GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 5.1 |
|
 |
pamtosvg(1) |
 |
pamtosvg
Updated: 23 April 2006
Table Of Contents
NAME
pamtosvg - convert a Netpbm image to a SVG (Scalable Vector Graphics) image
SYNOPSIS
pamtosvg
[-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-factor=float] [-preserve-width]
[-remove-adjacent-corners] [-log]
[-report-progress] [pnmfile]
Minimum unique abbreviation of
option is 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.
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 compose
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.
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.
-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
bordered
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
Send a detailed progress report to the file named
inputfile.log,
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
happens.
-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-factor
Weight factor for fitting the linewidth.
SEE ALSO
pnmquant, pbmclean, pnm, Autotrace
HISTORY
pamtosvg 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 duplicates 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 for it.
_________________________________________________________________
Table Of Contents
* SYNOPSIS
* DESCRIPTION
* OPTIONS
* SEE ALSO
* HISTORY
|
pamtosvg(1) | |