\
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.\" Do not hand-hack it!  If you have bug fixes or improvements, please find
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.TH "Pampaintspill User Manual" 0 "02 November 2021" "netpbm documentation"

.SH NAME
pampaintspill - smoothly spill colors into the background

.UN synopsis
.SH SYNOPSIS
.PP
\fBpampaintspill\fP
[\fB--bgcolor\fP=\fIcolor\fP]
[\fB--wrap\fP]
[\fB--all\fP]
[\fB--downsample\fP=\fInumber\fP]
[\fB--near\fP=\fInumber\fP]
[\fB--power\fP=\fInumber\fP] [\fIfilename\fP]
[\fB-randomseed=\fP\fIinteger\fP]
.PP
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.

.UN description
.SH DESCRIPTION
.PP
This program is part of
.BR "Netpbm" (1)\c
\&.
.PP
\fBpampaintspill\fP produces a smooth color gradient from all of the
non-background-colored pixels in an input image, effectively "spilling
paint" onto the background.  \fBpampaintspill\fP is similar to
\fBpamgradient\fP but differs in the following characteristics:


.IP \(bu
\fBpampaintspill\fP accepts any number of paint
      sources (non-background-colored pixels), which can lie anywhere
      on the canvas.  \fBpamgradient\fP accepts exactly
      four paint sources, one in each corner of the image.

.IP \(bu
\fBpampaintspill\fP requires an input image while
      \fBpamgradient\fP generates a new image from
      scratch.

.IP \(bu
\fBpampaintspill\fP can produce tileable output and
      can control how tightly the gradient colors bind to their source
      pixels.

.PP
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.

.UN options
.SH OPTIONS
.PP
In addition to the options common to all programs based on libnetpbm
(most notably \fB-quiet\fP, see 
.UR index.html#commonoptions
 Common Options
.UE
\&), \fBpampaintspill\fP recognizes the following
command line options:


.TP
\fB--bgcolor\fP=\fIcolor\fP
  
Explicitly specify the background color. \fIcolor\fP can be
      specified using any of the formats accepted by the 
.UR libnetpbm_image.html#colorname
\f(CWpnm_parsecolor()\fP library       routine
.UE
\& such as \f(CWred\fP or \f(CW#ff0000\fP.  If
      \fB--bgcolor\fP is not specified, \fBpampaintspill\fP makes an
      educated guess about the background color based on the colors in the
      image's corners.

.TP
\fB--wrap\fP
  
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. \fB--wrap\fP makes images tileable, which is nice for
      producing desktop backgrounds.

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

.TP
\fB--downsample\fP=\fInumber\fP
  
Ignore all but \fInumber\fP non-background-colored pixels.
      When a large number of pixels in the input image differ in color from
      the background, \fBpampaintspill\fP runs very slowly. The
      \fB--downsample\fP 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.

.TP
\fB--near\fP=\fInumber\fP
  
Consider only the nearest \fInumber\fP paint sources when computing
      a pixel's new color.  The default is to consider all paint sources.
      In most cases, \fInumber\fP 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.
.sp
This option was new in Netpbm 10.97 (December 2021).

.TP
\fB--power\fP=\fInumber\fP
  
Control how color intensity changes as a function of the
      distance from a paint source. The default value for \fInumber\fP 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.

.TP
\fB-randomseed=\fP\fIinteger\fP
  
This is the seed for the random number generator that generates the
  pixels.
.sp
Use this to ensure you get the same image on separate invocations.
.sp
This option was new in Netpbm 10.94 (March 2021).



.UN seealso
.SH SEE ALSO


.IP \(bu

.BR "\fBpamgradient\fP" (1)\c
\&
.IP \(bu

.BR "\fBppmmake\fP" (1)\c
\&,
.IP \(bu

.BR "\fBppmrainbow\fP" (1)\c
\&,
.IP \(bu

.BR "\fBpgmramp\fP" (1)\c
\&,
.IP \(bu

.BR "\fBppmpat\fP" (1)\c
\&,
.IP \(bu

.BR "\fBpam\fP" (5)\c
\&


.UN history
.SH HISTORY
.PP
\fBpampaintspill\fP was new in Netpbm 10.50 (March 2010).


.UN copyright
.SH COPYRIGHT
.PP
Copyright\ \(co 2010–2021 Scott Pakin,
\fI\fIscott+pbm@pakin.org\fP\fP.

.UN index
.SH Table Of Contents


.IP \(bu

.UR #synopsis
SYNOPSIS
.UE
\&
.IP \(bu

.UR #description
DESCRIPTION
.UE
\&
.IP \(bu

.UR #options
OPTIONS
.UE
\&
.IP \(bu

.UR #seealso
SEE ALSO
.UE
\&
.IP \(bu

.UR #history
HISTORY
.UE
\&
.IP \(bu

.UR #copyright
COPYRIGHT
.UE
\&
.SH DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML
source.  The master documentation is at
.IP
.B http://netpbm.sourceforge.net/doc/pampaintspill.html
.PP