Class Handles

src/main/java/fieldbox/boxes/plugins/Handles.java:24–399

Extends FLineInteraction to include, essentially, a node editor. Unlike Field1 this is going to be much more pluggable

	static public final Dict.Prop<Boolean> editable = new Dict.Prop<Boolean>("editable").type()
		.toCanon()
		.doc("Set this to true on an FLine to have it be editable by the handles system");
	static public final Dict.Prop<Handles> handles = new Dict.Prop<Handles>("handles").type()
		.toCanon()
		.doc("Provides customizeable node editing for FLines");

	static public final Dict.Prop<IdempotencyMap<Draggable>> draggables = new Dict.Prop<>("draggables").type()
		.toCanon()
		.doc("Collection of Draggable instances that offer interactive elements on the canvas. Can be inserted on FLine nodes")
		.autoConstructs(() -> new IdempotencyMap<Draggable>(Draggable.class));
	static public final Dict.Prop<Boolean> hasDraggables = new Dict.Prop<>("hasDraggables").type()
		.toCanon()
		.doc("set to mark that an FLine contains Draggables inside it, and that it should be searched for draggable Nodes");

	static public final Dict.Prop<Viewport> inside = new Dict.Prop<>("inside").type().toCanon().set(Dict.domain, "flines");


	public interface SetAndConstrain {
		Vec3 apply(Vec3 next, Vec3 previous, Vec3 initial);
	}

	static public class Draggable {
		public Vec3 cachePosition = null;
		public Vec3 initialPosition = null;
		public Vec3 sourcePosition = null;

		public String name;

		public boolean selected = false;

		public Supplier<Vec3> get;
		public SetAndConstrain setAndConstrain;
		public Function<Boolean, Boolean> select;
		public Supplier<Collection<FLine>> appearance;
		public Function<Vec3, Vec3> finisher;
		public Runnable commit;

		protected FLine source;

		public Draggable(Supplier<Vec3> get, SetAndConstrain setAndConstrain, Function<Boolean, Boolean> select, Supplier<Collection<FLine>> appearance, Function<Vec3, Vec3> finisher,
				 Runnable commit) {
			this.get = get;
			this.setAndConstrain = setAndConstrain;
			this.select = select;
			this.appearance = appearance;
			this.finisher = finisher;
			this.commit = commit;
			init();
		}

		public Draggable(FLine.Node on, SetAndConstrain setAndConstrain, Function<Boolean, Boolean> select, Supplier<Collection<FLine>> appearance, Function<Vec3, Vec3> finisher, Runnable
			commit) {
			this.get = () -> on.to;
			this.setAndConstrain = (next, previous, initial) -> {
				Vec3 v = setAndConstrain.apply(next, previous, initial);
				on.to.set(v);
				return v;
			};