Pixelorama/src/UI/Canvas/Rulers/Guide.gd

class_name Guide extends Line2D

enum Types {HORIZONTAL, VERTICAL}

var font := preload("res://assets/fonts/Roboto-Regular.tres")
var has_focus := true
var mouse_pos := Vector2.ZERO
var type = Types.HORIZONTAL
var project = Global.current_project


func _ready() -> void:
	width = Global.camera.zoom.x * 2
	default_color = Global.guide_color
	project.guides.append(self)


func _input(_event : InputEvent):
	var tmp_transform = get_canvas_transform().affine_inverse()
	var tmp_position = Global.main_viewport.get_local_mouse_position()
	mouse_pos = tmp_transform.basis_xform(tmp_position) + tmp_transform.origin

	if points.size() < 2:
		return
	var point0 := points[0]
	var point1 := points[1]
	if type == Types.HORIZONTAL:
		point0.y -= width * 3
		point1.y += width * 3
	else:
		point0.x -= width * 3
		point1.x += width * 3
	if Global.can_draw and Global.has_focus and point_in_rectangle(mouse_pos, point0, point1) and Input.is_action_just_pressed("left_mouse") and visible:
		if !point_in_rectangle(Global.canvas.current_pixel, Vector2.ZERO, project.size):
			has_focus = true
			Global.has_focus = false
			update()
	if has_focus and visible:
		if Input.is_action_pressed("left_mouse"):
			if type == Types.HORIZONTAL:
				var yy = stepify(mouse_pos.y, 0.5)
				points[0].y = yy
				points[1].y = yy
			else:
				var xx = stepify(mouse_pos.x, 0.5)
				points[0].x = xx
				points[1].x = xx
		if Input.is_action_just_released("left_mouse"):
			Global.has_focus = true
			has_focus = false
			if !outside_canvas():
				update()


func _draw() -> void:
	if has_focus:
		var viewport_size: Vector2 = Global.main_viewport.rect_size
		var zoom: Vector2 = Global.camera.zoom

		# viewport_poly is an array of the points that make up the corners of the viewport
		var viewport_poly:= [Vector2.ZERO, Vector2(viewport_size.x, 0), viewport_size, Vector2(0, viewport_size.y)]
		# Adjusting viewport_poly to take into account the camera offset, zoom, and rotation
		for p in range(viewport_poly.size()):
			viewport_poly[p] = viewport_poly[p].rotated(Global.camera.rotation) * zoom + Vector2(Global.camera.offset.x - (viewport_size.rotated(Global.camera.rotation).x / 2) * zoom.x, Global.camera.offset.y - (viewport_size.rotated(Global.camera.rotation).y / 2) * zoom.y)

		var string = "%spx" % str(stepify(mouse_pos.y if type == Types.HORIZONTAL else mouse_pos.x, 0.5))
		# X and Y offsets for nicer looking spacing
		var x_offset := 5
		var y_offset := -7 # Only used where the string is above the guide

		# Draw the string where the guide intersects with the viewport poly 
		# Priority is top edge, then left, then right
		var intersection = Geometry.segment_intersects_segment_2d(points[0], points[1], viewport_poly[0], viewport_poly[1])
		if intersection:
			draw_set_transform(intersection, Global.camera.rotation, zoom * 2)
			if intersection.distance_squared_to(viewport_poly[0]) < intersection.distance_squared_to(viewport_poly[1]):
				draw_string(font, Vector2(x_offset, font.get_height()), string)
			else:
				draw_string(font, Vector2(-font.get_string_size(string).x - x_offset, font.get_height()), string)
			return
		intersection = Geometry.segment_intersects_segment_2d(points[0], points[1], viewport_poly[3], viewport_poly[0])
		if intersection:
			draw_set_transform(intersection, Global.camera.rotation, zoom * 2)
			if intersection.distance_squared_to(viewport_poly[3]) < intersection.distance_squared_to(viewport_poly[0]):
				draw_string(font, Vector2(x_offset, y_offset), string)
			else:
				draw_string(font, Vector2(x_offset, font.get_height()), string)
			return
		intersection = Geometry.segment_intersects_segment_2d(points[0], points[1], viewport_poly[1], viewport_poly[2])
		if intersection:
			draw_set_transform(intersection, Global.camera.rotation, zoom * 2)
			if intersection.distance_squared_to(viewport_poly[1]) < intersection.distance_squared_to(viewport_poly[2]):
				draw_string(font, Vector2(-font.get_string_size(string).x - x_offset, font.get_height()), string)
			else:
				draw_string(font, Vector2(-font.get_string_size(string).x - x_offset, y_offset), string)
			return

		# If there's no intersection with a viewport edge, show string in top left corner
		draw_set_transform(viewport_poly[0], Global.camera.rotation, zoom * 2)
		draw_string(font, Vector2(x_offset, font.get_height()), string)


func outside_canvas() -> bool:
	if type == Types.HORIZONTAL:
		if points[0].y < 0 || points[0].y > project.size.y:
			project.guides.erase(self)
			queue_free()
			return true
	else:
		if points[0].x < 0 || points[0].x > project.size.x:
			project.guides.erase(self)
			queue_free()
			return true
	return false


func point_in_rectangle(p : Vector2, coord1 : Vector2, coord2 : Vector2) -> bool:
	return p.x > coord1.x && p.y > coord1.y && p.x < coord2.x && p.y < coord2.y