Link params

Make one knob drive others, like a macro.

To make one param move others (a macro, a linked pair, a one-knob morph), override onParamChanged. It runs off the audio thread on a discrete edit, and ctx.setParam moves another param through the normal undo path, so the whole gesture is one undo entry.

const MACRO = 0, A = 1, B = 2;

onParamChanged(index: i32, ctx: ControlCtx): void {
  if (index == MACRO) {
    const v = ctx.param(MACRO);
    ctx.setParam(A, v);       // A follows the macro
    ctx.setParam(B, 1.0 - v); // B runs the other way
  }
}

Note

onParamChanged fires on discrete edits: a knob release, a preset load, an automation point. It does not fire for continuous modulation, which flows through ctx.modulatedParam(idx, i) in process.

Reference another param by name with ctx.paramIndex("id") if you don't want to track indices. Full handler list in the control surface reference.

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