Conversion between gnuplot's coordinates systems

Question

TL;DR

Is there a way to align corners of different plots in a multiplot setup?

Is there a way to convert axis coordinates to screen c

Answer 1

In order to achieve an exact overlap, I think that an option would be to adjust the margin manually:

set terminal pngcairo
set output 'fig.png'

eps_h = 0.1
eps_w = 0.1

set multiplot
unset key

set lmargin at screen 2*eps_w
set tmargin at screen 1 - eps_h
set rmargin at screen 1 - eps_w
set bmargin at screen eps_h

plot cos(x) w lp lc rgb 'dark-red'

set border ls 4;
unset xlabel
unset ylabel
unset tics

plot 2*cos(x+pi) w lp lc rgb 'royalblue'

which gives: