Difference between revisions of "Generating TSP art from a stippled image"

Revision as of 19:28, 27 September 2010

Preliminaries

At this point, you should have a PBM file containing the stippling information for the image you are working with. Without this information, you cannot proceed. See

Producing a stippled image with Gimp

for further details.

Also, you must already have installed a copy of Concorde TSP's linkern executable. For directions, please see

Obtaining a TSP solver

Finally, you need to obtain the latest versions of the following three files,

• tspart.py
• tspbitcity.py
• tspsolution.py

These three files are hosted at the Eggbot code site,

http://code.google.com/p/eggbotcode/downloads/list

Download the lastest version of the tsp_art_tools zip file, tsp_art_tools_x_y.zip. After you unzip that file, you will see those three files within it. Copy those files to a convenient work directory.

Getting to work

For best results with a fine point Sharpie pen, you do not want too much detail. Try to start with an image which has around 2000 or 3000 stipples. With too much detail, you will need a very fine point on your Eggbot's pen. You can get a simple report of the number of stipples in an input file using the --count switch to tspart.py. However, that's getting a bit ahead of ourselves.

To generate TSP art from a PBM file, just move to the directory with the tspart.py and other two .py files. Then issue the command

% python tspart.py input-file

where input-file is the name of your PBM file. tspart.py will begin running, providing updates on its progress. On Macs and Linux machines, there will be a lot of output from the linkern solver as well. When tspart.py is done, it produce output similar to that shown below,

% python tspart.py zebra.pbm

...

Solver finished successfully

Loading solver results from zebra.tour ... done

Writing SVG file zebra.svg ... done

Once tspart.py has finished, look at the resulting SVG file with Inkscape! The two SVG files shown below used approximately 3,200 and 16,000 stipples. They correspond to the stippled images shown at the top of this page.

Additional options to tspart.py

To obtain a count of the number of stipples in a PBM file, use the --count option of tspart.py,

% python tspart.py --count zebra.pbm

Loading bitmap file ../zebra.pbm ... done; 3201 stipples

When running the linkern solver, tspart.py tells linkern to do three successive runs over the data. Each run, refines the results of the prior run. You can control the number of runs with the --runs option. For example,

% python tspart.py --runs=1 zebra.pbm

To obtain a listing of tspart.py's options, use the --help option,

% python tspart.py --help

Notes for Window users

The script tspart.py is a Python script. Python is a programming language that is not normally part of Windows. However, having installed Inkscape, you now have a copy of Python. (If you have not yet installed Inkscape, then please refer to the instructions for installing Eggbot software for assistance.) To run tspart.py you will need to open a command window. If you are unfamiliar with how to do this, please see the Windows section of

Obtaining a TSP solver

for directions on how to do so on Windows XP.

Once you have an open command window, navigate to the directory containing the Inkscape executable, inkscape.exe. This will usually be C:\Program Files\Inkscape.

C:\Documents and Settings\Judy User>cd C:\Program Files\inkscape

C:\Program Files\inkscape>

Note that if you have installed Inkscape on a drive other than C:, you first need to move to that drive letter. For example, if Inkscape is installed on drive E:, use the commands

C:\Documents and Settings\Judy User>E:

E:\>cd E:\Program Files\inkscape

E:\Program Files\inkscape>

Once in that directory, the Python program should be in the python subdirectory. However, you must run that program from the Inkscape directory. To run tspart.py, issue the command

C:\Program Files\inkscape>python\python C:\tspart.py C:\image.pbm

In the above command, it is assumed that tspart.py, tspbitcity.py, tspsolution.py, and image.pbm are all in the top-level directory of the C: drive. Be sure to give the correct path to those files.