About

diagram.ink draws technical diagrams from a small language called Platen. You say where things go; the engine routes the lines, sizes the gutters and resolves every overlap the same way every time.

Why the author places

Auto-layout optimises for a metric nobody asked for. Composition carries meaning — flow left to right, tiers top to bottom — and an optimiser destroys it. So there is no auto-layout here and there never will be. What the engine does instead is everything that is genuinely mechanical: routing lines so they can be followed, breaking one where it crosses another, opening a gap in a boundary rather than a break in a path.

Determinism

The same source produces the same drawing, byte for byte, on any machine. That is what makes a diagram reviewable in a pull request, and it is why the drawing has an address that can be cached forever.

Who makes it

Built by btn.io. The notation is published in full at /platen — it is meant to be written by hand and generated by machines, and neither works if the grammar is a secret.