How to export non-blurry eps images?

Question

I\'m exporting an image in Matlab using the eps format, but it smooths the image. Matlab does not blur the image using other formats such as png. I would like to know how to

Answer 1

A note regarding Yoda's answer: in Preview in Mac OS X, you can make the thin white diagonal lines across each of the squares disappear by unchecking "Anti-alias text and screen art". Of course, the downside is that then any text (e.g. figure axes, etc) is not anti-aliased. Unfortunately, unchecking that has no effect on blurriness if you're using imagesc.

Another note is that if you use preview to make a pdf from your eps, the resulting pdf still displays correctly (non-blurry) when you open it in Acrobat.

Answer 2

I just wrote this simple drop-in replacement for imagesc. It doesn't support all but the most basic features, but I still hope it helps.

function h = imagesc4pdf(C)

[ny nx] = size(C);

px = bsxfun(@plus, [-0.5; 0.5; 0.5; -0.5], reshape(1:nx, [1 1 nx]));
py = bsxfun(@plus, [-0.5; -0.5; 0.5; 0.5], 1:ny);

n = numel(C);
px = reshape(repmat(px, [1 ny 1]), 4, n);
py = reshape(repmat(py, [1 1 nx]), 4, n);

h = patch(px, py, reshape(C,1,n), 'linestyle', 'none');

xlim([.5 nx+.5]);
ylim([.5 ny+.5]);
set(gca, 'ydir', 'reverse');

Answer 3

not sure why it works but you can try doing the following:

eps2eps oldfile newfile

does the trick for me (on a mac os)

Answer 4

UPDATE:

The problem is reproducible on a Mac, and the issue is with the eps renderer rather than MATLAB. For e.g., saving imagesc(rand(20)) and viewing with Preview and GSview results in the following:

Preview screenshot

GSview screenshot

Clearly, the information is not lost. It is just not interpreted/read correctly by some EPS viewers. The solution is simple: use GSview to view your eps images. You can download it from here

On Macs especially, if your end application is latex/pdflatex, you will have to explicitly set it to use GS/GSview, because otherwise, it will default to the Quartz engine, which is baked into the OS.

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PREVIOUS ANSWER:

I am unable to reproduce the behavior your described. Here is the code I used, tested using R2010b on WinXP 32-bit:

M = fspecial('gaussian',[20 20],5);
imagesc(M)
print('-dpng','a.png')
print('-depsc2','b.eps')

a.png

b.eps

Perhaps this is an issue with your EPS viewer...