Update documentation, refactoring

druid/base/drag.lua

@@ -1,14 +1,30 @@
---- Component to handle drag action on node
+--- Component to handle drag action on node.
+-- Drag have correct handling for multitouch and swap
+-- touched while dragging. Drag will be processed even
+-- the cursor is outside of node, if drag is already started
 -- @module druid.drag
 
---- Components fields
--- @table Fields
-
 --- Component events
 -- @table Events
+-- @tfield druid_event on_touch_start (self) Event on touch start
+-- @tfield druid_event on_touch_end (self) Event on touch end
+-- @tfield druid_event on_drag_start (self) Event on drag start
+-- @tfield druid_event on_drag (self, dx, dy) Event on drag progress
+-- @tfield druid_event on_drag_end (self) Event on drag end
+
+--- Components fields
+-- @table Fields
+-- @tfield bool is_touch Is component now touching
+-- @tfield bool is_drag Is component now dragging
+-- @tfield bool can_x Is drag component process vertical dragging. Default - true
+-- @tfield bool can_y Is drag component process horizontal. Default - true
+-- @tfield number x Current touch x position
+-- @tfield number y Current touch y position
+-- @tfield vector3 touch_start_pos Touch start position
 
 --- Component style params
 -- @table Style
+-- @tfield number DRAG_DEADZONE Distance in pixels to start dragging
 
 local Event = require("druid.event")
 local const = require("druid.const")
@@ -49,12 +65,13 @@ local function process_touch(self, touch)
 	if not self.can_x then
 		self.touch_start_pos.x = touch.x
 	end
+
 	if not self.can_y then
 		self.touch_start_pos.y = touch.y
 	end
 
 	local distance = helper.distance(touch.x, touch.y, self.touch_start_pos.x, self.touch_start_pos.y)
-	if not self.is_drag and distance >= self.drag_deadzone then
+	if not self.is_drag and distance >= self.style.DRAG_DEADZONE then
 		self.is_drag = true
 		self.on_drag_start:trigger(self:get_context())
 		self:increase_input_priority()
@@ -62,6 +79,8 @@ local function process_touch(self, touch)
 end
 
 
+--- Return current touch action from action input data
+-- If touch_id stored - return exact this touch action
 local function find_touch(action_id, action, touch_id)
 	local act = helper.is_mobile() and const.ACTION_MULTITOUCH or const.ACTION_TOUCH
 
@@ -83,6 +102,8 @@ local function find_touch(action_id, action, touch_id)
 end
 
 
+--- Process on touch release. We should to find, if any other
+-- touches exists to switch to another touch.
 local function on_touch_release(self, action_id, action)
 	if #action.touch >= 2 then
 		-- Find next unpressed touch
@@ -107,14 +128,14 @@ local function on_touch_release(self, action_id, action)
 end
 
 
---- Component init function
+--- Drag component constructor
+-- @tparam node node GUI node to detect dragging
+-- @tparam function on_drag_callback Callback for on_drag_event(self, dx, dy)
 -- @function drag:init
 function M.init(self, node, on_drag_callback)
 	self.style = self:get_style()
 	self.node = self:get_node(node)
 
-	self.drag_deadzone = self.style.DRAG_DEADZONE or 10
-
 	self.dx = 0
 	self.dy = 0
 	self.touch_id = 0
@@ -162,8 +183,6 @@ function M.on_input(self, action_id, action)
 		return false
 	end
 
-	self.dx = 0
-	self.dy = 0
 
 	local touch = find_touch(action_id, action, self.touch_id)
 	if not touch then
@@ -174,6 +193,9 @@ function M.on_input(self, action_id, action)
 		self.touch_id = touch.id
 	end
 
+	self.dx = 0
+	self.dy = 0
+
 	if touch.pressed and not self.is_touch then
 		start_touch(self, touch)
 	end