int
im_lindetect( IMAGE *in, IMAGE *out, INTMASK *mask )
{
IMAGE *filtered[4];
IMAGE *absed[4];
int i;
if( im_open_local_array( out, filtered, 4, "im_lindetect:1", "p" ) ||
im_open_local_array( out, absed, 4, "im_lindetect:2", "p" ) )
return( -1 );
for( i = 0; i < 4; i++ ) {
if( im_conv( in, filtered[i], mask ) ||
!(mask = (INTMASK *) im_local( out,
(im_construct_fn) im_rotate_imask45,
(im_callback_fn) im_free_imask,
mask, mask->filename, NULL )) )
return( -1 );
}
for( i = 0; i < 4; i++ )
if( im_abs( filtered[i], absed[i] ) )
return( -1 );
return( im_maxvalue( absed, out, 4 ) );
}
static int
maxvalue_vec( im_object *argv )
{
im_imagevec_object *iv = (im_imagevec_object *) argv[0];
return( im_maxvalue( iv->vec, argv[1], iv->n ) );
}
/**
* im_compass:
* @in: input image
* @out: output image
* @mask: convolution mask
*
* @in is convolved 8 times with @mask, each time @mask is rotated by 45
* degrees. Each output pixel is the largest absolute value of the 8
* convolutions.
*
* See also: im_lindetect(), im_gradient(), im_conv().
*
* Returns: 0 on success, -1 on error
*/
int
im_compass( IMAGE *in, IMAGE *out, INTMASK *mask )
{
IMAGE *filtered[8];
IMAGE *absed[8];
int i;
if( im_open_local_array( out, filtered, 8, "im_compass:1", "p" ) ||
im_open_local_array( out, absed, 8, "im_compass:2", "p" ) )
return( -1 );
for( i = 0; i < 8; i++ ) {
if( im_conv( in, filtered[i], mask ) ||
!(mask = im_local_imask( out,
im_rotate_imask45( mask, mask->filename ) )) )
return( -1 );
}
for( i = 0; i < 8; i++ )
if( im_abs( filtered[i], absed[i] ) )
return( -1 );
return( im_maxvalue( absed, out, 8 ) );
}
