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        im_msb, im_msb_band - Convert to uchar by discarding bits


       #include <vips/vips.h>

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

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


       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.


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


       im_lintra(3), im_scale(3), im_clip(3)


       Copyright 2006, The Nottingham Trent University.


       Tom Vajzovic

                                  06 May 2006                        IM_MSB(3)