Add transitions between steps of guided tours

This allows us to guide the user better during the
tour, making position changes between steps less
abrupt.

globals/Controller.gd

@@ -277,8 +277,7 @@ func get_info_popup() -> InfoPopup:
 
 
 func show_window_popup(popup: WindowPopup, popup_size: Vector2) -> void:
-	popup.size = popup_size
-	popup.popup_anchored(Vector2(0.5, 0.5), PopupManager.Direction.OMNI, true)
+	popup.popup_anchored(Vector2(0.5, 0.5), popup_size, PopupManager.Direction.OMNI, true)
 
 
 func show_welcome_message() -> void:

globals/HelpManager.gd

@@ -171,7 +171,7 @@ func _show_current_step() -> void:
 		return
 
 	_clear_trigger()
-	_info_popup.clear()
+	_info_popup.clear(true) # Avoid resetting size and position, as this breaks animations.
 
 	var step := _current_guide.steps[_current_step]
 	_info_popup.title = step.title
@@ -189,17 +189,12 @@ func _show_current_step() -> void:
 	else:
 		_info_popup.add_button("FINISH", _finish_guide)
 
-	# Resize, position, and show the popup.
+	# Resize, reposition, and show the popup.
 
-	_info_popup.size = step.size
 	if _info_popup.is_popped():
-		# TODO: It would be nice to have these transitions animated, but that requires additional work.
-		# The final size and the final position are calculated behind the scenes as we adjust anchors.
-		# Working around this would require us to replicate anchor calculations in scripts, and then
-		# change position instead. Maybe some day...
-		_info_popup.move_anchored(step.position_anchor, step.position_direction)
+		_info_popup.transform_anchored(step.position_anchor, step.size, step.position_direction)
 	else:
-		_info_popup.popup_anchored(step.position_anchor, step.position_direction, false)
+		_info_popup.popup_anchored(step.position_anchor, step.size, step.position_direction, false)
 
 	# Navigate to the target view and highlight the target control, if there is one.
 	Controller.navigate_to(step.navigation_target)

globals/PopupManager.gd

@@ -121,7 +121,7 @@ func create_anchored_popup(popup: PopupControl, anchor_position: Vector2, direct
 		_click_catcher.visible = true
 
 
-func translate_popup(popup: PopupControl, delta: Vector2) -> void:
+func adjust_popup_position(popup: PopupControl, delta: Vector2) -> void:
 	if not has_popup(popup):
 		printerr("PopupManager: Popup %s is not shown." % [ popup ])
 		return
@@ -131,14 +131,21 @@ func translate_popup(popup: PopupControl, delta: Vector2) -> void:
 	anchor.update_absolute_position(next_position, popup.size, popup._last_direction)
 
 
-func translate_anchored_popup(popup: PopupControl, anchor_position: Vector2, direction: Direction) -> void:
+func transform_anchored_popup(popup: PopupControl, anchor_position: Vector2, popup_size: Vector2, direction: Direction, smooth: bool = false) -> void:
 	if not has_popup(popup):
 		printerr("PopupManager: Popup %s is not shown." % [ popup ])
 		return
 
+	var original_position := popup.global_position
+	var original_size := popup.size
+
+	popup.size = popup_size
 	var anchor := popup.get_popup_anchor()
-	anchor.update_relative_position(anchor_position, popup.size, direction)
+	anchor.update_relative_position(anchor_position, popup_size, direction)
 	popup.align_popup(direction)
+
+	if smooth:
+		popup.animate_transform(original_position, original_size)
 
 
 func has_popup(popup: PopupControl) -> bool:
@@ -184,14 +191,14 @@ static func move_popup(popup: PopupControl, delta: Vector2) -> void:
 	if not _instance:
 		return
 
-	_instance.translate_popup(popup, delta)
+	_instance.adjust_popup_position(popup, delta)
 
 
-static func move_popup_anchored(popup: PopupControl, anchor_position: Vector2, direction: Direction) -> void:
+static func transform_popup_anchored(popup: PopupControl, anchor_position: Vector2, popup_size: Vector2, direction: Direction, smooth: bool = false) -> void:
 	if not _instance:
 		return
 
-	_instance.translate_anchored_popup(popup, anchor_position, direction)
+	_instance.transform_anchored_popup(popup, anchor_position, popup_size, direction, smooth)
 
 
 static func hide_popup(popup: PopupControl) -> void:
@@ -229,7 +236,10 @@ class PopupControl extends Control:
 	signal about_to_popup()
 	signal about_to_hide()
 
+	const TRANSFORM_DURATION := 0.18
+
 	var _last_direction: Direction = Direction.BOTTOM_RIGHT
+	var _tween: Tween = null
 
 
 	# Input events.
@@ -272,6 +282,25 @@ class PopupControl extends Control:
 				set_anchors_and_offsets_preset(Control.PRESET_CENTER, Control.PRESET_MODE_KEEP_SIZE)
 				grow_horizontal = Control.GROW_DIRECTION_BOTH
 				grow_vertical = Control.GROW_DIRECTION_BOTH
+
+
+	func animate_transform(original_position: Vector2, original_size: Vector2) -> void:
+		# We immediately reset position and size to their old values. This all
+		# happens in the same frame, so it should be seamless. New position and
+		# size are our tweening targets.
+
+		var target_position := global_position
+		var target_size := size
+
+		global_position = original_position
+		size = original_size
+
+		if _tween:
+			_tween.kill()
+
+		_tween = get_tree().create_tween().set_parallel()
+		_tween.tween_property(self, "global_position", target_position, TRANSFORM_DURATION)
+		_tween.tween_property(self, "size", target_size, TRANSFORM_DURATION)
 
 
 class PopupAnchor extends Control:

gui/widgets/popups/IOConfigPopup.gd

@@ -33,10 +33,10 @@ func _notification(what: int) -> void:
 # Lifecycle.
 
 ## Override.
-func clear() -> void:
+func clear(keep_size: bool = false) -> void:
 	activate_view(View.NONE)
 
-	super()
+	super(keep_size)
 
 
 # Config views.

gui/widgets/popups/InfoPopup.gd

@@ -34,7 +34,7 @@ func _ready() -> void:
 # Lifecycle.
 
 ## Override.
-func clear() -> void:
+func clear(keep_size: bool = false) -> void:
 	content = ""
 	_ref_image = null
 	_ref_image_size = Vector2.ZERO
@@ -43,7 +43,7 @@ func clear() -> void:
 	if is_node_ready():
 		_update_image()
 
-	super()
+	super(keep_size)
 
 
 # Content.

gui/widgets/popups/WindowPopup.gd

@@ -109,27 +109,29 @@ func is_popped() -> bool:
 	return PopupManager.is_popup_shown(self)
 
 
-func popup_anchored(anchor_position: Vector2, direction: PopupManager.Direction = PopupManager.Direction.BOTTOM_RIGHT, blocking: bool = true) -> void:
+func popup_anchored(anchor_position: Vector2, popup_size: Vector2, direction: PopupManager.Direction = PopupManager.Direction.BOTTOM_RIGHT, blocking: bool = true) -> void:
+	size = popup_size
 	_update_before_popup()
 	PopupManager.show_popup_anchored(self, anchor_position, direction, blocking)
 
 
-func move_anchored(anchor_position: Vector2, direction: PopupManager.Direction = PopupManager.Direction.BOTTOM_RIGHT) -> void:
-	PopupManager.move_popup_anchored(self, anchor_position, direction)
+func transform_anchored(anchor_position: Vector2, popup_size: Vector2, direction: PopupManager.Direction = PopupManager.Direction.BOTTOM_RIGHT) -> void:
+	PopupManager.transform_popup_anchored(self, anchor_position, popup_size, direction, true)
 
 
 func close_popup() -> void:
 	mark_click_handled()
 	PopupManager.hide_popup(self)
 
 
-func clear() -> void:
+func clear(keep_size: bool = false) -> void:
 	title = DEFAULT_TITLE
 	_clear_buttons()
 
-	custom_minimum_size = Vector2.ZERO
-	set_anchors_and_offsets_preset(Control.PRESET_TOP_LEFT, Control.PRESET_MODE_MINSIZE)
-	size = Vector2.ZERO
+	if not keep_size:
+		custom_minimum_size = Vector2.ZERO
+		set_anchors_and_offsets_preset(Control.PRESET_TOP_LEFT, Control.PRESET_MODE_MINSIZE)
+		size = Vector2.ZERO
 
 
 # Content.