this is the first time in the notebook that the key API is revealed: "legend: true" and it is burried in the middle of a lot of code. Perhaps we could put a much simpler example at the very start to show how easy it is to add a legend? Without that I fear many people will be intimidated by the custom legend code (presumably many are already motivated not to write custom code already).

I try to keep a consistent order in Plot.plot calls, always putting the marks option last. The order I use is: 1. Layout options. 2. Scale definitions. 3. Facet definition. 4. Marks. Also, I prefer no spaces inside curly braces.

We will wait for the legends for the radius scale:-)

can we start off with this before getting into the details? that way the first thing people see is how easy and convenient the 80% use case is

It feels strange to lead-off this notebook with custom legends. My expectation is that this notebook should be about Plot’s built-in legends. I recommend we remove this section and jump straight in to Plot legends. (We can always link to Plot: Scales for more on scales.)

I removed the resin identification codes (https://en.wikipedia.org/wiki/Resin_identification_code) since I found them distracting and also they remind me of how the plastic industry shifts the burden of recycling to the consumer rather than the producer.

Changed this to “Appendix” for consistency with our other notebooks.

For your consideration 😉 https://observablehq.com/@mbostock/color-rendering-of-spectra/2

wow 🤯 I already thought this was too much code.

Is it possible to rotate this ramp legend (e.g. vertical ramp legend)?

Not at the moment. You can already apply arbitrary styles, but I doubt that rotating the whole legend — with style: {transform: "rotate(90deg)"} — will be satisfying. (Please don't hesitate to open an issue or a pull-request on the github repo.)

Should be "a horizontal ramp" instead of "an horizontal ramp"

Thanks, fixed.

This seems like a bug to me: if you set a label on the scale explicitly within the chart, that label will be shown in the legend below. We only ignore the label if it was set implicitly from the channels, but that feels like an oversight.

tracking in https://github.com/observablehq/plot/issues/605

Is there a way to move the legends inside the plot?

No. It's just a lightweight way of calling the legend. You can compose your own structure by naming the chart and calling chart.legend().

How do I pass options to the legend when it is part of a Plot.plot call?

This cell should not be collapsed as there is some great stuff here, like columns:

If figured it would be lighter this way, since the options are just repeats of the inputs above.

While a notebook is embedded, the legend doesn't show in print view. However, it does appear within the Notebook itself