Support Waterfall plot type

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Unreleased
 
+- Support `Waterfall` plot type [#583](https://github.com/MakieOrg/AlgebraOfGraphics.jl/pull/583).
+
 ## v0.8.13 - 2024-10-21
 
 - Added aesthetics for `Stairs` [#573](https://github.com/MakieOrg/AlgebraOfGraphics.jl/pull/573).
@@ -120,4 +122,4 @@
 - **Breaking**: Analyses now require parentheses (i.e. `linear()` instead of `linear`).
 - **Breaking**: Rename `layout_x` and `layout_y` to `col` and `row`.
 - **Breaking**: Rename `wts` keyword argument to `weights`.
-- **Breaking**: `categorical` has been replaced by `nonnumeric`.
+- **Breaking**: `categorical` has been replaced by `nonnumeric`.

src/aesthetics.jl

@@ -118,6 +118,23 @@ function aesthetic_mapping(::Type{BarPlot}, N::Int)
     ])
 end
 
+aesthetic_mapping(::Type{Waterfall}, ::Normal) = aesthetic_mapping(Waterfall, 1)
+aesthetic_mapping(::Type{Waterfall}, ::Normal, ::Normal) = aesthetic_mapping(Waterfall, 2)
+function aesthetic_mapping(::Type{Waterfall}, N::Int)
+    @assert 1 <= N <= 2
+    positionals = if N == 1
+        [1 => AesY]
+    elseif N == 2
+        [1 => AesX, 2 => AesY]
+    end
+    dictionary([
+        positionals...,
+        :color => AesColor,
+        :width => AesDeltaX,
+        :dodge => AesDodgeX,
+    ])
+end
+
 function aesthetic_mapping(::Type{Violin}, ::Normal, ::Normal)
     dictionary([
         1 => :orientation => dictionary([
@@ -461,4 +478,4 @@ function aesthetic_mapping(::Type{Stairs}, N::Int)
         :color => AesColor,
         :linestyle => AesLineStyle,
     ])
-end
+end

src/guides/legend.jl

@@ -372,6 +372,12 @@ function legend_elements(T::Type{<:Union{BarPlot,Violin,BoxPlot,Choropleth,Poly,
     )]
 end
 
+function legend_elements(T::Type{Waterfall}, attributes, scale_args::MixedArguments)
+    [PolyElement(
+        color = _get(T, scale_args, attributes, :color),
+    )]
+end
+
 function legend_elements(T::Type{RainClouds}, attributes, scale_args::MixedArguments)
     [PolyElement(
         color = _get(T, scale_args, attributes, :color),

test/reference_tests.jl

@@ -1018,3 +1018,17 @@ reftest("stairs") do
         visual(Stairs)
     draw(spec)
 end
+
+reftest("waterfall") do
+    df = (
+        x=repeat(1:2, inner=5),
+        y=[6, 4, 2, -8, 3, 5, 1, -2, -3, 7],
+        group=repeat('A':'E', outer=2),
+    )
+    f = Figure()
+    fg = draw!(f[1, 1], data(df) * visual(Waterfall, show_final=true) * mapping(:x, :y, color=:group, dodge=:group)) 
+    legend!(f[1, 2], fg)
+    draw!(f[2, 1:2], data(df) * visual(Waterfall, show_direction=true) * mapping(:y))
+    f
+end
+