25 mai 2014

Famo.us polaroid tutorial in CoffeeScript and within Meteor


Since Famo.us v0.2.0, some new tutorials have been added to the Famo.us University. The 1st available project is a Polaroid tutorial which teaches you how to create your own app and widget with Famo.us. Just play this little video to check how incredible the animations are with plain simple HTML5 technologies. Note that, this example is completely responsive and I've tested it on smartphones, tablets and desktops.
This example project is not just beautiful. It works very well in iOS, Chrome on Android, Chrome, Safari and Opera. There are little flickers on Firefox but it seems more due to the browser than to the framework. Though, it is completely useable. As ever, the stock Android browser is definitely a knightmare. Meaning that, if you plan on encapsulating your WebApp in a native browser, Apache Cordova is the way to go for iOS but you will need to encapsulate Chromium if you plan on shipping your WebApp for Android. This can be achieve with projects such as Crosswalk, for instance.

Though, the tutorial is incredibly nice and goes smoothly over every difficulties that you may encounter (one of the best tutorial, that I've seen so far), I didn't choose the same way as described. Actually, JavaScript's inheritance model is such a pain to write, that I prefer avoiding it as much as I can. Thus, I've recreated it using another set of tools and it runs as smoothly as the original:
The result is a very small set of code that produces the same WebApp in a fraction of the necessary code and installation steps.

Note that the following tutorial is not a replacement of the one from the Famo.us University. It is a complement to show how this framework is easily integrable with other powerful HTML5 technologies.

Configuring your Meteor project

Create your Meteor project with the dead simple following command:
meteor create Polaroid
cd Polaroid
Now create a common fullstack JS directory structure only targeted for a client WebApp without server side integration:
mkdir -p client/lib client/models client/startup client/stylesheets client/views lib packages public/img
Remove the automatically created files:
rm -rf Polaroid.*
Add the following package with Meteor:
meteor add coffeescript
meteor add stylus
And this one with Meteorite:
mrt add jade
mrt add famono
Easy as pie.

Get the unique required asset from Famo.us

This example WebApp needs a simple public/img/camera.png that you'll find in the Zip file that Famo.us provides in their download section.

Create your style file

The style file client/stylesheets/app.styl is kept as its minimum as most of the CSS rules are handled by Famo.us.
@import 'nib'

  background: #404040

  -webkit-touch-callout: none
  user-select: none
  font-family: 'AvenirNext-Medium'

Create your HTML file with Jade

As before for the style file, the main HTML file client/index.jade is kept as its minimum as most of the tags are handled by Famo.us
  title Famo.us Polaroid

That's it, a simple template loaded by Meteor.

Create some namespaces

I like to isolate my code from the code that I import. Thus, I create 2 namespaces in 2 separate files.
  • One is dedicated to the WebApp in client/lib/polaroid.coffee:
    # Declare Polaroid namespace
    window.Polaroid ?= {}
  • The other one is dedicated to Famo.us in client/lib/famous.coffee:
    # Declare Famo.us namespace
    window.Famous ?= {}
The lib directory is used as it is loaded first by Meteor.

The model, a Picasa album

With this example, we do not leverage the power of the full JS stack that Meteor provides. We only use its features of live reloading the code and its easy to use build capability. The model is the same as the one provided in the Famo.us Zip file that you've downloaded except that it is created as a CoffeeScript file named client/models/slidedata.coffee:
Polaroid.SlideData =
  userId: "109813050055185479846"
  albumId: "6013105701911614529"
  picasaUrl: "https://picasaweb.google.com/data/feed/api/user/"
  queryParams: "?alt=json&hl=en_US&access=visible&fields=entry(id,media:group(media:content,media:description,media:keywords,media:title))"
  defaultImage: "https://lh4.googleusercontent.com/-HbYp2q1BZfQ/U3LXxmWoy7I/AAAAAAAAAJk/VqI5bGooDaA/s1178-no/1.jpg"
  getUrl: ->
    @picasaUrl + @userId + "/albumid/" + @albumId + @queryParams
  parse: (data) ->
    urls = []
    data = JSON.parse(data)
    entries = data.feed.entry
    i = 0

    while i < entries.length
      media = entries[i].media$group
      urls.push media.media$content[0].url
A simple dictionary with 2 methods.

Requiring the Famo.us libraries

I simply load all the Famo.us libraries in a single location. This drastically reduces the amount of code. I use the same file client/startup/famous.coffee to load the polyfills and to create the Famo.us's singleton so that if I enhance this WebApp with multiple page loaded with a router, there will be no additional loadings or instantiations.
# Import famous.css
require 'famous/core/famous'
# Adds the famo.us dependencies
require 'famous-polyfills'
# Wait for document ready
$(document).ready ->
  # Load Famo.us libraries
  Famous.Engine           = require 'famous/core/Engine'
  Famous.View             = require 'famous/core/View'
  Famous.Transform        = require 'famous/core/Transform'
  Famous.Surface          = require 'famous/core/Surface'
  Famous.StateModifier    = require 'famous/modifiers/StateModifier'
  Famous.Timer            = require 'famous/utilities/Timer'
  Famous.ImageSurface     = require 'famous/surfaces/ImageSurface'
  Famous.ContainerSurface = require 'famous/surfaces/ContainerSurface'
  Famous.Lightbox         = require 'famous/views/Lightbox'
  Famous.Utility          = require 'famous/utilities/Utility'
  Famous.Easing           = require 'famous/transitions/Easing'
  Famous.ContainerSurface = require 'famous/surfaces/ContainerSurface'
  Famous.Transitionable   = require 'famous/transitions/Transitionable'
  Famous.SpringTransition = require 'famous/transitions/SpringTransition'
  # Register transitions
  Famous.Transitionable.registerMethod 'spring', Famous.SpringTransition
  # Create main context
  Polaroid.mainCtx = Famous.Engine.createContext()

Instantiate the main template

The content of the main template is set under the client/index.coffee that goes along with our Jade file:
Template.index.rendered = ->
  # Get request to Picasa API
  Famous.Utility.loadURL Polaroid.SlideData.getUrl(), (data) ->
    data = Polaroid.SlideData.parse data
    # Instantiate the AppView with our URL's data
    Polaroid.appView = new Polaroid.AppView data: data
    Polaroid.mainCtx.add Polaroid.appView

Creating the views

The rest of this tutorial is pretty close to the one from the Famo.us University except that it uses the object model provided by CoffeeScript instead of the one from JavaScript. You should fill this 3 files while following the tutorial from the Famo.us University so that you get the nice explanations that they provided us.

The views are composed of 3 files:
  • client/views/appview.coffee
    $(document).ready ->
      class Polaroid.AppView extends Famous.View
          data: undefined
          cameraWidth: 0.6 * window.innerHeight
        constructor: (@options) ->
          @DEFAULT_OPTIONS.slideWidth = 0.8 * @DEFAULT_OPTIONS.cameraWidth
          @DEFAULT_OPTIONS.slideHeight = @DEFAULT_OPTIONS.slideWidth + 40
          @DEFAULT_OPTIONS.slidePosition = 0.77 * @DEFAULT_OPTIONS.cameraWidth
          @constructor.DEFAULT_OPTIONS = @DEFAULT_OPTIONS
          super @options
        createCamera: ->
          camera = new Famous.ImageSurface
            size: [@options.cameraWidth, true]
            content: 'img/camera.png'
              width: '100%'
          cameraModifier = new Famous.StateModifier
            origin: [0.5, 0]
            align: [0.5, 0]
            transform: Famous.Transform.behind
          @add(cameraModifier).add camera
        createSlideshow: ->
          slideshowView = new Polaroid.SlideshowView
            size: [@options.slideWidth, @options.slideHeight]
            data: @options.data
          slideshowModifier = new Famous.StateModifier
            origin: [0.5, 0]
            align: [0.5, 0]
            transform: Famous.Transform.translate 0, @options.slidePosition, 0
          slideshowContainer = new Famous.ContainerSurface
              overflow: 'hidden'
          @add(slideshowModifier).add slideshowContainer
          slideshowContainer.add slideshowView
          slideshowContainer.context.setPerspective 1000
  • client/views/slideshowview.coffee
    $(document).ready ->
      class Polaroid.SlideshowView extends Famous.View
          size: [450, 500]
          data: undefined
            inOpacity: 1
            outOpacity: 0
            inOrigin: [0, 0]
            outOrigin: [0, 0]
            showOrigin: [0, 0]
            inTransform: Famous.Transform.thenMove Famous.Transform.rotateX(0.9), [0, -300, -300]
            outTransform: Famous.Transform.thenMove Famous.Transform.rotateZ(0.7), [0, window.innerHeight, -1000]
            inTransition: duration: 500, curve: Famous.Easing.outBack
            outTransition: duration: 350, curve: Famous.Easing.inQuad
        constructor: (@options) ->
          @constructor.DEFAULT_OPTIONS = @DEFAULT_OPTIONS
          super @options
          @rootModifier = new Famous.StateModifier
            size: @options.size
            origin: [0.5, 0]
            align: [0.5, 0]
          @mainNode = @add @rootModifier
        createLightbox: ->
          @lightbox = new Famous.Lightbox @options.lightboxOpts
          @mainNode.add @lightbox
        createSlides: =>
          @slides = []
          @currentIndex = 0
          console.log @options.data
          for url in @options.data
            slide = new Polaroid.SlideView
              size: @options.size
              photoUrl: url
            @slides.push slide
            slide.on 'click', @showNexSlide
        showCurrentSlide: ->
          @ready = false
          slide = @slides[@currentIndex]
          @lightbox.show slide, =>
            @ready = true
        showNexSlide: =>
          return if @ready isnt true
          if @currentIndex is @slides.length
            @currentIndex = 0
  • client/views/slideview.coffee
    $(document).ready ->
      class Polaroid.SlideView extends Famous.View
          size: [400, 450]
          filmBorder: 15
          photoBorder: 3
          photoUrl: Polaroid.SlideData.defaultImage
          angle: -0.5
        constructor: (@options) ->
          @constructor.DEFAULT_OPTIONS = @DEFAULT_OPTIONS
          super @options
          @rootModifier = new Famous.StateModifier
            size: @options.size
          @mainNode = @add @rootModifier
        createBackground: ->
          background = new Famous.Surface
              backgroundColor: '#fffff5'
              boxShadow: '0 10px 20px -5px rgba(0, 0, 0, 0.5)'
              cursor: 'pointer'
          @mainNode.add background
          background.on 'click', =>
            @_eventOutput.emit 'click'
        createFilm: ->
          @options.filmSize = @options.size[0] - 2 * @options.filmBorder
          film = new Famous.Surface
            size: [@options.filmSize, @options.filmSize]
              backgroundColor: '#222'
              zIndex: 1
              # Make surface invisible to pointer events
              pointerEvents: 'none'
          filmModifier = new Famous.StateModifier
            origin: [0.5, 0]
            align: [0.5, 0]
            transform: Famous.Transform.translate 0, @options.filmBorder, 1
            .add filmModifier
            .add film
        createPhoto: ->
          photoSize = @options.filmSize - 2 * @options.photoBorder
          photo = new Famous.ImageSurface
            size: [photoSize, photoSize]
            content: @options.photoUrl
              zIndex: 2
              # Make surface invisible to pointer events
              pointerEvents: 'none'
          @photoModifier = new Famous.StateModifier
            origin: [0.5, 0]
            align: [0.5, 0]
            transform: Famous.Transform.translate 0, @options.filmBorder + @options.photoBorder, 2
            opacity: 0.01
            .add @photoModifier
            .add photo
        fadeIn: =>
          @photoModifier.setOpacity 1, {duration: 1500, curve: 'easeIn'}
        shake: ->
          @rootModifier.setTransform Famous.Transform.rotateX(@options.angle), {duration: 200, curve: 'easeOut'}
          @rootModifier.setTransform Famous.Transform.identity, {method: 'spring', period: 600, dampingRatio: 0.15}

Further words

My integration is not as proper as I would like it to be. Each class declaration relies on a ready event that I did not succeed in removing. Identically, my class constructors call their parent's one explicitly. Feel free to post some comments if you have a better integration.

Aucun commentaire:

Enregistrer un commentaire