Speed up print

[henrik josefsson]

Running the script below takes around a minute on my system. Increasing 
the size of the mesh greatly increases the time to run the print 
command. What can be done to make print command run faster?

N = 100;
M = 5000;
x = linspace(0,1,N);
y = linspace(0,1,M);
[X, Y] = meshgrid(x,y);
mesh(X,Y,ones(M,N));
print('output.pdf') %takes a long time to run!

The time to execute the print command seems to be around the same for 
different octave versions (3.8.x 4.0.2 and 4.2.0) and operating systems 
(Ubuntu, Linux Mint and Windows 10)