From 715ac4dd67b766d3917c107e66609cecd700f2b2 Mon Sep 17 00:00:00 2001
From: fpi
Date: Sun, 19 Jun 2022 20:30:08 +0200
Subject: Add function to plot live data streams

---
 gnuplot.org | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/gnuplot.org b/gnuplot.org
index a9ec9f4..06359c9 100644
--- a/gnuplot.org
+++ b/gnuplot.org
@@ -4,6 +4,7 @@
 First create a symlink to the desired config location.
 #+begin_src shell :results silent :tangle tangle/symlink.sh :shebang "#!/bin/bash"
 ln -siv $(pwd)/tangle/.gnuplot ~/
+ln -siv $(pwd)/tangle/gnuplotwindow.sh ~/.local/bin
 #+end_src
 * General Configuration
 Start off by resetting most settings.
@@ -105,6 +106,80 @@ Support function to set x/y tic formatting with ~set format x formatter(".0","m"
 #+begin_src gnuplot
 formatter(prec,unit)=sprintf("%%%ss %%c%s", prec, unit)
 #+end_src
+* Live data streams
+[[http://flux242.blogspot.com/2016/02/visualization-of-live-data-streams-with.html][Alex's blog: Visualization of live data streams with the gnuplot and bash]] describes how continuous data streams can be fed to gnuplot using the script below.
+#+begin_src sh :eval never :tangle tangle/gnuplotwindow.sh :tangle-mode (identity #o555)
+#!/usr/bin/env bash
+
+# Example:
+# nc -luk 6666 | jq --unbuffered -c 'select(.id==129)|.temperature_C' | \
+#  GNUPLOT_TERM='sixelgd animate' ~/bin/gp/gnuplotwindow.sh 6000 "10:25" "Outside temperature;2;red"
+
+terminal="${GNUPLOT_TERM:-qt}"     # terminal type (x11,wxt,qt,pdfcairo,pngcairo,..)
+output="${GNUPLOT_OUT}"
+output_ext="${GNUPLOT_EXT}"
+winsize=${1:-60}   # number of samples to show
+yrange=${2:-0:100} # min:max values of displayed y range.
+                   # ":" for +/- infinity. Default "0:100"
+shift;shift        # the rest are the titles
+
+styles_def=( "filledcurves x1" "boxes" "lines" )
+# remove the color adjustment line below to get
+# default gnuplot colors for the first six plots
+# colors_def=("red" "blue" "green" "yellow" "cyan" "magenta")
+colors=( "${colors_def[@]}" )
+
+# parsing input plots descriptions
+i=0
+IFS=$';'
+while [ -n "$1" ]; do
+  tmparr=( $1 )
+  titles[$i]=${tmparr[0]}
+  styles[$i]=${styles_def[${tmparr[1]}]-${styles_def[0]}}
+  colors[$i]=${tmparr[2]-${colors_def[$i]}}
+  i=$((i+1))
+  shift
+done
+
+IFS=$'\n'
+samples=0          # samples counter
+(while read newLine; do
+  [ -n "$newLine" ] && {
+    #nf=$(echo "$newLine"|awk '{print NF}')
+    nf=0;TMPIFS=$IFS;IFS=$' 	\n'
+      for j in $newLine;do nf=$((nf+1));done
+    IFS=$TMPIFS
+    a=("${a[@]}" "$newLine") # add to the end
+    [ "${#a[@]}" -gt "$winsize" ] && {
+      a=("${a[@]:1}") # pop from the front
+      samples=$((samples + 1))
+    }
+    echo "set term $terminal noraise"
+    [[ -n "$output" ]] && {
+      echo "set output "\""${output}.$samples.${output_ext}"\"
+    }
+    echo "set yrange [$yrange]"
+    echo "set xrange [${samples}:$((samples+${#a[@]}-1))]"
+    echo "set style fill transparent solid 0.5"
+    echo -n "plot "
+    for ((j=0;j<nf;++j)); do
+      echo -n " '-' u 1:$((j+2)) t '${titles[$j]}' "
+      echo -n "w ${styles[$j]-${styles_def[0]}} "
+      [ -n "${colors[$j]}" ] && echo -n "lc rgb '${colors[$j]}'"
+      echo -n ","
+    done
+    echo
+    for ((j=0;j<nf;++j)); do
+      tc=0 # temp counter
+      for i in "${a[@]}"; do
+        echo "$((samples+tc)) $i"
+        tc=$((tc+1))
+      done
+      echo e # gnuplot's end of dataset marker
+    done
+  }
+done) | gnuplot 2>/dev/null
+#+end_src
 * A4 plots
 See [[https://milianw.de/blog/how-to-generate-proper-din-a4-sized-plots-with-gnuplot.html][How to generate proper DIN A4 sized plots with Gnuplot - Milian Wolff]].
 
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