/usr/share/ferret-vis/jnls/go/ellipse.jnl is in ferret-vis 6.9.3-4build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | \cancel mode verify
! ellipse.jnl - draw an ellipse inscribed in the indicated corners
! 8/94
! Description: Overlay an ellipse outline from inscribing rectangle coordinates
! usage: GO ellipse xlo xhi ylo yhi [pen_number]
! (arguments identical to GO box)
! Notes:
! 1) use GO line_samples to view the first 6 pen numbers
! Higher pen numbers cycle with thicker lines (max 18)
! test pen_number before performing any actions
query/ignore $1%<Usage: GO ellipse xlo xhi ylo yhi [pen_number]%
query/ignore $2%<Usage: GO ellipse xlo xhi ylo yhi [pen_number]%
query/ignore $3%<Usage: GO ellipse xlo xhi ylo yhi [pen_number]%
query/ignore $4%<Usage: GO ellipse xlo xhi ylo yhi [pen_number]%
query/ignore $5%1|red>1|green>1|blue>1|thick>1|0>1|1>1|2>1|3>1|4>1|5>1|6>1|7>1|8>1|9>1|10>1|11>1|12>1|13>1|14>1|15>1|16>1|17>1|18>1|<GO ellipse xlo xhi ylo yhi pen with pen = 0(back), 1(fore), thick, 2-18 or a color%
LET/QUIET xellipse_axis = ($2) - ($1)
LET/QUIET yellipse_axis = ($4) - ($3)
LET/QUIET xellipse_center = (($2)+($1))/2
LET/QUIET yellipse_center = (($4)+($3))/2
LET/QUIET ellipse_theta = i * (6.29/100) ! just over 2 PI in 100 points
LET/QUIET xellipse = xellipse_axis/2 * COS(ellipse_theta) + xellipse_center
LET/QUIET yellipse = yellipse_axis/2 * SIN(ellipse_theta) + yellipse_center
! set up PLOT+
! Note: The "line=" could be used to specify the line style but the command
! gets too ungainly to read
PLOT/VS/NOLAB/OVER/line=1/SET_UP/I=1:101 xellipse, yellipse
! select line style
ppl pen 1,$5"1|red>2|green>3|blue>4|thick>7|0>0|1>1|2>2|3>3|4>4|5>5|6>6|7>7|8>8|9>9|10>10|11>11|12>12|13>13|14>14|15>15|16>16|17>17|18>18|"
! plot it
PPL PLOT/OVERLAY
! clean up
ppl pen 1,1
set mode/last verify
|