In [1]:

struct PNG{T}
    s::T
end

function Base.show(io::IO, ::MIME"image/png", png::PNG)
    write(io, png.s)
end

In [2]:

gstdin, gstdout, gstderr = Pipe(), Pipe(), Pipe()
gproc = run(pipeline(`gnuplot`, stdin=gstdin, stdout=gstdout, stderr=gstderr), wait=false)

Out[2]:

Process(`gnuplot`, ProcessRunning)

In [3]:

filename = tempname() * ".png"

command = """
set terminal pngcairo enhanced
set output '$(filename)'
plot sin(x), cos(x)
"""

@show write(gstdin, command)
flush(gstdin)
sleep(0.1)
read(filename) |> PNG

write(gstdin, command) = 117

Out[3]:

In [ ]: