How to create v0 scatter example in v1

[tomwayson]

I'm not sure how make this scatterplot in amCharts using the v1 API:

Ideally what we want is to be able to run one query, get all the results back and tell amCharts to assign a color from a pallet based on the Type field. However, when I tested amChart's colorField it did not work that way - it appears that colorField has to contain actual color values.

So the next best thing we could do is use a transform function (once we decide what to do in #285) to create a synthetic colorField on the fly that has a unique color for each Type. However, if we want existing v0 charts defined using the above definition to work in v1, then can't require users to go back and explicitly add a transform to their charts. Instead we'd need to infer that we need to do a transform internally based on the existence of series.color.field.

Also note that the v1 scatterplot spec currently doesn't even have a legend. I'm not even sure that if we used internal logic to generate a colorField that it would show up in the chart's legend as above (w/o generating a custom legend). We may need an actual series for each Type. So now that internal logic may need to not only run a transform that would create a colorField out of the 'Type' field, but also create multiple graphs for this single series - each w/ it's own color

[benstoltz]

@tomwayson when I did that repo to see how we could take the proposed AGO chart spec and convert it over to cedar I ended up writing a few functions to convert a color to the mouseover color. I'm pretty confident I could write up some to take a base assumed color and then create new ones for n number of series. I think that's a potential option?

[tomwayson]

Thanks @benstoltz, that sounds like a good idea and that code might be useful.

However, I'm less concerned about how we generate the colors (ideally they'll come from the theme) and more concerned about a series property forcing a transform. Up until now we've been planning (again depending on what we decide in #285) to apply transforms in flatten, which happens before we get to the point of converting series to graphs. Maybe it's not a big deal for renderChart() to apply it's own internal transforms since right now it's making a copy of the data that gets passed to it and handing the copy to amCharts. It just seems like the logic is going to get prickly (loop through series, find "special" properties like color that require transforming the data, then loop through the data creating a copy and applying those transforms), especially if we have to repeat the pattern for anything other than color in the future. Maybe I'm overthinking this.

[benstoltz]

Explanation for why this isn't working:

fillInSpec() currently isn't handling color/size properly. this needs to be done. PR forthcoming.