classify/xform2d.cpp File Reference

#include "xform2d.h"
#include <math.h>

Go to the source code of this file.

Functions

• void RotateMatrix (MATRIX_2D_PTR Matrix, FLOAT32 Angle)

  Rotate the coordinate system (as specified by Matrix) about its origin by Angle radians.
  

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Function Documentation

void RotateMatrix	(	MATRIX_2D_PTR	Matrix,
		FLOAT32	Angle
	)

Rotate the coordinate system (as specified by Matrix) about its origin by Angle radians.

Parameters:

	Matrix	Transformation matrix to rotate
	Angle	Angle to rotate matrix

Returns:

none (Matrix is modified)

In matrix notation the effect is as follows:

		Matrix = R X Matrix

	where R is the following matrix

    cos Angle   sin Angle   0
    -sin Angle  cos Angle   0
    0           0           1

Note:

Exceptions: none

Date:

7/27/89, DSJ, Create.

Definition at line 51 of file xform2d.cpp.

Referenced by ComputeBulges().

                                                       { 
  FLOAT32 Cos, Sin;
  FLOAT32 NewA, NewB;

  Cos = cos ((double) Angle);
  Sin = sin ((double) Angle);

  NewA = Matrix->a * Cos + Matrix->c * Sin;
  NewB = Matrix->b * Cos + Matrix->d * Sin;
  Matrix->c = Matrix->a * -Sin + Matrix->c * Cos;
  Matrix->d = Matrix->b * -Sin + Matrix->d * Cos;
  Matrix->a = NewA;
  Matrix->b = NewB;

}                                /* RotateMatrix */

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