4 files changed, 61 insertions, 11 deletions
diff --git a/include/cru/ui/controls/flex_layout.hpp b/include/cru/ui/controls/flex_layout.hpp
index 7422bc05..46c4ea55 100644
--- a/include/cru/ui/controls/flex_layout.hpp
+++ b/include/cru/ui/controls/flex_layout.hpp
@@ -1,13 +1,17 @@
 #pragma once
 #include "../layout_control.hpp"
 
-#include <memory>
+#include "../render/flex_layout_render_object.hpp"
+#include "../window.hpp"
 
-namespace cru::ui::render {
-class FlexLayoutRenderObject;
-}
+#include <memory>
 
 namespace cru::ui::controls {
+// import these basic entities
+using render::FlexChildLayoutData;
+using render::FlexCrossAlignment;
+using render::FlexDirection;
+using render::FlexMainAlignment;
 
 class FlexLayout : public LayoutControl {
  public:
@@ -31,6 +35,16 @@ class FlexLayout : public LayoutControl {
 
   render::RenderObject* GetRenderObject() const override;
 
+  FlexMainAlignment GetContentMainAlign() const {
+    return render_object_->GetContentMainAlign();
+  }
+
+  void SetContentMainAlign(FlexMainAlignment value) {
+    if (value == GetContentMainAlign()) return;
+    render_object_->SetContentMainAlign(value);
+    GetWindow()->InvalidateLayout();
+  }
+
  protected:
   void OnAddChild(Control* child, int position) override;
   void OnRemoveChild(Control* child, int position) override;
diff --git a/include/cru/ui/render/flex_layout_render_object.hpp b/include/cru/ui/render/flex_layout_render_object.hpp
index 99ec1247..8d881239 100644
--- a/include/cru/ui/render/flex_layout_render_object.hpp
+++ b/include/cru/ui/render/flex_layout_render_object.hpp
@@ -11,13 +11,32 @@ enum class FlexDirection {
   VertivalReverse
 };
 
-enum class Alignment { Start, End, Center };
+namespace internal {
+constexpr int align_start = 0;
+constexpr int align_end = align_start + 1;
+constexpr int align_center = align_end + 1;
+//constexpr int align_stretch = align_center + 1;
+}  // namespace internal
+
+enum class FlexMainAlignment {
+  Start = internal::align_start,
+  End = internal::align_end,
+  Center = internal::align_center
+};
+enum class FlexCrossAlignment {
+  Start = internal::align_start,
+  End = internal::align_end,
+  Center = internal::align_center,
+//  Stretch = internal::align_stretch
+};
 
 struct FlexChildLayoutData {
-  std::optional<float> flex_basis;  // nullopt stands for content
+  // nullopt stands for looking at my content
+  std::optional<float> flex_basis = std::nullopt;
   float flex_grow = 0;
   float flex_shrink = 0;
-  Alignment alignment = Alignment::Center;
+  // nullopt stands for looking at parent's setting
+  std::optional<FlexCrossAlignment> cross_alignment = std::nullopt;
 };
 
 class FlexLayoutRenderObject : public RenderObject {
@@ -33,8 +52,15 @@ class FlexLayoutRenderObject : public RenderObject {
   FlexDirection GetFlexDirection() const { return direction_; }
   void SetFlexDirection(FlexDirection direction) { direction_ = direction; }
 
-  Alignment GetContentMainAlign() const { return content_main_align_; }
-  void SetContentMainAlign(Alignment align) { content_main_align_ = align; }
+  FlexMainAlignment GetContentMainAlign() const { return content_main_align_; }
+  void SetContentMainAlign(FlexMainAlignment align) {
+    content_main_align_ = align;
+  }
+
+  FlexCrossAlignment GetItemCrossAlign() const { return item_cross_align_; }
+  void SetItemCrossAlign(FlexCrossAlignment align) {
+    item_cross_align_ = align;
+  }
 
   FlexChildLayoutData* GetChildLayoutData(int position);
 
@@ -51,7 +77,8 @@ class FlexLayoutRenderObject : public RenderObject {
 
  private:
   FlexDirection direction_ = FlexDirection::Horizontal;
-  Alignment content_main_align_ = Alignment::Start;
+  FlexMainAlignment content_main_align_ = FlexMainAlignment::Start;
+  FlexCrossAlignment item_cross_align_ = FlexCrossAlignment::Center;
   std::vector<FlexChildLayoutData> child_layout_data_{};
 };
 }  // namespace cru::ui::render
diff --git a/include/cru/ui/ui_manager.hpp b/include/cru/ui/ui_manager.hpp
index 2dc9cf6b..f3f78722 100644
--- a/include/cru/ui/ui_manager.hpp
+++ b/include/cru/ui/ui_manager.hpp
@@ -9,6 +9,7 @@ struct IFontDescriptor;
 }  // namespace cru::platform
 
 namespace cru::ui {
+//TODO: Make this theme resource.
 class PredefineResources : public Object {
  public:
   PredefineResources();
diff --git a/include/cru/ui/window.hpp b/include/cru/ui/window.hpp
index 4bc0e41d..e175b234 100644
--- a/include/cru/ui/window.hpp
+++ b/include/cru/ui/window.hpp
@@ -1,6 +1,7 @@
 #pragma once
 #include "content_control.hpp"
 
+#include "cru/common/self_resolvable.hpp"
 #include "cru/platform/native/native_event.hpp"
 #include "event/ui_event.hpp"
 
@@ -16,7 +17,7 @@ namespace render {
 class WindowRenderObject;
 }
 
-class Window final : public ContentControl {
+class Window final : public ContentControl, public SelfResovable<Window> {
  public:
   static constexpr auto control_type = L"Window";
 
@@ -46,6 +47,11 @@ class Window final : public ContentControl {
 
   Control* GetMouseHoverControl() const { return mouse_hover_control_; }
 
+  //*************** region: layout ***************
+  void Relayout();
+
+  void InvalidateLayout();
+
   //*************** region: focus ***************
 
   // Request focus for specified control.
@@ -93,5 +99,7 @@ class Window final : public ContentControl {
   Control* mouse_hover_control_;
 
   Control* focus_control_;  // "focus_control_" can't be nullptr
+
+  bool need_layout_ = false;
 };
 }  // namespace cru::ui