Gnuplot simple background color

By default gnuplot will produce graphes with white background color. We can change it by drawing a colored rectangle at the lowest layer:

set object <index_number> rectangle \
         from screen 0,0 to screen 1,1 fillcolor rgb"<rgb-color>" behind 

In this command line, <index_number> is used to mark the rectangle object, if we want to change the background color later it will be usefull, "from screen 0,0 to screen 1,1" means the rectangle is as large as the whole picture, <rgb-color> is the background color and "behind" put the rectangle behind all other elements of the picture，i.e., the lowest layer.

Now let's have a look at an example script which produce two graphes with pink and light green background color respectively.

reset #reset gnuplot options
set term png font ",22" linewidth 3  #set terminal to png with fontsize=22,linewidth=3
set xlabel "x"  #set xlable and ylabel
set ylabel "y=sin(x)"
#set a pink(#ffcccc) background color
set object 1 rectangle from screen 0,0 to screen 1,1 fillcolor rgb"#ffcccc" behind
set output "pink.png"
plot sin(x) with lines linecolor rgb"green" notitle
#set a light green(#ccffcc) background color
set object 1 rectangle from screen 0,0 to screen 1,1 fillcolor rgb"#ccffcc" behind
set output "lightgreen.png"
plot sin(x) with lines linecolor rgb"red" notitle

And pink.png and lightgreen.png are shown below:

Pink background color

Light green background color