heatmap: Irregular Categories

Example by @walra356 (modified)

using CairoMakie, Random
Random.seed!(13)


n= 5
x = rand(n)                        # specify x steplength
y = rand(n)                        # specify y steplength
σ = rand(length(x), length(y))      # beware of dims

# custom ticks
function steps(x::Vector{T} where T<:Real)
    sum(x .< 0) == 0 || error("Error: $x - negative step length not allowed")
    return (s = append!(eltype(x)[0],x); [Base.sum(s[1:i]) for i ∈ Base.eachindex(s)])
end
function stepcenters(x::Vector{T} where T<:Real)
    δ = x .* 0.5
    s = append!(eltype(x)[0],x)
    return [Base.sum(s[1:i]) for i ∈ Base.eachindex(x)] .+ δ
end
stepedges(x::Vector{T} where T<:Real) = steps(x)

# the actual plot
theme = Theme(fontsize = 16, colormap = :gist_earth, ; size = (750,450))
set_theme!(theme)

attr1 = (xticks = (stepcenters(x),string.(1:n)),
    yticks = (stepcenters(y), string.(1:n)), xlabel = "cat", )
attr2 = (xticks = (stepedges(x),string.(0:n)),
    yticks = (stepedges(y), string.(0:n)), xlabel="cat", )

fig = Figure()
ax1 = Axis(fig[1,1]; attr1...)
ax2 = Axis(fig[1,2]; attr2...)
heatmap!(ax1, steps(x), steps(y), σ)
heatmap!(ax2, steps(x), steps(y), σ)
fig