KnotPlot script for 22jan05a

This page gives an example of a KnotPlot script that can be used to generate an Encapsulated PostScript (EPS) file. A bitmap preview of the EPS file is shown below. The EPS file is vector graphics, and is generally higher quality than the preview. To play with the KnotPlot script, you will need to download a copy of KnotPlot.

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Following is a detailed description on how the KnotPlot script was used to generate the files on this page. Example shown is for letter size paper. See the note (right) about printing to A4 paper. If you're only generating an EPS file for inclusion in another document, then you don't need to worry about setting the pagesize.

Run KnotPlot in non-graphics mode to generate the EPS file.

knotplot -nog < 22jan05a.kps

We now have the file 22jan05a.eps which could be printed directly on a PostScript printer. For printing to a non-PostScript printer, generate a PDF file 22jan05a.pdf from the EPS file 22jan05a.eps using GhostScript.

# Note: enter the following three lines on one command line
gs -dCompatibilityLevel=1.3 -q -dNOPAUSE -dBATCH
   -sPAPERSIZE=letter -sDEVICE=pdfwrite
   -sOutputFile=22jan05a.pdf -c .setpdfwrite -f 22jan05a.eps

The remainder of this example shows how the preview image seen above was created. This is only useful for including an image on a web page. Printing the EPS or PDF file will give much higher quality than printing the preview image. These files, 22jan05a.eps and 22jan05a.pdf, as well as their counterparts for A4 paper, 22jan05a_a4.eps and 22jan05a_a4.pdf, can be downloaded using the links in the right hand panel on this page.

# run GhostScript to generate a temporary PPM file
# Note: enter the following two lines on one command line
gs -q -dNOPAUSE -dBATCH -sPAPERSIZE=letter -sDEVICE=ppmraw
   -sOutputFile=22jan05a.ppm -r200 -f 22jan05a.eps
 
# scale it down
pnmscale -xsize 600 22jan05a.ppm > 22jan05aS.ppm
 
# reduce the number of distinct colours
ppmquant 32 22jan05aS.ppm > 22jan05aSq.ppm
 
# create the GIF file
ppmtogif 22jan05aSq.ppm > 22jan05a.gif
 
# delete temporary files
/bin/rm 22jan05a.ppm 22jan05aS.ppm 22jan05aSq.ppm

KnotPlot script that generated the Encapsulated PostScript (EPS) file:

% KnotPlot script: 22jan05a.kps
 
cyl=1.5
psmode=41
pserase=1.7

% this example uses the undocumented `celtic' command!

celtic cgrid 54 2 22
celtic copy

scale 2 2 2
ago 2
refine 2

% and also the undocumented `fancy' psoption!

psoption fancy draw 15
psoption fancy eofill 1 1 0
psoption fancy fill 1 .6 0
psoption fancy circ 0 0 .4
psoption fancy circ size 1 3
 
psout 22jan05a
 
% End of KnotPlot script

This script generates a EPS file (download below) suitable for printing on letter size paper. For printing on A4 size paper, use the command psop pagesize a4 prior to the psout command.

Download a high quality PDF or EPS file (for either letter or A4 size paper):

• 22jan05a.pdf (67 kbytes)
• 22jan05a_a4.pdf (67 kbytes)
• 22jan05a.eps (161 kbytes)
• 22jan05a_a4.eps (161 kbytes)

The PDF files and the preview image seen on this page were generated from the EPS files using Ghostscript (details in left panel on this page).