using ColorTypes, FileIO

]st ImageIO

struct PNG{T}
    data::T
end

PNG(filename::AbstractString) = read(filename) |> PNG

function PNG(img::AbstractMatrix{<:Colorant})
    buf = IOBuffer()
    save(Stream(format"PNG", buf), img)
    take!(buf) |> PNG
end

function Base.show(io::IO, ::MIME"image/png", p::PNG)
    write(io, p.data)
    flush(io)
end

hcat(
    fill(rand(RGB), 240, 100),
    fill(rand(RGB), 240, 100),
    fill(rand(RGB), 240, 100)
) |> PNG

Base.showable(::MIME"image/svg+xml", ::AbstractMatrix{<:Colorant}) = false

function Base.show(io::IO, mime::MIME"image/png", img::AbstractMatrix{<:Colorant})
    show(io, mime, PNG(img))
end

img = fill(rand(RGB), 240, 300)
img[30:180, 50:200] .= rand(RGB)

ix = filter(CartesianIndices(img)) do cix
    i, j = cix.I
    (i-150)^2 + (j-200)^2 < 80^2
end

img[ix] .= rand(RGB)
img

using Base64

function Base.show(io::IO, ::MIME"text/html", p::PNG)
    write(io, "<img src=\"data:image/png;base64,")
    enc = Base64EncodePipe(io)
    write(enc, p.data)
    close(enc)
    write(io, "\" />")
    flush(io)
end

function Base.show(io::IO, mime::MIME"text/html", img::AbstractMatrix{<:Colorant})
    show(io, mime, PNG(img))
end

img