# -*- coding: utf-8-unix -*-
#+PROPERTY: header-args:gnuplot :tangle tangle/.gnuplot :eval query
* Symlink
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 ~/
#+end_src
* General Configuration
Start off by resetting most settings.
#+begin_src gnuplot
reset
#+end_src

Plot data using linepoints and make solid regions transparent.
#+begin_src gnuplot
set style data lp
set style fill transparent solid 0.4 noborder
#+end_src

Enable macros and make gnuplot interpret =NaN= as missing data.
#+begin_src gnuplot
set macros
set datafile missing NaN
#+end_src

A macro to easily reset gnuplot and also reload my settings.
#+begin_src gnuplot
init="load '~/.gnuplot'"
before_refresh="" # Commands to eval before each refresh
r="@before_refresh;refresh"
#+end_src

Here is a handy function to define colors with individual rgb integers instead of the hex notation. Example usage: ~plot x w l lc rgb rgb(255,80,0)~. Alternatively gnuplot also supports hsv colors with ~hsv2rgb(h,s,v)~.
#+begin_src gnuplot
rgb(r,g,b) = 65536 * int(r) + 256 * int(g) + int(b)
#+end_src

When setting the column using a variable you can not use the shorthand syntax ~$2~. Instead setup a function so I only have to write ~c(i)~ instead of ~column(i)~.
#+begin_src gnuplot
c(a)=column(a)
#+end_src
* Mathematical functions
A collection of functions that can calculate a running average.
#+begin_src gnuplot
# running averages
samples(x,n) = $0>(n-1) ? n : ($0+1)
init(x)=(back1=back2=back3=back4=back5=back6=back7=back8=back9=back10=back11=back12=sum=0)
if(init(0)){} # what is the best way to run functions without showing output?
avg1(x)=(back1=x,back1)
avg2(x)=(back2=back1,(avg1(x)+back2)/samples($0,2))
avg3(x)=(back3=back2,(samples($0,2)*avg2(x)+back3)/samples($0,3))
avg4(x)=(back4=back3,(samples($0,3)*avg3(x)+back4)/samples($0,4))
avg5(x)=(back5=back4,(samples($0,4)*avg4(x)+back5)/samples($0,5))
avg6(x)=(back6=back5,(samples($0,5)*avg5(x)+back6)/samples($0,6))
avg7(x)=(back7=back6,(samples($0,6)*avg6(x)+back7)/samples($0,7))
avg8(x)=(back8=back7,(samples($0,7)*avg7(x)+back8)/samples($0,8))
avg9(x)=(back9=back8,(samples($0,8)*avg8(x)+back9)/samples($0,9))
avg10(x)=(back10=back9,(samples($0,9)*avg9(x)+back10)/samples($0,10))
avg11(x)=(back11=back10,(samples($0,10)*avg10(x)+back11)/samples($0,11))
avg12(x)=(back12=back11,(samples($0,11)*avg11(x)+back12)/samples($0,12))
#+end_src

And some derivatives functions.
#+begin_src gnuplot
d(y) = ($0 == 0) ? (y1 = y, 1/0) : (y2 = y1, y1 = y, y1-y2)
d2(x,y) = ($0 == 0) ? (x1 = x, y1 = y, 1/0) : (x2 = x1, x1 = x, y2 = y1, y1 = y, (y1-y2)/(x1-x2))
#+end_src

Functions to convert between radians and degrees.
#+begin_src gnuplot
rad(deg)=deg/180*pi
deg(rad)=rad/pi*180
#+end_src
* Colors
=podo= is a good standard colorblind friendly colorsequence.
#+begin_src gnuplot
# use colorblind friendly colorsequence
set colorsequence podo
#+end_src

I just reorder the =podo= colors, mainly to make black not the default color.
#+begin_src gnuplot
# use colorsequence podo but reorder some colors
set linetype 1 lc rgb "#0072b2" lw 2 pt 1 ps default
set linetype 2 lc rgb "#d55e00" lw 2 pt 2 ps default
set linetype 3 lc rgb "#009e73" lw 2 pt 3 ps default
set linetype 4 lc rgb "#cc79a7" lw 2 pt 4 ps default
set linetype 5 lc rgb "#56b4e9" lw 2 pt 5 ps default
set linetype 6 lc rgb "#e69f00" lw 2 pt 6 ps default
set linetype 7 lc rgb "#f0e442" lw 2 pt 7 ps default
set linetype 8 lc rgb "black"   lw 2 pt 8 ps default
#+end_src
* Grid, Border, Tics
I store the default grid, border and tics settings in the =gbt= variable. So I can easily reset these with the macro call ~@gbt~. The =gbt(col)= function also allows setting grid and border to some other color, but needs to be called using eval, e.g. ~eval(gbt("black"))~.
#+begin_src gnuplot
# grid border tics settings
# call @gbt for defaults
# call eval(gbt("color")) to use color instead of default
gbt(col)=sprintf("set tics nomirror; set border 3 back lc '%s'; set grid back lw 1 lc '%s'",col,col)
gbt="set tics nomirror; set border 3 back lc 'gray50'; set grid back lw 1 lc 'gray50'"
@gbt
#+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]].

#+begin_src gnuplot
a4="set size ratio 0.71; set terminal postscript enhanced landscape;"
#+end_src
Also set output to a =.ps= file. After that:
#+begin_src bash :eval never
ps2ps -sPAGESIZE=a4 yourfilename.ps new_dina4_file.ps
#+end_src
To finish either use something like =ps2pdf= or view the =.ps= file with =ghostview=.
* Interactive Label Placement
[[http://www.gnuplotting.org/interactive-label-placing/][Source]]. I adapted the =label_loop= function to newer gnuplot syntax &
added functionality for multiple arguments. The function call to
=label_loop= is stored inside a string and can then be executed as a
macro like this: ~@iLabel "label1" "label2"~

#+begin_src gnuplot
iLabel = "call '~/git/projects/dotfiles/tangle/label_loop.gp' "
#+end_src

#+begin_src gnuplot :tangle tangle/label_loop.gp
# label_loop
# This loop adds a label to a plot by pressing the left mouse key.
# If you are not convinced with your chosen position, just klick the mouse key
# again and it will be positioned at another place. If you are finished, just
# press another key.
#
# Original AUTHOR: Hagen Wierstorf

# Initialize a label number
if (!exists("label_number")) { label_number = 1 }

do for [ELEMENT in ARG1." ".ARG2." ".ARG3." ".ARG4." ".ARG5] {
  while (1) {
    # Waiting for the  key press
    pause mouse any ELEMENT

    # Check if the left mouse key is pressed and add the given label to the plot.
    # Otherwise stop the loop and count the added label
    if( MOUSE_BUTTON==1 ) {
      set label label_number ELEMENT at MOUSE_X,MOUSE_Y textcolor ls 1
      print " at ",MOUSE_X,MOUSE_Y
      replot
    } else {
      label_number = label_number+1
      print "\n"
      break
    }
  }
}
#+end_src

We can also interactively place rotated labels. Getting the label rotation correct is somewhat tricky and heavily relies on macros. Also the use of ~refresh~ limits the usefulness of this for multiplots.
#+begin_src gnuplot :tangle tangle/label.gp
# label
# Script to interactively position a rotated label.
#
# To update after changing graph size rotation angles are scaled with
# the scaling() function. List of useful macros you should define:
# scaling(_)= (1.0*(GPVAL_TERM_YMAX-GPVAL_TERM_YMIN)/(GPVAL_TERM_XMAX-GPVAL_TERM_XMIN))/((GPVAL_Y_MAX-GPVAL_Y_MIN)/(GPVAL_X_MAX-GPVAL_X_MIN))
# label_reset= "@label_unset;@label_labels;replot;"
# label_init= "undefine label_labels label_unset"

if (!exists("label_number")) {label_number = 1}
if (!exists("label_labels")) {label_labels = ""}
if (!exists("label_unset")) {label_unset = ""}

do for [ELEMENT in ARG1." ".ARG2." ".ARG3." ".ARG4." ".ARG5] {
  print(ELEMENT)
  while (1) {
  next=0

  array pointsX[2]; array pointsY[2]
  do for [point=1:2]{
    pause mouse any
    if( MOUSE_BUTTON==1 ) {
    pointsX[point]=MOUSE_X
    pointsY[point]=MOUSE_Y
    } else { next=1;break }
  }
  if(next){break}
  if (pointsX[2] == pointsX[1]){ dx = 1e-20 }
  else { dx = pointsX[2] - pointsX[1] }
  dy = pointsY[2] - pointsY[1]

  cmd=sprintf("set label %i \"%s\" at %f,%f rotate by deg(atan(%f*scaling(NaN)));",\
    label_number, ELEMENT, pointsX[1], pointsY[1],dy/dx)
  eval(cmd); refresh
  }
  print cmd
  label_labels = label_labels.cmd
  label_unset = label_unset.sprintf("unset label %i;", label_number)
  label_number=label_number+1
}
refresh
#+end_src

To make using the script easier define a few macros/functions.
#+begin_src gnuplot
scaling(_)= (1.0*(GPVAL_TERM_YMAX-GPVAL_TERM_YMIN)/(GPVAL_TERM_XMAX-GPVAL_TERM_XMIN))/((GPVAL_Y_MAX-GPVAL_Y_MIN)/(GPVAL_X_MAX-GPVAL_X_MIN)) # functions need to have at least one argument
label="call '~/git/projects/dotfiles/tangle/label.gp' "

label_reset= "@label_unset;@label_labels;refresh;"
before_refresh = before_refresh."set output GPVAL_OUTPUT;@label_unset;@label_labels;"
label_init= "@label_unset;label_labels='';label_unset=''"
@label_init # clear labels each @init
#+end_src