add multiple slots in gesture detector

So that gesture detecting in one slot won't block gestures in the other slots.

frontend/ui/gesturedetector.lua

@@ -59,30 +59,30 @@ GestureDetector = {
 	-- distance parameters
 	DOUBLE_TAP_DISTANCE = 50,
 	PAN_THRESHOLD = 50,
-
-	track_id = {},
-	tev_stack = {},
-	-- latest feeded touch event
-	last_tev = {},
-	is_on_detecting = false,
-	first_tev = nil,
-	state = function(self, tev)
-		self:switchState("initialState", tev)
-	end,
-
-	last_tap = nil, -- for single/double tap
+	
+	-- states are stored in separated slots
+	states = {},
+	track_ids = {},
+	tev_stacks = {},
+	-- latest feeded touch event in each slots
+	last_tevs = {},
+	first_tevs = {},
+	-- detecting status on each slots
+	detectings = {},
+	-- for single/double tap
+	last_taps = {},
 }
 
 function GestureDetector:feedEvent(tev)
-	-- for now, only handle single point touch
-	if tev.slot ~= 0 then
-		return nil
+	local slot = tev.slot
+	if not self.states[slot] then
+		self:clearState(slot) -- initiate state
 	end
-	re = self.state(self, tev)
+	local ges = self.states[slot](self, tev)
 	if tev.id ~= -1 then
-		self.last_tev = tev
+		self.last_tevs[slot] = tev
 	end
-	return re
+	return ges
 end
 
 function GestureDetector:deepCopyEv(tev)
@@ -111,14 +111,15 @@ function GestureDetector:isDoubleTap(tap1, tap2)
 end
 
 --[[
-compare last_pan with self.first_tev
+compare last_pan with first_tev in this slot
 if it is a swipe, return direction of swipe gesture.
 --]]
-function GestureDetector:isSwipe()
-	local tv_diff = self.first_tev.timev - self.last_tev.timev
+function GestureDetector:isSwipe(tev)
+	local slot = tev.slot
+	local tv_diff = self.first_tevs[slot].timev - self.last_tevs[slot].timev
 	if (tv_diff.sec == 0) and (tv_diff.usec < self.SWIPE_INTERVAL) then
-		x_diff = self.last_tev.x - self.first_tev.x
-		y_diff = self.last_tev.y - self.first_tev.y
+		local x_diff = self.last_tevs[slot].x - self.first_tevs[slot].x
+		local y_diff = self.last_tevs[slot].y - self.first_tevs[slot].y
 		if x_diff == 0 and y_diff == 0 then
 			return nil
 		end
@@ -145,32 +146,33 @@ end
 Warning! this method won't update self.state, you need to do it
 in each state method!
 --]]
-function GestureDetector:switchState(state_new, tev)
+function GestureDetector:switchState(state_new, tev, param)
 	--@TODO do we need to check whether state is valid?    (houqp)
-	return self[state_new](self, tev)
+	return self[state_new](self, tev, param)
 end
 
-function GestureDetector:clearState()
-	self.state = self.initialState
-	self.last_tev = {}
-	self.is_on_detecting = false
-	self.first_tev = nil
+function GestureDetector:clearState(slot)
+	self.states[slot] = self.initialState
+	self.last_tevs[slot] = {}
+	self.detectings[slot] = false
+	self.first_tevs[slot] = nil
 end
 
 function GestureDetector:initialState(tev)
+	local slot = tev.slot
 	if tev.id then
 		-- a event ends
 		if tev.id == -1 then
-			self.is_on_detecting = false
+			self.detectings[slot] = false
 		else
-			self.track_id[tev.id] = tev.slot
+			self.track_ids[slot] = tev.id
 		end
 	end
 	if tev.x and tev.y then
 		-- user starts a new touch motion
-		if not self.is_on_detecting then
-			self.is_on_detecting = true
-			self.first_tev = self:deepCopyEv(tev)
+		if not self.detectings[slot] then
+			self.detectings[slot] = true
+			self.first_tevs[slot] = self:deepCopyEv(tev)
 			-- default to tap state
 			return self:switchState("tapState", tev)
 		end
@@ -182,14 +184,15 @@ this method handles both single and double tap
 --]]
 function GestureDetector:tapState(tev)
 	DEBUG("in tap state...", tev)
+	local slot = tev.slot
 	if tev.id == -1 then
 		-- end of tap event
 		local ges_ev = {
 			-- default to single tap
 			ges = "tap",
 			pos = Geom:new{
-				x = self.last_tev.x,
-				y = self.last_tev.y,
+				x = self.last_tevs[slot].x,
+				y = self.last_tevs[slot].y,
 				w = 0, h = 0,
 			}
 		}
@@ -200,57 +203,58 @@ function GestureDetector:tapState(tev)
 			timev = tev.timev,
 		}
 
-		if self.last_tap ~= nil and
-		self:isDoubleTap(self.last_tap, cur_tap) then
+		if self.last_taps[slot] ~= nil and
+		self:isDoubleTap(self.last_taps[slot], cur_tap) then
 			-- it is a double tap
-			self:clearState()
+			self:clearState(slot)
 			ges_ev.ges = "double_tap"
-			self.last_tap = nil
-			DEBUG("double tap detected")
+			self.last_taps[slot] = nil
+			DEBUG("double tap detected in slot", slot)
 			return ges_ev
 		end
 
 		-- set current tap to last tap
-		self.last_tap = cur_tap
+		self.last_taps[slot] = cur_tap
 
 		DEBUG("set up tap timer")
-		local deadline = self.last_tev.timev + TimeVal:new{
-				sec = 0, usec = self.DOUBLE_TAP_INTERVAL,
-			}
+		-- deadline should be calculated by adding current tap time and the interval
+		local deadline = cur_tap.timev + TimeVal:new{
+			sec = 0, usec = self.DOUBLE_TAP_INTERVAL,
+		}
 		Input:setTimeout(function()
-			DEBUG("in tap timer", self.last_tap ~= nil)
+			DEBUG("in tap timer", self.last_taps[slot] ~= nil)
 			-- double tap will set last_tap to nil so if it is not, then
 			-- user must only tapped once
-			if self.last_tap ~= nil then
-				self.last_tap = nil
+			if self.last_taps[slot] ~= nil then
+				self.last_taps[slot] = nil
 				-- we are using closure here
-				DEBUG("single tap detected")
+				DEBUG("single tap detected in slot", slot)
 				return ges_ev
 			end
 		end, deadline)
 		-- we are already at the end of touch event
 		-- so reset the state
-		self:clearState()
-	elseif self.state ~= self.tapState then
+		self:clearState(slot)
+	elseif self.states[slot] ~= self.tapState then
 		-- switched from other state, probably from initialState
 		-- we return nil in this case
-		self.state = self.tapState
+		self.states[slot] = self.tapState
 		DEBUG("set up hold timer")
 		local deadline = tev.timev + TimeVal:new{
-				sec = 0, usec = self.HOLD_INTERVAL
-			}
+			sec = 0, usec = self.HOLD_INTERVAL
+		}
 		Input:setTimeout(function()
-			if self.state == self.tapState then
+			if self.states[slot] == self.tapState then
 				-- timer set in tapState, so we switch to hold
-				DEBUG("hold gesture detected")
-				return self:switchState("holdState")
+				DEBUG("hold gesture detected in slot", slot)
+				return self:switchState("holdState", tev, true)
 			end
 		end, deadline)
 	else
 		-- it is not end of touch event, see if we need to switch to
 		-- other states
-		if (tev.x and math.abs(tev.x - self.first_tev.x) >= self.PAN_THRESHOLD) or
-		(tev.y and math.abs(tev.y - self.first_tev.y) >= self.PAN_THRESHOLD) then
+		if (tev.x and math.abs(tev.x - self.first_tevs[slot].x) >= self.PAN_THRESHOLD) or
+		(tev.y and math.abs(tev.y - self.first_tevs[slot].y) >= self.PAN_THRESHOLD) then
 			-- if user's finger moved long enough in X or
 			-- Y distance, we switch to pan state
 			return self:switchState("panState", tev)
@@ -259,18 +263,19 @@ function GestureDetector:tapState(tev)
 end
 
 function GestureDetector:panState(tev)
-	DEBUG("in pan state...")
+	DEBUG("in pan state...", tev)
+	local slot = tev.slot
 	if tev.id == -1 then
 		-- end of pan, signal swipe gesture if necessary
-		swipe_direct = self:isSwipe()
+		local swipe_direct = self:isSwipe(tev)
 		if swipe_direct then
-			DEBUG("swipe detected!")
+			DEBUG("swipe", swipe_direct, "detected in slot", slot)
 			local start_pos = Geom:new{
-					x = self.first_tev.x,
-					y = self.first_tev.y,
+					x = self.first_tevs[slot].x,
+					y = self.first_tevs[slot].y,
 					w = 0, h = 0,
 			}
-			self:clearState()
+			self:clearState(slot)
 			return {
 				ges = "swipe",
 				direction = swipe_direct,
@@ -279,10 +284,10 @@ function GestureDetector:panState(tev)
 				--@TODO add start and end points?    (houqp)
 			}
 		end
-		self:clearState()
+		self:clearState(slot)
 	else
-		if self.state ~= self.panState then
-			self.state = self.panState
+		if self.states[slot] ~= self.panState then
+			self.states[slot] = self.panState
 		end
 
 		local pan_ev = {
@@ -294,40 +299,43 @@ function GestureDetector:panState(tev)
 			},
 			pos = nil,
 		}
-		pan_ev.relative.x = tev.x - self.last_tev.x
-		pan_ev.relative.y = tev.y - self.last_tev.y
+		pan_ev.relative.x = tev.x - self.last_tevs[slot].x
+		pan_ev.relative.y = tev.y - self.last_tevs[slot].y
 		pan_ev.pos = Geom:new{
-			x = self.last_tev.x,
-			y = self.last_tev.y,
+			x = self.last_tevs[slot].x,
+			y = self.last_tevs[slot].y,
 			w = 0, h = 0,
 		}
 		return pan_ev
 	end
 end
 
-function GestureDetector:holdState(tev)
-	DEBUG("in hold state...")
-	-- when we switch to hold state, we pass no ev
-	-- so ev = nil
-	if not tev and self.last_tev.x and self.last_tev.y then
-		self.state = self.holdState
+function GestureDetector:holdState(tev, hold)
+	DEBUG("in hold state...", tev, hold)
+	local slot = tev.slot 
+	-- when we switch to hold state, we pass additional param "hold"
+	if tev.id ~= -1 and hold and self.last_tevs[slot].x and self.last_tevs[slot].y then
+		self.states[slot] = self.holdState
 		return {
 			ges = "hold",
 			pos = Geom:new{
-				x = self.last_tev.x,
-				y = self.last_tev.y,
+				x = self.last_tevs[slot].x,
+				y = self.last_tevs[slot].y,
 				w = 0, h = 0,
 			}
 		}
 	end
 	if tev.id == -1 then
 		-- end of hold, signal hold release
-		self:clearState()
+		DEBUG("hold_release detected in slot", slot)
+		local last_x = self.last_tevs[slot].x
+		local last_y = self.last_tevs[slot].y
+		self:clearState(slot)
 		return {
 			ges = "hold_release",
 			pos = Geom:new{
-				x = self.last_tev.x,
-				y = self.last_tev.y,
+				x = last_x,
+				y = last_y,
 				w = 0, h = 0,
 			}
 		}