docs: Unstack area to render cumulative chart correctly

[joelostblom]

This has likely been broken since Vega-Lite changed the default behavior in
https://github.com/vega/vega-lite/releases/tag/v5.14.1

You can see the current broken chart here https://altair-viz.github.io/gallery/cumulative_count_chart.html

After this PR:

[dangotbanned]

So in vega/vega-lite#9170 the change is quite obvious.

Screenshot

However in this example, I'm having a hard time understanding the visual difference between the two.

I'm assuming the font change is unrelated, but that is all I can see.

User Guide	This PR
Vega Editor (stack:true)	Vega Editor (stack:false)

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Am I missing something that stands out to you?

[joelostblom]

Oh, I had to rerun the command to update the webpage and forgot that I had already done these changes locally when I did that. So these PR updates are now accidentally already included in the built docs. You can see that the change suggested in the PR is already there in the code and if I run the code without stack(False) I see this (which is how the docs looked up until I rebuilt the doc web site):

[joelostblom]

I'm curious about the font change you are observing. To me, all the chart fonts in the docs look like the right most figure (arial-like sans serif font), but it seems like you are seeing a monospace font by default, is this the case for you with all the figures in the docs?

It also seems like the blue hue is slightly different in your screenshots compared to mine.

[dangotbanned]

I'm curious about the font change you are observing. To me, all the chart fonts in the docs look like the right most figure (arial-like sans serif font), but it seems like you are seeing a monospace font by default, is this the case for you with all the figures in the docs?

The font seems to be a contribution from a browser extension I'm using to enforce a constant monospace font within codeblocks on documentation websites.
I think I need to update the CSS to exclude whatever altair-plot ends up displaying in.

I'm seeing the same font as you when browsing the examples on my phone

[dangotbanned]

Oh that is incredibly clear in #3558 (comment)

I spent far too long doubting myself trying to figure out what changed 😅

[dangotbanned]

LGTM