BoundMotion.bind constructor

BoundMotion.bind(MotionDocument doc, SceneDocument scene)

Implementation

factory BoundMotion.bind(MotionDocument doc, SceneDocument scene) {
  var nodes = {for (var (n, _) in scene.walk()) n};
  var bound = <AnimateGroup, BoundGroup>{};
  for (var g in doc.groups) {
    // The guard survives even though nothing is resolved: a motion still
    // has to be played against the scene it was authored against, and a
    // group pointing outside it is a wiring mistake worth naming.
    if (!nodes.contains(g.node)) {
      throw StateError(
        'the motion animates a node this scene does not have '
        '("${g.node.name}", from group "${g.name}") — bound against a '
        'different scene? Bind the pair that was authored together.',
      );
    }
    bound[g] = BoundGroup._(g);
  }
  return BoundMotion._(
    doc,
    scene,
    bound,
    playTimeline(doc.timeline, into: bound),
  );
}