Tricontourf plot

CairoMakie/src/overrides.jl

@@ -186,3 +186,38 @@ function draw_plot(scene::Scene, screen::CairoScreen,
 
     nothing
 end
+
+#################################################################################
+#                                  Tricontourf                                  #
+# Tricontourf creates many disjoint polygons that are adjacent and form contour #
+#  bands, however, at the gaps we see white antialiasing artifacts. Therefore   #
+#               we override behavior and draw each band in one go               #
+#################################################################################
+
+function draw_plot(scene::Scene, screen::CairoScreen, tric::Tricontourf)
+
+    pol = only(tric.plots)::Poly
+    colornumbers = pol.color[]
+    colors = numbers_to_colors(colornumbers, pol)
+
+    polygons = pol[1][]
+
+    model = pol.model[]
+    space = to_value(get(pol, :space, :data))
+    projected_polys = project_polygon.(Ref(scene), space, polygons, Ref(model))
+
+    function draw_tripolys(polys, colornumbers, colors)
+        for (i, (pol, colnum, col)) in enumerate(zip(polys, colornumbers, colors))
+            polypath(screen.context, pol)
+            if i == length(colornumbers) || colnum != colornumbers[i+1]
+                Cairo.set_source_rgba(screen.context, rgbatuple(col)...)
+                Cairo.fill(screen.context)
+            end
+        end
+        return
+    end
+
+    draw_tripolys(projected_polys, colornumbers, colors)
+
+    return
+end

NEWS.md

@@ -2,6 +2,7 @@
 
 ## master
 
+- Added the `tricontourf` plotting function [#2226](https://github.com/JuliaPlots/Makie.jl/pull/2226).
 - Fix per character attributes in text [#2244](https://github.com/JuliaPlots/Makie.jl/pull/2244)
 - `Axis` does now accept both a `Bool` and a `Tuple{Bool, Bool}` as values for `xtrimspine` and `ytrimspine` to trim only one end of the spine [#2171](https://github.com/JuliaPlots/Makie.jl/pull/2171).
 - Added `BezierPath` which can be constructed from SVG like command list, SVG string or from a `Polygon`.

Project.toml

@@ -32,6 +32,7 @@ MakieCore = "20f20a25-4f0e-4fdf-b5d1-57303727442b"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 Match = "7eb4fadd-790c-5f42-8a69-bfa0b872bfbf"
 MathTeXEngine = "0a4f8689-d25c-4efe-a92b-7142dfc1aa53"
+MiniQhull = "978d7f02-9e05-4691-894f-ae31a51d76ca"
 Observables = "510215fc-4207-5dde-b226-833fc4488ee2"
 OffsetArrays = "6fe1bfb0-de20-5000-8ca7-80f57d26f881"
 Packing = "19eb6ba3-879d-56ad-ad62-d5c202156566"
@@ -49,6 +50,7 @@ Statistics = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
 StatsBase = "2913bbd2-ae8a-5f71-8c99-4fb6c76f3a91"
 StatsFuns = "4c63d2b9-4356-54db-8cca-17b64c39e42c"
 StructArrays = "09ab397b-f2b6-538f-b94a-2f83cf4a842a"
+TriplotBase = "981d1d27-644d-49a2-9326-4793e63143c3"
 UnicodeFun = "1cfade01-22cf-5700-b092-accc4b62d6e1"
 
 [compat]
@@ -75,6 +77,7 @@ KernelDensity = "0.5, 0.6"
 LaTeXStrings = "1.2"
 MakieCore = "=0.4.0"
 Match = "1.1"
+MiniQhull = "0.3"
 MathTeXEngine = "0.5"
 Observables = "0.5.1"
 OffsetArrays = "1"
@@ -88,5 +91,6 @@ SnoopPrecompile = "1.0"
 StatsBase = "0.31, 0.32, 0.33"
 StatsFuns = "0.9, 1.0"
 StructArrays = "0.3, 0.4, 0.5, 0.6"
+TriplotBase = "=0.1.0"
 UnicodeFun = "0.4"
 julia = "1.3"

ReferenceTests/src/tests/examples2d.jl

@@ -545,6 +545,61 @@ end
     f
 end
 
+@reference_test "tricontourf" begin
+    x = RNG.randn(50)
+    y = RNG.randn(50)
+    z = -sqrt.(x .^ 2 .+ y .^ 2) .+ 0.1 .* RNG.randn.()
+
+    f, ax, tr = tricontourf(x, y, z)
+    scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black)
+    Colorbar(f[1, 2], tr)
+    f
+end
+
+@reference_test "tricontourf extendhigh extendlow" begin
+    x = RNG.randn(50)
+    y = RNG.randn(50)
+    z = -sqrt.(x .^ 2 .+ y .^ 2) .+ 0.1 .* RNG.randn.()
+
+    f, ax, tr = tricontourf(x, y, z, levels = -1.8:0.2:-0.4, extendhigh = :red, extendlow = :orange)
+    scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black)
+    Colorbar(f[1, 2], tr)
+    f
+end
+
+@reference_test "tricontourf relative mode" begin
+    x = RNG.randn(50)
+    y = RNG.randn(50)
+    z = -sqrt.(x .^ 2 .+ y .^ 2) .+ 0.1 .* RNG.randn.()
+
+    f, ax, tr = tricontourf(x, y, z, mode = :relative, levels = 0.2:0.1:1, colormap = :batlow)
+    scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black, colormap = :batlow)
+    Colorbar(f[1, 2], tr)
+    f
+end
+
+@reference_test "tricontourf manual vs delaunay" begin
+    n = 20
+    angles = range(0, 2pi, length = n+1)[1:end-1]
+    x = [cos.(angles); 2 .* cos.(angles .+ pi/n)]
+    y = [sin.(angles); 2 .* sin.(angles .+ pi/n)]
+    z = (x .- 0.5).^2 + (y .- 0.5).^2 .+ 0.5 .* RNG.randn.()
+
+    triangulation_inner = reduce(hcat, map(i -> [0, 1, n] .+ i, 1:n))
+    triangulation_outer = reduce(hcat, map(i -> [n-1, n, 0] .+ i, 1:n))
+    triangulation = hcat(triangulation_inner, triangulation_outer)
+
+    f, ax, _ = tricontourf(x, y, z, triangulation = triangulation,
+        axis = (; aspect = 1, title = "Manual triangulation"))
+    scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black)
+
+    tricontourf(f[1, 2], x, y, z, triangulation = Makie.DelaunayTriangulation(),
+        axis = (; aspect = 1, title = "Delaunay triangulation"))
+    scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black)
+
+    f
+end
+
 @reference_test "marker offset in data space" begin
     f = Figure()
     ax = Axis(f[1, 1]; xticks=0:1, yticks=0:10)
@@ -571,4 +626,4 @@ end
 
         f
     end
-end
+end

docs/examples/plotting_functions/tricontourf.md

@@ -0,0 +1,100 @@
+# tricontourf
+
+{{doc tricontourf}}
+
+## Examples
+
+\begin{examplefigure}{svg = true}
+```julia
+using CairoMakie
+CairoMakie.activate!() # hide
+Makie.inline!(true) # hide
+using Random
+Random.seed!(1234)
+
+x = randn(50)
+y = randn(50)
+z = -sqrt.(x .^ 2 .+ y .^ 2) .+ 0.1 .* randn.()
+
+f, ax, tr = tricontourf(x, y, z)
+scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black)
+Colorbar(f[1, 2], tr)
+f
+```
+\end{examplefigure}
+
+\begin{examplefigure}{svg = true}
+```julia
+using CairoMakie
+CairoMakie.activate!() # hide
+Makie.inline!(true) # hide
+using Random
+Random.seed!(1234)
+
+x = randn(200)
+y = randn(200)
+z = x .* y
+
+f, ax, tr = tricontourf(x, y, z, colormap = :batlow)
+scatter!(x, y, color = z, colormap = :batlow, strokewidth = 1, strokecolor = :black)
+Colorbar(f[1, 2], tr)
+f
+```
+\end{examplefigure}
+
+#### Triangulation modes
+
+\begin{examplefigure}{svg = true}
+```julia
+using CairoMakie
+CairoMakie.activate!() # hide
+Makie.inline!(true) # hide
+using Random
+Random.seed!(123)
+
+n = 20
+angles = range(0, 2pi, length = n+1)[1:end-1]
+x = [cos.(angles); 2 .* cos.(angles .+ pi/n)]
+y = [sin.(angles); 2 .* sin.(angles .+ pi/n)]
+z = (x .- 0.5).^2 + (y .- 0.5).^2 .+ 0.5.*randn.()
+
+triangulation_inner = reduce(hcat, map(i -> [0, 1, n] .+ i, 1:n))
+triangulation_outer = reduce(hcat, map(i -> [n-1, n, 0] .+ i, 1:n))
+triangulation = hcat(triangulation_inner, triangulation_outer)
+
+f, ax, _ = tricontourf(x, y, z, triangulation = triangulation,
+    axis = (; aspect = 1, title = "Manual triangulation"))
+scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black)
+
+tricontourf(f[1, 2], x, y, z, triangulation = Makie.DelaunayTriangulation(),
+    axis = (; aspect = 1, title = "Delaunay triangulation"))
+scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black)
+
+f
+```
+\end{examplefigure}
+
+#### Relative mode
+
+Sometimes it's beneficial to drop one part of the range of values, usually towards the outer boundary.
+Rather than specifying the levels to include manually, you can set the `mode` attribute
+to `:relative` and specify the levels from 0 to 1, relative to the current minimum and maximum value.
+
+\begin{examplefigure}{svg = true}
+```julia
+using CairoMakie
+CairoMakie.activate!() # hide
+Makie.inline!(true) # hide
+using Random
+Random.seed!(1234)
+
+x = randn(50)
+y = randn(50)
+z = -sqrt.(x .^ 2 .+ y .^ 2) .+ 0.1 .* randn.()
+
+f, ax, tr = tricontourf(x, y, z, mode = :relative, levels = 0.2:0.1:1)
+scatter!(x, y, color = z, strokewidth = 1, strokecolor = :black)
+Colorbar(f[1, 2], tr)
+f
+```
+\end{examplefigure}

src/Makie.jl

@@ -48,6 +48,8 @@ import GridLayoutBase
 import ImageIO
 import FileIO
 import SparseArrays
+import TriplotBase
+import MiniQhull
 
 using IntervalSets: IntervalSets, (..), OpenInterval, ClosedInterval, AbstractInterval, Interval, endpoints
 using FixedPointNumbers: N0f8
@@ -140,6 +142,7 @@ include("basic_recipes/stairs.jl")
 include("basic_recipes/stem.jl")
 include("basic_recipes/streamplot.jl")
 include("basic_recipes/timeseries.jl")
+include("basic_recipes/tricontourf.jl")
 include("basic_recipes/volumeslices.jl")
 include("basic_recipes/wireframe.jl")
 

src/basic_recipes/contourf.jl

@@ -72,60 +72,26 @@ end
 function Makie.plot!(c::Contourf{<:Tuple{<:AbstractVector{<:Real}, <:AbstractVector{<:Real}, <:AbstractMatrix{<:Real}}})
     xs, ys, zs = c[1:3]
 
-
     c.attributes[:_computed_levels] = lift(zs, c.levels, c.mode) do zs, levels, mode
         _get_isoband_levels(Val(mode), levels, vec(zs))
     end
 
     colorrange = lift(c._computed_levels) do levels
         minimum(levels), maximum(levels)
     end
-    computed_colormap = lift(c._computed_levels, c.colormap, c.extendlow,
-                             c.extendhigh) do levels, cmap, elow, ehigh
-        levels_scaled = (levels .- minimum(levels)) ./ (maximum(levels) - minimum(levels))
-        n = length(levels_scaled)
-
-        if elow == :auto && !(ehigh == :auto)
-            cm_base = cgrad(cmap, n + 1; categorical=true)[2:end]
-            cm = cgrad(cm_base, levels_scaled; categorical=true)
-        elseif ehigh == :auto && !(elow == :auto)
-            cm_base = cgrad(cmap, n + 1; categorical=true)[1:(end - 1)]
-            cm = cgrad(cm_base, levels_scaled; categorical=true)
-        elseif ehigh == :auto && elow == :auto
-            cm_base = cgrad(cmap, n + 2; categorical=true)[2:(end - 1)]
-            cm = cgrad(cm_base, levels_scaled; categorical=true)
-        else
-            cm = cgrad(cmap, levels_scaled; categorical=true)
-        end
-        return cm
-    end
+    computed_colormap = lift(compute_contourf_colormap, c._computed_levels, c.colormap, c.extendlow,
+                             c.extendhigh)
     c.attributes[:_computed_colormap] = computed_colormap
 
     lowcolor = Observable{RGBAf}()
-    map!(lowcolor, c.extendlow, c.colormap) do el, cmap
-        if isnothing(el)
-            return RGBAf(0, 0, 0, 0)
-        elseif el === automatic || el == :auto
-            return RGBAf(to_colormap(cmap)[begin])
-        else
-            return to_color(el)::RGBAf
-        end
-    end
+    map!(compute_lowcolor, lowcolor, c.extendlow, c.colormap)
     c.attributes[:_computed_extendlow] = lowcolor
-    is_extended_low = lift(x -> !isnothing(x), lowcolor)
+    is_extended_low = lift(!isnothing, lowcolor)
 
     highcolor = Observable{RGBAf}()
-    map!(highcolor, c.extendhigh, c.colormap) do eh, cmap
-        if isnothing(eh)
-            return RGBAf(0, 0, 0, 0)
-        elseif eh === automatic || eh == :auto
-            return RGBAf(to_colormap(cmap)[end])
-        else
-            return to_color(eh)::RGBAf
-        end
-    end
+    map!(compute_highcolor, highcolor, c.extendhigh, c.colormap)
     c.attributes[:_computed_extendhigh] = highcolor
-    is_extended_high = lift(x -> !isnothing(x), highcolor)
+    is_extended_high = lift(!isnothing, highcolor)
 
     PolyType = typeof(Polygon(Point2f[], [Point2f[]]))
 
@@ -143,13 +109,9 @@ function Makie.plot!(c::Contourf{<:Tuple{<:AbstractVector{<:Real}, <:AbstractVec
         lows = levels[1:end-1]
         highs = levels[2:end]
 
-        nbands = length(lows)
         # zs needs to be transposed to match rest of makie
         isos = Isoband.isobands(xs, ys, zs', lows, highs)
 
-        allvertices = Point2f[]
-        allfaces = NgonFace{3,OffsetInteger{-1,UInt32}}[]
-        allids = Int[]
         levelcenters = (highs .+ lows) ./ 2
 
         for (i, (center, group)) in enumerate(zip(levelcenters, isos))