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LERP(9.1)                                                            LERP(9.1)



NAME
       lerp, sub - linear combinations of images

SYNOPSIS
       fb/lerp file fraction [ file fraction ...  ]

       fb/sub file1 file2

DESCRIPTION
       Lerp  computes  a linear combination of a number of input images.  Each
       input file name is followed by a floating-point fraction  by  which  to
       scale its pixel values.  The fraction after the last image may be omit-
       ted, in which case one minus the sum of the other  fractions  is  used.
       The resulting image is written to standard output.

       Nothing  prevents  the fractions from being smaller than zero or larger
       than one.  Output pixel values that fall below zero or  above  255  are
       clamped.

       Sub  reads  two  images,  which must be the same size and have the same
       number of channels.  Each channel of each pixel of the output image  is
       the  absolute  value  of the difference between the corresponding input
       values.

SOURCE
       /sys/src/fb/lerp.c
       /sys/src/fb/sub.c

SEE ALSO
       picfile(9.6)



                                                                     LERP(9.1)