NAME

float_to_exp - Convert floating point values into "exponential" pixels.

SYNOPSIS

#include <rle.h>

float_to_exp( count, floats, pixels )
int count;
float * floats;
rle_pixel * pixels;

DESCRIPTION

The function float_to_exp converts count floating point numbers (pointed to by floats) into count+1 bytes (pointed to by pixels) using an "exponential" format. This format generates count pixels as eight bit "mantissa" values, and another byte containing a common exponent for all of the data values. This format has a wider dynamic range of values with little extra overhead. The inverse mapping is

	float expnt, flt_val;
	rle_pixel exponent, val;
	expnt = ldexp( 1/256.0, (int)exponent - 127 );
	flt_val = (float)val * expnt;

Files containing exponential data may be converted into displayable images using the unexp(1) command. Unexp should be used before using any tools that perform arithmetic on pixel values, or displaying the image. Unexp expects files containing exponential data to have an "exponential_data" picture comment.

AUTHOR

John W. Peterson, based on code by Spencer Thomas.
University of Utah

NAME

SYNOPSIS

DESCRIPTION

SEE ALSO

AUTHOR