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BWSCALE(1)		     BRL-CAD User Commands		    BWSCALE(1)

NAME
       bwscale - change	the size of a black and	white bw file

SYNOPSIS
       bwscale [-r] [-s	squareinsize] [-w in_width] [-n	in_height]
	       [-S squareoutsize] [-W out_width] [-N out_height] [infile.bw] >
	       outfile.bw

DESCRIPTION
       bwscale will take a black and white bw(5) format	file of	given
       dimensions and produce a	larger or smaller scaled version. The -w and
       -n flags	specify	the input file width and number	of scan	lines in
       pixels; they can	be set to the same value via -s.  Similarly, the -W
       and -N flags specify the	desired	output file width and number of	scan
       lines in	pixels;	they can be set	to the same value via -S.  Defaults of
       512 are assumed for any unspecified dimensions.

       By default, the algorithm used is bilinear interpolation	if scaling up,
       and a box filter	of arbitrary size if scaling down. For the box filter
       a "square pixel"	assumption is made; that is, all whole and fractional
       input pixels falling into a rectangle the size of an output pixel
       contribute equally according to the fraction of the output pixel	area
       they cover. When	interpolating, the edge	pixels are preserved, i.e.,
       all of the interpolated pixels fall inside of the edges.	This can be a
       bit surprising when doubling the	size of	a file,	for example, as	only
       the edge	pixels will fall at exactly the	location of an output pixel.

       Specifying the -r flag changes from bilinear interpolation to nearest
       neighbor	interpolation, i.e., it	enlarges the image by pixel
       replication.

SEE ALSO
       brlcad(1), bwcrop(1), bwrect(1),	bw(5), pixscale(1)

BUGS
       This program cannot scale up in one dimension and down in the other at
       the same	time.

       The box filter used for scaling down results in the usual
       high-frequency ripple.

       Optional	cubic interpolation would be nice.

AUTHOR
       BRL-CAD Team

COPYRIGHT
       This software is	Copyright (c) 1984-2019	United States Government as
       represented by the U.S. Army Research Laboratory.

BUG REPORTS
       Reports of bugs or problems should be submitted via electronic mail to
       devs@brlcad.org

BRL-CAD				  08/29/2020			    BWSCALE(1)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | BUGS | AUTHOR | COPYRIGHT | BUG REPORTS

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