-h, --help

print help message and exit.

-v, --version

print version info and exit.

-l, --license

print license info and exit.

-V, --show-defaults

print the defaults which were compiled into this version of potrace, and exit.

--progress

display a progress bar for each bitmap that is processed. This is useful for interactive use, and requires a terminal. The default behavior is not to show any progress information.

filename

If filename arguments are given, then potrace 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 according to the chosen backend. If changing the suffix is impossible because the names of the input and output files would be identical, then the output filename is created by adding the "-out" suffix to the name of the input file. If no filename arguments are given, then potrace 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.

-o filename, --output filename

write output to this file. All output is directed to the specified file. If this option is used, then multiple input filenames are allowed only for those backends which can handle multiple bitmaps; these are currently the PostScript and PGM backends. In this case, each input file may contain one or more bitmaps, and all the bitmaps from all the input files are processed and the output concatenated into a single file. A filename of "-" may be given to specify writing to standard output.

-b name, --backend name

Select backend by name, where name is one of eps, postscript, ps, pdf, svg, pgm, gimppath, xfig. Backend names can be abbreviated by an unambiguous prefix.

-e, --eps

Encapsulated PostScript backend (default). The input is a single bitmap; the output is a stand-alone, encapsulated PostScript file which can be included in other documents.

-p, --postscript

PostScript backend. For this backend, the input may consist of multiple concatenated bitmaps, which will be turned into a multi-page PostScript document.

-b pdf, --backend pdf

PDF backend. For this backend, the input may consist of multiple concatenated bitmaps, which will be turned into a multi-page PDF document. Rotation (option -A) is not yet implemented for this backend.

-s, --svg

SVG backend. This backend produces a scalable vector graphics (SVG) file. This backend can process one bitmap per output file.

-g, --pgm

PGM backend. This backend produces a portable greymap (PGM) file. It is a convenient backend for antialiasing a bitmap image. The input may consist of multiple concatenated bitmaps, in which case multiple greymaps will be written to the output.

-b gimppath, --backend gimppath

Experimental gimppath backend. This backend produces a path which can be imported by the GNU Image Manipulation Program (Gimp) (in the Layers, Channels & Paths dialog, select Paths, then right-click and select Import Path). Note that Gimp's paths have some peculiar features: they have no bounding box, they cannot be scaled, and all control points are forced to be integers. For these reasons, it is difficult to produce good Gimp paths at low resolutions. The gimppath backend ignores almost all scaling and placement options; instead, the --unit option must be used to set the desired magnification. The --rotate option is also recognized. Note that the imported path can lie outside the bounds of the current image in Gimp; in this case, one needs to move the path (alt-click) or work with a larger image.

-b xfig, --backend xfig

XFig backend. Note that XFig uses X-splines instead of Bezier curves, thus it is not possible to translate the output of potrace into the XFig format with absolute accuracy. This backend does a reasonable approximation using two control points for each Bezier curve segment. Note that the -u option has no effect for this backend, as control points are always rounded to the nearest 1/1200 of an inch in XFig. Rotation and color are implemented. Curve optimization is disabled.

For more detailed information on these options, see TECHNICAL DOCUMENTATION below.

-z policy, --turnpolicy policy

specify how to resolve ambiguities in path decomposition. Must be one of black, white, right, left, minority, majority, or random. Default is minority. Turn policies can be abbreviated by an unambigous prefix, e.g., one can specify min instead of minority.

-t n, --turdsize n

suppress speckles of up to this many pixels.

-a n, --alphamax n

set the corner threshold parameter. The default value is 1. The smaller this value, the more sharp corners will be produced. If this parameter is negative, then no smoothing will be performed and the output is a polygon. The largest useful value is 4/3 or 1.334, which suppresses all corners and leads to completely smooth output.

-n, --longcurve

turn off curve optimization. Normally potrace tries to join adjacent Bezier curve segments when this is possible. This option disables this behavior, resulting in a larger file size.

-O n, --opttolerance n

set the curve optimization tolerance. The default value is 0.2. Larger values allow more consecutive Bezier curve segments to be joined together in a single segment, at the expense of accuracy.

-u n, --unit n

set output quantization. Coordinates in the output are rounded to 1/unit pixels. The default of 10 usually gives good results. For some of the debug modes, a value of 100 gives more accurate output. In the case of the gimppath backend, the -u option is used to set the desired magnification. This option has no effect for the XFig backend, which always rasterizes to 1/1200 inch.

-d n, --debug n

produce debugging output of type n. This has different effects for different backends. For the PostScript/EPS backends, the values n=1,2,3 illustrate the intermediate stages of the potrace algorithm.

-W dim, --width dim

set the width of output image. If only one of width and height is specified, the other is adjusted accordingly so that the aspect ratio is preserved.

-H dim, --height dim

set the height of output image. See -W for details.

-r n[xn], --resolution n[xn]

set the resolution (in dpi). One inch in the output image corresponds to this many pixels in the input. Note that it follows that a larger value results in a smaller output image. It is possible to specify different resolutions in the x and y directions by giving an argument of the form nxn. This option has no effect for the PGM backend.

-x n[xn], --scale n[xn]

set the scaling factor (PGM backend only). A value greater than 1 enlarges the output, a value between 0 and 1 makes the output smaller. It is possible to specify different scaling factors in the x and y directions by giving an argument of the form nxn.

-S n, --stretch n

set the aspect ratio. A value greater than 1 means the image will be stretched in the y direction. A value between 0 and 1 means the image will be stretched in the x direction.

-A angle, --rotate angle

set the rotation angle (in degrees). The output will be rotated counterclockwise by this angle. This is useful for compensating for images that were scanned not quite upright.

-M dim, --margin dim

set all four margins. The effect of this depends on the backend. For variable-sized backends (EPS, PGM, SVG), the margins will simply be added around the output image (or subtracted, in case of negative margins). For fixed-size backends (PostScript, XFig), the margins settings can be used to control the placement of the image on the page. If only one of the left and right margin is given, the image will be placed this distance from the respective edge of the page, and similarly for top and bottom. If margins are given on opposite sides, the image is scaled to fit between these margins, but not if the scaling is already determined explicitly by one or more of the -W, -H, -r, or -x options.

-L dim, --leftmargin dim

set the left margin. See -M for details.

-R dim, --rightmargin dim

set the right margin. See -M for details.

-T dim, --topmargin dim

set the top margin. See -M for details.

-B dim, --bottommargin dim

set the bottom margin. See -M for details.

These options are only supported by certain backends.

-C #rrggbb, --color #rrggbb

set the foreground color of the output image. The default is black. This option works for the PS/EPS, SVG, and XFig backends.

--fillcolor #rrggbb

set the fill color of the output image, i.e., the color of the "white" parts. The default is to leave these parts transparent. This option works for the PS/EPS, SVG, and XFig backends. Implies --opaque.

--opaque

fill in the white parts of the image opaquely, instead of leaving them transparent. This only applies to interior white parts, i.e., those which are enclosed inside a black outline. This option works for the PS/EPS and SVG backends. Opaqueness is always in effect for the XFig backend.

--group

try to group related paths together in the SVG output. Each path is grouped together with all paths that are contained inside it, so that they can be moved around as a unit with an SVG editor. This makes coloring individual components slightly more cumbersome, and thus it is not the default.

-P format, --pagesize format

set page size. This is primarily used for the PostScript backend. In case of the EPS backend, it may influence the default image size. The following formats can be specified: a4, a3, a5, b5, letter, legal, tabloid, statement, executive, folio, quarto, 10x14. Also, an argument of the form dimxdim is accepted to specify arbitrary dimensions. The default page size is letter (or a4, if this was configured at compile time, see COMPILE TIME CONFIGURATION below). Page format names can be abbreviated by an unambigous prefix.

-c, --cleartext

do not compress the output. This option disables the use of compression filters in the PostScript output. If the -q option is also used, the resulting output can be easily read by other programs or even by humans.

-2, --level2

use PostScript level 2 compression (default). The resulting file size is ca. 40% smaller than if the -c option is used.

-3, --level3

use PostScript level 3 compression, if available. This gives slightly smaller files than using -2, but the resulting files may not print on older PostScript level 2 printers. If support for PostScript level 3 compression has been disabled at compile time, a warning message is printed and level 2 compression is used instead.

-q, --longcoding

turn off optimized numerical coding. Normally, potrace uses a very compact numerical format to represent Bezier curves in PostScript, taking advantage of some redundancy in the curve parameters. This option disables this behavior, resulting in longer, but more readable output (particularly if the -c option is also used).

-G n, --gamma n

set the gamma value for anti-aliasing (default is 2.2). Most computer displays do not render shades of grey linearly, i.e., a grey value of 0.5 is not displayed as being exactly half-way between black and white. The gamma parameter corrects for this, and therefore leads to nicer looking output. The default value of 2.2 is appropriate for most normal CRT displays.

-k n, --blacklevel n

set the threshold level for converting input images to bitmaps. The potrace algorithm expects a bitmap, thus all pixels of the input images are converted to black or white before processing begins. Pixels whose brightness is less than n are converted to black, all other pixels to white. Here n is a number between 0 and 1. One case is treated specially: if the input is in an indexed color format with exactly 2 colors, then the blacklevel is ignored and the darker of the two colors is mapped to black.

Note: the method used by potrace for converting greymaps to bitmaps is very crude; much better results can be obtained if a separate program, such as mkbitmap(1), is used for this purpose. In particular, mkbitmap(1), which is distributed with potrace, has the ability to scale and interpolate the image before thresholding, which results in much better preservation of detail.

-i, --invert

invert the input bitmap before processing.