Pamtosvg User Manual(0) Pamtosvg User Manual(0)NAMEpamtosvg - convert a Netpbm image to a SVG (Scalable Vector Graphics)
image
SYNOPSISpamtosvg
[-background-color=colorname] [-centerline] [-corner-threshold=angle]
[-corner-always-threshold=angle] [-corner-surround=integer] [-tangent-
surround=integer] [-error-threshold=float] [-filter-iterations=count]
[-line-reversion-threshold=float] [-line-threshold=float] [-width-
weight-factor=float] [-preserve-width] [-remove-adjacent-corners]
[-log] [-report-progress] [pnmfile]
Minimum unique abbreviation of option is acceptable. You may use dou‐
ble 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).
pamtosvg reads a PNM image as input and produce an SVG (Scalable Vector
Graphics) image as output. Thus, it traces curves in the input image
and creates a set of splines that represent the image.
SVG is a vector image format, which means it describes curves that com‐
pose an image. By contrast, PNM is a raster format, which means it
describes dots that compose an image. The main practical difference
between the two types is that you can scale vector images better. A
vector image also takes a lot less data to describe an image if the
image is composed of simple curves.
That means it is really an understatement to say that pamtosvg is an
image format converter. It's really an image tracer. Its main job is
to trace a raster image and find the lines in it. It then represents
its findings in SVG format.
pamtosvg does the same kind of thing that StreamLine, CorelTrace, and
Autotrace do. It is in fact derived from Autotrace.
SVG is a gigantic format, capable of amazing things. pamtosvg exploits
only a morsel of it. The SVG image produced by pamtosvg consists of a
single <svg> element, which has a 'width' attribute and a 'height'
attribute. The value of that element is composed of <path> elements.
That's it.
In the SVG output, distances are unitless, with one unit corresponding
to one pixel of the input.
So that pamtosvg will find simple curves in the image, you may want to
remove speckles from it with pbmclean and consolidate multiple shades
into single colors with pnmquant first.
For more information on SVG, see the Worldwide Web Consortium's SVG web
page ⟨http://www.w3.org/Graphics/SVG/⟩ .
OPTIONS
-background-color=colorname
Treat the specified color as the background color and ignore it.
If you don't specify this option, pamtosvg does not recognize
any background color.
Specify the color (colorname) as described for the argument of
the ppm_parsecolor() library routine ⟨libppm.html#colorname⟩ .
-centerline
Trace an object's centerline.
By default, pamtosvg traces an object's outline.
-corner-always-threshold=angle
Consider any angle at a pixel which falls below angle angle (in
decimal floating point degrees) as a corner, even if it is bor‐
dered by other corner pixels. Default is 60 degrees.
-corner-surround=integer
Consider the specified number of pixels on either side of a
point when determining if that point is a corner. Default is 4.
-corner-threshold=angle
Consider any pixel which forms an angle with its predecessors
and successors that is smaller than angle (in decimal floating
point degrees) as a corner. Default is 100.
-error-threshold=float
Subdivide fitted curves that are offset by a number of pixels
exceeding the specified number. Default is 2.0.
-filter-iterations=integer
Smooth the curve the specified number of times prior to fitting
Default is 4.
-line-reversion-threshold=float
When a spline is closer to a straight line than the specified
real number weighted by the square of the curve length, maintain
it as a straight line, even if it is a list with curves.
Default is .01.
-line-threshold=float
If a spline does not deviate from the straight line defined by
its endpoints by more than the specified number of pixels, then
treat it as a straight line.
Default is 1.
-log Create a log of the curve tracing process (suitable for debug‐
ging). Put it in the file named inputfile.log in the current
directory, where inputfile is the root of the input file name,
or 'pamtosvg' if the input is from Standard Input or a file with
a weird name.
-preserve-width
Preserve line width prior to thinning. Meaningful only with
-centerline.
remove-adjacent-corners
Remove adjacent corners.
-report-progress
Report the progress of the tracing to Standard Error as it hap‐
pens.
-tangent-surround
Consider the specified number of points to either side of a
point when computing the tangent at that point. Default is 3.
-width-weight-factor
Weight factor for fitting the linewidth.
Application Notes
A convenient way to view an SVG document is with a web browser. Many
understand a file whose name ends in '.svg' to be an SVG image and can
render it.
SEE ALSOpnmquant(1), pbmclean(1), pnm(1), Autotrace
⟨http://autotrace.sourceforge.net⟩
HISTORYpamtosvg was added to Netpbm in Version 10.33 (March 2006).
The core of pamtosvg-- the curve tracing logic -- was taken nearly
unmodified from Martin Weber's Autotrace program. That program dupli‐
cates a lot of Netpbm function, so pamtosvg is a much leaner program.
Bryan Henderson created pamtosvg, basically just by adapting Autotrace
to Netpbm.
Autotrace was first released in 2000 and updates were released through
2002. A number of people wrote the code in it, but Masatake Yamato and
Martin Weber appear to be the principal creators of it.
As of June 2006, there was a Sourceforge project
⟨http://autotrace.sourceforge.net⟩ for it.
netpbm documentation 23 April 2006 Pamtosvg User Manual(0)
