Under The BridgeUnder The Bridge

Musings
Swift Mushroom Clouds

Our friends at DZone have a new guide out worth reading for a grand overview of the cloudscape these days:

DZone’s 2016 Guide to Building and Deploying Applications on the Cloud

The question isn’t whether or not to use the cloud; it’s when and how. This guide contains everything from building 12-factor apps to hiring full-stack engineers. Navigate through a 90+ cloud solutions directory and start coding right away. Dive into the research findings from 700+ developers on *aaS adoption, cloud security models, container use (including Docker), and more.

Historically we’ve tended to have a fairly detached regard for the state of the cloud, it being so far over our heads and all, but we’ve been contemplating the idea of moving into full stack engineering due to the way Swift clouds are mushrooming all over the place. No, seriously, mushrooming; just check out the current list from awesome-ios:

  • Perfect – Server-side Swift. The Perfect library, application server, connectors and example apps.
  • Swifter – Tiny http server engine written in Swift programming language.
  • CocoaHTTPServer – A small, lightweight, embeddable HTTP server for Mac OS X or iOS applications.
  • Curassow – Swift HTTP server using the pre-fork worker model. [And check out the rest at github/kylef!]
  • Zewo – Venice based HTTP server for Swift 2.2 on Linux
  • Vapor – Elegant web framework for Swift that works on iOS, OS X, and Ubuntu.
  • swiftra – Sinatra-like DSL for developing web apps in Swift
  • blackfish – A fast HTTP web server based on Node.js and Express written in Swift
  • swift-http – HTTP Implementation for Swift on Linux and Mac OS X
  • Trevi – A powerful Swift Web Application Server Framework Project
  • Express – Swift Express is a simple, yet unopinionated web application server written in Swift
  • Aeon – Aeon is a GCD based HTTP server for Swift 2.
  • Taylor – A lightweight library for writing HTTP web servers with Swift
  • Frank – Frank is a DSL for quickly writing web applications in Swift
  • Kitura – Web framework and HTTP server for Swift by IBM
  • Swifton – A Ruby on Rails inspired Web Framework for Swift that runs on Linux and OS X
  • Dynamo – High Performance (nearly)100% Swift Web server supporting dynamic content.

Personally, we’re inclined to agree with people who like the look of Swift Express

Being perfectionists, we took the best from what we think is the best: power of Play Framework and simplicity of Express.js

Express is an asynchronous, simple, powerful, yet unopinionated web application server written in Swift…

…but we may just be biased because the authors are from Lviv. We were there a couple years back, it’s pretty cool.

Here’s some helpful introductions to server-y Swiftness:

Hello Server Side Swift

Getting Started with OpenWhisk Server Side Swift

Swift + Kitura on DigitalOcean

swift-for-backend-SNAPSHOT-2016-03

And some help that’s not server specific, but likely to be of interest to living out on the bleeding edge here:

Cross-platform Swift

Practical Cross-Platform Swift

Swift And C: Everything You Need to Know

swiftenv: “Swift Version Manager — allows you to easily install, and switch between multiple versions of Swift.”

Let us know about your experiences with any of these frameworks!

Too True Tone

So did you skip past those bits about the “True Tone” ambient light sensing display in the hobbit-sized iPad Pro as sounding kinda gimmicky? Well, turns out that this DCI-P3 thing is actually A Very Big Deal:

Understanding the 9.7″ iPad Pro’s Display: How DCI-P3 & True Tone Work

DCI-P3 will be the gamut to have when UltraHD content rolls around, and Apple choosing it instead of Adobe RGB was a well planned move. While it’s not very relevant now, it certainly will be in the future, and Apple has already ensured that iOS and its app ecosystem manages color correctly to render sRGB content and DCI-P3 content correctly…

Looking at the Future

As with most things released by Apple, there is an amazing amount of underlying technology that makes this new display shine. This new product is also a glimpse of how our screen technology will evolve over the coming years, so now is a good time to start understanding how these changes are going to affect our products.

As a developer, you’ll quickly realize that the scope of these changes will make your update to Retina graphics look like a walk in the park…

In case you missed it, there’s ColorSync Support in iOS 9.3 (!)

… but if you actually start using color management right now, there’s issues to be aware of.

Whilst we await the brand new color management day to dawn, if you have a cutting edge iMac or iPad, here’s some more links to try this stuff out:

The Wide Gamut World of Color — iMac Edition

The 9.7-inch iPad Pro Color Gamut

Wide Gamut Test Paget

And if you don’t, well there’s your excuse to treat yourself!

h/t: Michael Tsai!

Make The App Store Great Again

In case you didn’t visit the Dev Portal this week, there’s a new mini-site worth flipping through:

Making Great Apps for the App Store

Hopefully this facelift presages attempts to address the not-so simmering frustration out there:

Life and Death in the App Store

For all but a few developers, the App Store itself now resembles a lottery: for every breakout hit like Candy Crush, hundreds or even thousands of apps languish in obscurity…

Just Landed Is Shutting Down

Essentially, there’s a massive oversupply of apps, and the app markets are now saturated and suffering from neglect and short-term thinking by the companies who operate them…

What no indie developer wants to hear about the App Store

But the truth is, even if Apple gave indie developers everything they wanted, it wouldn’t matter much over the long term…

Nostalgianomics

People don’t pay for functionality, at least not anymore. They do pay for content and services, but they don’t pay for functionality…

Fixing the Apple App Store

My take: I don’t think the App Stores are broken; I think they’re doing exactly what Apple wants them to, because Apple’s interest is in supporting the corporate app developers and the larger studio developers…

Et cetera. Perhaps we’ve already had a trial balloon for one of those presaged attempts; if so, it went over … poorly.

Paid App Store Search

  • “It’s downright embarrassing that App Store search is still so bad…”
  • “They need to de-crappify the Store…”
  • “Apple has done some dumb things in the company’s history, but this stands out as particularly stupid…”
  • “Why wasn’t search already better?”
  • “would exacerbate much of the App Store’s dysfunction…”

Well, that’s kinda a downer of a post so far, isn’t it. So let’s pick it up a bit with this inspiring manifesto:

Built an iOS game. It became #1 in the App Store. Here are revenue numbers and what I learned.

I built an iOS app called A Dark Room that hit the #1 spot in the App Store. Here is the article The New Yorker wrote about it.

  • 2.26 million downloads in under two years (free and paid combined).
  • #1 game in the US for 18 days straight (20 days overall).
  • 26,859 ratings of which 23,833 are 5-stars (4.73 average rating)…

Long list of Do’s and Don’ts for developing, marketing getting featured, and making sustainable income. Read them!

Another interesting metrics-laden post-mortem on Almost Impossible! here: iOS Game Revenue & Launch Details

Now that you’re all fired up, for massive collections of marketing resources check out:

App Marketing Stack: “A Curated Directory of Tools & Resources on App Marketing and Mobile Growth.”

iOS Dev ToolsApp Store & Sales

ios-marketing-resources: “Awesome list of iOS app branding/marketing tools.”

The iOS App Marketing Strategy Guide

And there might be some more nuggets in our earlier roundups on marketing, landing pages, videos, and screenshots.

And finally, whether you’re indie or not, handling marketing or not, no doubt a bane of your App Store development is the review process, ’tis it not? Besides Apple’s new Guidelines page mentioned up at the top, here’s some more help:

Under the Radar #21: App Store Rejection – “Tips on avoiding rejections by Apple’s app-review staff and what to do when your app get rejected.”

App Store Review Guidelines History: An annotated list of all changes to the Review Guidelines back to 2014.

Good luck!

Sequences: The .next() Generator

Here’s a nice gentle introduction (h/t: This Week In Swift) to modelling an algorithmic collection using the SequenceType and GeneratorType protocols:

Sequences and Generators

Let’s imagine, that we want to learn the new language. Spanish, for example. Your professor told you, that you will have one lesson each N days starting from today. But the bad thing – your professor doesn’t want to work on Sundays. So if the lesson is on Sunday, it will be rescheduled to the next day. We want to receive the schedule – Array<NSDate> for M days.

Grab the playground here, and walk through creating an NSDate sequence with

  1. A generator class for a defined number of iterations
  2. Using AnyGenerator for a bounded number of iterations
  3. A generator class for an infinite number of dates

along with using .prefix(), .filter() and .lazy() to make that infinite sequence actually usable in Swift 2, since filter() is no longer a free function like in Swift 1. More detailed explorations of laziness can be found here:

Being Lazy

True Lazy Sequences

Experimenting with Swift Sequences and Generators

And what do you get when you add indexability to a sequence? Why, a collection:

Swift Collections

Generic Collections, SubSequences and Overloading

For an application of the generator concept to a no doubt common modelling problem you’re presented with, check out

Practical Swift: pages generator – build once, use many

In the real world, at some point, we all have to deal with data that is fetched from a backend service, page by page. It’s called paging. Everybody does this! Nothing to be ashamed of 😉 Here is one of the ways in which a Swift pattern (well, not specific to Swift, but visible in Swift) can be used to build a neat solution that allows me to fetch data in chunks and display it in the application…

And finally, check out SwiftSequence, “A μframework of extensions for SequenceType in Swift 2.0, inspired by Python’s itertools, Haskell’s standard library, and other things,” for some handy manipulations:

Architectural Pattern Landscape

Great article here (h/t: ManiacDev) on selecting an architectural pattern for your apps:

iOS Architecture Patterns: Demystifying MVC, MVP, MVVM and VIPER

Let’s define features of a good architecture:

  1. Balanced distribution of responsibilities among entities with strict roles.
  2. Testability usually comes from the first feature.
  3. Ease of use and a low maintenance cost.

Starts out going through the Massive View Controller we’re all familiar with,

…it might seem that Cocoa MVC is a pretty bad pattern to choose. But let’s assess it in terms of features defined in the beginning of the article:

  • Distribution — the View and the Model in fact separated, but the View and the Controller are tightly coupled.
  • Testability — due to the bad distribution you’ll probably only test your Model.
  • Ease of use — the least amount of code among others patterns. In addition everyone is familiar with it, thus, it’s easily maintained even by the unexperienced developers.

Cocoa MVC is the pattern of your choice if you are not ready to invest more time in your architecture, and you feel that something with higher maintenance cost is an overkill for your tiny pet project.

Next, the MVP option is “Cocoa MVC’s promises delivered” by redefining the UIViewController as the View,

… Does this mean that Apple’s MVC is in fact a MVP? No, its not, because if you recall, there, the View is tightly coupled with the Controller, while the MVP’s mediator, Presenter, has nothing to do with the life cycle of the view controller, and the View can be mocked easily, so there is no layout code in the Presenter at all, but it is responsible for updating the View with data and state.

In terms of the MVP, the UIViewController subclasses are in fact the Views and not the Presenters. This distinction provides superb testability, which comes at cost of the development speed, because you have to make manual data and event binding…

  • Distribution —we have the most of responsibilities divided between the Presenter and the Model, with the pretty dumb View…
  • Testability — is excellent, we can test most of the business logic due to the dumb View.
  • Ease of use —… the amount of code is doubled compared to the MVC, but at the same time, idea of the MVP is very clear.

Thirdly, No doubt you’ve heard at least in passing of MVVM and its enablers of the Reactive Cocoa ilk, which decouple similarly to MVP,

  • the MVVM treats the view controller as the View
  • There is no tight coupling between the View and the Model

In addition, it does binding like the Supervising version of the MVP; however, this time not between the View and the Model, but between the View and the View Model.

So what is the View Model in the iOS reality? It is basically UIKit independent representation of your View and its state. The View Model invokes changes in the Model and updates itself with the updated Model, and since we have a binding between the View and the View Model, the first is updated accordingly…

There is one bitter truth about reactive frameworks: the great power comes with the great responsibility. It’s really easy to mess up things when you go reactive. In other words, if do something wrong, you might spend a lot of time debugging the app…

Yes. Yes, you might. If you mix your FRP with Core Data, you will, we confidently predict.

  • Distribution —…the MVVM’s View has more responsibilities than the MVP’s View. Because the first one updates it’s state from the View Model by setting up bindings, when the second one just forwards all events to the Presenter and doesn’t update itself.
  • Testability —the View Model knows nothing about the View, this allows us to test it easily. The View might be also tested, but since it is UIKit dependant you might want to skip it.
  • Ease of use —…in the real app where you’d have to forward all events from the View to the Presenter and to update the View manually, MVVM would be much skinnier if you used bindings.

Some other worth reading discussions on architecting with MVVM:

And lastly, we’d skipped past this VIPER thing up to now, but anything described as “LEGO building experience transferred into the iOS app design” must be fun, yes?

VIPER makes another iteration on the idea of separating responsibilities, and this time we have five layers. Topping the View,

  • Interactor — contains business logic related to the data (Entities) or networking, like creating new instances of entities or fetching them from the server. For those purposes you’ll use some Services and Managers which are not considered as a part of VIPER module but rather an external dependency.
  • Presenter — contains the UI related (but UIKit independent) business logic, invokes methods on the Interactor.
  • Entities — your plain data objects, not the data access layer, because that is a responsibility of the Interactor.
  • Router — responsible for the segues between the VIPER modules.

Basically, VIPER module can be a one screen or the whole user story of your application — think of authentication, which can be one screen or several related ones. How small are your “LEGO” blocks supposed to be? — It’s up to you…

  • Distribution —undoubtedly, VIPER is a champion in distribution of responsibilities.
  • Testability —no surprises here, better distribution — better testability.
  • Ease of use —finally, two above come in cost of maintainability as you already guessed. You have to write huge amount of interface for classes with very small responsibilities.

To help with that “huge amount”, check out Generamba, introduced here :

… An average iOS developer creates only one class per screen. But for the one who uses VIPER that’s a moment of suffering. To be true – it’s a little longer than just a moment. Usually he has to create and fill with boilerplate code for around five classes, six protocols and five test-cases … That were the reasons to create our own code generator called Generamba. We got a highly extensible tool for a wide range of different code generation tasks though originally it was developed with just VIPER modules in mind.

Another application of the VIPER principles to simplifying view controllers is

Humble Object Pattern in Swift

For a side assist to the model view whatever patterns when networking is involved — and when isn’t it these days? — check out

Exploring MVC-N in Swift

… So, you cache the data, change the layer, and each one of the ViewControllers will stick it in the cache as they get data. When any other ViewController comes up, they can get the data out of the cache. No. This is bad.

This is what I refer to as the “anti-pattern”. I cannot count the number of times I have seen this, or done it myself. This is the pattern I am attacking. I am openly saying: please stop doing this. We want to write code, we want to see results right away, and we end up doing this. This is a problem…

That is what we should be doing at design time, not at the 11th hour when we are shipping tomorrow morning, and saying “I need to refactor all this”. When we have the UI/UX, we understand how the app needs to come together, and that is when we should be looking at it.

“I need data from the network. Where do I put that code to get the data out of the network?” This is where the MVC-N comes in…

For a completely different option, check out ReSwift (née ReduxKit/SwiftFlow), a Swift version of Redux:

Unidirectional Data Flow in Swift: An Alternative to Massive View Controllers

Redux is an alternative or a variation of the Flux framework that was developed at Facebook, and that Facebook now uses for most of their web applications. The main idea is that information always only flows in one single direction. We don’t have communication between individual view controllers, we don’t have individual delegator callback blocks. Information flow is structured and set in one very specific way…

Along the same Flux-inspired lines is Ziggurat iOS App Architecture.

Of course, if you have seriously simple needs, having a controller at all might be overkill:

Design Patterns in Swift: Document-View

The document-view pattern was once the preferred pattern used in Visual C++ development. Microsoft built the original Microsoft Foundation Classes around this pattern, in fact, back in the dark ages. It’s not used much today, but it’s useful when you have simple data management needs…

And finally, here’s a resource for even more deep diving into architectural patterns:

fantastic-ios-architecture

UPDATES:

A Declarative Architecture for Swift Apps

Improve your iOS Architecture with FlowControllers

Swift Pitfalls: Here Be Dragons

It’s always exciting to live through a period of exploration and evolution, isn’t it? A bit too exciting at times, you might think. Here’s a collection of subtleties you might run into out in the unexplored regions of the new ecosystem, particularly on the Objective-C borderlands where the ground is treacherous and monsters roam:

Surprises with Swift Extensions

Today, we received a report for a very weird crash with a stack trace that contained only UIKit symbols, but was clearly triggered by a specific action in PSPDFKit…

… That was it. These seemingly innocent extensions were overriding private API. Apple’s private API detection is not super sophisticated and wasn’t triggered when the app was uploaded to the App Store. It’s also not a public symbol so there were no warnings, not even a log message. Unprefixed categories are always dangerous, especially on classes that you do not own, like UIViewController. In PSPDFKit, we use categories for shared code, but prefix any method with pspdf_ to be absolutely sure we do not hit any name clashes. It’s certainly not pretty, and prefixes in Swift look even more alien, yet as you can see in this bug hunt, they are definitely necessary.

The whole story is worth a read, if you haven’t run into the overriding private API problem before — especially not of the “crash immediately on launch with the new OS point release” variety, but that’s another story altogether — or you can just cut to the chase with

tl;dr: Swift extensions on Objective-C classes still need to be prefixed. You can use @objc(prefix_name) to keep the name pretty in Swift and expose a prefixed version for the ObjC runtime.

To Optional or Not to Optional: IBOutlet

“When you declare an outlet in Swift, you should make the type of the outlet an implicitly unwrapped optional … When your class is initialized from a storyboard or xib file, you can assume that the outlet has been connected.” — Using Swift with Cocoa and Objective-C, Apple

… Except in practice there are tons of edge cases in the lifecycle of a view controller where this simply isn’t true. And what happens when you try to access emailField when the view isn’t loaded for some reason? The app crashes…

UIKit was written during the era of nil messaging, and I’ve come to realize it isn’t safe to 100% assume IBOutlets can’t be nil. Going forward I’ll be using optionals for my IBOutlets. I have a task in my bug tracker to scrub all my IBOutlets to covert them from implicitly unwrapped to standard optionals. A few extra question marks never hurt anyone; I’d rather my app not crash.

Some more discussion of appropriate outlet semantics in Outlets: Strong! Or Weak?

Seven Swift Snares & How to Avoid Them

⚠ Double-check attribute names that override protocol extensions.

⚠ For every attribute defined in a protocol extension, declare it in the protocol itself.

⚠ Do not extend an imported protocol with a new attribute that may need dynamic dispatch.

⚠ Avoid extending a protocol with a restriction if the new attribute might need dynamic dispatch.

⚠ Avoid assigning the result of an expression with side-effects to left-hand-side with optional chaining.

⚠ Avoid in-out parameters in closures.

⚠ Avoid currying with in-out parameters because the code will fail if you later change it to explicitly create a closure.

Be careful out there!

h/t: iOS Dev Weekly!

UPDATES:

Swift Golf

Hipster Swift: Demystifying the Mysterious

10 Swift One Liners To Impress Your Friends

10 Tips when moving from Objective-C to Swift

Swift With Two Twos!

It’s update day! New iOS 9.3, OS X 10.11.4, Xcode 7.3 (+ Alcatraz 1.17), and … Swift 2.2! Time to check out the latest changes — and to perk up your heart rate just a little bit, it’s “mostly source-compatible with Swift 2.1”. Which is true, but be prepared for many selector-related warnings:

We are very pleased to announce the release of Swift 2.2! This is first official release of Swift since it was open-sourced on December 3, 2015. Notably, the release includes contributions from 212 non-Apple contributors — changes that span from simple bug fixes to enhancements and alterations to the core language and Swift Standard Library.

Language Changes

Swift 2.2 is a minor language release that is mostly source-compatible with Swift 2.1. It contains the following language changes that went through the Swift’s evolution process:

Beyond these language changes Swift 2.2 also contains numerous bug fixes, enhancements to diagnostics, and produces even faster-running code…

Details on those bug fixes and diagnostics at swift/CHANGELOG.md and in the Xcode 7.3 release notes. Good discussion of the important changes over at hackingwithswift.com too:

What’s new in Swift 2.2

Naturally, those on top of things objc.io folk have their latest magnum opus Advanced Swift ready to go with 2.2 now, which looks like a worthwhile read: check out the online preview.

UPDATES:

New Features in Swift 2.2

Parse Drops the BaaS

So the veritably seismic news of the week, should you rely on Parse for mBaaS services, is their pulling a StackMob:

We have a difficult announcement to make. Beginning today we’re winding down the Parse service, and Parse will be fully retired after a year-long period ending on January 28, 2017. We’re proud that we’ve been able to help so many of you build great mobile apps, but we need to focus our resources elsewhere…

If you think hosted services are a business opportunity, here’s source for a head start :

Parse Server was built in Node.js and works with the Express web application framework. It can be added to existing web applications, or run by itself. Check out the server and migration guides here, the open-source repository here, and the example project here. We encourage you to provide bug reports and feedback via the GitHub issues on the Parse Server repository. There’s even a developer wiki, which can be found here.

Nearly everything you’ll need for your app is supported in Parse Server, with the main exceptions of Push delivery, Analytics, and Config…

So that’s something. For a great roundup of rants and insights on just how little that something is, head over to Michael Tsai’s and check out Sunsetting Parse. All worth reading to share the pain, but here’s some particularly good giggles:

Guy English:

If it had been me shutting down Parse I would have changed the home page to not point out how many “Trust Us”.

Jeff Lawson:

“But seriously developers, trust us next time your needs temporarily overlap our strategic interests. And here’s a t-shirt.”

Joel Bernstein:

The subtext to the Parse shutdown is “never trust a Facebook platform ever again, for any reason”

Feel the burn!

Moving on, you can always take Marco Arment’s advice:

For whatever it’s worth, running your own Linux servers today with boring old databases and stable languages is neither difficult nor expensive. This isn’t to say “I told you so” — rather, if you haven’t tried before, “You can do this.

But if you’d really, seriously, rather not have to add maintaining your own backend to your load, there’s a crowdsourced list here that looks good:

ParseAlternatives: A collaborative list of Parse alternative backend service providers.

Current categories are:

Personally, we’d like to try out CloudKit one of these days…

UPDATES:

iOS Dev Tools: Backend Services

How To Migrate Your App And Protect It From Shutdowns Like Parse’s

Top 5 Parse Alternatives

Migrating My Data From Parse

AppCoda.com Parse series:

Deploying Parse Dashboard

The Grand Opening

So, just in case you spent the weekend being dead — and probably didn’t miss it even if you were — Swift.org is a thing!

And unlike previously accustomed source dumps, this is going to be the working repo going forward:

“The Swift team will be developing completely in the open on GitHub,” Federighi told Ars. “As they’re working day-to-day and making modifications to the language, including their work on Swift 3.0, all of that is going to be happening out in the open on GitHub.”

Open, indeed — to general surprise, the entire commit history of Swift went public; check this visualization out:

Over 5 years of work, 23,000+ commits condensed into 8 minutes

Rather interesting is the focus in bringing Swift to the cloud. There’d been these Perfect people,

Wouldn’t it be amazing if you could develop every aspect of your apps, front and back end, all using Swift™? We think so. That’s the vision behind Perfect. Perfect is the first enterprise-grade web server and web toolkit for the Swift programming language…

which looked like a rather … selective … interest. But that’s not what Apple thinks:

“IBM has been a major source of that feedback for us, and they’ve been eager since they got started with Swift, saying “how can we take these applications we’re writing for enterprise all the way from the mobile platform into the cloud?” …

Where we expect the community to really push is the cloud framework, and we think there will be a lot of energy to adapt Swift into the datacenter…

And why yes, IBM is right out of the gate with support for Swift, in your browser no less:

Today, IBM introduced an online 2.2 Swift Sandbox. John Petitto writes, “We love Swift here and thought you would too so we are making our IBM Swift Sandbox available to developers on developerWorks.”

Another Swift browser REPL is at Swiftstub.com.

Well, the idea that community participation will drive adoption might work out, and might not, but we know one thing for sure in less than a week:

Swift’s comments and test suite are on track to be one of the most correctly spelled and best indented ones in the industry! 🐙🐱

Indeed. If you can’t find any more speling misteaks and feel like getting in on the Linux development action, here’s a great start:

Introduction to Open Source Swift on Linux

In this tutorial, you’ll set up a Linux environment on your Mac, install Swift, and compile and run some basic Swift examples on Linux. Then you’ll take stock of the new bits offered by Apple, and finish off with a look into into the misty crystal ball of time, and guess what this all means for the future…

Oh, that’s not hard to guess, is it now?

And here’s some more suggestions for getting involved:

  • Search for FIXME in the code base and make the fix – @ayanonagon
  • Add more Unit Tests (something I wrote down as my personal strategy) – @KostiaKoval
  • Fix bugs! Yes, Swift bugs are tracked publicly via Jira!
  • As many have noticed, the Foundation Project has a lot of NSUnimplemented(). Instead of complaining (or worse, laughing about it), contribute to it! The nice things is that it’s in Swift – you don’t need to know C++. Here is a great example PR from @simjp!
  • For larger changes, write a proposal and ask for reviews from the community – amazing example by @ericasadun

As Jesse Squires said it the best: Let the revolution begin!

Pencil This In

Managed to get your Apple Pencil delivered yet? If you have, and you’ve gone through some introductory tutorials, here’s a remarkable burst of creative applications from the redoubtable FlexMonkey for you to try out:

PencilScale – Using an Apple Pencil with an iPad Pro as an Electronic Scale

Following all the interest created by my Plum-O-Meter, I couldn’t resist trying a similar experiment with my newly arrived Apple Pencil, so here’s PencilScale, an iPad Pro application that uses the Pencil as an electronic scale … The update() method simply subtract’s the touch’s force from a base weight (which is set as the current touch force when the ‘zero’ button is pressed) and multiplies it by 140 which gives the weight in grams (very roughly) …and amazingly, that is pretty much all there is to it!

PencilController – Using Apple Pencil as a 3D Controller for Image Editing

My PencilController project is a Swift app for iPad Pro that applies two Core Image filters to an image: a hue adjustment and a colour controls which I use to control the saturation … The hue filter’s value is controlled by the azimuth angle and the saturation is controlled by the altitude angle: when the pencil is vertical, the saturation is zero and when it’s horizontal the saturation is eight (although when the pencil is totally horizontal, its tip isn’t actually touching the screen, so the highest saturation the app can set is about six and three quarters).

PencilSynth – An Apple Pencil Controlled Synthesiser

PencilSynth is an AudioKit powered synthesiser (mis)using the Pencil as a joystick controller. It’s based on AudioKit’s TouchRegions demonstration and works like this:

  • The Pencil’s horizontal position on the screen defines the output frequency
  • The Pencil’s vertical position on the screen defines the output modulating multiplier
  • The Pencil’s altitude angle defines the output carrier multiplier
  • The Pencil’s azimuth angle defines the output modulation index

FurrySketch: Hirsute Drawing with an Apple Pencil

I thought it was about time to play with the Pencil for its intended purpose, sketching, and see how I could use its orientation data to affect brush strokes.

FurrySketch is a Pencil powered drawing application that draws a sort of multicoloured hair and, most excitingly, the hair’s direction matches the angle of the Pencil. It was super simple to write and, at least in my opinion, gives really nice results … If you are writing drawing apps, adding Pencil support is not only super easy, it adds real value for your users. The technique I’ve used here to draw hair is only a few lines of code way from spray cans and air brushes and I genuinely believe the iPad Pro will prove to be an amazing device for creatives.

Seen any other creative applications? Let us know! And if you’re still pondering over getting one, check out Gus Mueller’s love letter:

The Hype is Real

Every single stylus that has been made for the iPad or iPhone has been a pile of dog shit when compared to what you can do with a Wacom tablet. Even compared to what you could do 20 years ago with a Wacom tablet. The KoalaPad on an Apple //e was probably better.

It’s been hard, and upsetting. And so much money wasted on crappy iOS styluses. I stopped paying attention whenever a new stylus was announced, since I was inevitably let down.

And then this week I got the Apple Pencil (which is Apple speak for a stylus) and an iPad Pro. This new tablet from Apple has the hardware support needed to make a useful stylus. Hardware support that has been missing for five long, very long, agonizing years.

And It’s God Damn Amazing.

It feels absolutely right. Super low latency, palm rejection, and … it just works.

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