pamtosvg1

Usage

Overview

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 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 ⟨http://www.w3.org/Graphics/SVG/⟩ .

Options

In addition to the options common to all programs based on libnetpbm (most notably -quiet, see
Common Options ⟨index.html#commonoptions⟩ ), pamtosvg recognizes the following command line 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 pnm_parsecolor() library routine ⟨libnetpbm_image.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 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

Create a log of the curve tracing process (suitable for debugging). 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 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-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.

Document source

This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master documentation is at

http://netpbm.sourceforge.net/doc/pamtosvg.html