How to change image dpi using compiled matlab code run on aws ec2?
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I can generate an image with 300dpi using print function on my local matlab on a linux box (example code below), however on aws ec2 (ubuntu), the image is always saved as 72dpi with the same code no matter what dpi value I set. I am running Matlab 2014a with compiler version 5.1.
figure('paperunits','inches','paperposition',[0 0 6 6]);
n = 20;
cm = jet(n);
for i = 1:n
plot(ceil(i/4), mod((i-1),4)+1,'s','MarkerFaceColor',cm(i,:), 'markeredgecolor','k','markersize',30); hold on;
print('figure_dpng.png', '-dpng', '-r300');
Usha Duddu on 8 Sep 2015
I understand that when you are executing your compiled MATLAB application in aws ec2(Ubuntu), resolution of the image generated is lesser than the stated resolution parameter in "print" command.
This behavior is directly correlated with the display environment. If you launch MATLAB-compiled application in 'nodisplay' mode, MATLAB uses Ghostscript to generate output instead of using built-in MATLAB drivers. Thus you cannot vary the resolution of image files when running in 'nodisplay' mode, which explains the differing behavior in resolution of PNG files in base MATLAB and compiled application.
Hope this answers your question.