Pie chart gnuplot

Does anyone have example code in gnuplot for a pie chart? I can't find any great example with a simple graph and the text around it and in it with the % signs that shows easily how much each part has of the circle.

Some example data:

Management frames   4596
Control frames  70173
Data frames 40347
TCP packets 36864
HTTP packets    525
ICMP packets    47
Total frames    115116

Solution

Updated: After some years, I came again across this post, and I thought the code looked pretty messy. Therefore an attempt to improve and clean it up.

The following code is a bit different from the link I referenced above.

instead of a predefined color sequence or number codes in a separate list, the colors of the sections are given in the datablock (or datafile) next to the item/number by the names of predefined colors in gnuplot (see also https://stackoverflow.com/a/55736522/7295599). Because palette is used you can enter either colorname or hex-code, e.g. magenta or 0xff00ff.
the labels are aligned left or right depending on their position relative to 0.
you can choose the starting angle by PieStart and "rotation"-direction by PieDirection of the pie-chart
you can add individual radial and angular offsets for segments and labels
as you can see, there is no need for the total sum in the raw data. The total sum will be calculated automatically.
the reason why I define various functions f(n) which actually do not depend on n is to get the current values of other variables (at the time of calling the function) instead of passing a lot of parameters to the functions.

I hope you can adapt this code to your needs.

Code: (works with gnuplot>=5.0.0)

### pie-chart with labels with gnuplot
reset session

set size square
set angle degrees
set border 0
unset colorbox
unset tics
unset key 

$Data <<EOD
# label     value   color      SRoff   SAoff   LRoff   LAoff
"Alpha"     85843   red          0       0      0      0
"Beta"      44000   green        0.2    45      0.2    0
"Gamma"     25399   blue         0       0      0      0
"Delta"     18451   magenta      0       0      0      0
"Epsilon"   12344   yellow       0       0      0      0
"Zeta"      11999   cyan         0       0      0      0
"Eta"       9000    orange       0       0      0      0
"Theta"     8500    0xb0f060     0       0      0.03   0
"Iota"      4711    dark-violet  0       0      0.12   0
EOD

colLabel   = 1     # label
colValue   = 2     # segment value
colColor   = 3     # segment color, either color name or 0xRRGGBB value
colSegRoff = 4     # radial  segment offset
colSegAoff = 5     # angular segment offset
colLabRoff = 6     # radial  label   offset
colLabAoff = 7     # angular label   offset

# define a palette from colornames of the datafile/datablock in column colColor
set table $Dummy
    myPalette = ''
    plot $Data u (myPalette = myPalette.(myPalette eq '' ? '' : ', ').sprintf('%d "%s"',$0,strcol(colColor)),$0) with table
    myPalette = '('.myPalette.')'
unset table
set palette defined @myPalette

stats $Data u colValue nooutput    # get total sum from column colValue
TotalSum = STATS_sum

set xrange[-1.5:1.5]
set yrange[-1.5:1.5]

PieStart       = 90      # 0 = 3 o'clock, 90 = 12 o'clock
PieDirection   = -1      # -1 clockwise, 1 counterclockwise
Radius         = 1.0
RadiusLabelOff = 0.05    # default radial label offset
SegPosX(n)     = column(colSegRoff)*cos((a2+a1+column(colSegAoff))*0.5)
SegPosY(n)     = column(colSegRoff)*sin((a2+a1+column(colSegAoff))*0.5)
LabPosX(n)     = (Radius+RadiusLabelOff+column(colLabRoff))*cos((a2+a1+column(colLabAoff))*0.5)
LabPosY(n)     = (Radius+RadiusLabelOff+column(colLabRoff))*sin((a2+a1+column(colLabAoff))*0.5)
a1=a2=PieStart
getAngles(n)   = (a1=a2, a2=a2+sgn(PieDirection)*column(colValue)/TotalSum*360)
getLabel(n)    = sprintf("%s %.1f%%", strcol(colLabel),  column(colValue)/TotalSum*100)

set multiplot layout 2,1

    plot $Data u (getAngles(0), SegPosX(0)):(SegPosY(0)):(Radius):(PieDirection<0?a2:a1):(PieDirection<0?a1:a2):($0) \
           with circles fs solid 1.0 lc palette notitle,\
        '' u ( getAngles(0), Align=LabPosX(0)):(LabPosY(0)): (Align>0? getLabel(0) : '') with labels font ",10" left, \
        '' u ( getAngles(0), Align=LabPosX(0)):(LabPosY(0)): (Align<0? getLabel(0) : '') with labels font ",10" right

    PieDirection = +1
    a1=a2=PieStart
    replot

unset multiplot
### end of code

Result: