Adjust the resolution of PNG plot image on a remote terminal

Generated plot image files using MATLAB R2009b on a remote UNIX terminal are always a low resolution image. I tried using the resolution option of the "print" command but that does not change the resolution of the output image at all.

How can I increase the resolution of the generated image files?

Answer 1

[MathWorks Support Team]

When running MATLAB R2009b or any release prior to R2014b that uses HG1 in the UNIX terminal or in "nodisplay" mode, there is a known limitation on increasing the resolution of an image with the print command.

The PostScript and Ghostscript devices all function in "nodisplay" mode on UNIX. The graphic devices -djpeg, -dpng, -dtiff (compressed TIFF bitmaps) and -tiff (EPS with TIFF preview) work as well, but under "nodisplay" they use Ghostscript to generate output instead of using the drivers built into MATLAB. However, Ghostscript ignores the -r option when generating -djpeg, -dpng, -dtiff and -tiff image files and always uses the default resolution of 72DPI.

A workaround is to set the "PaperUnits" and "PaperPosition" of the figure to increase its size.

Workaround: 

% Example graph
plot(1:10)

% Set the "PaperUnits" and "PaperPosition" of the figure to increase its size
% Using [0 0 16 12] in "PaperPosition" creates an image that has the dimensions of 1152x864 pixels or (16*72) x (12*72) pixels
set(gcf,'PaperUnits','inches','PaperPosition',[0 0 16 12])

% Print to the PNG file
print -dpng filename