1 files changed, 170 insertions, 0 deletions
diff --git a/include/cru/ui/UiHost.hpp b/include/cru/ui/UiHost.hpp
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--- /dev/null
+++ b/include/cru/ui/UiHost.hpp
@@ -0,0 +1,170 @@
+#pragma once
+#include "Base.hpp"
+
+#include "cru/common/Event.hpp"
+#include "cru/common/SelfResolvable.hpp"
+#include "render/Base.hpp"
+
+namespace cru::ui {
+struct AfterLayoutEventArgs {};
+
+// The host of all controls and render objects.
+//
+// 3 situations on destroy:
+// 1. Native window destroyed, IsRetainAfterDestroy: false:
+// OnNativeDestroy(set native_window_destroyed_ to true, call ~Window due to
+// deleting_ is false and IsRetainAfterDestroy is false) -> ~Window ->
+// ~UiHost(not destroy native window repeatedly due to native_window_destroyed_
+// is true)
+// 2. Native window destroyed, IsRetainAfterDestroy: true:
+// OnNativeDestroy(set native_window_destroyed_ to true, not call ~Window
+// because deleting_ is false and IsRetainAfterDestroy is true)
+// then, ~Window -> ~UiHost(not destroy native window repeatedly due to
+// native_window_destroyed_ is true)
+// 3. Native window not destroyed, ~Window is called:
+// ~Window -> ~UiHost(set deleting_ to true, destroy native window
+// due to native_window_destroyed is false) -> OnNativeDestroy(not call ~Window
+// due to deleting_ is true and IsRetainAfterDestroy is whatever)
+// In conclusion:
+// 1. Set native_window_destroyed_ to true at the beginning of OnNativeDestroy.
+// 2. Set deleting_ to true at the beginning of ~UiHost.
+// 3. Destroy native window when native_window_destroy_ is false in ~Window.
+// 4. Delete Window when deleting_ is false and IsRetainAfterDestroy is false in
+// OnNativeDestroy.
+class UiHost : public Object, public SelfResolvable<UiHost> {
+ public:
+  // This will create root window render object and attach it to window.
+  // It will also create and manage a native window.
+  UiHost(Window* window);
+
+  CRU_DELETE_COPY(UiHost)
+  CRU_DELETE_MOVE(UiHost)
+
+  ~UiHost() override;
+
+ public:
+  // Mark the layout as invalid, and arrange a re-layout later.
+  // This method could be called more than one times in a message cycle. But
+  // layout only takes place once.
+  void InvalidateLayout();
+
+  // Mark the paint as invalid, and arrange a re-paint later.
+  // This method could be called more than one times in a message cycle. But
+  // paint only takes place once.
+  void InvalidatePaint();
+
+  IEvent<AfterLayoutEventArgs>* AfterLayoutEvent() {
+    return &after_layout_event_;
+  }
+
+  void Relayout();
+
+  // Get current control that mouse hovers on. This ignores the mouse-capture
+  // control. Even when mouse is captured by another control, this function
+  // return the control under cursor. You can use `GetMouseCaptureControl` to
+  // get more info.
+  Control* GetMouseHoverControl() const { return mouse_hover_control_; }
+
+  //*************** region: focus ***************
+
+  // Request focus for specified control.
+  bool RequestFocusFor(Control* control);
+
+  // Get the control that has focus.
+  Control* GetFocusControl();
+
+  //*************** region: focus ***************
+
+  // Pass nullptr to release capture. If mouse is already capture by a control,
+  // this capture will fail and return false. If control is identical to the
+  // capturing control, capture is not changed and this function will return
+  // true.
+  //
+  // When capturing control changes,
+  // appropriate event will be sent. If mouse is not on the capturing control
+  // and capture is released, mouse enter event will be sent to the mouse-hover
+  // control. If mouse is not on the capturing control and capture is set, mouse
+  // leave event will be sent to the mouse-hover control.
+  bool CaptureMouseFor(Control* control);
+
+  // Return null if not captured.
+  Control* GetMouseCaptureControl();
+
+  Control* HitTest(const Point& point);
+
+  void UpdateCursor();
+
+  std::shared_ptr<platform::native::INativeWindowResolver>
+  GetNativeWindowResolver() {
+    return native_window_resolver_;
+  }
+
+  bool IsRetainAfterDestroy() { return retain_after_destroy_; }
+
+  void SetRetainAfterDestroy(bool destroy) { retain_after_destroy_ = destroy; }
+
+ private:
+  //*************** region: native messages ***************
+  void OnNativeDestroy(platform::native::INativeWindow* window, std::nullptr_t);
+  void OnNativePaint(platform::native::INativeWindow* window, std::nullptr_t);
+  void OnNativeResize(platform::native::INativeWindow* window,
+                      const Size& size);
+
+  void OnNativeFocus(platform::native::INativeWindow* window,
+                     cru::platform::native::FocusChangeType focus);
+
+  void OnNativeMouseEnterLeave(
+      platform::native::INativeWindow* window,
+      cru::platform::native::MouseEnterLeaveType enter);
+  void OnNativeMouseMove(platform::native::INativeWindow* window,
+                         const Point& point);
+  void OnNativeMouseDown(
+      platform::native::INativeWindow* window,
+      const platform::native::NativeMouseButtonEventArgs& args);
+  void OnNativeMouseUp(
+      platform::native::INativeWindow* window,
+      const platform::native::NativeMouseButtonEventArgs& args);
+
+  void OnNativeKeyDown(platform::native::INativeWindow* window,
+                       const platform::native::NativeKeyEventArgs& args);
+  void OnNativeKeyUp(platform::native::INativeWindow* window,
+                     const platform::native::NativeKeyEventArgs& args);
+
+  //*************** region: event dispatcher helper ***************
+
+  void DispatchMouseHoverControlChangeEvent(Control* old_control,
+                                            Control* new_control,
+                                            const Point& point, bool no_leave,
+                                            bool no_enter);
+
+ private:
+  bool need_layout_ = false;
+
+  Event<AfterLayoutEventArgs> after_layout_event_;
+
+  std::shared_ptr<platform::native::INativeWindowResolver>
+      native_window_resolver_;
+
+  // See remarks of UiHost.
+  bool retain_after_destroy_ = false;
+  // See remarks of UiHost.
+  bool deleting_ = false;
+
+  // We need this because calling Resolve on resolver in handler of destroy
+  // event is bad and will always get the dying window. But we need to label the
+  // window as destroyed so the destructor will not destroy native window
+  // repeatedly. See remarks of UiHost.
+  bool native_window_destroyed_ = false;
+
+  std::vector<EventRevokerGuard> event_revoker_guards_;
+
+  Window* window_control_;
+  std::unique_ptr<render::WindowRenderObject> root_render_object_;
+
+  Control* mouse_hover_control_;
+
+  Control* focus_control_;  // "focus_control_" can't be nullptr
+
+  Control* mouse_captured_control_;
+};
+}  // namespace cru::ui