/************************************************************************ *宏定義 ************************************************************************/#define sign(a)        ((a) < 0 ? -1 : 1)#define Int(a)          ((a) < 0 ? (int)(a-0.5) : (int)(a))#define mnint(a)	((a) < 0 ? (int)(a - 0.5) : (int)(a + 0.5))#define mfloor(a)       ((a) < 0 ? (int)(a - 0.5) : (int)(a))#define mmax(a, b)        ((a) > (b) ? (a) : (b))#define mmin(a, b)        ((a) < (b) ? (a) : (b))#define limit(x) \{ \    if (x > 255) x = 255; \    if (x <   0)   x = 0; \}