Touch screen pans and zooms on canvas by using drag and pinch

lorien/InfiniteCanvas/PanZoomCamera.gd

@@ -16,6 +16,11 @@ var _zoom_active := false
 var _current_zoom_level := 1.0
 var _start_mouse_pos := Vector2(0.0, 0.0)
 
+var _touch_events = {}
+var _touch_last_drag_distance := 0.0
+var _touch_last_drag_median := Vector2.ZERO
+var _multidrag_valid = false
+
 # -------------------------------------------------------------------------------------------------
 func set_zoom_level(zoom_level: float) -> void:
 	_current_zoom_level = _to_nearest_zoom_step(zoom_level)
@@ -27,7 +32,55 @@ func do_center(screen_space_center_point: Vector2) -> void:
 	var delta := screen_space_center - screen_space_center_point
 	get_viewport().warp_mouse(screen_space_center)
 	_do_pan(delta)
+
+# -------------------------------------------------------------------------------------------------
+func _process(delta):
+	_touch_events
+	pass
 
+# -------------------------------------------------------------------------------------------------
+func touch_event(event):
+		# Keep track of the fingers on the screen
+		if event is InputEventScreenTouch:
+			if event.pressed:
+				_touch_events[event.index] = event
+				_multidrag_valid = false
+			else:
+				_touch_events.erase(event.index)
+				#_touch_last_drag_distance = 0
+			get_tree().set_input_as_handled()
+
+		if event is InputEventScreenDrag:
+			_touch_events[event.index] = event
+			# At least one finger to drag
+			if _touch_events.size() == 1:
+				_do_pan(event.relative)
+			if _touch_events.size() == 2:
+				var events = []
+				for key in _touch_events.keys():
+					events.append(_touch_events.get(key))
+
+				var median_point = Vector2.ZERO
+				for e in events:
+					median_point += e.position
+				median_point /= events.size()
+				if _multidrag_valid:
+					_do_pan(median_point - _touch_last_drag_median)
+				_touch_last_drag_median = median_point
+				median_point = get_canvas_transform().affine_inverse().xform(median_point)
+				median_point = get_global_transform().affine_inverse().xform(median_point)
+
+				var drag_distance = events[0].position.distance_to(events[1].position)
+				var delta = -(drag_distance - _touch_last_drag_distance) * _current_zoom_level / 800
+				if _multidrag_valid:
+					_zoom_canvas(_current_zoom_level + delta, median_point)
+				_touch_last_drag_distance = drag_distance
+				_multidrag_valid = true
+			get_tree().set_input_as_handled()
+
+func _input(event):
+	touch_event(event)
+
 # -------------------------------------------------------------------------------------------------
 func tool_event(event: InputEvent) -> void:
 	if _is_input_enabled:

lorien/project.godot

@@ -491,6 +491,10 @@ canvas_pan_right={
  ]
 }
 
+[input_devices]
+
+pointing/emulate_mouse_from_touch=false
+
 [locale]
 
 translation_remaps={