NAME
im_offsets45, im_offsets90, im_rotate_imask45, im_rotate_dmask45,
im_rotate_imask90, im_rotate_dmask90 - rotate square masks
SYNOPSIS
int *im_offsets45( size )
int size;
int *im_offsets90( size )
int size;
INTMASK *im_rotate_imask45( m, name )
INTMASK *m;
char *name;
DOUBLEMASK *im_rotate_dmask45( m, name )
DOUBLEMASK *m;
char *name;
INTMASK *im_rotate_imask90( m, name )
INTMASK *m;
char *name;
DOUBLEMASK *im_rotate_dmask90( m, name )
DOUBLEMASK *m;
char *name;
DESCRIPTION
These functions can be used to produce the integer offsets needed to
rotate masks by 45 or 90 degrees clockwise.
im_offsets45() accepts only even size and returns a pointer to an int
buffer of size*size. The program mallocs the buffer and puts into it
the integer offsets needed to rotate a mask of even size size by 45
degrees. For instance if size is 3 the program returns the buffer 3 0
1 6 4 2 7 8 5 which is the offsets needed to rotate a mask with
offsets 0 1 2 3 4 5 6 7 8. The function return a pointer to valid
data on success or NULL on error. Since the program mallocs a buffer,
the user should free the returned pointer accordingly.
im_offsets90() accepts any size and returns a pointer to an int buffer
of size*size. The program mallocs the buffer and puts into it the
integer offsets needed to rotate a mask of size size by 90 degrees.
For instance if size is 3 the program returns the buffer 6 3 0 7 4 1
8 5 2 which is the offsets needed to rotate a mask with offsets 0 1 2
3 4 5 6 7 8. The function return a pointers to valid data on success
or NULL on error. Since the program mallocs a buffer, the user should
free the returned pointer accordingly.
im_rotate_imask45() rotates the INTMASK m by 45 degrees and returns the
rotated mask. The filename member of the returned structure is set to
name. The program allocates memory for the new mask and therefore the
user must free the returned mask by a call to im_free_imask(3). The
returned mask is rotated by 45 degrees clockwise. The function return
a valid INTMASK pointer on success or NULL on error.
im_rotate_dmask45() rotates the DOUBLEMASK m by 45 degrees and returns
the rotated mask. The filename member of the returned structure is set
to name. The program allocates memory for the new mask and therefore
the user must free the returned mask by a call to im_free_dmask(3).
The returned mask is rotated by 45 degrees clockwise. The function
return a valid DOUBLEMASK pointer on success or NULL on error.
im_rotate_imask90() rotates the INTMASK m by 90 degrees and returns the
rotated mask. The filename member of the returned structure is set to
name. The program allocates memory for the new mask and therefore the
user must free the returned mask by a call to im_free_imask(3). The
returned mask is rotated by 90 degrees clockwise. The function return
a valid INTMASK pointer on success or NULL on error.
im_rotate_dmask90() rotates the DOUBLEMASK m by 90 degrees and returns
the rotated mask. The filename member of the returned structure is set
to name. The program allocates memory for the new mask and therefore
the user must free the returned mask by a call to im_free_dmask(3).
The returned mask is rotated by 90 degrees clockwise. The function
return a valid DOUBLEMASK pointer on success or NULL on error.
RETURN VALUE
SEE ALSO
im_read_imask(3), im_read_dmask(3), im_free_imask(3), im_free_dmask(3),
im_gradient(3), im_compass(3), im_conv(3).
COPYRIGHT
N. Dessipris
AUTHOR
N. Dessipris -28/05/1991
28 May 1991 IM_OFFSETS45(3)