Scroll refactoring process

druid/base/drag.lua

@@ -0,0 +1,214 @@
+--- Component to handle drag action on node
+-- @module druid.drag
+
+--- Components fields
+-- @table Fields
+
+--- Component events
+-- @table Events
+
+--- Component style params
+-- @table Style
+
+local Event = require("druid.event")
+local const = require("druid.const")
+local helper = require("druid.helper")
+local component = require("druid.component")
+
+local M = component.create("drag", { const.ON_INPUT_HIGH })
+
+
+local function start_touch(self, touch)
+	self.is_touch = true
+	self.is_drag = false
+
+	self.touch_start_pos.x = touch.screen_x
+	self.touch_start_pos.y = touch.screen_y
+
+	self.screen_x = touch.screen_x
+	self.screen_y = touch.screen_y
+
+	self.on_touch_start:trigger(self:get_context())
+end
+
+
+local function end_touch(self)
+	if self.is_drag then
+		self.on_drag_end:trigger(self:get_context())
+	end
+
+	self.is_drag = false
+	self.is_touch = false
+	self.on_touch_end:trigger(self:get_context())
+	self.touch_id = 0
+end
+
+
+local function process_touch(self, touch)
+	if not self.can_x then
+		self.touch_start_pos.x = touch.screen_x
+	end
+	if not self.can_y then
+		self.touch_start_pos.y = touch.screen_y
+	end
+
+	local distance = helper.distance(touch.screen_x, touch.screen_y, self.touch_start_pos.x, self.touch_start_pos.y)
+	if not self.is_drag and distance >= self.drag_deadzone then
+		self.is_drag = true
+		self.on_drag_start:trigger(self:get_context())
+	end
+end
+
+
+local function find_touch(action_id, action, touch_id)
+	local act = const.ACTION_TOUCH
+
+	if action_id ~= act then
+		return
+	end
+
+	if action.touch then
+		local touch = action.touch
+		for i = 1, #touch do
+			if touch[i].id == touch_id then
+				return touch[i]
+			end
+		end
+		return touch[1]
+	else
+		return action
+	end
+end
+
+
+local function on_touch_release(self, action_id, action)
+	if #action.touch >= 2 then
+		-- Find next unpressed touch
+		local next_touch
+		for i = 1, #action.touch do
+			if not action.touch[i].released then
+				next_touch = action.touch[i]
+				break
+			end
+		end
+
+		if next_touch then
+			self.screen_x = next_touch.screen_x
+			self.screen_y = next_touch.screen_y
+			self.touch_id = next_touch.id
+		else
+			end_touch(self)
+		end
+	elseif #action.touch == 1 then
+		end_touch(self)
+	end
+end
+
+
+--- Component init function
+-- @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
+	self.screen_x = 0
+	self.screen_y = 0
+	self.is_touch = false
+	self.is_drag = false
+	self.touch_start_pos = vmath.vector3(0)
+
+	self.can_x = true
+	self.can_y = true
+
+	self.click_zone = nil
+	self.on_touch_start = Event()
+	self.on_touch_end = Event()
+	self.on_drag_start = Event()
+	self.on_drag = Event(on_drag_callback)
+	self.on_drag_end = Event()
+end
+
+
+function M.on_input(self, action_id, action)
+	if action_id ~= const.ACTION_TOUCH then
+		return
+	end
+
+	if not helper.is_enabled(self.node) then
+		return false
+	end
+
+	local is_pick = gui.pick_node(self.node, action.x, action.y)
+	if self.click_zone then
+		is_pick = is_pick and gui.pick_node(self.click_zone, action.x, action.y)
+	end
+
+	if not is_pick and not self.is_drag then
+		end_touch(self)
+		return false
+	end
+
+	self.dx = 0
+	self.dy = 0
+
+	local touch = find_touch(action_id, action, self.touch_id)
+	if not touch then
+		return false
+	end
+
+	if touch.id then
+		self.touch_id = touch.id
+	end
+
+	if touch.pressed and not self.is_touch then
+		start_touch(self, touch)
+	end
+
+	if touch.released and self.is_touch then
+		if action.touch then
+			-- Mobile
+			on_touch_release(action_id, action, self)
+		else
+			-- PC
+			end_touch(self)
+		end
+	end
+
+	if self.is_touch then
+		process_touch(self, touch)
+	end
+
+	local touch_modified = find_touch(action_id, action, self.touch_id)
+	if touch_modified and self.is_drag then
+		self.dx = touch_modified.screen_x - self.screen_x
+		self.dy = touch_modified.screen_y - self.screen_y
+	end
+
+	if touch then
+		self.screen_x = touch.screen_x
+		self.screen_y = touch.screen_y
+	end
+
+	if self.is_drag then
+		self.on_drag:trigger(self:get_context(), self.dx, self.dy)
+	end
+
+	return self.is_drag
+end
+
+
+--- Strict drag click area. Useful for
+-- restrict events outside stencil node
+-- @function drag:set_click_zone
+-- @tparam node zone Gui node
+function M.set_click_zone(self, zone)
+	self.click_zone = self:get_node(zone)
+end
+
+
+return M