Pampaintspill User Manual(0)

NAME
pampaintspill - smoothly spill colors into the background

SYNOPSIS

pampaintspill [--bgcolor=color] [--wrap] [--all] [--downsample=number] [--near=number] [--power=number] [filename] [-randomseed=integer]

Minimum unique abbreviations of option are acceptable. You may use double hyphens instead of single hyphen to denote options. You may use white space in place of the equals sign to separate an option name from its value.

DESCRIPTION

This program is part of Netpbm(1) .

pampaintspill produces a smooth color gradient from all of the non-background-colored pixels in an input image, effectively "spilling paint" onto the background. pampaintspill is similar to pamgradient but differs in the following characteristics:

•   pampaintspill accepts any number of paint
          sources (non-background-colored pixels), which can lie anywhere
          on the canvas. pamgradient accepts exactly
          four paint sources, one in each corner of the image.

•   pampaintspill requires an input image while
          pamgradient generates a new image from
          scratch.

•   pampaintspill can produce tileable output and
          can control how tightly the gradient colors bind to their source
          pixels.

Results are generally best when the input image contains just a few, crisp spots of color. Use your drawing program's pencil tool - as opposed to a paintbrush or airbrush tool - with a small nib.

OPTIONS

In addition to the options common to all programs based on libnetpbm (most notably -quiet, see
 Common Options index.html#commonoptions ), pampaintspill recognizes the following command line options:

--bgcolor=color

    Explicitly specify the background color. color can be
          specified using any of the formats accepted by the pnm_parsecolor() library routine (libnetpbm_image.html#colorname) such as red or #ff0000. If
          --bgcolor is not specified, pampaintspill makes an
          educated guess about the background color based on the colors in the
          image's corners.

--wrap

    Allow gradients to wrap around image borders. That is, colors
          that spill off the right side of the image reappear on the left side of
          the image and likewise for left/right, top/bottom, and
          bottom/top. --wrap makes images tileable, which is nice for
          producing desktop backgrounds.

--all

    Recolor all pixels, not just background pixels. Normally,
          non-background-colored pixels in the input image appear unmodified in
          the output image. With --all, all pixels are colored
          based on their distance from all of the (other) non-background-colored
          pixels.

--downsample=number

    Ignore all but number non-background-colored pixels.
          When a large number of pixels in the input image differ in color from
          the background, pampaintspill runs very slowly. The
          --downsample option randomly selects a given number of colored
          pixels to use as paint sources for the gradients and ignores the rest,
          thereby trading off image quality for speed of execution.

--near=number

    Consider only the nearest number paint sources when computing
          a pixel's new color. The default is to consider all paint sources.
          In most cases, number should be fairly small, or its impact
          will be minimal and execution time will increase unnecessarily. A
          value of 1 produces a coloring that looks a lot like a Voronoi
          diagram.

    This option was new in Netpbm 10.97 (December 2021).

--power=number

    Control how color intensity changes as a function of the
          distance from a paint source. The default value for number is
          -2.0, which means that intensity drops (because of the minus sign) with
          the square (because of the 2.0) of the distance from each paint
          source. -2.0 generally works well in practice, but other values can be
          specified for various special effects. With very small numbers of paint
          sources, -1.0 may produce subtler gradients, but these get muddier as
          the number of paint sources increases. Positive numbers (e.g., 1.0 and
          2.0) make the paint sources stand out in the output image by pushing the
          gradients away from them.

-randomseed=integer

    This is the seed for the random number generator that generates the
      pixels.

    Use this to ensure you get the same image on separate invocations.

    This option was new in Netpbm 10.94 (March 2021).

SEE ALSO

•   pamgradient(1)

•   ppmmake(1) ,

•   ppmrainbow(1) ,

•   pgmramp(1) ,

•   ppmpat(1) ,

•   pam(1)

HISTORY

pampaintspill was new in Netpbm 10.50 (March 2010).

COPYRIGHT

Copyright © 2010&ndash;2021 Scott Pakin, scott+pbm@pakin.org.

Table Of Contents

•   SYNOPSIS (#synopsis)

•   DESCRIPTION (#description)

•   OPTIONS (#options)

•   SEE ALSO (#seealso)

•   HISTORY (#history)

•   COPYRIGHT (#copyright)

DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master documentation is at

    http://netpbm.sourceforge.net/doc/pampaintspill.html