3 files changed, 55 insertions, 17 deletions

diff --git a/src/main.cpp b/src/main.cpp
index f5eb655a..19e821a8 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -118,7 +118,7 @@ int APIENTRY wWinMain(
         const auto button = Button::Create();
         button->GetLayoutParams()->padding = Thickness(20, 5);
         button->AddChild(TextBlock::Create(L"Show popup window parenting this."));
-        button->mouse_click_event.AddHandler([window](auto)
+        button->mouse_click_event.AddHandler([window, button](auto)
         {
             const auto popup = Window::CreatePopup(window);
 
@@ -140,6 +140,7 @@ int APIENTRY wWinMain(
             popup->AddChild(menu);
 
             popup->SetSizeFitContent();
+            popup->SetWindowPosition(window->PointToScreen(button->GetPositionAbsolute()));
 
             popup->Show();
         });
diff --git a/src/ui/window.cpp b/src/ui/window.cpp
index 41104924..f8e6d4f3 100644
--- a/src/ui/window.cpp
+++ b/src/ui/window.cpp
@@ -98,6 +98,15 @@ namespace cru::ui
         );
     }
 
+    inline POINT DipToPi(const Point& dip_point)
+    {
+        POINT result;
+        result.x = graph::DipToPixelX(dip_point.x);
+        result.y = graph::DipToPixelY(dip_point.y);
+        return result;
+    }
+
+
     namespace
     {
         Cursor::Ptr GetCursorInherit(Control* control)
@@ -275,6 +284,41 @@ namespace cru::ui
         }
     }
 
+    void Window::SetWindowPosition(const Point& position)
+    {
+        if (IsWindowValid()) {
+            SetWindowPos(
+                hwnd_, nullptr,
+                graph::DipToPixelX(position.x),
+                graph::DipToPixelY(position.y),
+                0, 0,
+                SWP_NOZORDER | SWP_NOSIZE
+            );
+        }
+    }
+
+    Point Window::PointToScreen(const Point& point)
+    {
+        if (!IsWindowValid())
+            return Point::Zero();
+
+        auto p = DipToPi(point);
+        if (::ClientToScreen(GetWindowHandle(), &p) == 0)
+            throw Win32Error(::GetLastError(), "Failed transform point from window to screen.");
+        return PiToDip(p);
+    }
+
+    Point Window::PointFromScreen(const Point& point)
+    {
+        if (!IsWindowValid())
+            return Point::Zero();
+
+        auto p = DipToPi(point);
+        if (::ScreenToClient(GetWindowHandle(), &p) == 0)
+            throw Win32Error(::GetLastError(), "Failed transform point from screen to window.");
+        return PiToDip(p);
+    }
+
     bool Window::HandleWindowMessage(HWND hwnd, int msg, WPARAM w_param, LPARAM l_param, LRESULT & result) {
 
         if (!native_message_event.IsNoHandler())
@@ -444,14 +488,14 @@ namespace cru::ui
 
     void Window::Relayout()
     {
-        OnMeasureCore(GetSize());
+        Measure(GetSize());
         OnLayoutCore(Rect(Point::Zero(), GetSize()));
         is_layout_invalid_ = false;
     }
 
     void Window::SetSizeFitContent(const Size& max_size)
     {
-        OnMeasureCore(max_size);
+        Measure(max_size);
         SetClientSize(GetDesiredSize());
         OnLayoutCore(Rect(Point::Zero(), GetSize()));
         is_layout_invalid_ = false;
@@ -579,15 +623,6 @@ namespace cru::ui
         }
     }
 
-    Size Window::OnMeasureContent(const Size& available_size)
-    {
-        for (auto control: GetChildren())
-        {
-            control->Measure(available_size);
-        }
-        return available_size;
-    }
-
     void Window::OnDestroyInternal() {
         WindowManager::GetInstance()->UnregisterWindow(hwnd_);
         hwnd_ = nullptr;
diff --git a/src/ui/window.hpp b/src/ui/window.hpp
index 05b1a259..b2b8cde0 100644
--- a/src/ui/window.hpp
+++ b/src/ui/window.hpp
@@ -162,6 +162,13 @@ namespace cru::ui
         //The lefttop of the rect is relative to screen lefttop.
         void SetWindowRect(const Rect& rect);
 
+        //Set the lefttop of the window relative to screen.
+        void SetWindowPosition(const Point& position);
+
+        Point PointToScreen(const Point& point);
+
+        Point PointFromScreen(const Point& point);
+
         //Handle the raw window message.
         //Return true if the message is handled and get the result through "result" argument.
         //Return false if the message is not handled.
@@ -254,11 +261,6 @@ namespace cru::ui
         void SetCursorInternal(HCURSOR cursor);
  
  
-        //*************** region: layout ***************
- 
-        Size OnMeasureContent(const Size& available_size) override;
- 
- 
         //*************** region: native messages ***************
  
         void OnDestroyInternal();