text: // dear imgui: Platform Binding for Windows (standard windows API for 32 and 64 bits applications)
  // This needs to be used along with a Renderer (e.g. DirectX11, OpenGL3, Vulkan..)
  
  // Implemented features:
  //  [X] Platform: Clipboard support (for Win32 this is actually part of core imgui)
  //  [X] Platform: Mouse cursor shape and visibility. Disable with 'io.ConfigFlags |= ImGuiConfigFlags_NoMouseCursorChange'.
  //  [X] Platform: Keyboard arrays indexed using VK_* Virtual Key Codes, e.g. ImGui::IsKeyPressed(VK_SPACE).
  //  [X] Platform: Multi-viewport support (multiple windows). Enable with 'io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable'.
  // Missing features:
  //  [ ] Platform: Gamepad support (best leaving it to user application to fill io.NavInputs[] with gamepad inputs from their source of choice).
  
  #include "imgui.h"
  #include "imgui_impl_win32.h"
  #ifndef WIN32_LEAN_AND_MEAN
  #define WIN32_LEAN_AND_MEAN
  #endif
  #include <windows.h>
  #include <tchar.h>
  
  // CHANGELOG
  // (minor and older changes stripped away, please see git history for details)
  //  2018-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
  //  2018-11-30: Misc: Setting up io.BackendPlatformName so it can be displayed in the About Window.
  //  2018-06-29: Inputs: Added support for the ImGuiMouseCursor_Hand cursor.
  //  2018-06-10: Inputs: Fixed handling of mouse wheel messages to support fine position messages (typically sent by track-pads).
  //  2018-06-08: Misc: Extracted imgui_impl_win32.cpp/.h away from the old combined DX9/DX10/DX11/DX12 examples.
  //  2018-03-20: Misc: Setup io.BackendFlags ImGuiBackendFlags_HasMouseCursors and ImGuiBackendFlags_HasSetMousePos flags + honor ImGuiConfigFlags_NoMouseCursorChange flag.
  //  2018-02-20: Inputs: Added support for mouse cursors (ImGui::GetMouseCursor() value and WM_SETCURSOR message handling).
  //  2018-02-06: Inputs: Added mapping for ImGuiKey_Space.
  //  2018-02-06: Inputs: Honoring the io.WantSetMousePos by repositioning the mouse (when using navigation and ImGuiConfigFlags_NavMoveMouse is set).
  //  2018-02-06: Misc: Removed call to ImGui::Shutdown() which is not available from 1.60 WIP, user needs to call CreateContext/DestroyContext themselves.
  //  2018-01-20: Inputs: Added Horizontal Mouse Wheel support.
  //  2018-01-08: Inputs: Added mapping for ImGuiKey_Insert.
  //  2018-01-05: Inputs: Added WM_LBUTTONDBLCLK double-click handlers for window classes with the CS_DBLCLKS flag.
  //  2017-10-23: Inputs: Added WM_SYSKEYDOWN / WM_SYSKEYUP handlers so e.g. the VK_MENU key can be read.
  //  2017-10-23: Inputs: Using Win32 ::SetCapture/::GetCapture() to retrieve mouse positions outside the client area when dragging. 
  //  2016-11-12: Inputs: Only call Win32 ::SetCursor(NULL) when io.MouseDrawCursor is set.
  
  // Win32 Data
  static HWND                 g_hWnd = 0;
  static INT64                g_Time = 0;
  static INT64                g_TicksPerSecond = 0;
  static ImGuiMouseCursor     g_LastMouseCursor = ImGuiMouseCursor_COUNT;
  static bool                 g_WantUpdateMonitors = true;
  
  // Forward Declarations
  static void ImGui_ImplWin32_InitPlatformInterface();
  static void ImGui_ImplWin32_ShutdownPlatformInterface();
  static void ImGui_ImplWin32_UpdateMonitors();
  
  // Functions
  bool    ImGui_ImplWin32_Init(void* hwnd)
  {
      if (!::QueryPerformanceFrequency((LARGE_INTEGER *)&g_TicksPerSecond))
          return false;
      if (!::QueryPerformanceCounter((LARGE_INTEGER *)&g_Time))
          return false;
  
      // Setup back-end capabilities flags
      ImGuiIO& io = ImGui::GetIO();
      io.BackendFlags |= ImGuiBackendFlags_HasMouseCursors;         // We can honor GetMouseCursor() values (optional)
      io.BackendFlags |= ImGuiBackendFlags_HasSetMousePos;          // We can honor io.WantSetMousePos requests (optional, rarely used)
      io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;    // We can create multi-viewports on the Platform side (optional)
      io.BackendFlags |= ImGuiBackendFlags_HasMouseHoveredViewport; // We can set io.MouseHoveredViewport correctly (optional, not easy)
      io.BackendPlatformName = "imgui_impl_win32";
  
      // Our mouse update function expect PlatformHandle to be filled for the main viewport
      g_hWnd = (HWND)hwnd;
      ImGuiViewport* main_viewport = ImGui::GetMainViewport();
      main_viewport->PlatformHandle = (void*)g_hWnd;
      if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
          ImGui_ImplWin32_InitPlatformInterface();
  
      // Keyboard mapping. ImGui will use those indices to peek into the io.KeysDown[] array that we will update during the application lifetime.
      io.KeyMap[ImGuiKey_Tab] = VK_TAB;
      io.KeyMap[ImGuiKey_LeftArrow] = VK_LEFT;
      io.KeyMap[ImGuiKey_RightArrow] = VK_RIGHT;
      io.KeyMap[ImGuiKey_UpArrow] = VK_UP;
      io.KeyMap[ImGuiKey_DownArrow] = VK_DOWN;
      io.KeyMap[ImGuiKey_PageUp] = VK_PRIOR;
      io.KeyMap[ImGuiKey_PageDown] = VK_NEXT;
      io.KeyMap[ImGuiKey_Home] = VK_HOME;
      io.KeyMap[ImGuiKey_End] = VK_END;
      io.KeyMap[ImGuiKey_Insert] = VK_INSERT;
      io.KeyMap[ImGuiKey_Delete] = VK_DELETE;
      io.KeyMap[ImGuiKey_Backspace] = VK_BACK;
      io.KeyMap[ImGuiKey_Space] = VK_SPACE;
      io.KeyMap[ImGuiKey_Enter] = VK_RETURN;
      io.KeyMap[ImGuiKey_Escape] = VK_ESCAPE;
      io.KeyMap[ImGuiKey_A] = 'A';
      io.KeyMap[ImGuiKey_C] = 'C';
      io.KeyMap[ImGuiKey_V] = 'V';
      io.KeyMap[ImGuiKey_X] = 'X';
      io.KeyMap[ImGuiKey_Y] = 'Y';
      io.KeyMap[ImGuiKey_Z] = 'Z';
  
      return true;
  }
  
  void    ImGui_ImplWin32_Shutdown()
  {
      ImGui_ImplWin32_ShutdownPlatformInterface();
      g_hWnd = (HWND)0;
  }
  
  static bool ImGui_ImplWin32_UpdateMouseCursor()
  {
      ImGuiIO& io = ImGui::GetIO();
      if (io.ConfigFlags & ImGuiConfigFlags_NoMouseCursorChange)
          return false;
  
      ImGuiMouseCursor imgui_cursor = ImGui::GetMouseCursor();
      if (imgui_cursor == ImGuiMouseCursor_None || io.MouseDrawCursor)
      {
          // Hide OS mouse cursor if imgui is drawing it or if it wants no cursor
          ::SetCursor(NULL);
      }
      else
      {
          // Show OS mouse cursor
          LPTSTR win32_cursor = IDC_ARROW;
          switch (imgui_cursor)
          {
          case ImGuiMouseCursor_Arrow:        win32_cursor = IDC_ARROW; break;
          case ImGuiMouseCursor_TextInput:    win32_cursor = IDC_IBEAM; break;
          case ImGuiMouseCursor_ResizeAll:    win32_cursor = IDC_SIZEALL; break;
          case ImGuiMouseCursor_ResizeEW:     win32_cursor = IDC_SIZEWE; break;
          case ImGuiMouseCursor_ResizeNS:     win32_cursor = IDC_SIZENS; break;
          case ImGuiMouseCursor_ResizeNESW:   win32_cursor = IDC_SIZENESW; break;
          case ImGuiMouseCursor_ResizeNWSE:   win32_cursor = IDC_SIZENWSE; break;
          case ImGuiMouseCursor_Hand:         win32_cursor = IDC_HAND; break;
          }
          ::SetCursor(::LoadCursor(NULL, win32_cursor));
      }
      return true;
  }
  
  // This code supports multiple OS Windows mapped into different ImGui viewports, 
  // Because of that, it is a little more complicated than your typical single-viewport binding code.
  // A) In Single-viewport mode imgui needs:
  //   - io.MousePos ............... mouse position, in client window coordinates (what you'd get from GetCursorPos+ScreenToClient() or from WM_MOUSEMOVE) 
  //                                 io.MousePos is (0,0) when the mouse is on the upper-left corner of the application window.
  // B) In Multi-viewport mode imgui needs: (when ImGuiConfigFlags_ViewportsEnable is set)
  //   - io.MousePos ............... mouse position, in OS absolute coordinates (what you'd get from GetCursorPos(), or from WM_MOUSEMOVE+viewport->Pos). 
  //                                 io.MousePos is (0,0) when the mouse is on the upper-left of the primary monitor.
  //   - io.MouseHoveredViewport ... [optional] viewport which mouse is hovering, with _VERY_ specific and strict conditions (Read comments next to io.MouseHoveredViewport. This is _NOT_ easy to provide in many high-level engine because of how we use the ImGuiViewportFlags_NoInputs flag)
  static void ImGui_ImplWin32_UpdateMousePos()
  {
      ImGuiIO& io = ImGui::GetIO();
  
      // Set OS mouse position if requested (rarely used, only when ImGuiConfigFlags_NavEnableSetMousePos is enabled by user)
      // (When multi-viewports are enabled, all imgui positions are same as OS positions.)
      if (io.WantSetMousePos)
      {
          POINT pos = { (int)io.MousePos.x, (int)io.MousePos.y };
          if ((io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable) == 0)
              ::ClientToScreen(g_hWnd, &pos);
          ::SetCursorPos(pos.x, pos.y);
      }
  
      io.MousePos = ImVec2(-FLT_MAX, -FLT_MAX);
      io.MouseHoveredViewport = 0;
  
      // Set mouse position and viewport
      // (Note that ScreenToClient() and adding +viewport->Pos are mutually cancelling each others when we have multi-viewport enabled. In single-viewport mode, viewport->Pos will be zero)
      POINT pos;
      if (!::GetCursorPos(&pos))
          return;
      if (HWND focused_hwnd = ::GetActiveWindow())
          if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)focused_hwnd))
          {
              POINT client_pos = pos;
              ::ScreenToClient(focused_hwnd, &client_pos);
              io.MousePos = ImVec2(viewport->Pos.x + (float)client_pos.x, viewport->Pos.y + (float)client_pos.y);
          }
  
      // Our back-end can tell which window is under the mouse cursor (not every back-end can), so pass that info to imgui
      if (HWND hovered_hwnd = ::WindowFromPoint(pos))
          if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)hovered_hwnd))
              io.MouseHoveredViewport = viewport->ID;
  }
  
  void    ImGui_ImplWin32_NewFrame()
  {
      ImGuiIO& io = ImGui::GetIO();
  
      // Setup display size (every frame to accommodate for window resizing)
      RECT rect;
      ::GetClientRect(g_hWnd, &rect);
      io.DisplaySize = ImVec2((float)(rect.right - rect.left), (float)(rect.bottom - rect.top));
      if (g_WantUpdateMonitors)
          ImGui_ImplWin32_UpdateMonitors();
  
      // Setup time step
      INT64 current_time;
      ::QueryPerformanceCounter((LARGE_INTEGER *)&current_time);
      io.DeltaTime = (float)(current_time - g_Time) / g_TicksPerSecond;
      g_Time = current_time;
  
      // Read keyboard modifiers inputs
      io.KeyCtrl = (::GetKeyState(VK_CONTROL) & 0x8000) != 0;
      io.KeyShift = (::GetKeyState(VK_SHIFT) & 0x8000) != 0;
      io.KeyAlt = (::GetKeyState(VK_MENU) & 0x8000) != 0;
      io.KeySuper = false;
      // io.KeysDown[], io.MousePos, io.MouseDown[], io.MouseWheel: filled by the WndProc handler below.
  
      // Update OS mouse position
      ImGui_ImplWin32_UpdateMousePos();
  
      // Update OS mouse cursor with the cursor requested by imgui
      ImGuiMouseCursor mouse_cursor = io.MouseDrawCursor ? ImGuiMouseCursor_None : ImGui::GetMouseCursor();
      if (g_LastMouseCursor != mouse_cursor)
      {
          g_LastMouseCursor = mouse_cursor;
          ImGui_ImplWin32_UpdateMouseCursor();
      }
  }
  
  // Allow compilation with old Windows SDK. MinGW doesn't have default _WIN32_WINNT/WINVER versions.
  #ifndef WM_MOUSEHWHEEL
  #define WM_MOUSEHWHEEL 0x020E
  #endif
  
  // Process Win32 mouse/keyboard inputs. 
  // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs.
  // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application.
  // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application.
  // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags.
  // PS: In this Win32 handler, we use the capture API (GetCapture/SetCapture/ReleaseCapture) to be able to read mouse coordinations when dragging mouse outside of our window bounds.
  // PS: We treat DBLCLK messages as regular mouse down messages, so this code will work on windows classes that have the CS_DBLCLKS flag set. Our own example app code doesn't set this flag.
  IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
  {
      if (ImGui::GetCurrentContext() == NULL)
          return 0;
  
      ImGuiIO& io = ImGui::GetIO();
      switch (msg)
      {
      case WM_LBUTTONDOWN: case WM_LBUTTONDBLCLK:
      case WM_RBUTTONDOWN: case WM_RBUTTONDBLCLK:
      case WM_MBUTTONDOWN: case WM_MBUTTONDBLCLK:
      {
          int button = 0;
          if (msg == WM_LBUTTONDOWN || msg == WM_LBUTTONDBLCLK) button = 0;
          if (msg == WM_RBUTTONDOWN || msg == WM_RBUTTONDBLCLK) button = 1;
          if (msg == WM_MBUTTONDOWN || msg == WM_MBUTTONDBLCLK) button = 2;
          if (!ImGui::IsAnyMouseDown() && ::GetCapture() == NULL)
              ::SetCapture(hwnd);
          io.MouseDown[button] = true;
          return 0;
      }
      case WM_LBUTTONUP:
      case WM_RBUTTONUP:
      case WM_MBUTTONUP:
      {
          int button = 0;
          if (msg == WM_LBUTTONUP) button = 0;
          if (msg == WM_RBUTTONUP) button = 1;
          if (msg == WM_MBUTTONUP) button = 2;
          io.MouseDown[button] = false;
          if (!ImGui::IsAnyMouseDown() && ::GetCapture() == hwnd)
              ::ReleaseCapture();
          return 0;
      }
      case WM_MOUSEWHEEL:
          io.MouseWheel += (float)GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
          return 0;
      case WM_MOUSEHWHEEL:
          io.MouseWheelH += (float)GET_WHEEL_DELTA_WPARAM(wParam) / (float)WHEEL_DELTA;
          return 0;
      case WM_KEYDOWN:
      case WM_SYSKEYDOWN:
          if (wParam < 256)
              io.KeysDown[wParam] = 1;
          return 0;
      case WM_KEYUP:
      case WM_SYSKEYUP:
          if (wParam < 256)
              io.KeysDown[wParam] = 0;
          return 0;
      case WM_CHAR:
          // You can also use ToAscii()+GetKeyboardState() to retrieve characters.
          if (wParam > 0 && wParam < 0x10000)
              io.AddInputCharacter((unsigned short)wParam);
          return 0;
      case WM_SETCURSOR:
          if (LOWORD(lParam) == HTCLIENT && ImGui_ImplWin32_UpdateMouseCursor())
              return 1;
          return 0;
      case WM_DISPLAYCHANGE:
          g_WantUpdateMonitors = true;
          return 0;
      }
      return 0;
  }
  
  //--------------------------------------------------------------------------------------------------------
  // DPI handling
  // Those in theory should be simple calls but Windows has multiple ways to handle DPI, and most of them
  // require recent Windows versions at runtime or recent Windows SDK at compile-time. Neither we want to depend on.
  // So we dynamically select and load those functions to avoid dependencies. This is the scheme successfully 
  // used by GLFW (from which we borrowed some of the code here) and other applications aiming to be portable.
  //---------------------------------------------------------------------------------------------------------
  // At this point ImGui_ImplWin32_EnableDpiAwareness() is just a helper called by main.cpp, we don't call it automatically.
  //---------------------------------------------------------------------------------------------------------
  
  static BOOL IsWindowsVersionOrGreater(WORD major, WORD minor, WORD sp)
  {
      OSVERSIONINFOEXW osvi = { sizeof(osvi), major, minor, 0, 0,{ 0 }, sp };
      DWORD mask = VER_MAJORVERSION | VER_MINORVERSION | VER_SERVICEPACKMAJOR;
      ULONGLONG cond = VerSetConditionMask(0, VER_MAJORVERSION, VER_GREATER_EQUAL);
      cond = VerSetConditionMask(cond, VER_MINORVERSION, VER_GREATER_EQUAL);
      cond = VerSetConditionMask(cond, VER_SERVICEPACKMAJOR, VER_GREATER_EQUAL);
      return VerifyVersionInfoW(&osvi, mask, cond);
  }
  #define IsWindows8Point1OrGreater()  IsWindowsVersionOrGreater(HIBYTE(0x0602), LOBYTE(0x0602), 0) // _WIN32_WINNT_WINBLUE
  #define IsWindows10OrGreater()       IsWindowsVersionOrGreater(HIBYTE(0x0A00), LOBYTE(0x0A00), 0) // _WIN32_WINNT_WIN10
  
  #ifndef DPI_ENUMS_DECLARED
  typedef enum { PROCESS_DPI_UNAWARE = 0, PROCESS_SYSTEM_DPI_AWARE = 1, PROCESS_PER_MONITOR_DPI_AWARE = 2 } PROCESS_DPI_AWARENESS;
  typedef enum { MDT_EFFECTIVE_DPI = 0, MDT_ANGULAR_DPI = 1, MDT_RAW_DPI = 2, MDT_DEFAULT = MDT_EFFECTIVE_DPI } MONITOR_DPI_TYPE;
  #endif
  #ifndef _DPI_AWARENESS_CONTEXTS_
  DECLARE_HANDLE(DPI_AWARENESS_CONTEXT);
  #define DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE    (DPI_AWARENESS_CONTEXT)-3
  #define DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2 (DPI_AWARENESS_CONTEXT)-4
  #endif
  typedef HRESULT(WINAPI * PFN_SetProcessDpiAwareness)(PROCESS_DPI_AWARENESS);                     // Shcore.lib+dll, Windows 8.1
  typedef HRESULT(WINAPI * PFN_GetDpiForMonitor)(HMONITOR, MONITOR_DPI_TYPE, UINT*, UINT*);        // Shcore.lib+dll, Windows 8.1
  typedef DPI_AWARENESS_CONTEXT(WINAPI * PFN_SetThreadDpiAwarenessContext)(DPI_AWARENESS_CONTEXT); // User32.lib+dll, Windows 10 v1607 (Creators Update)
  
  void ImGui_ImplWin32_EnableDpiAwareness()
  {
      // if (IsWindows10OrGreater()) // FIXME-DPI: This needs a manifest to succeed. Instead we try to grab the function pointer.
      {
          static HINSTANCE user32_dll = ::LoadLibraryA("user32.dll"); // Reference counted per-process
          if (PFN_SetThreadDpiAwarenessContext SetThreadDpiAwarenessContextFn = (PFN_SetThreadDpiAwarenessContext)::GetProcAddress(user32_dll, "SetThreadDpiAwarenessContext"))
          {
              SetThreadDpiAwarenessContextFn(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
              return;
          }
      }
      if (IsWindows8Point1OrGreater())
      {
          static HINSTANCE shcore_dll = ::LoadLibraryA("shcore.dll"); // Reference counted per-process
          if (PFN_SetProcessDpiAwareness SetProcessDpiAwarenessFn = (PFN_SetProcessDpiAwareness)::GetProcAddress(shcore_dll, "SetProcessDpiAwareness"))
              SetProcessDpiAwarenessFn(PROCESS_PER_MONITOR_DPI_AWARE);
      }
      else
      {
          SetProcessDPIAware();
      }
  }
  
  float ImGui_ImplWin32_GetDpiScaleForMonitor(void* monitor)
  {
      UINT xdpi = 96, ydpi = 96;
      if (IsWindows8Point1OrGreater())
      {
          static HINSTANCE shcore_dll = ::LoadLibraryA("shcore.dll"); // Reference counted per-process
          if (PFN_GetDpiForMonitor GetDpiForMonitorFn = (PFN_GetDpiForMonitor)::GetProcAddress(shcore_dll, "GetDpiForMonitor"))
              GetDpiForMonitorFn((HMONITOR)monitor, MDT_EFFECTIVE_DPI, &xdpi, &ydpi);
      }
      else
      {
          const HDC dc = ::GetDC(NULL);
          xdpi = ::GetDeviceCaps(dc, LOGPIXELSX);
          ydpi = ::GetDeviceCaps(dc, LOGPIXELSY);
          ::ReleaseDC(NULL, dc);
      }
      IM_ASSERT(xdpi == ydpi); // Please contact me if you hit this assert!
      return xdpi / 96.0f;
  }
  
  float ImGui_ImplWin32_GetDpiScaleForHwnd(void* hwnd)
  {
      HMONITOR monitor = ::MonitorFromWindow((HWND)hwnd, MONITOR_DEFAULTTONEAREST);
      return ImGui_ImplWin32_GetDpiScaleForMonitor(monitor);
  }
  
  float ImGui_ImplWin32_GetDpiScaleForRect(int x1, int y1, int x2, int y2)
  {
      RECT viewport_rect = { (LONG)x1, (LONG)y1, (LONG)x2, (LONG)y2 };
      HMONITOR monitor = ::MonitorFromRect(&viewport_rect, MONITOR_DEFAULTTONEAREST);
      return ImGui_ImplWin32_GetDpiScaleForMonitor(monitor);
  }
  
  //--------------------------------------------------------------------------------------------------------
  // IME (Input Method Editor) basic support for e.g. Asian language users
  //--------------------------------------------------------------------------------------------------------
  
  #if defined(_WIN32) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS) && !defined(IMGUI_DISABLE_WIN32_DEFAULT_IME_FUNCTIONS) && !defined(__GNUC__)
  #define HAS_WIN32_IME   1
  #include <imm.h>
  #ifdef _MSC_VER
  #pragma comment(lib, "imm32")
  #endif
  static void ImGui_ImplWin32_SetImeInputPos(ImGuiViewport* viewport, ImVec2 pos)
  {
      COMPOSITIONFORM cf = { CFS_FORCE_POSITION,{ (LONG)(pos.x - viewport->Pos.x), (LONG)(pos.y - viewport->Pos.y) },{ 0, 0, 0, 0 } };
      if (HWND hwnd = (HWND)viewport->PlatformHandle)
          if (HIMC himc = ::ImmGetContext(hwnd))
          {
              ::ImmSetCompositionWindow(himc, &cf);
              ::ImmReleaseContext(hwnd, himc);
          }
  }
  #else
  #define HAS_WIN32_IME   0
  #endif
  
  //--------------------------------------------------------------------------------------------------------
  // MULTI-VIEWPORT / PLATFORM INTERFACE SUPPORT
  // This is an _advanced_ and _optional_ feature, allowing the back-end to create and handle multiple viewports simultaneously.
  // If you are new to dear imgui or creating a new binding for dear imgui, it is recommended that you completely ignore this section first..
  //--------------------------------------------------------------------------------------------------------
  
  struct ImGuiViewportDataWin32
  {
      HWND    Hwnd;
      bool    HwndOwned;
      DWORD   DwStyle;
      DWORD   DwExStyle;
  
      ImGuiViewportDataWin32() { Hwnd = NULL; HwndOwned = false;  DwStyle = DwExStyle = 0; }
      ~ImGuiViewportDataWin32() { IM_ASSERT(Hwnd == NULL); }
  };
  
  static void ImGui_ImplWin32_CreateWindow(ImGuiViewport* viewport)
  {
      ImGuiViewportDataWin32* data = IM_NEW(ImGuiViewportDataWin32)();
      viewport->PlatformUserData = data;
  
      bool no_decoration = (viewport->Flags & ImGuiViewportFlags_NoDecoration) != 0;
      bool no_task_bar_icon = (viewport->Flags & ImGuiViewportFlags_NoTaskBarIcon) != 0;
      if (no_decoration)
      {
          data->DwStyle = WS_POPUP;
          data->DwExStyle = no_task_bar_icon ? WS_EX_TOOLWINDOW : WS_EX_APPWINDOW;
      }
      else
      {
          data->DwStyle = WS_OVERLAPPEDWINDOW;
          data->DwExStyle = no_task_bar_icon ? WS_EX_TOOLWINDOW : WS_EX_APPWINDOW;
      }
      if (viewport->Flags & ImGuiViewportFlags_TopMost)
          data->DwExStyle |= WS_EX_TOPMOST;
  
      // Create window
      RECT rect = { (LONG)viewport->Pos.x, (LONG)viewport->Pos.y, (LONG)(viewport->Pos.x + viewport->Size.x), (LONG)(viewport->Pos.y + viewport->Size.y) };
      ::AdjustWindowRectEx(&rect, data->DwStyle, FALSE, data->DwExStyle);
      data->Hwnd = ::CreateWindowEx(
          data->DwExStyle, _T("ImGui Platform"), _T("No Title Yet"), data->DwStyle,   // Style, class name, window name
          rect.left, rect.top, rect.right - rect.left, rect.bottom - rect.top,        // Window area
          g_hWnd, NULL, ::GetModuleHandle(NULL), NULL);                               // Parent window, Menu, Instance, Param
      data->HwndOwned = true;
      viewport->PlatformRequestResize = false;
      viewport->PlatformHandle = data->Hwnd;
  }
  
  static void ImGui_ImplWin32_DestroyWindow(ImGuiViewport* viewport)
  {
      if (ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData)
      {
          if (::GetCapture() == data->Hwnd)
          {
              // Transfer capture so if we started dragging from a window that later disappears, we'll still receive the MOUSEUP event.
              ::ReleaseCapture();
              ::SetCapture(g_hWnd);
          }
          if (data->Hwnd && data->HwndOwned)
              ::DestroyWindow(data->Hwnd);
          data->Hwnd = NULL;
          IM_DELETE(data);
      }
      viewport->PlatformUserData = viewport->PlatformHandle = NULL;
  }
  
  static void ImGui_ImplWin32_ShowWindow(ImGuiViewport* viewport)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      if (viewport->Flags & ImGuiViewportFlags_NoFocusOnAppearing)
          ::ShowWindow(data->Hwnd, SW_SHOWNA);
      else
          ::ShowWindow(data->Hwnd, SW_SHOW);
  }
  
  static ImVec2 ImGui_ImplWin32_GetWindowPos(ImGuiViewport* viewport)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      POINT pos = { 0, 0 };
      ::ClientToScreen(data->Hwnd, &pos);
      return ImVec2((float)pos.x, (float)pos.y);
  }
  
  static void ImGui_ImplWin32_SetWindowPos(ImGuiViewport* viewport, ImVec2 pos)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      RECT rect = { (LONG)pos.x, (LONG)pos.y, (LONG)pos.x, (LONG)pos.y };
      ::AdjustWindowRectEx(&rect, data->DwStyle, FALSE, data->DwExStyle);
      ::SetWindowPos(data->Hwnd, NULL, rect.left, rect.top, 0, 0, SWP_NOZORDER | SWP_NOSIZE | SWP_NOACTIVATE);
  }
  
  static ImVec2 ImGui_ImplWin32_GetWindowSize(ImGuiViewport* viewport)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      RECT rect;
      ::GetClientRect(data->Hwnd, &rect);
      return ImVec2(float(rect.right - rect.left), float(rect.bottom - rect.top));
  }
  
  static void ImGui_ImplWin32_SetWindowSize(ImGuiViewport* viewport, ImVec2 size)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      RECT rect = { 0, 0, (LONG)size.x, (LONG)size.y };
      ::AdjustWindowRectEx(&rect, data->DwStyle, FALSE, data->DwExStyle); // Client to Screen
      ::SetWindowPos(data->Hwnd, NULL, 0, 0, rect.right - rect.left, rect.bottom - rect.top, SWP_NOZORDER | SWP_NOMOVE | SWP_NOACTIVATE);
  }
  
  static void ImGui_ImplWin32_SetWindowFocus(ImGuiViewport* viewport)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      ::BringWindowToTop(data->Hwnd);
      ::SetForegroundWindow(data->Hwnd);
      ::SetFocus(data->Hwnd);
  }
  
  static bool ImGui_ImplWin32_GetWindowFocus(ImGuiViewport* viewport)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      return ::GetActiveWindow() == data->Hwnd;
  }
  
  static bool ImGui_ImplWin32_GetWindowMinimized(ImGuiViewport* viewport)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      return ::IsIconic(data->Hwnd) != 0;
  }
  
  static void ImGui_ImplWin32_SetWindowTitle(ImGuiViewport* viewport, const char* title)
  {
      // ::SetWindowTextA() doesn't properly handle UTF-8 so we explicitely convert our string.
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      int n = ::MultiByteToWideChar(CP_UTF8, 0, title, -1, NULL, 0);
      ImVector<wchar_t> title_w;
      title_w.resize(n);
      ::MultiByteToWideChar(CP_UTF8, 0, title, -1, title_w.Data, n);
      ::SetWindowTextW(data->Hwnd, title_w.Data);
  }
  
  static void ImGui_ImplWin32_SetWindowAlpha(ImGuiViewport* viewport, float alpha)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      IM_ASSERT(data->Hwnd != 0);
      IM_ASSERT(alpha >= 0.0f && alpha <= 1.0f);
      if (alpha < 1.0f)
      {
          DWORD style = ::GetWindowLongW(data->Hwnd, GWL_EXSTYLE) | WS_EX_LAYERED;
          ::SetWindowLongW(data->Hwnd, GWL_EXSTYLE, style);
          ::SetLayeredWindowAttributes(data->Hwnd, 0, (BYTE)(255 * alpha), LWA_ALPHA);
      }
      else
      {
          DWORD style = ::GetWindowLongW(data->Hwnd, GWL_EXSTYLE) & ~WS_EX_LAYERED;
          ::SetWindowLongW(data->Hwnd, GWL_EXSTYLE, style);
      }
  }
  
  static float ImGui_ImplWin32_GetWindowDpiScale(ImGuiViewport* viewport)
  {
      ImGuiViewportDataWin32* data = (ImGuiViewportDataWin32*)viewport->PlatformUserData;
      if (data && data->Hwnd)
          return ImGui_ImplWin32_GetDpiScaleForHwnd(data->Hwnd);
  
      // The first frame a viewport is created we don't have a window yet
      return ImGui_ImplWin32_GetDpiScaleForRect(
          (int)(viewport->Pos.x), (int)(viewport->Pos.y),
          (int)(viewport->Pos.x + viewport->Size.x), (int)(viewport->Pos.y + viewport->Size.y));
  }
  
  // FIXME-DPI: Testing DPI related ideas
  static void ImGui_ImplWin32_OnChangedViewport(ImGuiViewport* viewport)
  {
      (void)viewport;
  #if 0
      ImGuiStyle default_style;
      //default_style.WindowPadding = ImVec2(0, 0);
      //default_style.WindowBorderSize = 0.0f;
      //default_style.ItemSpacing.y = 3.0f;
      //default_style.FramePadding = ImVec2(0, 0);
      default_style.ScaleAllSizes(viewport->DpiScale);
      ImGuiStyle& style = ImGui::GetStyle();
      style = default_style;
  #endif
  }
  
  static LRESULT CALLBACK ImGui_ImplWin32_WndProcHandler_PlatformWindow(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
  {
      if (ImGui_ImplWin32_WndProcHandler(hWnd, msg, wParam, lParam))
          return true;
  
      if (ImGuiViewport* viewport = ImGui::FindViewportByPlatformHandle((void*)hWnd))
      {
          switch (msg)
          {
          case WM_CLOSE:
              viewport->PlatformRequestClose = true;
              return 0;
          case WM_MOVE:
              viewport->PlatformRequestMove = true;
              break;
          case WM_SIZE:
              viewport->PlatformRequestResize = true;
              break;
          case WM_NCHITTEST:
              // Let mouse pass-through the window. This will allow the back-end to set io.MouseHoveredViewport properly (which is OPTIONAL).
              // The ImGuiViewportFlags_NoInputs flag is set while dragging a viewport, as want to detect the window behind the one we are dragging.
              // If you cannot easily access those viewport flags from your windowing/event code: you may manually synchronize its state e.g. in
              // your main loop after calling UpdatePlatformWindows(). Iterate all viewports/platform windows and pass the flag to your windowing system.
              if (viewport->Flags & ImGuiViewportFlags_NoInputs)
                  return HTTRANSPARENT;
              break;
          }
      }
  
      return DefWindowProc(hWnd, msg, wParam, lParam);
  }
  
  static BOOL CALLBACK ImGui_ImplWin32_UpdateMonitors_EnumFunc(HMONITOR monitor, HDC, LPRECT, LPARAM)
  {
      MONITORINFO info = { 0 };
      info.cbSize = sizeof(MONITORINFO);
      if (!::GetMonitorInfo(monitor, &info))
          return TRUE;
      ImGuiPlatformMonitor imgui_monitor;
      imgui_monitor.MainPos = ImVec2((float)info.rcMonitor.left, (float)info.rcMonitor.top);
      imgui_monitor.MainSize = ImVec2((float)(info.rcMonitor.right - info.rcMonitor.left), (float)(info.rcMonitor.bottom - info.rcMonitor.top));
      imgui_monitor.WorkPos = ImVec2((float)info.rcWork.left, (float)info.rcWork.top);
      imgui_monitor.WorkSize = ImVec2((float)(info.rcWork.right - info.rcWork.left), (float)(info.rcWork.bottom - info.rcWork.top));
      imgui_monitor.DpiScale = ImGui_ImplWin32_GetDpiScaleForMonitor(monitor);
      ImGuiPlatformIO& io = ImGui::GetPlatformIO();
      if (info.dwFlags & MONITORINFOF_PRIMARY)
          io.Monitors.push_front(imgui_monitor);
      else
          io.Monitors.push_back(imgui_monitor);
      return TRUE;
  }
  
  static void ImGui_ImplWin32_UpdateMonitors()
  {
      ImGui::GetPlatformIO().Monitors.resize(0);
      ::EnumDisplayMonitors(NULL, NULL, ImGui_ImplWin32_UpdateMonitors_EnumFunc, NULL);
      g_WantUpdateMonitors = false;
  }
  
  static void ImGui_ImplWin32_InitPlatformInterface()
  {
      WNDCLASSEX wcex;
      wcex.cbSize = sizeof(WNDCLASSEX);
      wcex.style = CS_HREDRAW | CS_VREDRAW;
      wcex.lpfnWndProc = ImGui_ImplWin32_WndProcHandler_PlatformWindow;
      wcex.cbClsExtra = 0;
      wcex.cbWndExtra = 0;
      wcex.hInstance = ::GetModuleHandle(NULL);
      wcex.hIcon = NULL;
      wcex.hCursor = NULL;
      wcex.hbrBackground = (HBRUSH)(COLOR_BACKGROUND + 1);
      wcex.lpszMenuName = NULL;
      wcex.lpszClassName = _T("ImGui Platform");
      wcex.hIconSm = NULL;
      ::RegisterClassEx(&wcex);
  
      ImGui_ImplWin32_UpdateMonitors();
  
      // Register platform interface (will be coupled with a renderer interface)
      ImGuiPlatformIO& platform_io = ImGui::GetPlatformIO();
      platform_io.Platform_CreateWindow = ImGui_ImplWin32_CreateWindow;
      platform_io.Platform_DestroyWindow = ImGui_ImplWin32_DestroyWindow;
      platform_io.Platform_ShowWindow = ImGui_ImplWin32_ShowWindow;
      platform_io.Platform_SetWindowPos = ImGui_ImplWin32_SetWindowPos;
      platform_io.Platform_GetWindowPos = ImGui_ImplWin32_GetWindowPos;
      platform_io.Platform_SetWindowSize = ImGui_ImplWin32_SetWindowSize;
      platform_io.Platform_GetWindowSize = ImGui_ImplWin32_GetWindowSize;
      platform_io.Platform_SetWindowFocus = ImGui_ImplWin32_SetWindowFocus;
      platform_io.Platform_GetWindowFocus = ImGui_ImplWin32_GetWindowFocus;
      platform_io.Platform_GetWindowMinimized = ImGui_ImplWin32_GetWindowMinimized;
      platform_io.Platform_SetWindowTitle = ImGui_ImplWin32_SetWindowTitle;
      platform_io.Platform_SetWindowAlpha = ImGui_ImplWin32_SetWindowAlpha;
      platform_io.Platform_GetWindowDpiScale = ImGui_ImplWin32_GetWindowDpiScale;
      platform_io.Platform_OnChangedViewport = ImGui_ImplWin32_OnChangedViewport; // FIXME-DPI
  #if HAS_WIN32_IME
      platform_io.Platform_SetImeInputPos = ImGui_ImplWin32_SetImeInputPos;
  #endif
  
      // Register main window handle (which is owned by the main application, not by us)
      ImGuiViewport* main_viewport = ImGui::GetMainViewport();
      ImGuiViewportDataWin32* data = IM_NEW(ImGuiViewportDataWin32)();
      data->Hwnd = g_hWnd;
      data->HwndOwned = false;
      main_viewport->PlatformUserData = data;
      main_viewport->PlatformHandle = (void*)g_hWnd;
  }
  
  static void ImGui_ImplWin32_ShutdownPlatformInterface()
  {
      ::UnregisterClass(_T("ImGui Platform"), ::GetModuleHandle(NULL));
  }
  