Updating Makie plot based on button action

Specific Domains Visualization
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7

You have a race condition because you set your offflag to true and immediately readjust the slider, but the async task only gets to the flag after setting the slider again itself. This logic here should be a bit more robust, async code is always more complicated to reason about than sync code:

function plot_random_with_button()
    f = Figure()
    ax = Axis(f[1, 1])
    
    buta = Button(f[2, :], label="Animate", tellwidth=false)
    buts = Button(f[3, :], label="Stop", tellwidth=false)
    sl = Slider(f[4, :], range=range(0, 2 * pi, 50))
    
    
    x = Observable(range(0, 2 * pi, 100))
    y = lift(x, sl.value) do x, p
        cos.(x .+ p)
    end
    p = plot!(x, y)

    
    taskref = Ref{Union{Nothing,Task}}(nothing)
    should_close = Ref(false)

    on(buta.clicks) do _
        if taskref[] === nothing
            taskref[] = @async begin
                for val in Iterators.cycle(sl.range[])
                    sleep(1 / 30)
                    set_close_to!(sl, val)
                    should_close[] && break
                end
                should_close[] = false
            end
        end
        Consume(true)
    end

    on(buts.clicks) do _
        if taskref[] !== nothing && !should_close[]
            should_close[] = true
            wait(taskref[])
            taskref[] = nothing
            set_close_to!(sl, 0)
        end
        Consume(true)
    end
    f
end

plot_random_with_button()