stack and color legend are in reverse order

[ssfrr]

Bug description

The colors in the legend end up inverted from the blocks in a stacked bar chart, which makes it a little harder to scan.

Steps to reproduce

using DataFrames
using AlgebraOfGraphics
using CairoMakie

df = DataFrame(x=repeat(1:3, 3), y = rand(9), z=["a", "a", "a", "b", "b", "b", "c", "c", "c"])
draw(data(df) * mapping(:x, :y; stack=:z, color=:z) * visual(BarPlot))

generates the plot:

Notice the color ordering in the stacking and legend are reversed.

Version info

AlgebraOfGraphics v0.6.16

[jkrumbiegel]

You can achieve reverse order now by passing categories = reverse to the Stack scale.

df = DataFrame(x=repeat(1:3, 3), y = rand(9), z=["a", "a", "a", "b", "b", "b", "c", "c", "c"])
draw(
    data(df) * mapping(:x, :y; stack=:z, color=:z) * visual(BarPlot),
    scales(Stack = (; categories = reverse))
)

I agree that it makes for a more intuitive reading order, but on the other hand I think the process of stacking makes sense to think of as going bottom-up, also reverse order would work less well for horizontal barplots:

So I don't think I'm going to change the default here.