**NAME**

im_rightshift_size - Decrease size by a power-of-two factor

**SYNOPSIS**

**#include** **<vips/vips.h>**
**int** **im_rightshift_size(** **IMAGE** __*in__**,** **IMAGE** __*out__**,** **int** __xshift__**,** **int** __yshift__**,** **int** __band_fmt__ **);**

**DESCRIPTION**

**im_rightshift_size(3)** decreases the size of an integer type image by a
power-of-two factor, very quickly, by summing the values of adjacent
pixels. The sum is shifted to produce output of the specified band
format. __xshift__ and __yshift__ are positive and give the base-two
logarithms of the scale factors.
If the input image is a signed type, then __band_fmt__ must be one of
IM_BANDFMT_CHAR, IM_BANDFMT_SHORT or IM_BANDFMT_INT. If it is an
unsigned type, then __band_fmt__ must be one of IM_BANDFMT_UCHAR,
IM_BANDFMT_USHORT or IM_BANDFMT_UINT.

**RETURN** **VALUE**

The functions returns 0 on success and -1 on error.

**SEE ALSO**

im_affine(3)

**COPYRIGHT**

Copyright 2006, Tom Vajzovic.

**AUTHOR**

Tom Vajzovic
12 August 2006