| .TH IM_MSB 3 "06 May 2006" |
| .SH NAME |
| im_msb, im_msb_band \- Convert to uchar by discarding bits |
| .SH SYNOPSIS |
| .nf |
| .B #include <vips/vips.h> |
| .sp |
| .BI "int im_msb( IMAGE " "*in" ", IMAGE " "*out" " ); |
| .br |
| |
| .BI "int im_msb_band( IMAGE " "*in" ", IMAGE " "*out" ", int " "band" " ); |
| .fi |
| .SH DESCRIPTION |
| .B 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. |
| .PP |
| For a signed short (16 bit) image, |
| .PP |
| im_msb( in, out ); |
| .PP |
| is equivalent to: |
| .PP |
| im_lintra( (1.0/256.0), in, 128.0, temp ); |
| .br |
| im_clip2fmt( temp, out, IM_BANDFMT_UCHAR ); |
| .PP |
| but much faster. |
| .PP |
| For any image which uses the whole range of values for its band format, |
| .PP |
| im_msb( in, out ); |
| .PP |
| is equivalent to: |
| .PP |
| im_scale( in, out ); |
| .PP |
| but a great deal faster, and without evaluating the input twice. |
| .PP |
| .B im_msb_band(3) |
| is as |
| .BR im_msb(3) , |
| except that all but one of the bands are also discarded. |
| .PP |
| im_msb_band( in, out, i ); |
| .PP |
| is equivalent to: |
| .PP |
| im_msb( in, temp ); |
| .br |
| im_extract_bands( temp, out, i, 1 ); |
| .PP |
| but again, faster. |
| .SH RETURN VALUE |
| The functions returns 0 on success and -1 on error. |
| .SH SEE ALSO |
| im_lintra(3), im_scale(3), im_clip(3) |
| .SH COPYRIGHT |
| .br |
| Copyright 2006, The Nottingham Trent University. |
| .SH AUTHOR |
| Tom Vajzovic |
