IM_MSB

Section: C Library Functions (3) Updated: 06 May 2006 Local index Up

NAME

im_msb, im_msb_band - Convert to uchar by discarding bits

SYNOPSIS

#include <vips/vips.h>

int im_msb( IMAGE *in, IMAGE *out );



int im_msb_band( IMAGE *in, IMAGE *out, int band );

DESCRIPTION

im_msb(3) converts char, short, or int images (including LABQ coded ones) into unsigned char images, very quickly, by discarding the lower order bits. Once scaled to char, signed values are converted to unsigned by adding 128.

For a signed short (16 bit) image,

im_msb( in, out );

is equivalent to:

im_lintra( (1.0/256.0), in, 128.0, temp );
im_clip2fmt( temp, out, IM_BANDFMT_UCHAR );

but much faster.

For any image which uses the whole range of values for its band format,

im_msb( in, out );

is equivalent to:

im_scale( in, out );

but a great deal faster, and without evaluating the input twice.

im_msb_band(3) is as im_msb(3), except that all but one of the bands are also discarded.

im_msb_band( in, out, i );

is equivalent to:

im_msb( in, temp );
im_extract_bands( temp, out, i, 1 );

but again, faster.

RETURN VALUE

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

COPYRIGHT

AUTHOR

Tom Vajzovic

This document was created by man2html, using the manual pages.
Time: 21:48:23 GMT, April 16, 2011

IM_MSB

NAME

SYNOPSIS

DESCRIPTION

RETURN VALUE

SEE ALSO

COPYRIGHT

AUTHOR

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