@gp args...

The @gp macro (and its companion @gsp, for splot operations) allows to exploit all of the Gnuplot package functionalities using an extremely efficient and concise syntax. Both macros accept the same syntax, as described below.

The macros accepts any number of arguments, with the following meaning:

• a symbol: the name of the session to use;
• a string: a command (e.g. "set key left") or plot specification (e.g. "with lines");
• a string starting with a $ sign: a data set name;
• an Int > 0: the plot destination in a multiplot session;
• a keyword/value pair: a keyword value (see below);
• any other type: a dataset to be passed to Gnuplot. Each dataset must be terminated by either:
  • a string starting with a $ sign (i.e. the data set name);
  • or a string with the plot specifications (e.g. "with lines");
• the :- symbol, used as first argument, avoids resetting the Gnuplot session. Used as last argument avoids immediate execution of the plot/splot command. This symbol can be used to split a single call into multiple ones.

All entries are optional, and there is no mandatory order. The plot specification can either be:

• a complete plot/splot command (e.g., "plot sin(x)", both "plot" and "splot" can be abbreviated to "p" and "s" respectively);
• or a partial specification starting with the "with" clause (if it follows a data set).

The list of accepted keyword is as follows:

• title::String: plot title;
• xlabel::String: X axis label;
• ylabel::String: Y axis label;
• zlabel::String: Z axis label;
• xlog::Bool: logarithmic scale for X axis;
• ylog::Bool: logarithmic scale for Y axis;
• zlog::Bool: logarithmic scale for Z axis;
• xrange::NTuple{2, Number}: X axis range;
• yrange::NTuple{2, Number}: Y axis range;
• zrange::NTuple{2, Number}: Z axis range;
• cbrange::NTuple{2, Number}: Color box axis range;

The symbol for the above-mentioned keywords may also be used in a shortened form, as long as there is no ambiguity with other keywords. E.g. you can use: xr=(1,10) in place of xrange=(1,10).

Examples:

Simple examples with no data:

@gp "plot sin(x)"
@gp "plot sin(x)" "pl cos(x)"
@gp "plo sin(x)" "s cos(x)"

# Split a `@gp` call in two
@gp "plot sin(x)" :-
@gp :- "plot cos(x)"

# Insert a 3 second pause between one plot and the next
@gp "plot sin(x)" 2 xr=(-2pi,2pi) "pause 3" "plot cos(4*x)"

Simple examples with data:

@gp "set key left" tit="My title" xr=(1,12) 1:10 "with lines tit 'Data'"

x = collect(1.:10)
@gp x
@gp x x
@gp x -x
@gp x x.^2
@gp x x.^2 "w l"

lw = 3
@gp x x.^2 "w l lw $lw"

A more complex example

@gp("set grid", "set key left", xlog=true, ylog=true,
    title="My title", xlab="X label", ylab="Y label",
    x, x.^0.5, "w l tit 'Pow 0.5' dt 2 lw 2 lc rgb 'red'",
    x, x     , "w l tit 'Pow 1'   dt 1 lw 3 lc rgb 'blue'",
    x, x.^2  , "w l tit 'Pow 2'   dt 3 lw 2 lc rgb 'purple'")

Multiplot example:

@gp(xr=(-2pi,2pi), "unset key",
    "set multi layout 2,2 title 'Multiplot title'",
    1, "p sin(x)"  ,
    2, "p sin(2*x)",
    3, "p sin(3*x)",
    4, "p sin(4*x)")

or equivalently

@gp xr=(-2pi,2pi) "unset key" "set multi layout 2,2 title 'Multiplot title'" :-
for i in 1:4
  @gp :- i "p sin($i*x)" :-
end
@gp

Multiple gnuplot sessions

@gp :GP1 "plot sin(x)"
@gp :GP2 "plot sin(x)"

Gnuplot.quitall()

Further examples

x = range(-2pi, stop=2pi, length=100);
y = 1.5 * sin.(0.3 .+ 0.7x) ;
noise = randn(length(x))./2;
e = 0.5 * fill(1, size(x));

name = "\$MyDataSet1"
@gp x y name "plot $name w l" "pl $name u 1:(2*\$2) w l"

@gsp randn(Float64, 30, 50)
@gp randn(Float64, 30, 50) "w image"
@gsp x y y

@gp("set key horizontal", "set grid",
    xrange=(-7,7), ylabel="Y label",
    x, y, "w l t 'Real model' dt 2 lw 2 lc rgb 'red'",
    x, y+noise, e, "w errorbars t 'Data'")

@gp "f(x) = a * sin(b + c*x); a = 1; b = 1; c = 1;"   :-
@gp :- x y+noise e name                               :-
@gp :- "fit f(x) $name u 1:2:3 via a, b, c;"         :-
@gp :- "set multiplot layout 2,1"                     :-
@gp :- "plot $name w points" ylab="Data and model"   :-
@gp :- "plot $name u 1:(f(\$1)) w lines"           :-
@gp :- 2 xlab="X label" ylab="Residuals"              :-
@gp :- "plot $name u 1:((f(\$1)-\$2) / \$3):(1) w errorbars notit"

# Retrieve values for a, b and c
a = Meta.parse(Gnuplot.exec("print a"))
b = Meta.parse(Gnuplot.exec("print b"))
c = Meta.parse(Gnuplot.exec("print c"))

# Save to a PDF file
save(term="pdf", output="gnuplot.pdf")

Display an image

using TestImages
img = testimage("lena");
@gp img "w image"
@gp "set size square" img "w rgbimage" # Color image with correct proportions
@gp "set size square" img "u 2:(-\$1):3:4:5 with rgbimage" # Correct orientation