68 lines
1.9 KiB
Groff
68 lines
1.9 KiB
Groff
|
.TH WRAPPERS 3 "11 April 1990"
|
||
|
|
.SH NAME
|
||
|
|
im_wrapone, im_wrapmany \- easy interface to partial image IO system
|
||
|
|
.SH SYNOPSIS
|
||
|
|
.B #include <vips/vips.h>
|
||
|
|
|
||
|
|
int im_wrapone( IMAGE *in, IMAGE *out,
|
||
|
|
im_wrapone_fn fn, void *a, void *b )
|
||
|
|
.br
|
||
|
|
int im_wrapmany( IMAGE **in, IMAGE *out,
|
||
|
|
im_wrapmany_fn fn, void *a, void *b )
|
||
|
|
|
||
|
|
where
|
||
|
|
|
||
|
|
typedef void (*im_wrapone_fn)( void *in, void *out, int n,
|
||
|
|
void *a, void *b )
|
||
|
|
.br
|
||
|
|
typedef void (*im_wrapmany_fn)( void **in, void *out, int n,
|
||
|
|
void *a, void *b )
|
||
|
|
|
||
|
|
.SH DESCRIPTION
|
||
|
|
These functions provide a simple way to use the VIPS partial image IO system,
|
||
|
|
provided that your image processing function involves no coordinate
|
||
|
|
transformations, that is, that each output PEL depends only upon the
|
||
|
|
corresponding PEL(s) in the input image(s).
|
||
|
|
|
||
|
|
You should write your operation as a buffer processing function --- for
|
||
|
|
example:
|
||
|
|
|
||
|
|
static void
|
||
|
|
invert_buffer( unsigned char *in, unsigned char *out,
|
||
|
|
int width )
|
||
|
|
{
|
||
|
|
int x;
|
||
|
|
|
||
|
|
for( x = 0; x < width; x++ )
|
||
|
|
*out++ = 255 - *in++;
|
||
|
|
}
|
||
|
|
|
||
|
|
This can now be turned into a full PIO image processing function by:
|
||
|
|
|
||
|
|
int
|
||
|
|
invert( IMAGE *in, IMAGE *out )
|
||
|
|
{
|
||
|
|
if( in->BandFmt != FMTUCHAR ||
|
||
|
|
in->Coding != NOCODING ||
|
||
|
|
in->Bands != 1 ) {
|
||
|
|
im_errormsg( "invert: bad input" );
|
||
|
|
return( -1 );
|
||
|
|
}
|
||
|
|
if( im_cp_desc( out, in ) )
|
||
|
|
return( -1 );
|
||
|
|
if( im_wrapone( in, out,
|
||
|
|
(im_wrapone_fn) invert_buffer, NULL, NULL ) )
|
||
|
|
return( 0 );
|
||
|
|
}
|
||
|
|
|
||
|
|
im_wrapmany(3) works as im_wrapone(3), but allows many input images. All the
|
||
|
|
inputs should be same Xsize and Ysize, but may vary in type. The array of
|
||
|
|
input images should be NULL-terminated, as for im_start_many(3).
|
||
|
|
|
||
|
|
.SH RETURN VALUE
|
||
|
|
All int-valued functions return zero on success and non-zero on error.
|
||
|
|
.SH COPYRIGHT
|
||
|
|
National Gallery, 1995
|
||
|
|
.SH AUTHOR
|
||
|
|
J. Cupitt \- 9/2/95
|