ff-crack.1

.Dd 2024-04-29
.Dt FF-CRACK 1
.Os farbfeld-utils
.Sh NAME
.Nm ff-crack
.Nd farbfeld filter that creates maze-like cracked lines
.Sh SYNOPSIS
.Nm
<?opt=int?> <?opt=int?> ...
.Sh DESCRIPTION
.Nm
reads a
.Xr farbfeld 5
image from stdin, applies the crack filter and writes the result to stdout.
.Pp
Opaque pixels of the input are considered as walls, and it makes new walls
branching from them, of the same colour. At least one pixel of the input must
be opaque.
.Pp
In case of an error
.Nm
writes a diagnostic message to stderr.
.Sh EXIT STATUS
.Bl -tag -width Ds
.It 0
Image processed successfully.
.It 1
An error occurred.
.El
.Sh OPTIONS
The arguments is a letter and then equal sign and then an integer number. All
options are optional.

The following options are available:
   b -- maximum allowed number of opaque pixels in the clearing (as set by c)
   c -- amount of space of clearing required
   d -- constrain direction of branches:
          0 = normal
          1 = horizontal/vertical
          2 = downward
          3 = upward
          4 = toward centre
          5 = mostly horizontal
          6 = mostly vertical
          7 = spiral
   e -- how much to darken new branches - from 0 to 255
   k -- the probability to break a line early - out of 1024
   o -- together with "c", if this is nonzero then use a circular clearing
        instead of a square clearing
   q -- queue length - this sets how much shorter the lines can be from the
        next wall
   s -- random number seed
   u -- maximum dead cycles
.Sh EXAMPLES
$
.Nm
< image.ff > image-crack.ff
.Pp
$
.Nm
s=142 u=33 d=7 q=2 < image.ff > image-crack.ff
.Sh SEE ALSO
.Xr farbfeld 5 ,
.Xr farbfeld-utils 7