Class FLineDrawing

src/main/java/fieldbox/boxes/FLineDrawing.java:48–518

## Fundamental drawing support for Boxes This is the ingest side of FLine drawing system --- the Field vector drawing framework. FLines are receptacles for geometry, both lines, tessellated shapes and text, and when added to certain properties of Boxes they will appear inside the FieldBoxWindow.

 * in the middle, a light grey gradient box, and a construction site selection trim.
 */
public class FLineDrawing extends Box implements Drawing.Drawer {

	static public final Dict.Prop<Map<String, Function<Box, FLine>>> frameDrawing = new Dict.Prop<>("frameDrawing").type()
		.toCanon()
		.doc("Functions that compute lines to be drawn along with this box")
		.set(IO.dontCopy, true)
		.set(Dict.readOnly, true).autoConstructs(() -> new IdempotencyMap<Function<Box, FLine>>(Function.class));

	static public final Dict.Prop<Map<String, Function<Box, FLine>>> appearance = new Dict.Prop<>("frameDrawing").type()
		.toCanon()
		.doc("set this to a function that returns a list of FLines; it will be called whenever the box is selected or when its frame changes. Boxes with `_.appearance` set don't get the default grey box treatment")
		.set(Dict.readOnly, true);

	static public final Dict.Prop<IdempotencyMap<Supplier<FLine>>> lines = new Dict.Prop<>("lines").type()
		.toCanon()
		.doc("Geometry to be drawn along with this box")
		.autoConstructs(() -> new IdempotencyMap<>(Supplier.class).configureResourceLimits(1500, "too many lines in _.lines"))
		.set(IO.dontCopy, true)
		.set(Dict.readOnly, true);

	static public final Dict.Prop<Vec4> boxBackground = new Dict.Prop<>("boxBackground").type().toCanon().doc("sets the background color of this box. Defaults to `" + Colors.boxBackground1 + "`").autoConstructs(() -> Colors.boxBackground1).set(IO.persistent, true);
	static public final Dict.Prop<Vec4> boxOutline = new Dict.Prop<>("boxOutline").type().toCanon().doc("sets the outline color of this box. Defaults to `" + Colors.boxStroke + "`").autoConstructs(() -> Colors.boxStroke).set(IO.persistent, true);

	static {
		// accessing 'lines' causes a redraw to happen
		lines.getAttributes().putToMap(Missing.watchRead, "drawOnLines", (box, v) -> {
			Drawing.dirty(box);
		});
	}

	static public final Dict.Prop<IdempotencyMap<Supplier<Collection<? extends Supplier<FLine>>>>> bulkLines = new Dict.Prop<>("bulkLines").type()
		.toCanon()
		.doc("Geometry to be drawn along with this box")
		.autoConstructs(() -> new IdempotencyMap<>(Supplier.class))
		.set(IO.dontCopy, true)
		.set(Dict.readOnly, true);

	static public final Dict.Prop<String> layer = new Dict.Prop<>("layer").type()
		.toCanon()
		.doc("which layer to draw to? Defaults to `__main__`, the other alternative right now is `__glass__` to draw on the blur layer above Field");

	private final Box root;

	static public final Dict.Prop<FunctionOfBox<Boolean>> redraw = new Dict.Prop<>("redraw").type().toCanon().doc("call `_.redraw()` to cause the window to be redrawn");

	public FLineDrawing(Box root) {
		this.root = root;
		this.properties.putToList(Drawing.drawers, this);
		this.properties.put(redraw, x -> {
			Drawing.dirty(x);
			return true;
		});
	}

	static public Function<Box, FLine> boxOrigin(Function<Box, FLine> wrap, Vec2 origin) {
		return new Cached<Box, Object, FLine>((box, previously) -> {
			Rect frame = box.properties.get(Box.frame);
			Vec2 o = new Vec2(frame.x + frame.w * origin.x, frame.y + frame.h * origin.y);