3 files changed, 35 insertions, 18 deletions

diff --git a/src/ui/controls/Control.cpp b/src/ui/controls/Control.cpp
index 41644755..2a94252f 100644
--- a/src/ui/controls/Control.cpp
+++ b/src/ui/controls/Control.cpp
@@ -110,7 +110,7 @@ void Control::InsertChildAt(Control* control, Index index) {
   OnChildInserted(control, index);
 
   if (host_) {
-    host_->InvalidateLayout();
+    host_->ScheduleRelayout();
   }
 }
 
@@ -131,7 +131,7 @@ void Control::RemoveChildAt(Index index) {
   OnChildRemoved(control, index);
 
   if (host_) {
-    host_->InvalidateLayout();
+    host_->ScheduleRelayout();
   }
 }
 
diff --git a/src/ui/controls/ControlHost.cpp b/src/ui/controls/ControlHost.cpp
index caa907da..7c934b7b 100644
--- a/src/ui/controls/ControlHost.cpp
+++ b/src/ui/controls/ControlHost.cpp
@@ -124,9 +124,9 @@ ControlHost::CreateNativeWindow() {
   return std::unique_ptr<platform::gui::INativeWindow>(native_window);
 }
 
-void ControlHost::InvalidatePaint() { native_window_->RequestRepaint(); }
+void ControlHost::ScheduleRepaint() { native_window_->RequestRepaint(); }
 
-void ControlHost::InvalidateLayout() {
+void ControlHost::ScheduleRelayout() {
   relayout_schedule_canceler_.Reset(
       platform::gui::IUiApplication::GetInstance()->SetImmediate(
           [this] { Relayout(); }));
@@ -139,7 +139,7 @@ bool ControlHost::IsLayoutPreferToFillWindow() const {
 void ControlHost::SetLayoutPreferToFillWindow(bool value) {
   if (value == layout_prefer_to_fill_window_) return;
   layout_prefer_to_fill_window_ = value;
-  InvalidateLayout();
+  ScheduleRelayout();
 }
 
 void ControlHost::Repaint() {
@@ -172,7 +172,7 @@ void ControlHost::RelayoutWithSize(const Size& available_size,
 
   AfterLayoutEvent_.Raise(nullptr);
 
-  InvalidatePaint();
+  ScheduleRepaint();
 }
 
 Control* ControlHost::GetFocusControl() { return focus_control_; }
@@ -250,7 +250,7 @@ void ControlHost::OnNativeResize(platform::gui::INativeWindow* window,
   CRU_UNUSED(window)
   CRU_UNUSED(size)
 
-  InvalidateLayout();
+  ScheduleRelayout();
 }
 
 void ControlHost::OnNativeFocus(platform::gui::INativeWindow* window,
diff --git a/src/ui/render/RenderObject.cpp b/src/ui/render/RenderObject.cpp
index 59dc6d6a..424fd2ee 100644
--- a/src/ui/render/RenderObject.cpp
+++ b/src/ui/render/RenderObject.cpp
@@ -10,7 +10,10 @@ namespace cru::ui::render {
 const BoxConstraint BoxConstraint::kNotLimit{Size::kMax, Size::kZero};
 
 RenderObject::RenderObject(std::string name)
-    : name_(std::move(name)), control_(nullptr), parent_(nullptr) {}
+    : name_(std::move(name)),
+      control_(nullptr),
+      parent_(nullptr),
+      layout_valid_(false) {}
 
 RenderObject::~RenderObject() { DestroyEvent_.Raise(this); }
 
@@ -82,25 +85,38 @@ void RenderObject::Measure(const MeasureRequirement& requirement) {
   CRU_LOG_TAG_DEBUG("{} Measure begins, requirement {}.",
                     this->GetDebugPathInTree(), requirement);
 
+  if (layout_valid_ && requirement == last_measure_requirement_) {
+    return;
+  }
+
   measure_result_size_ = OnMeasureCore(requirement);
   if (measure_result_size_.width < 0 || measure_result_size_.height < 0) {
     throw Exception("Measure result size is invalid.");
   }
 
+  last_measure_requirement_ = requirement;
+
   CRU_LOG_TAG_DEBUG("{} Measure ends, result size: {}.",
                     this->GetDebugPathInTree(), measure_result_size_);
 }
 
 void RenderObject::Layout(const Point& offset) {
-  CRU_LOG_TAG_DEBUG("{} Layout begins, offset: {}, size: {}.",
-                    this->GetDebugPathInTree(), offset, measure_result_size_);
+  Layout({offset, GetMeasureResultSize()});
+}
 
-  offset_ = offset;
-  size_ = measure_result_size_;
+void RenderObject::Layout(const Rect& rect) {
+  CRU_LOG_TAG_DEBUG("{} Layout begins, rect: {}.", this->GetDebugPathInTree(),
+                    rect);
 
-  OnResize(size_);
+  offset_ = rect.GetLeftTop();
+  auto new_size = rect.GetSize();
+  if (size_ != new_size) {
+    size_ = new_size;
+    OnResize(new_size);
+  }
 
-  OnLayoutCore();
+  OnLayoutCore(rect);
+  layout_valid_ = true;
 
   CRU_LOG_TAG_DEBUG("{} Layout ends.", this->GetDebugPathInTree());
 }
@@ -120,8 +136,8 @@ Size RenderObject::OnMeasureCore(const MeasureRequirement& requirement) {
   return space_size + content_size;
 }
 
-void RenderObject::OnLayoutCore() {
-  auto total_size = GetMeasureResultSize();
+void RenderObject::OnLayoutCore(const Rect& rect) {
+  auto total_size = rect.GetSize();
   auto outer_space = GetTotalSpaceThickness();
   auto content_size = (total_size - outer_space.GetTotalSize()).AtLeast0();
 
@@ -165,14 +181,15 @@ controls::ControlHost* RenderObject::GetControlHost() {
 }
 
 void RenderObject::InvalidateLayout() {
+  WalkUp([](RenderObject* ro) { ro->layout_valid_ = false; });
   if (auto host = GetControlHost()) {
-    host->InvalidateLayout();
+    host->ScheduleRelayout();
   }
 }
 
 void RenderObject::InvalidatePaint() {
   if (auto window = GetControlHost()) {
-    window->InvalidatePaint();
+    window->ScheduleRepaint();
   }
 }