static UINT CompatGetDpiForWindow(HWND hwnd)
{
	typedef UINT (WINAPI *GetDpiForWindowFn)(HWND);

	static GetDpiForWindowFn fn =
		(GetDpiForWindowFn)GetProcAddress(
			GetModuleHandleA("user32.dll"),
			"GetDpiForWindow"
		);

	if(fn)
		return fn(hwnd);

	// Windows 7: non esiste DPI per-monitor.
	HDC dc = GetDC(hwnd);
	UINT dpi = dc ? (UINT)GetDeviceCaps(dc, LOGPIXELSX) : 96;

	if(dc)
		ReleaseDC(hwnd, dc);

	return dpi ? dpi : 96;
}

static int CompatGetSystemMetricsForDpi(int index, UINT dpi)
{
	typedef int (WINAPI *GetSystemMetricsForDpiFn)(int, UINT);

	static GetSystemMetricsForDpiFn fn =
		(GetSystemMetricsForDpiFn)GetProcAddress(
			GetModuleHandleA("user32.dll"),
			"GetSystemMetricsForDpi"
		);

	if(fn)
		return fn(index, dpi);

	// Su Windows 7 il DPI è unico per tutto il desktop:
	// GetSystemMetrics restituisce già le metriche appropriate.
	return GetSystemMetrics(index);
}