properly deprecated to_colormap(cm, n) (MakieOrg#1901)

* properly deprecated to_colormap(cm, n)

* add resample_cmap

* actually mention the breaking change

NEWS.md

@@ -5,6 +5,7 @@
 - **Breaking** Added `space` as a generic attribute to switch between data, pixel, relative and clip space for positions. `space` in text has been renamed to `markerspace` because of this. `Pixel` and `SceneSpace` are no longer valid inputs for `space` or `markerspace` [#1596](https://github.com/JuliaPlots/Makie.jl/pull/1596).
 - **Breaking** Deprecated `mouse_selection(scene)` for `pick(scene)`.
 - **Breaking** Bumped `GridLayoutBase` version to `v0.7`, which introduced offset layouts. Now, indexing into row 0 doesn't create a new row 1, but a new row 0, so that all previous content positions stay the same. This makes building complex layouts order-independent [#1704](https://github.com/JuliaPlots/Makie.jl/pull/1704).
+- **Breaking** deprecate `to_colormap(cmap, ncolors)` in favor of `categorical_colors(cmap, ncolors)` and `resample_cmap(cmap, ncolors)`
 - Added `empty!(fig)` and changed `empty!(scene)` to remove all child plots without detaching windows [#1818](https://github.com/JuliaPlots/Makie.jl/pull/1818).
 - Switched to erroring instead of warning for deprecated events `mousebuttons`, `keyboardbuttons` and `mousedrag`.
 - `Layoutable` was renamed to `Block` and the infrastructure changed such that attributes are fixed fields and each block has its own `Scene` for better encapsulation [#1796](https://github.com/JuliaPlots/Makie.jl/pull/1796).

src/Makie.jl

@@ -191,7 +191,7 @@ export broadcast_foreach, to_vector, replace_automatic!
 
 # conversion infrastructure
 export @key_str, convert_attribute, convert_arguments
-export to_color, to_colormap, to_rotation, to_font, to_align, to_textsize
+export to_color, to_colormap, to_rotation, to_font, to_align, to_textsize, categorical_colors, resample_cmap
 export to_ndim, Reverse
 
 # Transformations

src/basic_recipes/series.jl

@@ -35,33 +35,6 @@ Curves can be:
     )
 end
 
-function categorical_colors(cols::AbstractVector{<: Colorant}, categories::Integer)
-    if length(cols) < categories
-        error("Not enough colors for number of categories. Categories: $(categories), colors: $(length(cols))")
-    end
-    return to_colormap(cols)
-end
-
-function categorical_colors(cols::AbstractVector, categories::Integer)
-    return categorical_colors(to_color.(cols), categories)
-end
-
-function categorical_colors(cs::Union{String, Symbol}, categories::Integer)
-    cs_string = string(cs)
-    if cs_string in all_gradient_names
-        cols = PlotUtils.get_colorscheme(Symbol(cs_string)).colors
-        categorical_colors(cols, categories)
-    else
-        error(
-            """
-            There is no color gradient named $cs.
-            See `available_gradients()` for the list of available gradients,
-            or look at http://makie.juliaplots.org/dev/generated/colors#Colormap-reference.
-            """
-        )
-    end
-end
-
 replace_missing(x) = ismissing(x) ? NaN : x
 
 function convert_arguments(T::Type{<: Series}, y::AbstractMatrix)

src/conversions.jl

@@ -291,7 +291,7 @@ function convert_arguments(SL::SurfaceLike, x::AbstractVecOrMat{<: Number}, y::A
     return map(el32convert, adjust_axes(SL, x, y, z))
 end
 
-convert_arguments(::SurfaceLike, x::AbstractMatrix, y::AbstractMatrix) = (x, y, zeros(size(y)))
+convert_arguments(sl::SurfaceLike, x::AbstractMatrix, y::AbstractMatrix) = convert_arguments(sl, x, y, zeros(size(y)))
 
 """
     convert_arguments(P, x, y, z)::Tuple{ClosedInterval, ClosedInterval, Matrix}
@@ -724,9 +724,9 @@ Converts a `color` symbol (e.g. `:blue`) to a color RGBA.
 convert_attribute(color, ::key"color") = to_color(color)
 
 """
-    to_colormap(cm[, N = 20])
+    to_colormap(cm)
 
-Converts a colormap `cm` symbol (e.g. `:Spectral`) to a colormap RGB array, where `N` specifies the number of color points.
+Converts a colormap `cm` symbol/string (e.g. `:Spectral`) to a colormap RGB array.
 """
 convert_attribute(colormap, ::key"colormap") = to_colormap(colormap)
 convert_attribute(rotation, ::key"rotation") = to_rotation(rotation)
@@ -744,7 +744,7 @@ struct Palette
    i::Ref{Int}
    Palette(colors) = new(to_color.(colors), zero(Int))
 end
-Palette(name::Union{String, Symbol}, n = 8) = Palette(to_colormap(name, n))
+Palette(name::Union{String, Symbol}, n = 8) = Palette(categorical_colors(name, n))
 function to_color(p::Palette)
     N = length(p.colors)
     p.i[] = p.i[] == N ? 1 : p.i[] + 1
@@ -1009,6 +1009,45 @@ function available_gradients()
     end
 end
 
+
+to_colormap(cm, categories::Integer) = error("`to_colormap(cm, categories)` is deprecated. Use `Makie.categorical_colors(cm, categories)` for categorical colors, and `resample_cmap(cmap, ncolors)` for continous resampling.")
+
+"""
+    categorical_colors(colormaplike, categories::Integer)
+
+Creates categorical colors and tries to match `categories`.
+Will error if color scheme doesn't contain enough categories. Will drop the n last colors, if request less colors than contained in scheme.
+"""
+function categorical_colors(cols::AbstractVector{<: Colorant}, categories::Integer)
+    if length(cols) < categories
+        error("Not enough colors for number of categories. Categories: $(categories), colors: $(length(cols))")
+    end
+    return cols[1:categories]
+end
+
+function categorical_colors(cols::AbstractVector, categories::Integer)
+    return categorical_colors(to_color.(cols), categories)
+end
+
+function categorical_colors(cs::Union{String, Symbol}, categories::Integer)
+    cs_string = string(cs)
+    if cs_string in all_gradient_names
+        if haskey(ColorBrewer.colorSchemes, cs_string)
+            return to_colormap(ColorBrewer.palette(cs_string, categories))
+        else
+            return categorical_colors(to_colormap(cs_string), categories)
+        end
+    else
+        error(
+            """
+            There is no color gradient named $cs.
+            See `available_gradients()` for the list of available gradients,
+            or look at http://makie.juliaplots.org/dev/generated/colors#Colormap-reference.
+            """
+        )
+    end
+end
+
 """
 Reverses the attribute T upon conversion
 """
@@ -1019,8 +1058,10 @@ end
 to_colormap(r::Reverse) = reverse(to_colormap(r.data))
 to_colormap(cs::ColorScheme) = to_colormap(cs.colors)
 
+
+
 """
-    to_colormap(b)
+    to_colormap(b::AbstractVector)
 
 An `AbstractVector{T}` with any object that [`to_color`](@ref) accepts.
 """
@@ -1033,6 +1074,8 @@ function to_colormap(cs::Tuple{<: Union{Reverse, Symbol, AbstractString}, Real})
 end
 
 """
+    to_colormap(cs::Union{String, Symbol})::Vector{RGBAf}
+
 A Symbol/String naming the gradient. For more on what names are available please see: `available_gradients()`.
 For now, we support gradients from `PlotUtils` natively.
 """

src/utilities/utilities.jl

@@ -13,6 +13,28 @@ function resample(A::AbstractVector, len::Integer)
     return interpolated_getindex.((A,), range(0.0, stop=1.0, length=len))
 end
 
+
+"""
+    resample_cmap(cmap, ncolors::Integer; alpha=1.0)
+
+* cmap: anything that `to_colormap` accepts
+* ncolors: number of desired colors
+* alpha: additional alpha applied to each color. Can also be an array, matching `colors`, or a tuple giving a start + stop alpha value.
+"""
+function resample_cmap(cmap, ncolors::Integer; alpha=1.0)
+    cols = to_colormap(cmap)
+    r = range(0.0, stop=1.0, length=ncolors)
+    if alpha isa Tuple{<:Number, <:Number}
+        alphas = LinRange(alpha..., ncolors)
+    else
+        alphas = alpha
+    end
+    return broadcast(r, alphas) do i, a
+        c = interpolated_getindex(cols, i)
+        return RGBAf(Colors.color(c), Colors.alpha(c) *  a)
+    end
+end
+
 """
     resampled_colors(attributes::Attributes, levels::Integer)
 

test/conversions.jl

@@ -176,7 +176,27 @@ end
     @test categorical_colors([to_color(:red)], 1) == [to_color(:red)]
     @test categorical_colors([:red], 1) == [to_color(:red)]
     @test_throws ErrorException categorical_colors([to_color(:red)], 2)
-    @test categorical_colors(:darktest, 1) == to_color.(Makie.PlotUtils.palette(:darktest))
+    @test categorical_colors(:darktest, 1) == to_color.(Makie.PlotUtils.palette(:darktest))[1:1]
+    @test_throws ErrorException to_colormap(:viridis, 10) # deprecated
+    @test categorical_colors(:darktest, 1) == to_color.(Makie.PlotUtils.palette(:darktest))[1:1]
+    @test categorical_colors(:viridis, 10) == to_colormap(:viridis)[1:10]
+    # TODO why don't they exactly match?
+    @test categorical_colors(:Set1, 9) ≈ to_colormap(:Set1)
+
+    @test_throws ArgumentError Makie.categorical_colors(:PuRd, 20) # not enough categories
+end
+
+@testset "resample colormap" begin
+    cs = Makie.resample_cmap(:viridis, 10; alpha=LinRange(0, 1, 10))
+    @test Colors.alpha.(cs) == Float32.(LinRange(0, 1, 10))
+    cs = Makie.resample_cmap(:viridis, 2; alpha=0.5)
+    @test all(x-> x == 0.5, Colors.alpha.(cs))
+    @test Colors.color.(cs) == Colors.color.(Makie.resample(to_colormap(:viridis), 2))
+    cs = Makie.resample_cmap(:Set1, 100)
+    @test all(x-> x == 1.0, Colors.alpha.(cs))
+    @test Colors.color.(cs) == Colors.color.(Makie.resample(to_colormap(:Set1), 100))
+    cs = Makie.resample_cmap(:Set1, 10; alpha=(0, 1))
+    @test Colors.alpha.(cs) == Float32.(LinRange(0, 1, 10))
 end
 
 @testset "colors" begin