As I mentioned, doing it this way is a bit fiddly. It relies on the figure window being big enough. I've already noticed that there tends to be a 1px offset depending on versions, so I'm not even sure that my results would match yours. I'm sure there's a convoluted workaround with setting figure properties, but maybe we should avoid that if it's being troublesome.
If you have Image Processing Toolbox, you can just export the image sufficiently oversized, and then rescale it directly so that it's exactly the size you want. It's slower, but it's not as prone to breaking.
contourf(X,Y,r_M,2560,'LineColor','none')
shading interp
axis square
% colorbar
% caxis([0 4])
colormap(flipud(gray(256)));
set(gca,'xtick',[])
set(gca,'ytick',[])
set(gca,'units','pixels')
outpict=export_fig('-a4','-m2'); % export a bigger image
outpict=imresize(outpict,[400 400]);
imwrite(outpict,'finallyworks.png')
If you don't have IPT installed, the MIMT (link below) has imresizeFB(), which should act as a direct replacement for imresize() in this case:
outpict=imresizeFB(outpict,[400 400]);
If someone else has some elegant, quick, and robust way to do this, I'd like to hear it.
