Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Matrix Functions /

RotateMatrix

The RotateMatrix function allows your application to modify the contents of a matrix so that it defines a rotation operation.

pascal void RotateMatrix (MatrixRecord *m, Fixed degrees, 
                           Fixed aboutX, Fixed aboutY);

m

Contains a pointer to a matrix structure. The RotateMatrix function updates the contents of this matrix so that the matrix describes a rotation operation--that is, it concatenates the rotation transformations onto whatever was initially in the matrix structure. You specify the direction and amount of rotation with the degrees parameter. You specify the point of rotation with the aboutX and aboutY parameters.

degrees

Specifies the number of degrees of rotation.

aboutX

Specifies the x coordinate of the anchor point of rotation.

aboutY

Specifies the y coordinate of the anchor point of rotation.

ERROR CODES

None

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