Bring back ControlHost and refactor tree management of control.

1 files changed, 424 insertions, 0 deletions

diff --git a/src/ui/controls/ControlHost.cpp b/src/ui/controls/ControlHost.cpp
new file mode 100644
index 00000000..09639465
--- /dev/null
+++ b/src/ui/controls/ControlHost.cpp
@@ -0,0 +1,424 @@
+#include "cru/ui/controls/ControlHost.h"
+
+#include "cru/platform/gui/UiApplication.h"
+#include "cru/platform/gui/Window.h"
+#include "cru/ui/Base.h"
+
+#include <cassert>
+
+namespace cru::ui::controls {
+ControlHost::ControlHost(Control* root_control)
+    : event_handling_count_(0),
+      root_control_(root_control),
+      native_window_(CreateNativeWindow()),
+      focus_control_(root_control),
+      mouse_hover_control_(nullptr),
+      mouse_captured_control_(nullptr),
+      layout_prefer_to_fill_window_(true) {
+  root_control->TraverseDescendents(
+      [this](Control* control) { control->host_ = this; }, true);
+}
+
+ControlHost::~ControlHost() {}
+
+platform::gui::INativeWindow* ControlHost::GetNativeWindow() {
+  return native_window_.get();
+}
+
+namespace {
+template <typename T>
+inline void BindNativeEvent(
+    ControlHost* host, platform::gui::INativeWindow* native_window,
+    IEvent<T>* event,
+    void (ControlHost::*handler)(platform::gui::INativeWindow*,
+                                 typename IEvent<T>::Args)) {
+  event->AddHandler(
+      std::bind(handler, host, native_window, std::placeholders::_1));
+}
+}  // namespace
+
+namespace {
+bool IsAncestor(Control* control, Control* ancestor) {
+  while (control != nullptr) {
+    if (control == ancestor) return true;
+    control = control->GetParent();
+  }
+  return false;
+}
+
+// Ancestor at last.
+std::vector<Control*> GetAncestorList(Control* control) {
+  if (control == nullptr) return {};
+
+  std::vector<Control*> l;
+  while (control != nullptr) {
+    l.push_back(control);
+    control = control->GetParent();
+  }
+  return l;
+}
+
+Control* FindLowestCommonAncestor(Control* left, Control* right) {
+  if (left == nullptr || right == nullptr) return nullptr;
+
+  auto&& left_list = GetAncestorList(left);
+  auto&& right_list = GetAncestorList(right);
+
+  // the root is different
+  if (left_list.back() != right_list.back()) return nullptr;
+
+  // find the last same control or the last control (one is ancestor of the
+  // other)
+  auto left_iter = left_list.crbegin();
+  auto right_iter = right_list.crbegin();
+
+  while (true) {
+    if (left_iter == left_list.crend()) {
+      return left_list.front();
+    }
+    if (right_iter == right_list.crend()) {
+      return right_list.front();
+    }
+    if (*left_iter != *right_iter) {
+      return *(--left_iter);
+    }
+    ++left_iter;
+    ++right_iter;
+  }
+}
+}  // namespace
+
+std::unique_ptr<platform::gui::INativeWindow>
+ControlHost::CreateNativeWindow() {
+  const auto ui_application = platform::gui::IUiApplication::GetInstance();
+
+  auto native_window = ui_application->CreateWindow();
+  assert(native_window);
+
+  BindNativeEvent(this, native_window, native_window->DestroyEvent(),
+                  &ControlHost::OnNativeDestroy);
+  BindNativeEvent(this, native_window, native_window->PaintEvent(),
+                  &ControlHost::OnNativePaint);
+  BindNativeEvent(this, native_window, native_window->ResizeEvent(),
+                  &ControlHost::OnNativeResize);
+  BindNativeEvent(this, native_window, native_window->FocusEvent(),
+                  &ControlHost::OnNativeFocus);
+  BindNativeEvent(this, native_window, native_window->MouseEnterLeaveEvent(),
+                  &ControlHost::OnNativeMouseEnterLeave);
+  BindNativeEvent(this, native_window, native_window->MouseMoveEvent(),
+                  &ControlHost::OnNativeMouseMove);
+  BindNativeEvent(this, native_window, native_window->MouseDownEvent(),
+                  &ControlHost::OnNativeMouseDown);
+  BindNativeEvent(this, native_window, native_window->MouseUpEvent(),
+                  &ControlHost::OnNativeMouseUp);
+  BindNativeEvent(this, native_window, native_window->MouseWheelEvent(),
+                  &ControlHost::OnNativeMouseWheel);
+  BindNativeEvent(this, native_window, native_window->KeyDownEvent(),
+                  &ControlHost::OnNativeKeyDown);
+  BindNativeEvent(this, native_window, native_window->KeyUpEvent(),
+                  &ControlHost::OnNativeKeyUp);
+
+  return std::unique_ptr<platform::gui::INativeWindow>(native_window);
+}
+
+void ControlHost::InvalidatePaint() {
+  repaint_schedule_canceler_.Reset(
+      platform::gui::IUiApplication::GetInstance()->SetImmediate(
+          [this] { Repaint(); }));
+}
+
+void ControlHost::InvalidateLayout() {
+  relayout_schedule_canceler_.Reset(
+      platform::gui::IUiApplication::GetInstance()->SetImmediate(
+          [this] { Relayout(); }));
+}
+
+bool ControlHost::IsLayoutPreferToFillWindow() const {
+  return layout_prefer_to_fill_window_;
+}
+
+void ControlHost::SetLayoutPreferToFillWindow(bool value) {
+  if (value == layout_prefer_to_fill_window_) return;
+  layout_prefer_to_fill_window_ = value;
+  InvalidateLayout();
+}
+
+void ControlHost::Repaint() {
+  auto painter = native_window_->BeginPaint();
+  painter->Clear(colors::white);
+  root_control_->GetRenderObject()->Draw(painter.get());
+  painter->EndDraw();
+}
+
+void ControlHost::Relayout() {
+  RelayoutWithSize(native_window_->GetClientSize());
+}
+
+void ControlHost::RelayoutWithSize(const Size& available_size,
+                                   bool set_window_size_to_fit_content) {
+  auto render_object = root_control_->GetRenderObject();
+  render_object->Measure(
+      render::MeasureRequirement{
+          available_size,
+          !set_window_size_to_fit_content && IsLayoutPreferToFillWindow()
+              ? render::MeasureSize(available_size)
+              : render::MeasureSize::NotSpecified()},
+      render::MeasureSize::NotSpecified());
+
+  if (set_window_size_to_fit_content) {
+    native_window_->SetClientSize(render_object->GetDesiredSize());
+  }
+
+  render_object->Layout(Point{});
+  CRU_LOG_TAG_DEBUG("A relayout is finished.");
+
+  AfterLayoutEvent_.Raise(nullptr);
+
+  InvalidatePaint();
+}
+
+Control* ControlHost::GetFocusControl() { return focus_control_; }
+
+void ControlHost::SetFocusControl(Control* control) {
+  if (control == nullptr) control = root_control_;
+  if (focus_control_ == control) return;
+
+  const auto old_focus_control = focus_control_;
+
+  focus_control_ = control;
+
+  DispatchFocusControlChangeEvent(old_focus_control, focus_control_, false);
+}
+
+Control* ControlHost::GetMouseCaptureControl() {
+  return mouse_captured_control_;
+}
+
+bool ControlHost::SetMouseCaptureControl(Control* control) {
+  if (!native_window_->CaptureMouse()) return false;
+
+  if (control == mouse_captured_control_) return true;
+
+  if (control == nullptr) {
+    native_window_->ReleaseMouse();
+    const auto old_capture_control = mouse_captured_control_;
+    mouse_captured_control_ =
+        nullptr;  // update this in case this is used in event handlers
+    if (old_capture_control != mouse_hover_control_) {
+      DispatchMouseHoverControlChangeEvent(
+          old_capture_control, mouse_hover_control_,
+          native_window_->GetMousePosition(), true, false);
+    }
+    UpdateCursor();
+    return true;
+  }
+
+  if (mouse_captured_control_) return false;
+
+  mouse_captured_control_ = control;
+  DispatchMouseHoverControlChangeEvent(
+      mouse_hover_control_, mouse_captured_control_,
+      native_window_->GetMousePosition(), false, true);
+  UpdateCursor();
+  return true;
+}
+
+std::shared_ptr<platform::gui::ICursor> ControlHost::GetOverrideCursor() {
+  return override_cursor_;
+}
+
+void ControlHost::SetOverrideCursor(
+    std::shared_ptr<platform::gui::ICursor> cursor) {
+  if (cursor == override_cursor_) return;
+  override_cursor_ = cursor;
+  UpdateCursor();
+}
+
+bool ControlHost::IsInEventHandling() { return event_handling_count_; }
+
+void ControlHost::OnNativeDestroy(platform::gui::INativeWindow* window,
+                                  std::nullptr_t) {
+  CRU_UNUSED(window)
+}
+
+void ControlHost::OnNativePaint(platform::gui::INativeWindow* window,
+                                std::nullptr_t) {
+  CRU_UNUSED(window)
+  InvalidatePaint();
+}
+
+void ControlHost::OnNativeResize(platform::gui::INativeWindow* window,
+                                 const Size& size) {
+  CRU_UNUSED(window)
+  CRU_UNUSED(size)
+
+  InvalidateLayout();
+}
+
+void ControlHost::OnNativeFocus(platform::gui::INativeWindow* window,
+                                platform::gui::FocusChangeType focus) {
+  CRU_UNUSED(window)
+
+  focus == platform::gui::FocusChangeType::Gain
+      ? DispatchEvent(focus_control_, &Control::GainFocusEvent, nullptr, true)
+      : DispatchEvent(focus_control_, &Control::LoseFocusEvent, nullptr, true);
+}
+
+void ControlHost::OnNativeMouseEnterLeave(
+    platform::gui::INativeWindow* window,
+    platform::gui::MouseEnterLeaveType type) {
+  CRU_UNUSED(window)
+
+  if (type == platform::gui::MouseEnterLeaveType::Leave) {
+    DispatchEvent(mouse_hover_control_, &Control::MouseLeaveEvent, nullptr);
+    mouse_hover_control_ = nullptr;
+  }
+}
+
+void ControlHost::OnNativeMouseMove(platform::gui::INativeWindow* window,
+                                    const Point& point) {
+  CRU_UNUSED(window)
+
+  // Find the first control that hit test succeed.
+  const auto new_mouse_hover_control = root_control_->HitTest(point);
+  const auto old_mouse_hover_control = mouse_hover_control_;
+  mouse_hover_control_ = new_mouse_hover_control;
+
+  if (mouse_captured_control_) {
+    const auto n = FindLowestCommonAncestor(new_mouse_hover_control,
+                                            mouse_captured_control_);
+    const auto o = FindLowestCommonAncestor(old_mouse_hover_control,
+                                            mouse_captured_control_);
+    bool a = IsAncestor(o, n);
+    if (a) {
+      DispatchEvent(o, &Control::MouseLeaveEvent, n);
+    } else {
+      DispatchEvent(n, &Control::MouseEnterEvent, o, point);
+    }
+    DispatchEvent(mouse_captured_control_, &Control::MouseMoveEvent, nullptr,
+                  point);
+    UpdateCursor();
+    return;
+  }
+
+  DispatchMouseHoverControlChangeEvent(
+      old_mouse_hover_control, new_mouse_hover_control, point, false, false);
+  DispatchEvent(new_mouse_hover_control, &Control::MouseMoveEvent, nullptr,
+                point);
+  UpdateCursor();
+}
+
+void ControlHost::OnNativeMouseDown(
+    platform::gui::INativeWindow* window,
+    const platform::gui::NativeMouseButtonEventArgs& args) {
+  CRU_UNUSED(window)
+
+  Control* control = mouse_captured_control_
+                         ? mouse_captured_control_
+                         : root_control_->HitTest(args.point);
+  DispatchEvent(control, &Control::MouseDownEvent, nullptr, args.point,
+                args.button, args.modifier);
+}
+
+void ControlHost::OnNativeMouseUp(
+    platform::gui::INativeWindow* window,
+    const platform::gui::NativeMouseButtonEventArgs& args) {
+  CRU_UNUSED(window)
+
+  Control* control = mouse_captured_control_
+                         ? mouse_captured_control_
+                         : root_control_->HitTest(args.point);
+  DispatchEvent(control, &Control::MouseUpEvent, nullptr, args.point,
+                args.button, args.modifier);
+}
+
+void ControlHost::OnNativeMouseWheel(
+    platform::gui::INativeWindow* window,
+    const platform::gui::NativeMouseWheelEventArgs& args) {
+  CRU_UNUSED(window)
+
+  Control* control = mouse_captured_control_
+                         ? mouse_captured_control_
+                         : root_control_->HitTest(args.point);
+  DispatchEvent(control, &Control::MouseWheelEvent, nullptr, args.point,
+                args.delta, args.modifier);
+}
+
+void ControlHost::OnNativeKeyDown(
+    platform::gui::INativeWindow* window,
+    const platform::gui::NativeKeyEventArgs& args) {
+  CRU_UNUSED(window)
+
+  DispatchEvent(focus_control_, &Control::KeyDownEvent, nullptr, args.key,
+                args.modifier);
+}
+
+void ControlHost::OnNativeKeyUp(platform::gui::INativeWindow* window,
+                                const platform::gui::NativeKeyEventArgs& args) {
+  CRU_UNUSED(window)
+
+  DispatchEvent(focus_control_, &Control::KeyUpEvent, nullptr, args.key,
+                args.modifier);
+}
+
+void ControlHost::DispatchFocusControlChangeEvent(Control* old_control,
+                                                  Control* new_control,
+                                                  bool is_window) {
+  if (new_control != old_control) {
+    const auto lowest_common_ancestor =
+        FindLowestCommonAncestor(old_control, new_control);
+    DispatchEvent(old_control, &Control::LoseFocusEvent, lowest_common_ancestor,
+                  is_window);
+    DispatchEvent(new_control, &Control::GainFocusEvent, lowest_common_ancestor,
+                  is_window);
+  }
+}
+
+void ControlHost::DispatchMouseHoverControlChangeEvent(Control* old_control,
+                                                       Control* new_control,
+                                                       const Point& point,
+                                                       bool no_leave,
+                                                       bool no_enter) {
+  if (new_control != old_control)  // if the mouse-hover-on control changed
+  {
+    const auto lowest_common_ancestor =
+        FindLowestCommonAncestor(old_control, new_control);
+    if (!no_leave && old_control != nullptr)
+      DispatchEvent(old_control, &Control::MouseLeaveEvent,
+                    lowest_common_ancestor);  // dispatch mouse leave event.
+    if (!no_enter && new_control != nullptr) {
+      DispatchEvent(new_control, &Control::MouseEnterEvent,
+                    lowest_common_ancestor,
+                    point);  // dispatch mouse enter event.
+    }
+  }
+}
+
+void ControlHost::UpdateCursor() {
+  if (override_cursor_) {
+    native_window_->SetCursor(override_cursor_);
+  } else {
+    const auto capture = GetMouseCaptureControl();
+    native_window_->SetCursor(
+        (capture ? capture : GetMouseHoverControl())->GetInheritedCursor());
+  }
+}
+
+void ControlHost::NotifyControlParentChange(Control* control,
+                                            Control* old_parent,
+                                            Control* new_parent) {
+  if (new_parent == nullptr) {
+    if (focus_control_->HasAncestor(control)) {
+      focus_control_ = old_parent;
+    }
+
+    if (mouse_captured_control_->HasAncestor(control)) {
+      mouse_captured_control_ = old_parent;
+    }
+
+    if (mouse_hover_control_->HasAncestor(control)) {
+      mouse_hover_control_ = old_parent;
+    }
+  }
+}
+}  // namespace cru::ui::controls