デジタル時計を作りました

#pragma comment(linker,"\"/manifestdependency:type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' processorArchitecture='*' publicKeyToken='6595b64144ccf1df' language='*'\"")

#include <windows.h>
#include "resource.h"

#define CLIENT_WIDTH 300
#define CLIENT_HEIGHT 128
#define FONT_SIZE (-75)

TCHAR szClassName[] = TEXT("clock");

LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
	static HGLOBAL hGlobal = NULL;
	static HANDLE hFontResource = NULL;
	static HFONT hFont = NULL;
	static SYSTEMTIME st = {};
	static WCHAR szTime[32] = {};
	switch (msg)
	{
	case WM_CREATE:
		{
			HRSRC hRes = FindResource(0, MAKEINTRESOURCE(IDR_FONT1), RT_FONT);
			if (!hRes)
			{
				return -1;
			}
			DWORD dwSize = SizeofResource(0, hRes);
			if (!dwSize)
			{
				return -1;
			}
			hGlobal = LoadResource(0, hRes);
			if (!hGlobal)
			{
				return -1;
			}
			LPVOID pBuffer = LockResource(hGlobal);
			if (!pBuffer)
			{
				return -1;
			}
			DWORD dwFonts;
			hFontResource = AddFontMemResourceEx(pBuffer, dwSize, 0, &dwFonts);
			if (!hFontResource)
			{
				return -1;
			}
		}
		hFont = CreateFontW(FONT_SIZE, 0, 0, 0, FW_NORMAL, 0, 0, 0, ANSI_CHARSET, 0, 0, 0, 0, L"DigitalNumber");
		SendMessage(hWnd, WM_TIMER, 0, 0);
		SetTimer(hWnd, 0x1234, 1, NULL);
		break;
	case WM_TIMER:
		{
			SYSTEMTIME st_ = {};
			double vt = 0.0, vt_ = 0.0;
			GetLocalTime(&st_);
			SystemTimeToVariantTime(&st, &vt);
			SystemTimeToVariantTime(&st_, &vt_);
			if (vt != vt_) {
				st = st_;
				wsprintfW(szTime, L"%02d:%02d:%02d", st.wHour, st.wMinute, st.wSecond);
				OutputDebugString(szTime);
				OutputDebugString(L"\r\n");
				InvalidateRect(hWnd, 0, 1);
			}
		}
		break;
	case WM_PAINT:
		{
			PAINTSTRUCT ps;
			HDC hdc = BeginPaint(hWnd, &ps);
			HFONT hOldFont = (HFONT)SelectObject(hdc, hFont);
			RECT rect = {};
			GetClientRect(hWnd, &rect);
			int nOldBkMode = SetBkMode(hdc, TRANSPARENT);
			COLORREF cOldColor = SetTextColor(hdc, RGB(38, 41, 52));
			DrawText(hdc, szTime, -1, &rect, DT_SINGLELINE | DT_VCENTER | DT_CENTER);
			SetTextColor(hdc, cOldColor);
			SetBkMode(hdc, nOldBkMode);
			SelectObject(hdc, hOldFont);
			EndPaint(hWnd, &ps);
		}
		break;
	case WM_NCHITTEST:
		wParam = DefWindowProc(hWnd, msg, wParam, lParam);
		if (wParam == HTCLIENT)
			return HTCAPTION;
		else
			return wParam;
	case WM_DESTROY:
		KillTimer(hWnd, 0x1234);
		DeleteObject(hFont);
		if (hFont)
			DeleteObject(hFont);
		if (hFontResource)
			RemoveFontMemResourceEx(hFontResource);
		if (hGlobal)
			FreeResource(hGlobal);
		PostQuitMessage(0);
		break;
	default:
		return DefWindowProc(hWnd, msg, wParam, lParam);
	}
	return 0;
}

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPreInst, LPWSTR pCmdLine, int nCmdShow)
{
	MSG msg;
	HBRUSH hBrush = CreateSolidBrush(RGB(130,135,103));
	WNDCLASS wndclass = {
		CS_HREDRAW | CS_VREDRAW,
		WndProc,
		0,
		0,
		hInstance,
		LoadIcon(hInstance,MAKEINTRESOURCE(IDI_ICON1)),
		LoadCursor(0,IDC_ARROW),
		hBrush,
		0,
		szClassName
	};
	RegisterClass(&wndclass);
	DWORD dwWindowStyle = WS_OVERLAPPEDWINDOW | WS_CLIPCHILDREN;
	RECT rect = {};
	SetRect(&rect, 0, 0, CLIENT_WIDTH, CLIENT_HEIGHT);
	AdjustWindowRect(&rect, dwWindowStyle, 0);
	HWND hWnd = CreateWindowEx(
		WS_EX_TOPMOST,
		szClassName,
		TEXT("clock"),
		dwWindowStyle,
		CW_USEDEFAULT,
		0,
		rect.right - rect.left,
		rect.bottom - rect.top,
		0,
		0,
		hInstance,
		0
	);
	ShowWindow(hWnd, SW_SHOWDEFAULT);
	UpdateWindow(hWnd);
	while (GetMessage(&msg, 0, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	DeleteObject(hBrush);
	return (int)msg.wParam;
}