Fix position cache bug.

5 files changed, 45 insertions, 11 deletions

diff --git a/src/ui/control.cpp b/src/ui/control.cpp
index 32168891..3987e818 100644
--- a/src/ui/control.cpp
+++ b/src/ui/control.cpp
@@ -125,7 +125,7 @@ namespace cru::ui
         TraverseDescendantsInternal(this, predicate);
     }
 
-    Point Control::GetPositionRelative()
+    Point Control::GetOffset()
     {
         return rect_.GetLeftTop();
     }
@@ -186,6 +186,33 @@ namespace cru::ui
             point.y - position_cache_.lefttop_position_absolute.y);
     }
 
+    void Control::RefreshDescendantPositionCache()
+    {
+        auto point = Point::Zero();
+        auto parent = this;
+        while ((parent = parent->GetParent()))
+        {
+            const auto p = parent->GetOffset();
+            point.x += p.x;
+            point.y += p.y;
+        }
+        RefreshControlPositionCacheInternal(this, point);
+    }
+
+    void Control::RefreshControlPositionCacheInternal(Control* control, const Point& parent_lefttop_absolute)
+    {
+        const auto position = control->GetOffset();
+        const Point lefttop(
+            parent_lefttop_absolute.x + position.x,
+            parent_lefttop_absolute.y + position.y
+        );
+        control->position_cache_.lefttop_position_absolute = lefttop;
+        for(auto c : control->GetInternalChildren())
+        {
+            RefreshControlPositionCacheInternal(c, lefttop);
+        }
+    }
+
     bool Control::IsPointInside(const Point & point)
     {
         const auto border_geometry = geometry_info_.border_geometry;
@@ -230,7 +257,7 @@ namespace cru::ui
 
         for (auto i = children.crbegin(); i != children.crend(); ++i)
         {
-            const auto&& lefttop = (*i)->GetPositionRelative();
+            const auto&& lefttop = (*i)->GetOffset();
             const auto&& coerced_point = Point(point.x - lefttop.x, point.y - lefttop.y);
             const auto child_hit_test_result = (*i)->HitTest(coerced_point);
             if (child_hit_test_result != nullptr)
@@ -254,7 +281,7 @@ namespace cru::ui
         D2D1::Matrix3x2F old_transform;
         device_context->GetTransform(&old_transform);
 
-        const auto position = GetPositionRelative();
+        const auto position = GetOffset();
         device_context->SetTransform(old_transform * D2D1::Matrix3x2F::Translation(position.x, position.y));
 
         OnDrawDecoration(device_context);
diff --git a/src/ui/control.hpp b/src/ui/control.hpp
index 41d1cfe9..6abcc365 100644
--- a/src/ui/control.hpp
+++ b/src/ui/control.hpp
@@ -18,7 +18,6 @@
 
 namespace cru::ui
 {
-    class Control;
     class Window;
 
 
@@ -68,6 +67,8 @@ namespace cru::ui
         //*************** region: tree ***************
         virtual StringView GetControlType() const = 0;
 
+        virtual const std::vector<Control*>& GetInternalChildren() const = 0;
+
         Control* GetParent() const
         {
             return parent_ == nullptr ? internal_parent_ : parent_;
@@ -84,9 +85,6 @@ namespace cru::ui
             return window_;
         }
 
-
-        virtual const std::vector<Control*>& GetInternalChildren() const = 0;
-
         void SetParent(Control* parent);
 
         void SetInternalParent(Control* internal_parent);
@@ -100,11 +98,12 @@ namespace cru::ui
         //*************** region: position and size ***************
 
         //Get the lefttop relative to its parent.
-        virtual Point GetPositionRelative();
+        virtual Point GetOffset();
 
         //Get the actual size.
         virtual Size GetSize();
 
+        // If offset changes, call RefreshDescendantPositionCache.
         virtual void SetRect(const Rect& rect);
 
         //Get lefttop relative to ancestor. This is only valid when
@@ -118,6 +117,13 @@ namespace cru::ui
         //Absolute point to local point.
         Point WindowToControl(const Point& point) const;
 
+        void RefreshDescendantPositionCache();
+
+    private:
+        static void RefreshControlPositionCacheInternal(Control* control, const Point& parent_lefttop_absolute);
+
+    public:
+
         // Default implement in Control is test point in border geometry's
         // fill and stroke with width of border.
         virtual bool IsPointInside(const Point& point);
diff --git a/src/ui/controls/scroll_control.cpp b/src/ui/controls/scroll_control.cpp
index ae99f414..622b4e4c 100644
--- a/src/ui/controls/scroll_control.cpp
+++ b/src/ui/controls/scroll_control.cpp
@@ -328,11 +328,12 @@ namespace cru::ui::controls
         {
             if (const auto child = GetChild())
             {
-                const auto old_position = child->GetPositionRelative();
+                const auto old_position = child->GetOffset();
                 child->SetRect(Rect(Point(
                     old_position.x + old_offset_x - offset_x_,
                     old_position.y + old_offset_y - offset_y_
                 ), child->GetSize()));
+                child->RefreshDescendantPositionCache();
             }
         }
         InvalidateDraw();
diff --git a/src/ui/window.cpp b/src/ui/window.cpp
index 6f1c4071..86fa4436 100644
--- a/src/ui/window.cpp
+++ b/src/ui/window.cpp
@@ -469,7 +469,7 @@ namespace cru::ui
         return PiToDip(point);
     }
 
-    Point Window::GetPositionRelative()
+    Point Window::GetOffset()
     {
         return Point();
     }
diff --git a/src/ui/window.hpp b/src/ui/window.hpp
index e4c910e8..e96d4d92 100644
--- a/src/ui/window.hpp
+++ b/src/ui/window.hpp
@@ -189,7 +189,7 @@ namespace cru::ui
         //*************** region: position and size ***************
 
         //Always return (0, 0) for a window.
-        Point GetPositionRelative() override final;
+        Point GetOffset() override final;
 
         //Get the size of client area for a window.
         Size GetSize() override final;