Add a Line2D above tagged ranges of text in a Label in Godot

text-overlay.gd

extends Control

# Scene structure:
# Main (Control Node)
# - HBox
# -- Multi-line Text label of 400px min width containing a bunch of text
# -- Control node that expands horizontally
# c (canvas node)

export var token = "#" # Marks start and end points of text to draw a line over

enum { IGNORE, START, END }

func _ready():
	var tbox = $HBox/Text
	var chunks = tbox.text.split(token)
	tbox.text = chunks.join("")
	var box_width = tbox.rect_size.x
	var pos = Vector2(0, 0)
	var points = []
	var line = ""
	var size_before = Vector2(0, 0)
	var idx = 0
	var state = IGNORE
	while idx < chunks.size():
		var l_size
		var words = chunks[idx].split(" ")
		var n = 0
		while n < words.size():
			if line == "":
				line = words[n]
			else:
				line = line + " " + words[n]
			var label = Label.new()
			$c.add_child(label)
			label.visible = false
			label.text = line
			# Resume execution the next frame.
			yield(get_tree(), "idle_frame")
			l_size = label.rect_size
			label.queue_free()
			if l_size.x > box_width:
				# New line
				size_before = Vector2(0,0)
				pos.y += (l_size.y + 3)
				# Spill word over to new line
				line = words[n]
			n += 1
			if state == START:
				pos.x = size_before.x
				points.append(pos)
				state = END
		idx += 1
		# Control the state at end of current chunk processing
		if state == IGNORE:
			size_before = l_size
			state = START
		else: # END
			pos.x = l_size.x
			points.append(pos)
			state = IGNORE
	idx = 0
	while idx < points.size():
		if idx + 1 < points.size():
			var l = Line2D.new()
			l.width = 4
			l.add_point(points[idx])
			l.add_point(points[idx + 1])
			tbox.add_child(l)
			idx += 1
		idx += 1