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 © 2010–2021 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