classify/xform2d.h

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#ifndef   XFORM2D_H
#define   XFORM2D_H

/* =================
          Include Files and Type Defines
 ==================== */
#include "fpoint.h"

typedef struct
{
  FLOAT32 a, b, c, d, tx, ty;
} MATRIX_2D, *MATRIX_2D_PTR;

/* =================
          Macros
 ==================== */
#define InitMatrix(M)      ((M)->a = 1, (M)->b = 0,      \
            (M)->c = 0, (M)->d = 1,    \
            (M)->tx = 0, (M)->ty = 0 )

#define CopyMatrix(A,B)    ((B)->a = (A)->a, (B)->b = (A)->b,  \
            (B)->c = (A)->c, (B)->d = (A)->d,   \
            (B)->tx = (A)->tx, (B)->ty = (A)->ty)

#define TranslateMatrix(M,X,Y)   ((M)->tx += (M)->a * (X) + (M)->c * (Y),  \
            (M)->ty += (M)->b * (X) + (M)->d * (Y) )

#define ScaleMatrix(M,X,Y) ((M)->a *= (X), (M)->b *= (X),      \
            (M)->c *= (Y), (M)->d *= (Y))

#define MirrorMatrixInX(M)  (ScaleMatrix((M),-1,1))

#define MirrorMatrixInY(M)  (ScaleMatrix((M),1,-1))

#define MirrorMatrixInXY(M) (ScaleMatrix((M),-1,-1))

#define MapX(M,X,Y)   ((M)->a * (X) + (M)->c * (Y) + (M)->tx)

#define MapY(M,X,Y)   ((M)->b * (X) + (M)->d * (Y) + (M)->ty)
/* using a matrix to map points */
#define MapPoint(M,A,B)    (Xof(B) = MapX (M, Xof(A), Yof(A)), \
            Yof(B) = MapY (M, Xof(A), Yof(A)))
#define MapDx(M,DX,DY)    ((M)->a * (DX) + (M)->c * (DY))
#define MapDy(M,DX,DY)    ((M)->b * (DX) + (M)->d * (DY))

/* =================
          Public Function Prototypes
 ==================== */
void RotateMatrix(MATRIX_2D_PTR Matrix, FLOAT32 Angle); 
#endif

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