Added fade in/out transition

README.md

@@ -162,6 +162,8 @@ The predefined transitions provided by ```monarch.transitions.gui``` are:
 * ```slide_out_bottom```
 * ```scale_in```
 * ```scale_out```
+* ```fade_in``` - Set node alpha to fully transparent (i.e. 0.0) and fade to fully opaque (i.e. 1.0)
+* ```fade_out``` - Set node alpha to fully opaque (i.e. 1.0) and fade to fully transparent (i.e. 0.0)
 
 Additionally there's functionality to create a full set of transitions for common transition styles:
 
@@ -169,6 +171,7 @@ Additionally there's functionality to create a full set of transitions for commo
 * ```transitions.in_left_out_right(node, duration, [delay], [easing])```
 * ```transitions.in_left_out_left(node, duration, [delay], [easing])```
 * ```transitions.in_right_out_right(node, duration, [delay], [easing])```
+* ```transitions.fade_in_out(node, duration, [delay], [easing])```
 
 **PARAMETERS**
 * ```node``` (node) - Gui node to animate.

example/menu.gui_script

@@ -6,7 +6,7 @@ function init(self)
 
 	gui.set_text(gui.get_node("timestamp"), os.date())
 
-	self.transition = transitions.in_right_out_left(gui.get_node("root"), 0.6, 0)
+	self.transition = transitions.fade_in_out(gui.get_node("root"), 0.6, 0)
 end
 
 function on_input(self, action_id, action)

monarch/monarch.lua

@@ -1,3 +1,5 @@
+local callback_tracker = require "monarch.utils.callback_tracker"
+
 local M = {}
 
 local CONTEXT = hash("monarch_context")
@@ -310,7 +312,6 @@ end
 
 local function back_in(screen, previous_screen, cb)
 	log("back_in()", screen.id)
-	print("back_in()", screen.id)
 	local co
 	co = coroutine.create(function()
 		active_transition_count = active_transition_count + 1
@@ -341,7 +342,6 @@ end
 
 local function back_out(screen, next_screen, cb)
 	log("back_out()", screen.id)
-	print("back_out()", screen.id)
 	local co
 	co = coroutine.create(function()
 		notify_listeners(M.SCREEN_TRANSITION_OUT_STARTED, { screen = screen.id, next_screen = next_screen.id })
@@ -401,8 +401,11 @@ end
 function M.show(id, options, data, cb)
 	assert(id, "You must provide a screen id")
 	if M.is_busy() then
+		log("show() monarch is busy, ignoring request")
 		return false
 	end
+
+	local callbacks = callback_tracker()
 	
 	id = tohash(id)
 	assert(screens[id], ("There is no screen registered with id %s"):format(tostring(id)))
@@ -424,13 +427,13 @@ function M.show(id, options, data, cb)
 			-- close all popups
 			while top.popup do
 				stack[#stack] = nil
-				show_out(top, screen)
+				show_out(top, screen, callbacks.track())
 				top = stack[#stack]
 			end
 			-- unload and transition out from top
 			-- unless we're showing the same screen as is already visible
 			if top and top.id ~= screen.id then
-				show_out(top, screen)
+				show_out(top, screen, callbacks.track())
 			end
 		end
 	end
@@ -447,7 +450,9 @@ function M.show(id, options, data, cb)
 	end
 
 	-- show screen
-	show_in(screen, top, options and options.reload, cb)
+	show_in(screen, top, options and options.reload, callbacks.track())
+
+	if cb then callbacks.when_done(cb) end
 
 	return true
 end
@@ -459,9 +464,12 @@ end
 -- @return true if successfully going back, false if busy performing another operation
 function M.back(data, cb)
 	if M.is_busy() then
+		log("back() monarch is busy, ignoring request")
 		return false
 	end
 
+	local callbacks = callback_tracker()
+	
 	local screen = table.remove(stack)
 	if screen then
 		log("back()", screen.id)
@@ -473,7 +481,7 @@ function M.back(data, cb)
 				if data then
 					top.data = data
 				end
-				back_in(top, screen, cb)
+				back_in(top, screen, callbacks.track())
 			end)
 		else
 			back_out(screen, top)
@@ -481,12 +489,13 @@ function M.back(data, cb)
 				if data then
 					top.data = data
 				end
-				back_in(top, screen, cb)
+				back_in(top, screen, callbacks.track())
 			end
 		end
-	elseif cb then
-		cb()
 	end
+
+	if cb then callbacks.when_done(cb) end
+	
 	return true
 end
 

monarch/transitions/gui.lua

@@ -88,6 +88,22 @@ function M.scale_out(node, from, easing, duration, delay, cb)
 	gui.animate(node, gui.PROP_SCALE, ZERO_SCALE, easing, duration, delay, cb)
 end
 
+function M.fade_out(node, from, easing, duration, delay, cb)
+	local to = gui.get_color(node)
+	to.w = 1
+	gui.set_color(node, to)
+	to.w = 0
+	gui.animate(node, gui.PROP_COLOR, to, easing, duration, delay, cb)
+end
+
+function M.fade_in(node, from, easing, duration, delay, cb)
+	local to = gui.get_color(node)
+	to.w = 0
+	gui.set_color(node, to)
+	to.w = 1
+	gui.animate(node, gui.PROP_COLOR, to, easing, duration, delay, cb)
+end
+
 --- Create a transition for a node
 -- @return Transition instance
 function M.create(node)
@@ -255,4 +271,16 @@ function M.in_left_out_left(node, duration, delay, easing)
 end
 
 
+function M.fade_in_out(node, duration, delay, easing)
+	assert(node, "You must provide a node")
+	assert(duration, "You must provide a duration")
+	easing = easing or easings.QUAD()
+	return M.create(node)
+	.show_in(M.fade_in, easing.OUT, duration, delay or 0)
+	.show_out(M.fade_out, easing.IN, duration, delay or 0)
+	.back_in(M.fade_in, easing.OUT, duration, delay or 0)
+	.back_out(M.fade_out, easing.IN, duration, delay or 0)
+end
+
+
 return M

monarch/utils/callback_tracker.lua

@@ -0,0 +1,39 @@
+local M = {}
+
+
+function M.create()
+	local instance = {}
+
+	local callback = nil
+	local callback_count = 0
+
+	--- Create a callback function and track when it is done
+	-- @return Callback function
+	function instance.track()
+		callback_count = callback_count + 1
+		return function()
+			callback_count = callback_count - 1
+			if callback_count == 0 and callback then
+				callback()
+			end
+		end
+	end
+
+	--- Call a function when all callbacks have been triggered
+	-- @param cb Function to call when all 
+	function instance.when_done(cb)
+		callback = cb
+		if callback_count == 0 then
+			callback()
+		end
+	end
+
+	return instance
+end
+
+
+return setmetatable(M, {
+	__call = function(_, ...)
+		return M.create(...)
+	end
+})