Option to use sans serif fonts for MathML

[poke1024]

I recently found that I like sans serif MathML fonts much better as they match the general Jupyter theme I use:

Maybe this is also interesting for #574, as this seems to use sans serif fonts for the code input? Here's what it looks like in the non-spiffified mathicsserver:

I wonder where this should be configured;settings.py doesn't seem a good place to me.

[teaalltr]

I like it too. We may use it as default output and use the current serif font for output in TraditionalForm.

[teaalltr]

I think the fraction doesn't look very good in Jupyter, unlike the traditional interface. It should have the same font size as the rest of the expression. In the traditional interface, the fraction bar seems a bit too think. There seems to be an option to control the fraction thinckess.

[poke1024]

Turns out the fraction size depends on the display type of the <math> tag; if it's inline the fractions are vertically compressed, if it's block they are as they are in the traditional interface. As we do not specify display for <math>, I suppose Jupyter's default is different from the Mathics traditional default. So I now added display="block" to all <math> output to fix this:

[teaalltr]

Looks better now 👍

[sn6uv]

can we add this as a settings option. Perhaps XML_FONT = None by default.

[GarkGarcia]

@poke1024 I belive this is the only thing preventing us from merging the PR (?)

[rocky]

@GarkGarcia @sn6uv From a user standpoint, what is a "settings option" and how does one add this?

I like this feature.

[mmatera]

Please see PR #908

[mmatera]

Would be possible to choose the output format as a command from inside Mathics?
Let's say
$UseSansserif=True;
from mathics turn the feature on, and

$UseSansserif=False;
brings to the default behavior.

I will try to take this on the weekend.

[rocky]

Good. The Mathematica way seems to be to do this as part of the web interface: https://community.wolfram.com/groups/-/m/t/402640

[axkr]

Not sure, but it seems that here:

Mathics/mathics/web/media/js/mathics.js

Line 233 in a2b7f78

mstyle.setAttribute('displaystyle', 'true');

a new line:

mstyle.setAttribute('mathvariant', 'sans-serif');

is also necessary?

[rocky]

@axkr It would be helpful if you could upload before and after screenshots.

@mmatera I've been thinking about what you were saying about adding a PyMathics context and was wondering if $SansSerif too shouldn't be in some context. For example we could add a Mathics context for those things that are specific to Mathics and not in WL. I don't know. What do you think?