Figures in Spherefun Examples

[ajt60gaibb]

The figures in the Spherefun examples on the web are quite blurry. Can this be easily fixed?

More specifically:

1. One can barely make out that the arrows in the quiver plots in http://www.chebfun.org/examples/sphere/HelmholtzDecomposition.html
2. The images in
   http://www.chebfun.org/examples/sphere/SphereHeatConduction.html
   seem very low quality.

If this could be fixed somehow, then @gradywright and I would be very pleased. I assume there is a parameter in an internal PHP script somewhere that is drastically compressing these images before uploading them to the Chebfun web folder. These figures appear fine when I do my own MATLAB publish and view in a web browser.

[aaustin141]

I've just republished both of these examples using my machine. For some reason, the graphics don't get anti-aliased when we publish on our desktop workstations. I think this fixes your second issue.

As for the first, there are some limitations to what we can do. Graphics for the web need to be of a certain fixed size in order for things to work correctly. This is not an issue of compression artifacts. I think the best thing to do would be to modify the example to plot fewer arrows but make them a little bigger.

[ajt60gaibb]

I am not really sure I see a difference in the images in the SphereHeatConduction Example... They still appear a little blurred.

We will look at modifying the Helmholtz Decomposition Example so that the arrows are visible.

Thank you, @aaustin141

[jrus]

One note about the white-yellow-orange-red-black color ramp in the heat conduction example: it’s okay at having a monotonically (albeit nonuniformly) decreasing lightness, but it still ends up causing some distracting visual artifacts, because the chroma has sharp peaks at about -0.3 and +0.6.

How easy is it to use custom color ramps, and what format do they need to be in? (I’m not an expert on Matlab plotting) If you want, I can spend 20 minutes coming up with a similar color ramp which performs a bit better by human-visual-perception standards.