From 0705dd00930cd993cc97a277dfdf043775da6d3a Mon Sep 17 00:00:00 2001
From: fpi
Date: Sun, 3 Apr 2022 15:27:33 +0200
Subject: Add script to interactively place rotated labels

---
 gnuplot.org | 69 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 66 insertions(+), 3 deletions(-)

diff --git a/gnuplot.org b/gnuplot.org
index 58e9dce..be820a4 100644
--- a/gnuplot.org
+++ b/gnuplot.org
@@ -26,6 +26,8 @@ set datafile missing NaN
 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)~.
@@ -37,7 +39,7 @@ When setting the column using a variable you can not use the shorthand syntax ~$
 #+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
@@ -63,6 +65,12 @@ And some derivatives functions.
 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
@@ -103,7 +111,6 @@ Also set output to a =.ps= file. After that:
 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
@@ -111,7 +118,7 @@ added functionality for multiple arguments. The function call to
 macro like this: ~@iLabel "label1" "label2"~
 
 #+begin_src gnuplot
-iLabel = "call '~/git/projects/dotfiles/tangle/label_loop.gp "
+iLabel = "call '~/git/projects/dotfiles/tangle/label_loop.gp' "
 #+end_src
 
 #+begin_src gnuplot :tangle tangle/label_loop.gp
@@ -145,3 +152,59 @@ do for [ELEMENT in ARG1." ".ARG2." ".ARG3." ".ARG4." ".ARG5] {
   }
 }
 #+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
-- 
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