Gnuplot

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Contents

Basics

Simple Plot

data = 'data.dat'
plot data
#or 
plot sin(x)

Plot multiple lines

plot\
 "1.dat" title "Eins"\
,"2.dat" title "Zwei"\
,"3.dat" title "Drei"\

png output

set terminal png giant size 1024,768
set output "plot.png"
plot sin(x)
unset output

Multiplot / 2 stacked plots

set multiplot layout 2,1 columnsfirst
plot sin(x)
plot cos(x)
unset multiplot

Plot different columns of same file using 2 y-axes

data = 'data.dat'
plot\
 data using 1:3 title "Drei" axes x1y2 \
,data using 1:2 title "Zwei"

Common Mistakes / Errors

Integer division:
use 10.0 / 3 instead of 10/3

Plot Region of Function

plot \
  (x<=0.0)||(x>=0.5)?1/0:sin(x) \
, (x<=0.5)||(x>=1.0)?1/0:cos(x)

Layout

Terminals

set terminal postscript enhanced eps color solid # solid!!!
set terminal png enhanced giant size 1024,768

For PostScript and MP you should

set border back

as otherwise the frame is drawn twice (can be found using inkscape)

My Favorite: Terminal MP (Metapost) (needs Latex and UbuntuPackage texlive-metapost)

#term = "png"
term = "mp"
if (term eq "png" ) set terminal png enhanced giant size 1024,768
if (term eq "mp"  ) set terminal mp color solid latex psnfss prologues 2 magnification 1.00
outfile="plot123"
set output outfile . "." . term
 plot sin(x)
unset output

if (term eq "mp"  ) \
 system ("mpost -tex=latex '".outfile.".mp'") 
 ; system ("mv " . outfile . ".0 " . outfile .".mps") \
 ; system ("convert -density 300 ".outfile.".mps ".outfile.".png") \
 ; system ("rm -f ".outfile.".mpx")
 ; system ("rm -f ".outfile.".log")
 ; system ("rm -f ".outfile.".mp")

General

set title "Plot Title"
# set default plot style
set style function points
# define linestyles
set style line 1 lt 1 lw 2
# Legend position
set key top right # or set key off
# advanced:
set key bottom left box width -3 reverse Left samplen 2 #invert title "Sinus"
# default:
set key on right top vertical Right noreverse noinvert samplen 4 spacing 1.25 title "" nobox

Axes

set xlabel "Time (s)"
set ylabel "Current (A)"
set grid xtics ytics

# set tics
set xtics mirror
set ytics mirror 
# add some tics
set xtics add (0.003, 0.03, 0.3) 
set xtics add ("Pi" 3.14159)

# Disable autorange of axes
set xrange [1:*]
set yrange [2.8E-08:3.0E-08]
set logscale y
# set format of number to 1e-03 etc
set format y "%1.e"
# 10^x
set format y "10^{%L}"
# "%" sign:
set format y "%g%%"
# % sign in Terminal MP (Latex)
set format y "%g".'\%%'
# NullAchsen einfügen
set zeroaxis
# or
set xzeroaxis ls -1 lw 2

Linked axes

Linked tics on top axes e.g. bottom=nanometer/top=eV [1]

set x2label "Temp (C)"
set x2tics (\
   "25" 1000/(c0C+25) \
,  "50" 1000/(c0C+50) \
,  "75" 1000/(c0C+75) \
,  "100" 1000/(c0C+100) \
,  "125" 1000/(c0C+125) \
)

Important: you have to set plot range for x and x2!!!

plot [xmin:xmax] [*:*] [xmin:xmax]

Links: [2]

Add Text to Plot

set label "text" at 3.3e-3,90e-3
plot ...

set label 1 sprintf("Ea = %3.5g",-b*ckb/ce) at 3.3e-3,90e-3
plot ...
unset label 1
# position can be given via differnet systems: first (=x axes), second (=x2 axes), graph (=pos in graph area 0.0..1.0) , screen, character
# see help set coordinates
set label "text" at graph 0.25, graph 0.75

Colors

set color of axes label or tics to that of line XYZ

set ylabel "Label" textcolor lt 1
set ytics textcolor lt 1

Draw Line/Arrow

set arrow nohead from 0,0 rto 10,1
set arrow from fitLow, graph 0 to fitLow, graph 1 nohead lc -1 lw 2
plot ...
unset arrow

Note: set arrow must be placed before the plot command

Draw circle, rectangle, ellipse, or polygon

set object 1 circle at xwert , ywert behind

Adjusting Margins/Distances

Axis label closer to tics (unit = characters, other units possible as well)

set xlabel offset 0.0,0.5
set ylabel offset 1.5,0.0
set x2label offset 0.0,-0.5
set y2label offset -1.5,0.0

margins: (l,r,t,bmargin)

set lmargin 3 # unit chars
set lmargin at screen 0.1 # useful for multiplots

Fonts

in Linux run

export GDFONTPATH=/usr/share/fonts/truetype/msttcorefonts

than you can use all the fonts in that dir. For example

set terminal png giant font "Arial,24"
Latex Fonts

From [3], needs Linux package "cm-super")

set term postscript fontfile '/usr/share/texmf/fonts/type1/public/cm-super/sfrm1000.pfb' "SFRM1000"

or after copying the file

set term postscript fontfile '/MessSoftware/sfrm1000.pfb' "SFRM1000"
Greek Symbols in Latex

To get a greek letter, you have to use the postscript terminal, with the option enhanced. Then, to add the alpha greek letter, you have to type {/Symbol a}. Analogously for other letters, changing the "a" by other, like "D" for Delta and so on... [4]

Modify Default Line Types/Styles

set style line  1 lw 2
set style line  2 lw 2
set style line  3 lw 2
set style line  4 lw 2
set style line  5 lw 2
set style line  6 lw 2
set style line  7 lw 2
set style line  8 lw 2
set style line  9 lw 2
set style line 10 lw 2
set style increment user # important!!! switch between linetypes (default) and userdefined linestyles

Fitting

b=5
f(x) = x**b
fit f(x) "data.dat" using 1:2 via b
plot "data.dat" title "data" notitle, f(x) title "fit"
# to weight the data (here by y^(-2)) use sth like the following:
# fit f(x) "data.dat" using 1:2:(1./$2**2) via b
f05(x)=a05*exp(b05*x)+0
fit [0.003:0.006] f05(x) "V6_05.dat" using (1./(($3/2+$4/2)+273.15)):($2*5380716) via a05,b05
a=1; b=1
f(x)=a*exp(b*x)
fitLow =0.0030
fitHigh=0.0055
fit [fitLow:fitHigh] f(x) "data.dat" via a,b
print a,b
set output "png/fit.png"
plot \
  "data.dat" title  "5V" with points pointsize 0.2\
, (x<=fitLow)||(x>=fitHigh)?1/0:f(x) notitle with lines \
unset output

Interpolate

smooth csplines

Advanced Fitting

FIT_LIMIT = 1e-8 # or even smaller

restricting fit parameters

f(x) = a   *exp(-(x-b   )*(x-b   )/c   /c   ) 
g(x) = A(a)*exp(-(x-B(b))*(x-B(b))/C(c)/C(c))

# trick: use atan as restriction function
A(x) = (2.0-1.1)/pi*(atan(x)+pi/2)+1.1 # Restrict a to the range of [1.1:2.0]
B(x) = (0.9-0.1)/pi*(atan(x)+pi/2)+0.1 # Restrict b to the range of [0.1:0.9]
C(x) = (1.5-0.5)/pi*(atan(x)+pi/2)+0.5 # Restrict c to the range of [0.5:1.5]

a =0.0 ; b =0.5 ; c =0.9 ; 
fit f(x) 'data.dat' via a, b, c
aa=1.5 ; bb=0.5 ; cc=0.9 ;
fit g(x) 'data.dat' via aa, bb, cc
plot "data.dat" , f(x) , g(x)

print A(aa), B(bb), C(cc) # do NOT use aa, bb, cc as they are not what you want!!!

Stats

In GP Ver>4.6 the new function stats is quite convenient.

stats data
STATS_records # total number of in-range data records
STATS_min     # minimum value of in-range data points
STATS_max     # maximum value of in-range data points
STATS_mean    # ...
STATS_median
STATS_stddev  # standard deviation
STATS_pos_min_y  # x coordinate of a point with minimum y value
STATS_pos_max_y  # x coordinate of a point with maximum y value

Finding Min and Max for X and Y

In GP Ver 4.2 (and above) these tricks, stolen from [5] are handy

data = 'stats2.dat'
# Retrieve statistical properties via dummy plot
plot data u 1:2
min_y = GPVAL_DATA_Y_MIN
max_y = GPVAL_DATA_Y_MAX
min_x = GPVAL_DATA_X_MIN
max_x = GPVAL_DATA_X_MAX

# X Pos of min_y and max_y
plot data u ($2 == min_y ? $2 : 1/0):1
min_y_x_pos = GPVAL_DATA_Y_MIN
plot data u ($2 == max_y ? $2 : 1/0):1
max_y_x_pos = GPVAL_DATA_Y_MAX

# Mean via fit + Std Deviation
f(x) = mean_y
fit f(x) data u 1:2 via mean_y
stddev_y = sqrt(FIT_WSSR / (FIT_NDF + 1 ))

Histogram

data="data.dat"
stats data # retrieve STATS_ variables ...
rows = STATS_records # num values
mu    = STATS_mean_y
sigma = STATS_stddev_y  # standard deviation

# histogram parameters
width=0.5 # box width (units of x!)
max = 0.0+ceil(mu+3*sigma) # plot range max
min = 0.0+floor(mu-3*sigma) # plot range min

# gaussean function
gauss(x) = 1. / (sigma * sqrt(2 * pi)) * exp(-(x - mu)**2 / (2 * sigma**2))
# histogram function
hist(x) = width * floor(x / width) + width / 2.0

# some settings
set key off
set tics out
set xrange [min:max] ; set x2range [min:max]
set yrange [0:]
set y2range [0:]
set grid x2tics ytics
# set xtics min, (max - min)/4.0, max
set x2tics ("-3s" mu-3*sigma, "-2s" mu-2*sigma, "-1s" mu-1*sigma, "µ" mu, "1s" mu+1*sigma, "2s" mu+2*sigma, "3s" mu+3*sigma)
set boxwidth width
set style fill solid 0.5
set tics out nomirror
set xlabel "Value"
set ylabel "rel. Density"
set format x "%g"
set format y "%g %%"

plot \
   data using (hist($1)):(100.0 / rows) smooth freq w boxes lc rgb"red" notitle \
 , gauss(x) * sigma * sqrt(2*pi) axes x1y2 notitle lc rgb"blue" lw 2 
unset output

Misc

Bar Chart Plot

set style fill solid 0.5 border 0
set boxwidth 0.75 relative
plot data u 3:xticlabels(1) with boxes
# y = data column 3
# x label = data column 1


Errorbars

plot data u ($1):($5):(0.1*$1):(0.1*$5) w xyerrorbars ps 0
plot data u ($1):($5):(0.1*$1) w xerrorbars
plot data u ($1):($5):(0.1*$5) w yerrorbars

Dashed lines

In terminal mp (which I prefere) use terminal option dashed and redefine the linestyles using lt 1 (solid) as template

set style line 1 lt 1 linecolor rgb "red"
set style line 2 lt 1 linecolor rgb "blue"
set style line 3 lt 1 linecolor rgb "magenta"

Furthermore define how your dashed (e.g. lt 6 as template) line shall look like and define e.g. ls 30 to it

set style line 30 lt 6 lw 1 linecolor rgb "dark-green"

Now you can plot data and line by

plot data u 1:5 ls 2
set arrow from 0.55, graph 0 to 0.55, graph 1 nohead ls 30 back

Number or points to plot for analytic function

set samples 200 # default = 100

pause

you can use

pause mouse

to let gnuplot stop continuing until you click the mouse

Find min / max value

Better use Gnuplot way, see Stats above

using Perl

max=`! perl -e '$max=-1e38; while (<>) {@t=split;  $max=$t[1] if $t[1]>$max}; print $max' < 22.5.dat`
min=`! perl -e '$min=+1e38; while (<>) {@t=split;  $min=$t[1] if $t[1]<$min}; print $min' < 22.5.dat`
print min,max

Version 2

s = '$col=2; $f='."'".data."'".'; use warnings; \
  open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
  @t=split /\t/ , shift @a ; $x=$t[$col-1];  print $x '
first=0.0+system("perl -e \"".s."\"")
print first

s = '$col=2; $f='."'".data."'".'; use warnings; \
  open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
  @t=split /\t/ , pop @a ; $x=$t[$col-1];  print $x '
last=0.0+system("perl -e \"".s."\"")
print last

s = '$col=2; $f='."'".data."'".'; use warnings; $x=1e38;\
  open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
  while ($l=shift @a) { @t=split /\t/,$l ; next if $#t<$col-1 ; $x=$t[$col-1] if $t[$col-1]<$x;} ;  print $x '
min=0.0+system("perl -e \"".s."\"")
print min

s = '$col=2; $f='."'".data."'".'; use warnings; $x=-1e38;\
  open (FH, $f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
  while ($l=shift @a) { @t=split /\t/,$l ; next if $#t<$col-1 ; $x=$t[$col-1] if $t[$col-1]>$x;} ;  print $x '
max=0.0+system("perl -e \"".s."\"")
print max

Version 2a - Linux ( excape $)

s = '\$col=2; \$f='."'".d."'".'; use warnings; \
  open (FH, \$f); @a = grep {not m/^#/ and not m/^\s*$/ } <FH>; close FH; \
  @t=split /\t/ , shift @a ; \$x=\$t[\$col-1];  print \$x '

Version 3 (when using Perl to gen Gnuplot script)

my $colX=3; my $colY=2; 
open (FH, $f);
my @a = grep {not m/^#/ and not m/^\s*$/} <FH>;
close FH;
my @b=split /\t/ , pop @a ; 
my $lastX=$b[$colX-1];
my $lastY=$b[$colY-1];

$cont .= "set object 1 circle at $lastX , ($lastY*1E9) behind\n";

Values of Tics in Logscale

of only 3 minor tics are visible they are at 0.2 ; 0.5 ; 0.8

Variables

a=123
print "Variable a=",a
undef a
Export (fit-)Variables
a=12
system(sprintf("echo A=%d >testausgabe.txt",a))

Schnippsel

c0C = 273.15
ckb = 1.38e-23
ce  = 1.602e-19
ckbeV = ckb/ce
set x2tics (\
   "25" (c0C+25) \
,  "50" (c0C+50) \
,  "75" (c0C+75) \
,  "100" (c0C+100) \
,  "125" (c0C+125) \
)

WARNING: you have to set x2 AND x ranges to the same! (so no autorange :-()

Multiplot V3 : 2x2

#!/usr/bin/gnuplot

term="eps"
color="sw"
color="color"
outtype="png-trans"
outtype="png-solid"
outtype="pdf"

if (color eq "sw")    set terminal postscript monochrome
if (color eq "color") set terminal postscript color
set terminal postscript eps enhanced clip dashed size 15cm,15cm font ",22pt"
#fontfile add "uopr8a.pfa" fontfile add "uopri8a.pfa" fontfile add "uopb8a.pfa" font "URWClassico-Reg,22pt" # 10x7 # fontsize 14 = default

set encoding utf8
set border back

set style data points
set style function lines

set style increment user
# LineWitdh + Symbols
set style line  1 lw 4 ps 3 pointtype  8 #= dreieck oben
set style line  2 lw 4 ps 3 pointtype 10 #= dreieck unten

if (color eq "sw") set style line  1 lt 1 # voll
if (color eq "sw") set style line  2 lt 5 # Strich-Punkt
if (color eq "color") set style line  1 lt 1 linecolor rgb "red"
if (color eq "color") set style line  2 lt 1 linecolor rgb "blue"


# grid
set style line 40 lt 1 lw 2 linecolor rgb "grey70"
set grid ls 40

set ytics  .4
set y2tics .4
set yrange  [-1.2:+1.4]
set y2range [-1.2:+1.4]
set mytics  4 # minor ytics
set my2tics 4
set samples 300

# text will be inserted later on
set label 2 "" left front font ",20" at graph 0.05, graph 0.90


marL=0.12
marT=0.04
plotX=(1.0-marL-0.005)/2
plotY=plotX/1.618 # Golden Ratio = a:b = 1.618

set key box height 0.1 width -2 reverse noinvert Left opaque samplen 1 font ",18"
set key t l at screen marL + 0.85*plotX, screen 1.0-marT-1.25*plotY
set key off

set output "plot" . ".gp" . term
set multiplot


# (a)
set label 2 "(a) n=1"
set lmargin at screen marL
set rmargin at screen marL + 1*plotX
set tmargin at screen 1.0-marT
set bmargin at screen 1.0-marT-1*plotY

unset xlabel; set xtics format ""
unset ylabel; set ytics format ""
unset x2label; set x2tics format ""
unset y2label; set y2tics format ""

set ytics format "%g" # y Tics on

set key on
plot sin(x) t "sin(n x)", cos(x) t "cos(n x)"


# (b)
set label 2 "(b) n=2"

set lmargin at screen marL + 1*plotX
set rmargin at screen marL + 2*plotX
set tmargin at screen 1.0-marT
set bmargin at screen 1.0-marT-plotY

unset xlabel; set xtics format ""
unset ylabel; set ytics format ""
unset x2label; set x2tics format ""
unset y2label; set y2tics format ""

set key off
plot sin(2*x), cos(2*x)


# (c)
set label 2 "(c) n=3"

set lmargin at screen marL
set rmargin at screen marL + 1*plotX
set tmargin at screen 1.0-marT-1*plotY
set bmargin at screen 1.0-marT-2*plotY

unset xlabel; set xtics format ""
unset ylabel; set ytics format ""
unset x2label; set x2tics format ""
unset y2label; set y2tics format ""

set ytics add ("" 1.2) # prevent overwriting of label of (a)

# Axis Labels
set xlabel "X-LABEL"  offset 13.5 , 0
set ylabel "Y-LABEL"  offset  0   , 5

set xtics format "%g" # x Tics on
set ytics format "%g" # y Tics on

plot sin(3*x), cos(3*x)
unset xlabel ; unset ylabel



# (d)
set label 2 "(d) n=4"
set lmargin at screen marL + 1*plotX
set rmargin at screen marL + 2*plotX
set tmargin at screen 1.0-marT-1*plotY
set bmargin at screen 1.0-marT-2*plotY

unset xlabel; set xtics format ""
unset ylabel; set ytics format ""
unset x2label; set x2tics format ""
unset y2label; set y2tics format ""

set xtics format "%g" # x Tics on
set xtics add ("" -10) # prevent overwriting of label of (c)

set key on
plot sin(4*x) t "sin(n x)", cos(4*x) t "cos(n x)"


unset multiplot
unset output


# trim eps
s = 'epstool --copy --quiet --bbox "plot.gpeps" "plot.eps"' ; system (s) ; system "rm plot.gpeps"
# eps -> pdf
if (outtype eq "pdf") s = 'epstopdf --embed "plot.eps"' ; system (s) #embed=embed fonts
# eps -> png
if (outtype eq "png-solid") s = 'convert -density 150 -trim +repage "plot.gpeps" -background white -flatten +matte -type Palette "plot.png"' ; system (s)
if (outtype eq "png-trans") s = 'convert -density 150 -trim +repage "plot.gpeps" -transparent white "plot.png"' ; system (s)
# remove eps
system "rm plot.eps"

Multiplot using macros and Xmargin at screen

#!/usr/bin/gnuplot
# Demonstration of a common use scenario of the multiplot environment. AUTHOR: Hagen Wierstorf
# http://www.gnuplotting.org/multiplot-placing-graphs-next-to-each-other/

# Functions (1/0 means not defined)
a = 0.9
f(x) = abs(x)<2*pi ? a*sin(x)           : 1/0
g(x) = abs(x)<2*pi ? a*sin(x+pi/2)      : 1/0
h(x) = abs(x)<2*pi ? a*sin(x+pi)        : 1/0
k(x) = abs(x)<2*pi ? a*sin(x+3.0/2*pi)  : 1/0

unset key
#set tics scale 0.5
set ytics 1
set xrange [-2.5*pi:2.5*pi]
set yrange [-1.5:1.5]

# MACROS
set macros  # Enable the use of macros
# x- and ytics for each row resp. column
NOXTICS = "set xtics ( -2*pi,  -pi, 0,  pi,  2*pi); \
          unset xlabel"
XTICS = "set xtics ('-2Pi' -2*pi, '-Pi' -pi,'0' 0, 'Pi' pi, '2Pi' 2*pi);\
          set xlabel 'x'"
NOYTICS = "set format y ; unset ylabel"
YTICS = "set format y '%.0f'; set ylabel 'y'"
# Margins for each row resp. column
TMARGIN = "set tmargin at screen 0.98; set bmargin at screen 0.58"
BMARGIN = "set tmargin at screen 0.58; set bmargin at screen 0.18"
LMARGIN = "set lmargin at screen 0.13; set rmargin at screen 0.56"
RMARGIN = "set lmargin at screen 0.56; set rmargin at screen 0.99"
# Placement of the a,b,c,d labels in the graphs
POS = "at graph 0.92,0.9 font ',18'"

### Start multiplot (2x2 layout)
set multiplot layout 2,2 rowsfirst
# --- GRAPH a
@TMARGIN; @LMARGIN
@NOXTICS; @YTICS
set label 1 'a' @POS
plot f(x) with lines ls 1
# --- GRAPH b
@TMARGIN; @RMARGIN
@NOXTICS; @NOYTICS
set label 1 'b' @POS
plot g(x) with lines ls 1
# --- GRAPH c
@BMARGIN; @LMARGIN
@XTICS; @YTICS
set label 1 'c' @POS
plot h(x) with lines ls 1
# --- GRAPH d
@BMARGIN; @RMARGIN
@XTICS; @NOYTICS
set label 1 'd' @POS
plot k(x) with lines ls 1
unset multiplot

Insets

# plot 2(inset)
set size 0.2,0.4
set origin 0.2,0.5
clear # !!! clears the plot area from grid lines etc
# draw frame
set object 1 rect from screen 0.2, screen 0.5 to screen 0.5, screen 0.9 back behind
set object 1 rect fc rgb "white" fillstyle solid 1.0
set lmargin 6; set bmargin 1.5; set rmargin 0;set tmargin 0
unset key
unset xlabel ;  unset ylabel ;  unset y2label

My Plot Template

allowing to choose between Terminal PNG or MetaPost

Main file plot.gp

#!/usr/bin/gnuplot
load "/MessSoftware/A_gnuplot-header.gp"

term = "png"
term = "mp"

plotfolder = "png_XYZ"
 
data1 = "data/Eins.dat"
data2 = "data/Zwei.dat"

set style data linespoints
set style increment user
set style line  1 linetype 1 lw 2 ps 2
set style line  2 linetype 2 lw 2 ps 2

if (term eq "mp"  ) set terminal mp color solid latex psnfss prologues 2
if (term eq "png" ) set terminal png enhanced giant size 1024,768

data = data1
load "plot_c_vs_d1.gp" # in here is the plot function

data = data2
load "plot_c_vs_d1.gp" # again...

if (term eq "mp"  ) s = "perl convert.pl " . plotfolder ; system (s)


plot file plot1.gp, executed for each data set

f(x) = m*x+b
fit f(x) data using (log($1)):(log($2)) via m,b
fe(x) = x**m * exp(b)
set label 1 sprintf("m=%.2f",m) at graph 0.05, graph 0.75
set output plotfolder . "/" . "." . term
plot \
  data u ($1):($2) notitle \
, fe(x) title "fit" w lines lw 1
unset output ; unset label 1


perl script convert.pl for converting .mp to png and .mps

#!/usr/bin/perl -w
use warnings;use strict;

my $del_mps = 1;
my $dpi = 222.841; # -> 28cm in ooimpress 

my $plotdir = "png";
$plotdir = shift if @ARGV;
chdir $plotdir or die $!;

my @a = <*.mp>;
foreach my $f (@a) {
  print "-->$f\n";
  $_ = $f;
  $f =~ s/ /_/g;
  `mv "$_" "$f"` unless ($_ eq $f);
  my $fname = $f;  
  $fname =~ s/\.[^\.]*?$//; # remove ext
  print system("mpost -tex=latex '$fname.mp'");
  print "\n";
  my @b = grep {m/\.[\d]+$/}  grep {-f $_} <$fname.*>;
  $f = $b[0];
  print `mv "$f" "$fname.mps"`;
  print `convert -density $dpi "$fname.mps" "$fname.png"`;
  print `rm "$fname.mps"` if $del_mps;
  unlink ( split " ", "$fname.eps $fname.mp $fname.mpx $fname.log");
  print "\n";
}

$_ = "mpxerr.tex"; unlink $_ if -f $_;


Filled Curves

set style fill solid 1.0 noborder
plot [:] [*:*] \
,f1(x) with filledcurve y1=0 lc rgb "gray80" \
 f2(x) with filledcurve y1=0 lc rgb "gray60" \
,f1(x) ls 2 \
,f2(x) ls 3
# first the areas, than the lines in the right linecolor
Filled Area between 2 Curves
f1(x) = sin(x)
f2(x) = x+1
set style fill solid 0.4 border
plot \
'+' using 1:(f1($1)):(f2($1)) with filledcurve
# '+' allows treatment of functions as data
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