1 files changed, 136 insertions, 0 deletions
diff --git a/src/ui/layout_base.h b/src/ui/layout_base.h
new file mode 100644
index 00000000..163b99b2
--- /dev/null
+++ b/src/ui/layout_base.h
@@ -0,0 +1,136 @@
+#pragma once
+
+#include "system_headers.h"
+#include <unordered_set>
+
+#include "base.h"
+#include "ui_base.h"
+
+namespace cru
+{
+    namespace ui
+    {
+        class Control;
+
+        enum class Alignment
+        {
+            Center,
+            Start,
+            End
+        };
+
+        enum class MeasureMode
+        {
+            Exactly,
+            Content,
+            Stretch
+        };
+
+        struct LayoutSideParams final
+        {
+            constexpr static LayoutSideParams Exactly(const float length, const Alignment alignment = Alignment::Center)
+            {
+                return LayoutSideParams(MeasureMode::Exactly, length, alignment);
+            }
+
+            constexpr static LayoutSideParams Content(const Alignment alignment = Alignment::Center)
+            {
+                return LayoutSideParams(MeasureMode::Content, 0, alignment);
+            }
+
+            constexpr static LayoutSideParams Stretch(const Alignment alignment = Alignment::Center)
+            {
+                return LayoutSideParams(MeasureMode::Stretch, 0, alignment);
+            }
+
+            constexpr LayoutSideParams() = default;
+
+            constexpr explicit LayoutSideParams(const MeasureMode mode, const float length, const Alignment alignment)
+                : length(length), mode(mode), alignment(alignment)
+            {
+
+            }
+
+            constexpr bool Validate() const
+            {
+                if (mode == MeasureMode::Exactly && length < 0.0)
+                {
+#ifdef CRU_DEBUG
+                    ::OutputDebugStringW(L"LayoutSideParams validation error: mode is Exactly but length is less than 0.\n");
+#endif
+                    return false;
+                }
+                return true;
+            }
+
+            float length = 0.0;
+            MeasureMode mode = MeasureMode::Content;
+            Alignment alignment = Alignment::Center;
+        };
+
+        struct BasicLayoutParams final
+        {
+            BasicLayoutParams() = default;
+            BasicLayoutParams(const BasicLayoutParams&) = default;
+            BasicLayoutParams(BasicLayoutParams&&) = default;
+            BasicLayoutParams& operator = (const BasicLayoutParams&) = default;
+            BasicLayoutParams& operator = (BasicLayoutParams&&) = default;
+            ~BasicLayoutParams() = default;
+
+            bool Validate() const
+            {
+                if (!width.Validate())
+                {
+#ifdef CRU_DEBUG
+                    ::OutputDebugStringW(L"Width(LayoutSideParams) is not valid.");
+#endif
+                    return false;
+                }
+                if (!height.Validate())
+                {
+#ifdef CRU_DEBUG
+                    ::OutputDebugStringW(L"Height(LayoutSideParams) is not valid.");
+#endif
+                    return false;
+                }
+                return true;
+            }
+
+            LayoutSideParams width;
+            LayoutSideParams height;
+        };
+
+
+        class LayoutManager : public Object
+        {
+        public:
+            static LayoutManager* GetInstance();
+
+        public:
+            LayoutManager() = default;
+            LayoutManager(const LayoutManager& other) = delete;
+            LayoutManager(LayoutManager&& other) = delete;
+            LayoutManager& operator=(const LayoutManager& other) = delete;
+            LayoutManager& operator=(LayoutManager&& other) = delete;
+            ~LayoutManager() override = default;
+
+            //Mark position cache of the control and its descendants invalid,
+            //(which is saved as an auto-managed list internal)
+            //and send a message to refresh them.
+            void InvalidateControlPositionCache(Control* control);
+
+            //Refresh position cache of the control and its descendants whose cache
+            //has been marked as invalid.
+            void RefreshInvalidControlPositionCache();
+
+            //Refresh position cache of the control and its descendants immediately.
+            static void RefreshControlPositionCache(Control* control);
+
+        private:
+            static void RefreshControlPositionCacheInternal(Control* control, const Point& parent_lefttop_absolute);
+
+        private:
+            std::unordered_set<Control*> cache_invalid_controls_;
+        };
+    }
+}