +92,7 @@ int main() {
                               gsl::narrow_cast<int>(committed_text.size());
 
       const auto cursor_lefttop =
-          text_layout->TextSingleRect(cursor_pos, false);
+          text_layout->TextSinglePoint(cursor_pos, false);
 
       painter->FillRectangle(Rect{cursor_lefttop.x, cursor_lefttop.y + anchor_y,
                                   3, font->GetFontSize()},
diff --git a/include/cru/platform/graph/text_layout.hpp b/include/cru/platform/graph/text_layout.hpp
index 0d104742..d91834c0 100644
--- a/include/cru/platform/graph/text_layout.hpp
+++ b/include/cru/platform/graph/text_layout.hpp
@@ -17,7 +17,7 @@ struct ITextLayout : virtual IGraphResource {
 
   virtual Rect GetTextBounds() = 0;
   virtual std::vector<Rect> TextRangeRect(const TextRange& text_range) = 0;
-  virtual Point TextSingleRect(gsl::index position, bool trailing) = 0;
+  virtual Point TextSinglePoint(gsl::index position, bool trailing) = 0;
   virtual TextHitTestResult HitTest(const Point& point) = 0;
 };
 }  // namespace cru::platform::graph
diff --git a/include/cru/platform/native/ui_application.hpp b/include/cru/platform/native/ui_application.hpp
index 006255db..afcc7117 100644
--- a/include/cru/platform/native/ui_application.hpp
+++ b/include/cru/platform/native/ui_application.hpp
@@ -32,11 +32,16 @@ struct IUiApplication : public virtual INativeResource {
   virtual void AddOnQuitHandler(std::function<void()> handler) = 0;
 
   virtual void InvokeLater(std::function<void()> action) = 0;
-  virtual unsigned long SetTimeout(std::chrono::milliseconds milliseconds,
-                                   std::function<void()> action) = 0;
-  virtual unsigned long SetInterval(std::chrono::milliseconds milliseconds,
-                                    std::function<void()> action) = 0;
-  virtual void CancelTimer(unsigned long id) = 0;
+  // Timer id should always be positive and never the same. So it's ok to use
+  // negative value to represent no timer.
+  virtual long long SetTimeout(std::chrono::milliseconds milliseconds,
+                               std::function<void()> action) = 0;
+  virtual long long SetInterval(std::chrono::milliseconds milliseconds,
+                                std::function<void()> action) = 0;
+  // Implementation should guarantee calls on timer id already canceled have no
+  // effects and do not crash. Also canceling negative id should always result
+  // in no-op.
+  virtual void CancelTimer(long long id) = 0;
 
   virtual std::vector<INativeWindow*> GetAllWindow() = 0;
   virtual std::shared_ptr<INativeWindowResolver> CreateWindow(
diff --git a/include/cru/ui/controls/text_block.hpp b/include/cru/ui/controls/text_block.hpp
index ec61a08c..61f568c4 100644
--- a/include/cru/ui/controls/text_block.hpp
+++ b/include/cru/ui/controls/text_block.hpp
@@ -29,14 +29,9 @@ class TextBlock : public NoChildControl {
   void SetText(std::string text);
 
   render::TextRenderObject* GetTextRenderObject();
-  render::CanvasRenderObject* GetCaretRenderObject();
-  std::shared_ptr<platform::graph::IBrush> GetCaretBrush();
 
  private:
-  std::unique_ptr<render::StackLayoutRenderObject> root_render_object_;
   std::unique_ptr<render::TextRenderObject> text_render_object_;
-  std::unique_ptr<render::CanvasRenderObject> caret_render_object_;
-  std::shared_ptr<platform::graph::IBrush> caret_brush_;
 
   std::unique_ptr<TextControlService<TextBlock>> service_;
 };
diff --git a/include/cru/ui/controls/text_box.hpp b/include/cru/ui/controls/text_box.hpp
index f5347430..c0160658 100644
--- a/include/cru/ui/controls/text_box.hpp
+++ b/include/cru/ui/controls/text_box.hpp
@@ -22,8 +22,6 @@ class TextBox : public NoChildControl {
   std::string_view GetControlType() const final { return control_type; }
 
   render::TextRenderObject* GetTextRenderObject();
-  render::CanvasRenderObject* GetCaretRenderObject();
-  std::shared_ptr<platform::graph::IBrush> GetCaretBrush();
 
   const TextBoxBorderStyle& GetBorderStyle();
   void SetBorderStyle(TextBoxBorderStyle border_style);
@@ -36,11 +34,8 @@ class TextBox : public NoChildControl {
 
  private:
   std::unique_ptr<render::BorderRenderObject> border_render_object_;
-  std::unique_ptr<render::StackLayoutRenderObject> stack_layout_render_object_;
   std::unique_ptr<render::TextRenderObject> text_render_object_;
-  std::unique_ptr<render::CanvasRenderObject> caret_render_object_;
 
-  std::shared_ptr<platform::graph::IBrush> caret_brush_;
   TextBoxBorderStyle border_style_;
 
   std::unique_ptr<TextControlService<TextBox>> service_;
diff --git a/include/cru/ui/render/text_render_object.hpp b/include/cru/ui/render/text_render_object.hpp
index c062c9f0..4b1e91e0 100644
--- a/include/cru/ui/render/text_render_object.hpp
+++ b/include/cru/ui/render/text_render_object.hpp
@@ -6,9 +6,13 @@
 namespace cru::ui::render {
 class TextRenderObject : public RenderObject {
  public:
+  constexpr static float default_caret_width = 2;
+
+ public:
   TextRenderObject(std::shared_ptr<platform::graph::IBrush> brush,
                    std::shared_ptr<platform::graph::IFont> font,
-                   std::shared_ptr<platform::graph::IBrush> selection_brush);
+                   std::shared_ptr<platform::graph::IBrush> selection_brush,
+                   std::shared_ptr<platform::graph::IBrush> caret_brush);
   TextRenderObject(const TextRenderObject& other) = delete;
   TextRenderObject(TextRenderObject&& other) = delete;
   TextRenderObject& operator=(const TextRenderObject& other) = delete;
@@ -19,30 +23,41 @@ class TextRenderObject : public RenderObject {
   void SetText(std::string new_text);
 
   std::shared_ptr<platform::graph::IBrush> GetBrush() const { return brush_; }
-  void SetBrush(std::shared_ptr<platform::graph::IBrush> new_brush) {
-    new_brush.swap(brush_);
-  }
+  void SetBrush(std::shared_ptr<platform::graph::IBrush> new_brush);
 
   std::shared_ptr<platform::graph::IFont> GetFont() const;
   void SetFont(std::shared_ptr<platform::graph::IFont> font);
 
   std::vector<Rect> TextRangeRect(const TextRange& text_range);
-  Point TextSingleRect(gsl::index position, bool trailing);
+  Point TextSinglePoint(gsl::index position, bool trailing);
   platform::graph::TextHitTestResult TextHitTest(const Point& point);
 
   std::optional<TextRange> GetSelectionRange() const {
     return selection_range_;
   }
-  void SetSelectionRange(std::optional<TextRange> new_range) {
-    selection_range_ = std::move(new_range);
-  }
+  void SetSelectionRange(std::optional<TextRange> new_range);
 
   std::shared_ptr<platform::graph::IBrush> GetSelectionBrush() const {
     return selection_brush_;
   }
-  void SetSelectionBrush(std::shared_ptr<platform::graph::IBrush> new_brush) {
-    new_brush.swap(selection_brush_);
+  void SetSelectionBrush(std::shared_ptr<platform::graph::IBrush> new_brush);
+
+  bool IsDrawCaret() const { return draw_caret_; }
+  void SetDrawCaret(bool draw_caret);
+  void ToggleDrawCaret() { SetDrawCaret(!IsDrawCaret()); }
+
+  // Caret position can be any value. When it is negative, 0 is used. When it
+  // exceeds the size of the string, the size of the string is used.
+  gsl::index GetCaretPosition() const { return caret_position_; }
+  void SetCaretPosition(gsl::index position);
+
+  std::shared_ptr<platform::graph::IBrush> GetCaretBrush() const {
+    return caret_brush_;
   }
+  void GetCaretBrush(std::shared_ptr<platform::graph::IBrush> brush);
+
+  float GetCaretWidth() const { return caret_width_; }
+  void SetCaretWidth(float width);
 
   void Draw(platform::graph::IPainter* painter) override;
 
@@ -61,5 +76,10 @@ class TextRenderObject : public RenderObject {
 
   std::optional<TextRange> selection_range_ = std::nullopt;
   std::shared_ptr<platform::graph::IBrush> selection_brush_;
+
+  bool draw_caret_ = false;
+  gsl::index caret_position_ = 0;
+  std::shared_ptr<platform::graph::IBrush> caret_brush_;
+  float caret_width_ = default_caret_width;
 };
 }  // namespace cru::ui::render
diff --git a/include/cru/win/graph/direct/text_layout.hpp b/include/cru/win/graph/direct/text_layout.hpp
index 90faadf9..2870db96 100644
--- a/include/cru/win/graph/direct/text_layout.hpp
+++ b/include/cru/win/graph/direct/text_layout.hpp
@@ -40,7 +40,7 @@ class DWriteTextLayout : public DirectGraphResource,
   // Return empty vector if text_range.count is 0. Text range could be in
   // reverse direction, it should be normalized first in implementation.
   std::vector<Rect> TextRangeRect(const TextRange& text_range) override;
-  Point TextSingleRect(gsl::index position, bool trailing) override;
+  Point TextSinglePoint(gsl::index position, bool trailing) override;
   TextHitTestResult HitTest(const Point& point) override;
 
  private:
diff --git a/include/cru/win/native/ui_application.hpp b/include/cru/win/native/ui_application.hpp
index 1c54cc05..250e855c 100644
--- a/include/cru/win/native/ui_application.hpp
+++ b/include/cru/win/native/ui_application.hpp
@@ -33,11 +33,11 @@ class WinUiApplication : public WinNativeResource,
   void AddOnQuitHandler(std::function<void()> handler) override;
 
   void InvokeLater(std::function<void()> action) override;
-  unsigned long SetTimeout(std::chrono::milliseconds milliseconds,
-                           std::function<void()> action) override;
-  unsigned long SetInterval(std::chrono::milliseconds milliseconds,
-                            std::function<void()> action) override;
-  void CancelTimer(unsigned long id) override;
+  long long SetTimeout(std::chrono::milliseconds milliseconds,
+                       std::function<void()> action) override;
+  long long SetInterval(std::chrono::milliseconds milliseconds,
+                        std::function<void()> action) override;
+  void CancelTimer(long long id) override;
 
   std::vector<INativeWindow*> GetAllWindow() override;
   std::shared_ptr<INativeWindowResolver> CreateWindow(
diff --git a/src/ui/controls/text_block.cpp b/src/ui/controls/text_block.cpp
index 1c20540d..a3ec9f54 100644
--- a/src/ui/controls/text_block.cpp
+++ b/src/ui/controls/text_block.cpp
@@ -11,24 +11,14 @@ using render::CanvasRenderObject;
 using render::StackLayoutRenderObject;
 using render::TextRenderObject;
 
-TextBlock::TextBlock()
-    : root_render_object_(new StackLayoutRenderObject()),
-      text_render_object_(),
-      caret_render_object_(new CanvasRenderObject()) {
+TextBlock::TextBlock() {
   const auto theme_resources = UiManager::GetInstance()->GetThemeResources();
 
   text_render_object_ = std::make_unique<TextRenderObject>(
       theme_resources->text_brush, theme_resources->default_font,
-      theme_resources->text_selection_brush);
+      theme_resources->text_selection_brush, theme_resources->caret_brush);
 
-  root_render_object_->AddChild(text_render_object_.get(), 0);
-  root_render_object_->AddChild(caret_render_object_.get(), 1);
-
-  root_render_object_->SetAttachedControl(this);
   text_render_object_->SetAttachedControl(this);
-  caret_render_object_->SetAttachedControl(this);
-
-  caret_brush_ = theme_resources->caret_brush;
 
   service_ = std::make_unique<TextControlService<TextBlock>>(this);
   service_->SetEnabled(true);
@@ -37,7 +27,7 @@ TextBlock::TextBlock()
 TextBlock::~TextBlock() = default;
 
 render::RenderObject* TextBlock::GetRenderObject() const {
-  return root_render_object_.get();
+  return text_render_object_.get();
 }
 
 std::string TextBlock::GetText() const {
@@ -51,12 +41,4 @@ void TextBlock::SetText(std::string text) {
 render::TextRenderObject* TextBlock::GetTextRenderObject() {
   return text_render_object_.get();
 }
-
-render::CanvasRenderObject* TextBlock::GetCaretRenderObject() {
-  return caret_render_object_.get();
-}
-
-std::shared_ptr<platform::graph::IBrush> TextBlock::GetCaretBrush() {
-  return caret_brush_;
-}
 }  // namespace cru::ui::controls
diff --git a/src/ui/controls/text_box.cpp b/src/ui/controls/text_box.cpp
index 99164b9b..7b63eea1 100644
--- a/src/ui/controls/text_box.cpp
+++ b/src/ui/controls/text_box.cpp
@@ -13,29 +13,22 @@ using render::CanvasRenderObject;
 using render::StackLayoutRenderObject;
 using render::TextRenderObject;
 
-TextBox::TextBox()
-    : border_render_object_(new BorderRenderObject()),
-      stack_layout_render_object_(new StackLayoutRenderObject()),
-      text_render_object_(),
-      caret_render_object_(new CanvasRenderObject()),
-      service_(new TextControlService<TextBox>(this)) {
+TextBox::TextBox() : border_render_object_(new BorderRenderObject()) {
   const auto theme_resources = UiManager::GetInstance()->GetThemeResources();
 
-  caret_brush_ = theme_resources->caret_brush;
   border_style_ = theme_resources->text_box_border_style;
 
   text_render_object_ = std::make_unique<TextRenderObject>(
       theme_resources->text_brush, theme_resources->default_font,
-      theme_resources->text_selection_brush);
+      theme_resources->text_selection_brush, theme_resources->caret_brush);
 
-  border_render_object_->AddChild(stack_layout_render_object_.get(), 0);
-  stack_layout_render_object_->AddChild(text_render_object_.get(), 0);
-  stack_layout_render_object_->AddChild(caret_render_object_.get(), 1);
+  border_render_object_->AddChild(text_render_object_.get(), 0);
 
   border_render_object_->SetAttachedControl(this);
-  stack_layout_render_object_->SetAttachedControl(this);
   text_render_object_->SetAttachedControl(this);
-  caret_render_object_->SetAttachedControl(this);
+
+  service_ = std::make_unique<TextControlService<TextBox>>(this);
+  service_->SetEnabled(true);
 
   GainFocusEvent()->Direct()->AddHandler([this](event::FocusChangeEventArgs&) {
     this->service_->SetEnabled(true);
@@ -54,14 +47,6 @@ render::TextRenderObject* TextBox::GetTextRenderObject() {
   return text_render_object_.get();
 }
 
-render::CanvasRenderObject* TextBox::GetCaretRenderObject() {
-  return caret_render_object_.get();
-}
-
-std::shared_ptr<platform::graph::IBrush> TextBox::GetCaretBrush() {
-  return caret_brush_;
-}
-
 const TextBoxBorderStyle& TextBox::GetBorderStyle() { return border_style_; }
 
 void TextBox::SetBorderStyle(TextBoxBorderStyle border_style) {
diff --git a/src/ui/controls/text_control_service.hpp b/src/ui/controls/text_control_service.hpp
index 0da8abed..57a6efa7 100644
--- a/src/ui/controls/text_control_service.hpp
+++ b/src/ui/controls/text_control_service.hpp
@@ -1,4 +1,5 @@
 #pragma once
+#include "../helper.hpp"
 #include "cru/common/logger.hpp"
 #include "cru/platform/graph/font.hpp"
 #include "cru/platform/graph/painter.hpp"
@@ -15,8 +16,6 @@ constexpr long long caret_blink_duration = 500;
 // TControl should inherits `Control` and has following methods:
 // ```
 // render::TextRenderObject* GetTextRenderObject();
-// render::CanvasRenderObject* GetCaretRenderObject();
-// std::shared_ptr<platform::graph::IBrush> GetCaretBrush();
 // ```
 template <typename TControl>
 class TextControlService : public Object {
@@ -44,8 +43,8 @@ class TextControlService : public Object {
  private:
   void AbortSelection();
 
-  void SetupCaretTimer();
-  void TearDownCaretTimer();
+  void SetupCaret();
+  void TearDownCaret();
 
   void SetupHandlers();
 
@@ -62,12 +61,7 @@ class TextControlService : public Object {
 
   bool caret_visible_ = false;
   int caret_position_ = 0;
-#ifdef CRU_DEBUG
-  bool caret_timer_set_ = false;
-#endif
-  unsigned long caret_timer_tag_;
-  // this is used for blinking of caret
-  bool caret_show_ = true;
+  long long caret_timer_id_ = -1;
 
   // nullopt means not selecting
   std::optional<MouseButton> select_down_button_;
@@ -82,101 +76,86 @@ TextControlService<TControl>::TextControlService(TControl* control)
 
 template <typename TControl>
 TextControlService<TControl>::~TextControlService() {
-  if (enable_ && caret_visible_) TearDownCaretTimer();
+  const auto application = GetUiApplication();
+  // Don't call TearDownCaret, because it use text render object of control,
+  // which may be destroyed already.
+  application->CancelTimer(this->caret_timer_id_);
 }
 
 template <typename TControl>
 void TextControlService<TControl>::SetEnabled(bool enable) {
-  if (enable == enable_) return;
+  if (enable == this->enable_) return;
   if (enable) {
-    AbortSelection();
-    SetupHandlers();
-    if (caret_visible_) {
-      SetupCaretTimer();
+    this->SetupHandlers();
+    if (this->caret_visible_) {
+      this->SetupCaret();
     }
   } else {
-    event_revoker_guards_.clear();
-    if (caret_visible_) {
-      TearDownCaretTimer();
-    }
+    this->AbortSelection();
+    this->event_revoker_guards_.clear();
+    this->TearDownCaret();
   }
 }
 
 template <typename TControl>
 void TextControlService<TControl>::SetCaretVisible(bool visible) {
-  if (visible == caret_visible_) return;
+  if (visible == this->caret_visible_) return;
+
+  this->caret_visible_ = visible;
 
-  if (enable_) {
+  if (this->enable_) {
     if (visible) {
-      SetupCaretTimer();
+      this->SetupCaretTimer();
+    } else {
+      this->TearDownCaretTimer();
     }
-  } else {
-    TearDownCaretTimer();
   }
 }  // namespace cru::ui::controls
 
 template <typename TControl>
-void TextControlService<TControl>::DrawCaret(
-    platform::graph::IPainter* painter) {
-  if (caret_show_) {
-    const auto text_render_object = control_->GetTextRenderObject();
-    const auto point = text_render_object->TextSingleRect(
-        caret_position_, false);  // Maybe cache the result???
-    painter->FillRectangle(
-        Rect{point,
-             Size{caret_width, text_render_object->GetFont()->GetFontSize()}},
-        control_->GetCaretBrush().get());
-  }
-}
-
-template <typename TControl>
 void TextControlService<TControl>::AbortSelection() {
-  if (select_down_button_.has_value()) {
-    control_->ReleaseMouse();
-    select_down_button_ = std::nullopt;
+  if (this->select_down_button_.has_value()) {
+    this->control_->ReleaseMouse();
+    this->select_down_button_ = std::nullopt;
   }
-  control_->GetTextRenderObject()->SetSelectionRange(std::nullopt);
+  this->control_->GetTextRenderObject()->SetSelectionRange(std::nullopt);
 }
 
 template <typename TControl>
-void TextControlService<TControl>::SetupCaretTimer() {
-#ifdef CRU_DEBUG
-  Expects(!caret_timer_set_);
-  caret_timer_set_ = true;
-#endif
-  caret_timer_tag_ =
-      platform::native::IUiApplication::GetInstance()->SetInterval(
-          std::chrono::milliseconds(caret_blink_duration), [this] {
-            this->caret_show_ = !this->caret_show_;
-            this->control_->GetCaretRenderObject()->InvalidatePaint();
-          });
+void TextControlService<TControl>::SetupCaret() {
+  const auto application = GetUiApplication();
+
+  // Cancel first anyhow for safety.
+  application->CancelTimer(this->caret_timer_id_);
+
+  this->control_->GetTextRenderObject()->SetDrawCaret(true);
+  this->caret_timer_id_ = application->SetInterval(
+      std::chrono::milliseconds(caret_blink_duration),
+      [this] { this->control_->GetTextRenderObject()->ToggleDrawCaret(); });
 }
 
 template <typename TControl>
-void TextControlService<TControl>::TearDownCaretTimer() {
-#ifdef CRU_DEBUG
-  Expects(!caret_timer_set_);
-  caret_timer_set_ = false;
-#endif
-  platform::native::IUiApplication::GetInstance()->CancelTimer(
-      caret_timer_tag_);
+void TextControlService<TControl>::TearDownCaret() {
+  const auto application = GetUiApplication();
+  application->CancelTimer(this->caret_timer_id_);
+  this->control_->GetTextRenderObject()->SetDrawCaret(false);
 }
 
 template <typename TControl>
 void TextControlService<TControl>::SetupHandlers() {
   Expects(event_revoker_guards_.empty());
-  event_revoker_guards_.push_back(
+  this->event_revoker_guards_.push_back(
       EventRevokerGuard{control_->MouseMoveEvent()->Direct()->AddHandler(
           std::bind(&TextControlService::MouseMoveHandler, this,
                     std::placeholders::_1))});
-  event_revoker_guards_.push_back(
+  this->event_revoker_guards_.push_back(
       EventRevokerGuard{control_->MouseDownEvent()->Direct()->AddHandler(
           std::bind(&TextControlService::MouseDownHandler, this,
                     std::placeholders::_1))});
-  event_revoker_guards_.push_back(EventRevokerGuard{
+  this->event_revoker_guards_.push_back(EventRevokerGuard{
       control_->MouseUpEvent()->Direct()->AddHandler(std::bind(
           &TextControlService::MouseUpHandler, this, std::placeholders::_1))});
-  event_revoker_guards_.push_back(
+  this->event_revoker_guards_.push_back(
       EventRevokerGuard{control_->LoseFocusEvent()->Direct()->AddHandler(
           std::bind(&TextControlService::LoseFocusHandler, this,
                     std::placeholders::_1))});
@@ -199,8 +178,6 @@ void TextControlService<TControl>::MouseMoveHandler(
         TextRange::FromTwoSides(
             static_cast<unsigned>(position),
             static_cast<unsigned>(this->select_start_position_)));
-    this->control_->GetTextRenderObject()->InvalidatePaint();
-    this->control_->GetCaretRenderObject()->InvalidatePaint();
   }
 }
 
diff --git a/src/ui/render/text_render_object.cpp b/src/ui/render/text_render_object.cpp
index e8368480..cd670db1 100644
--- a/src/ui/render/text_render_object.cpp
+++ b/src/ui/render/text_render_object.cpp
@@ -7,22 +7,23 @@
 
 #include <algorithm>
 
-// TODO: Null Check!!!
-
 namespace cru::ui::render {
 TextRenderObject::TextRenderObject(
     std::shared_ptr<platform::graph::IBrush> brush,
     std::shared_ptr<platform::graph::IFont> font,
-    std::shared_ptr<platform::graph::IBrush> selection_brush) {
+    std::shared_ptr<platform::graph::IBrush> selection_brush,
+    std::shared_ptr<platform::graph::IBrush> caret_brush) {
   Expects(brush);
   Expects(font);
   Expects(selection_brush);
+  Expects(caret_brush);
 
   SetChildMode(ChildMode::None);
 
   brush.swap(brush_);
   font.swap(font_);
   selection_brush.swap(selection_brush_);
+  caret_brush.swap(caret_brush_);
 
   const auto graph_factory = GetGraphFactory();
   text_layout_ = graph_factory->CreateTextLayout(font_, "");
@@ -38,11 +39,19 @@ void TextRenderObject::SetText(std::string new_text) {
   text_layout_->SetText(std::move(new_text));
 }
 
+void TextRenderObject::SetBrush(
+    std::shared_ptr<platform::graph::IBrush> new_brush) {
+  Expects(new_brush);
+  new_brush.swap(brush_);
+  InvalidatePaint();
+}
+
 std::shared_ptr<platform::graph::IFont> TextRenderObject::GetFont() const {
   return text_layout_->GetFont();
 }
 
 void TextRenderObject::SetFont(std::shared_ptr<platform::graph::IFont> font) {
+  Expects(font);
   text_layout_->SetFont(std::move(font));
 }
 
@@ -50,8 +59,8 @@ std::vector<Rect> TextRenderObject::TextRangeRect(const TextRange& text_range) {
   return text_layout_->TextRangeRect(text_range);
 }
 
-Point TextRenderObject::TextSingleRect(gsl::index position, bool trailing) {
-  return text_layout_->TextSingleRect(position, trailing);
+Point TextRenderObject::TextSinglePoint(gsl::index position, bool trailing) {
+  return text_layout_->TextSinglePoint(position, trailing);
 }
 
 platform::graph::TextHitTestResult TextRenderObject::TextHitTest(
@@ -59,6 +68,54 @@ platform::graph::TextHitTestResult TextRenderObject::TextHitTest(
   return text_layout_->HitTest(point);
 }
 
+void TextRenderObject::SetSelectionRange(std::optional<TextRange> new_range) {
+  selection_range_ = std::move(new_range);
+  InvalidatePaint();
+}
+
+void TextRenderObject::SetSelectionBrush(
+    std::shared_ptr<platform::graph::IBrush> new_brush) {
+  Expects(new_brush);
+  new_brush.swap(selection_brush_);
+  if (selection_range_ && selection_range_->count) {
+    InvalidatePaint();
+  }
+}
+
+void TextRenderObject::SetDrawCaret(bool draw_caret) {
+  if (draw_caret_ != draw_caret) {
+    draw_caret_ = draw_caret;
+    InvalidatePaint();
+  }
+}
+
+void TextRenderObject::SetCaretPosition(gsl::index position) {
+  if (position != caret_position_) {
+    caret_position_ = position;
+    if (draw_caret_) {
+      InvalidatePaint();
+    }
+  }
+}
+
+void TextRenderObject::GetCaretBrush(
+    std::shared_ptr<platform::graph::IBrush> brush) {
+  Expects(brush);
+  brush.swap(caret_brush_);
+  if (draw_caret_) {
+    InvalidatePaint();
+  }
+}
+
+void TextRenderObject::SetCaretWidth(const float width) {
+  Expects(width >= 0.0f);
+
+  caret_width_ = width;
+  if (draw_caret_) {
+    InvalidatePaint();
+  }
+}
+
 void TextRenderObject::Draw(platform::graph::IPainter* painter) {
   platform::graph::util::WithTransform(
       painter,
@@ -71,7 +128,28 @@ void TextRenderObject::Draw(platform::graph::IPainter* painter) {
           for (const auto& rect : rects)
             p->FillRectangle(rect, this->GetSelectionBrush().get());
         }
+
         p->DrawText(Point{}, text_layout_.get(), brush_.get());
+
+        if (this->draw_caret_ && this->caret_width_ != 0.0f) {
+          auto caret_pos = this->caret_position_;
+          gsl::index text_size = this->GetText().size();
+          if (caret_pos < 0) {
+            caret_pos = 0;
+          } else if (caret_pos > text_size) {
+            caret_pos = text_size;
+          }
+
+          const auto caret_top_center =
+              this->text_layout_->TextSinglePoint(caret_pos, false);
+
+          const auto font_height = this->font_->GetFontSize();
+          const auto caret_width = this->caret_width_;
+
+          p->FillRectangle(Rect{caret_top_center.x - caret_width / 2.0f,
+                                caret_top_center.y, caret_width, font_height},
+                           this->caret_brush_.get());
+        }
       });
 }
 
diff --git a/src/win/graph/direct/text_layout.cpp b/src/win/graph/direct/text_layout.cpp
index 4a742694..7b8d2ab0 100644
--- a/src/win/graph/direct/text_layout.cpp
+++ b/src/win/graph/direct/text_layout.cpp
@@ -105,7 +105,7 @@ std::vector<Rect> DWriteTextLayout::TextRangeRect(
   return result;
 }
 
-Point DWriteTextLayout::TextSingleRect(gsl::index position, bool trailing) {
+Point DWriteTextLayout::TextSinglePoint(gsl::index position, bool trailing) {
   const auto index =
       IndexUtf8ToUtf16(text_, static_cast<int>(position), w_text_);
 
diff --git a/src/win/native/ui_application.cpp b/src/win/native/ui_application.cpp
index 9aa3ebcd..599ecadc 100644
--- a/src/win/native/ui_application.cpp
+++ b/src/win/native/ui_application.cpp
@@ -73,19 +73,20 @@ void WinUiApplication::InvokeLater(std::function<void()> action) {
     throw Win32Error(::GetLastError(), "InvokeLater failed to post message.");
 }
 
-unsigned long WinUiApplication::SetTimeout(
-    std::chrono::milliseconds milliseconds, std::function<void()> action) {
-  return static_cast<unsigned long>(timer_manager_->CreateTimer(
+long long WinUiApplication::SetTimeout(std::chrono::milliseconds milliseconds,
+                                       std::function<void()> action) {
+  return gsl::narrow<long long>(timer_manager_->CreateTimer(
       static_cast<UINT>(milliseconds.count()), false, std::move(action)));
 }
 
-unsigned long WinUiApplication::SetInterval(
-    std::chrono::milliseconds milliseconds, std::function<void()> action) {
-  return static_cast<unsigned long>(timer_manager_->CreateTimer(
+long long WinUiApplication::SetInterval(std::chrono::milliseconds milliseconds,
+                                        std::function<void()> action) {
+  return gsl::narrow<long long>(timer_manager_->CreateTimer(
       static_cast<UINT>(milliseconds.count()), true, std::move(action)));
 }
 
-void WinUiApplication::CancelTimer(unsigned long id) {
+void WinUiApplication::CancelTimer(long long id) {
+  if (id < 0) return;
   timer_manager_->KillTimer(static_cast<UINT_PTR>(id));
 }