Draw Skin Window Using Pure Win32 API

#include "stdafx.h"
#define MAX_LOADSTRING 100

HINSTANCE hInst;
HWND hWindow;
TCHAR szTitle[MAX_LOADSTRING];
TCHAR szWindowClass[MAX_LOADSTRING];

ATOM				MyRegisterClass(HINSTANCE hInstance);
BOOL				InitInstance(HINSTANCE, int);
LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK	About(HWND, UINT, WPARAM, LPARAM);

//global variant which used to draw skin in current window
CSkinWindow SkinWin;

int APIENTRY _tWinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow) {
	MSG msg;
	HACCEL hAccelTable;

	LoadString(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
	LoadString(hInstance, IDC_DRAWWINDOW, szWindowClass, MAX_LOADSTRING);
	MyRegisterClass(hInstance);

	if (!InitInstance (hInstance, nCmdShow)) {
		return FALSE;
	}

	hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_DRAWWINDOW);

	// main message loop
	while (GetMessage(&msg, NULL, 0, 0)) {
		if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)) {
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}

	//release resource
	SkinWin.Free();
	return (int) msg.wParam;
}

ATOM MyRegisterClass(HINSTANCE hInstance) {
	WNDCLASSEX wcex;

	wcex.cbSize = sizeof(WNDCLASSEX); 

	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= (WNDPROC)WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= LoadIcon(hInstance, (LPCTSTR)IDI_DRAWWINDOW);
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	//wcex.lpszMenuName	= (LPCTSTR)IDC_DRAWWINDOW;
	wcex.lpszClassName	= szWindowClass;
	wcex.hIconSm		= LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL);

	return RegisterClassEx(&wcex);
}

BOOL InitInstance(HINSTANCE hInstance, int nCmdShow) {
   HWND hWnd;

   hInst = hInstance;

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd) {
      return FALSE;
   }

   //load skin from resource
   hWindow = hWnd;
   SkinWin.Load(hInstance, hWnd);

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
	int wmId, wmEvent;
	PAINTSTRUCT ps;
	HDC hdc;

	//handle some special window's message here
	if( SkinWin.IsHandledMessage( message ) )
		return SkinWin.WndProc( hWnd, message, wParam, lParam );

	switch (message)
	{
	case WM_COMMAND:
		wmId    = LOWORD(wParam); 
		wmEvent = HIWORD(wParam); 
		switch (wmId)
		{
		case IDM_ABOUT:
			DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
			break;
		case IDM_EXIT:
			DestroyWindow(hWnd);
			break;
		default:
			return DefWindowProc(hWnd, message, wParam, lParam);
		}
		break;
	case WM_PAINT:
		hdc = BeginPaint(hWnd, &ps);
		{
		}
		EndPaint(hWnd, &ps);
		break;
	case WM_DESTROY:
		PostQuitMessage(0);
		break;
	default:
		return DefWindowProc(hWnd, message, wParam, lParam);
	}
	return 0;
}

LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam) {
	switch (message)
	{
	case WM_INITDIALOG:
		return TRUE;

	case WM_COMMAND:
		if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL) {
			EndDialog(hDlg, LOWORD(wParam));
			return TRUE;
		}
		break;
	}
	return FALSE;
}