.TH PREDICATES 3 "11 April 1990"
.SH NAME
im_region_create, im_region_free \- region creation and destruction
.SH SYNOPSIS
.B #include <vips/vips.h>

REGION *im_region_create( im )
.br
IMAGE *im;

int im_region_free( reg )
.br
REGION *reg;
.SH DESCRIPTION
These functions create and destroy regions on images. Regions are used for
PIO, see accompanying documentation. Regions have type

    typedef struct {
        Rect valid  /* Area of im represented */
        IMAGE *im;  /* im we are defined on */

        ... more fields, all private and used for
        ... housekeeping
    } REGION;

im_region_create(3) returns a pointer to a new region, or NULL on error.
Regions are made blank, with no input or output possible. See im_prepare(3),
im_generate(3), im_start_one(3) and IM_REGION_ADDR(3).

im_region_free(3) frees a region and any resources associated with that
region.  When an image is closed, all regions which have been created on that
image are automatically freed.
.SH RETURN VALUE
All int-valued functions return zero on success and non-zero on error.
.SH COPYRIGHT
National Gallery, 1993
.SH AUTHOR
J. Cupitt \- 23/7/93