Warning, /graphics/glaxnimate/external/potrace/doc/mkbitmap.1.in is written in an unsupported language. File is not indexed.

 .\" Copyright (C) 2001-2019 Peter Selinger.
 .\" This file is part of Potrace. It is free software and it is covered
 .\" by the GNU General Public License. See the file COPYING for details.
 .\" 
 .TH mkbitmap 1 "@DATE@" "Version @VERSION@"
 .SH NAME
 mkbitmap \- transform images into bitmaps with scaling and filtering
 .SH SYNOPSIS
 
 .nf
 .B mkbitmap [\fIoptions\fP] [\fIfilename...\fP]
 .fi
 .SH DESCRIPTION
 
 \fBmkbitmap\fP reads an image, and applies one or more of the
 following operations to it, in this order: inversion, highpass
 filtering, scaling, and thresholding. Each operation can be
 individually controlled and turned on or off.
 
 The principal use of \fBmkbitmap\fP is to convert color or greyscale
 images into a format suitable as input for other programs,
 particularly the tracing program \fBpotrace\fP(1). It is particularly
 useful for converting scanned line art, such as cartoons, handwritten
 text, etc., to high-resolution bilevel images.
 
 \fIHighpass filtering\fP can be used to ensure that foreground
 features such as lines and text are preserved, while at the same time
 compensating for uneven background. Optional \fIblurring\fP can be
 applied to smooth out the image and remove visual noise. \fIScaling\fP
 is important because a scanned greyscale image contains more visual
 detail than a bilevel image at the same resolution. By scaling the
 image to a higher resolution (using interpolation) before thresholding
 it, some of this detail is preserved. \fIThresholding\fP means
 converting a greyscale image to a bilevel image using only black and
 white pixels. Pixels that are darker than a certain threshold value
 are converted to black.  Optional \fIinversion\fP is useful if the
 input image shows bright features on dark background, such as a
 picture of chalk drawings on a blackboard.
 
 Supported input formats are PNM (PBM, PGM, PPM) and BMP. The output
 formats are PBM for bitmaps, and PGM for greymaps. 
 .SH OPTIONS
 
 .SS General options:
 .TP 15
 .B -h, --help
 print help message and exit.
 .TP
 .B -v, --version
 print version info and exit.
 .TP
 .B -l, --license
 print license info and exit.
 .PD
 .SS Input/output options:
 .TP 15
 .B \fIfilename\fP
 If filename arguments are given, then \fBmkbitmap\fP will by default
 create one output file for each input filename given. The name of the
 output file is obtained from the input filename by changing its suffix
 to ".pbm" or ".pgm". If the name of the input file and output file
 would be identical, then an additional suffix "-out" is appended to
 the output filename. If no filename arguments are given, then
 \fBmkbitmap\fP acts as a filter, reading from standard input and
 writing to standard output. A filename of "-" may be given to specify
 reading from standard input; the output for this argument will then be
 written to standard output. Each input file may contain one or more
 images.
 .TP
 .B -o \fIfilename\fP, --output \fIfilename\fP
 write output to this file. All output is concatenated and directed to
 the specified file. This overrides the default behavior of creating
 one output file for each input file. A filename of "-" may be given to
 specify writing to standard output. 
 .PD
 .SS Image processing options:
 .TP 15
 .B -x, --nodefaults
 Turn off default options. Normally, the following options are
 preselected by default: \fB-f 4 -s 2 -3 -t 0.45\fP. The \fB-x\fP option
 disables these defaults; thus, \fBmkbitmap -x\fP does nothing but copy
 a greyscale image from the input to the output. Other processing
 options can then be added one by one; e.g., \fBmkbitmap -xf10\fP does
 only highpass filtering, \fBmkbitmap -xt0.5\fP does only thresholding,
 etc. 
 .TP
 .B -i, --invert
 Invert the input image. If this option is chosen, it is applied to the
 image before any other operation. It is used to deal with
 white-on-black images, such as photographs of chalk drawings on a
 blackboard. Note that the behavior of this option is not in general
 the same as inverting the \fIoutput\fP bitmap, unless the thresholding
 value is also inverted. 
 .TP
 .B -f \fIn\fP, --filter \fIn\fP
 Apply a highpass filter to the image. This filter is approximately
 Gaussian and non-directional. The effect is to preserve small detail
 while compensating for background gradients. The parameter \fIn\fP is
 a radius (in pixels) which corresponds approximately to the size of
 details which should be preserved. More precisely, the filter is
 implemented by subtracting a blurred version of the image from the
 original image. The parameter \fIn\fP is equal to the standard
 deviation of the blur. The output of the filtering step is a
 normalized image whose average brightness is exactly 0.5. The default
 filter radius is 4.
 .TP
 .B -n, --nofilter
 Turn off highpass filtering.
 .TP
 .B -b \fIn\fP, --blur \fIn\fP
 Blur the image. The effect is to smooth out fine details and to
 reduce visual noise in the image. The parameter \fIn\fP is the
 blurring radius, and should be chosen small (1 is a good value to
 start with). This is implemented as an approximately Gaussian,
 non-directional blur with standard deviation proportional to
 \fIn\fP. Blurring is applied after the highpass filter, but before
 scaling and thresholding.  If this option is not given, the default is
 not to apply any blurring.
 .TP
 .B -s \fIn\fP, --scale \fIn\fP
 Scale the image by an integer factor \fIn\fP>0. Scaling is done after
 highpass filtering, but before the thresholding step. A scaling factor
 of 1 indicates that no scaling is to be done. Otherwise, interpolation is
 used to fill in the in-between pixels. If the output of \fBmkbitmap\fP
 is to be used as input to a tracing program such as \fBpotrace\fP, a
 scaling factor of 2 is recommended. This preserved the right amount of
 detail for the tracing algorithm to work well. If a scaling factor of
 1 is used, too much detail is lost. If a scaling factor of 3 or higher
 is used, the interpolation tends to "invent" detail which was not
 present in the original image, thus preventing \fBpotrace\fP from
 doing a good job.
 .TP
 .B -1, --linear
 Use linear interpolation when scaling to a higher resolution. This is
 slightly faster, but less nice, than the default cubic interpolation.
 .TP
 .B -3, --cubic
 Use cubic interpolation when scaling to a higher resolution. This is
 the default. It is slower than linear interpolation, but leads to
 better results. 
 .TP
 .B -t \fIn\fP, --threshold \fIn\fP
 Set the threshold grey value for bilevel conversion. The parameter
 \fIn\fP is a brightness value between 0 for black and 1 for white. 
 Any pixels below this brightness will be converted to black (thus,
 smaller values of \fIn\fP will lead to whiter output).
 .TP
 .B -g, --grey
 Disable bilevel conversion. If this option is given, processing stops
 after the scaling step and a greymap is output. 
 .PD
 .SH EXIT STATUS
 
 The exit status is 0 on successful completion, 1 if the command line
 was invalid, and 2 on any other error. 
 .SH VERSION
 
 @VERSION@
 .SH AUTHOR
 
 Peter Selinger <selinger at users.sourceforge.net>
 .SH WEB SITE AND SUPPORT
 
 \fBmkbitmap\fP is distributed as part of the \fBpotrace\fP package,
 and the latest version is available from
 http://potrace.sourceforge.net/.  This site also contains
 documentation and information on how to obtain support.
 .SH SEE ALSO
 
 \fBpotrace\fP(1)
 .SH COPYRIGHT
 
 Copyright (C) 2001-2019 Peter Selinger
 
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
 the Free Software Foundation; either version 2 of the License, or
 (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software Foundation,
 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 See also http://www.gnu.org/.