KnotPlot script for qtmp2

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 < qtmp2.kps

We now have the file qtmp2.eps which could be printed directly on a PostScript printer. For printing to a non-PostScript printer, generate a PDF file qtmp2.pdf from the EPS file qtmp2.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=qtmp2.pdf -c .setpdfwrite -f qtmp2.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, qtmp2.eps and qtmp2.pdf, as well as their counterparts for A4 paper, qtmp2_a4.eps and qtmp2_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=qtmp2.ppm -r200 -f qtmp2.eps
 
# scale it down
pnmscale -xsize 600 qtmp2.ppm > qtmp2S.ppm
 
# reduce the number of distinct colours
ppmquant 32 qtmp2S.ppm > qtmp2Sq.ppm
 
# create the GIF file
ppmtogif qtmp2Sq.ppm > qtmp2.gif
 
# delete temporary files
/bin/rm qtmp2.ppm qtmp2S.ppm qtmp2Sq.ppm

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

% KnotPlot script: qtmp2.kps
 
load 3.1
psop phantom .3
pszinfo=t
draw broke
psop patchname a
psmode=2
cyl-rad = 0.220357
broff = -0.469395
ncurve = 7
nsegments = 10
twfix 528.819760
psout a
psop patchname b
psmode=13
cyl-rad = 1.052287
broff = -0.337073
ncurve = 6
nsegments = 5
twfix -844.504476
psout b
 
.merge-psout --delete  a b qtmp2
 
% 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):

• qtmp2.pdf (107 kbytes)
• qtmp2_a4.pdf (107 kbytes)
• qtmp2.eps (143 kbytes)
• qtmp2_a4.eps (143 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).