Pluto.jl notebook for echo MIDI input/output

echo_midi.jl

### A Pluto.jl notebook ###
# v0.11.8

using Markdown
using InteractiveUtils

# This Pluto notebook uses @bind for interactivity. When running this notebook outside of Pluto, the following 'mock version' of @bind gives bound variables a default value (instead of an error).
macro bind(def, element)
    quote
        local el = $(esc(element))
        global $(esc(def)) = Core.applicable(Base.get, el) ? Base.get(el) : missing
        el
    end
end

# ╔═╡ afd4a072-d3aa-11ea-3c8f-dda5bce82d86
using Plots

# ╔═╡ 79670ae0-d397-11ea-1f49-999d679323c5
@bind midi html"""
<canvas width=0 height=0></canvas>

<script>
	const input = this.document.querySelector('canvas');
	
	let sequence = new Array(16).fill(0);
	let output = null;

	input.value = sequence;
	input.dispatchEvent(new CustomEvent("input"));

	function onMIDIMessage(event) {	
		if (event.data.length > 1) { 
			sequence.push(event.data[1]);
			sequence.shift();
		
			input.value = sequence
			input.dispatchEvent(new CustomEvent('input'))
		}

		if (output && event.data.length > 1) output.send(event.data, event.timestamp);
	}

	navigator.requestMIDIAccess().then(midiAccess => {
		Array.from(midiAccess.inputs)[1][1].onmidimessage = onMIDIMessage
		output = midiAccess.outputs.values().next().value
	});
</script>
"""

# ╔═╡ c28ebe90-d3a9-11ea-2d4a-8586978579af
midi

# ╔═╡ d3663d30-d3ac-11ea-13c0-3f7d49b4e9ea
plot(midi, leg=false, marker=:o, linetype=:steppre)

# ╔═╡ Cell order:
# ╠═79670ae0-d397-11ea-1f49-999d679323c5
# ╠═c28ebe90-d3a9-11ea-2d4a-8586978579af
# ╠═afd4a072-d3aa-11ea-3c8f-dda5bce82d86
# ╠═d3663d30-d3ac-11ea-13c0-3f7d49b4e9ea