#define MM_TEXT             1   //1逻辑单位=1像素
#define MM_LOMETRIC         2   //1逻辑单位 = 0.1mm
#define MM_HIMETRIC         3   //1逻辑单位 = 0.01mm
#define MM_LOENGLISH        4
#define MM_HIENGLISH        5   //1 = 0.01in = 0.254mm
#define MM_TWIPS            6
#define MM_ISOTROPIC        7
#define MM_ANISOTROPIC      8

case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);
            
			int iMapMode = GetMapMode(hdc);
			
			SetMapMode(hdc, MM_TEXT);   //TEXT模式
			Rectangle(hdc, 200, 200, 400, 400);

			SetMapMode(hdc, MM_LOMETRIC);
			Rectangle(hdc, 200, -200, 400, -400);

			SetMapMode(hdc, MM_HIMETRIC);
			Rectangle(hdc, 200, -200, 400, -400);

			SetMapMode(hdc, iMapMode);

            EndPaint(hWnd, &ps);
        }
        break;