CocoaConf PDX wrap-up / Raleigh preview

Photo courtesy of Gordon Hughes

Last weekend I attended CocoaConf PDX in Portland, OR.  Dave Klein really upped his game with keynotes from Daniel Pasco and Brent Simmons, and speakers such as James Dempsey and Collin Donnell.  The event was sold out (the second one to do so I believe, the other being Chicago), so there was a good crowd of about 100 developers on hand.  As always it’s a great vibe with so many people eager to learn and share.

Recap

I presented talks on matrix transformations and collection views.  This was the 4th time I’ve given my matrix transformation talk, “Enter The Matrix: Reloaded“, and I feel like it’s really starting to hit its stride.  I revamped it in August to include a lot more information about flipping and folding animations as well as some general graphics performance tips.  Apparently it was voted the 2nd favorite session of the conference, losing out by a single vote to Jonathan Penn‘s UIAutomation talk.  I consider that a great compliment because Jonathan is a fantastic speaker and his automation talk is really a lot of fun (no, really!) and gets the crowd cheering by the end.  The slides are available here and the code is on GitHub.

My second talk, “Introducing Collection Views”, was a new talk.  I sought to cover the basics of collection views, layouts, and attributes while also covering the more advanced topics of custom layouts and animations and providing specific tips borne from personal (sometimes painful) experience.  The talk is accompanied by a sample app that displays a single collection view with five different layouts.  The slides are here and the code is on GitHub.

Next

I will be presenting at CocoaConf RTP in Raleigh, NC at the end of this month.  Tickets are still available and it looks to be another great conference.  Bill Dudney will be there (including an all-day graphics tutorial) – need I say more?

I will be presenting the same two talks for Raleigh.  I’m looking forward to the additional polish and reworking I can bring to the collection views talk for its second rendition.

Title: Introducing Collection Views

Abstract: UICollectionView, introduced in the iOS 6 SDK, is Apple’s new class for visualizing data in a grid or really any format other than a vertical list.  We’ll cover the basics and then explore the intricacies of UICollectionViewLayout,  UICollectionViewFlowLayout and related classes.  Along the way we’ll learn how to make both horizontal and vertical grids, cover flow, iPhoto-like stacks, and other custom layouts.  Apple has provided yet another tool that makes it easier and faster for you to provide rich experiences for your users – come learn how to hit the ground running with UICollectionView.  Plenty of source code will accompany the talk.

Title: Enter The Matrix: Reloaded

Abstract: Matrix transformations can make your user interfaces come to life: translate, scale, and rotate. Each on its own is relatively simple and straightforward. Yet many developers are daunted when 2 or more operations need to be combined. What if you need to rotate or zoom about an off-center (or even off-screen) point? How do you combine multiple transformations into a single animation? How do you make advanced, polished 3D animations such as folding and flipping views? Learn everything you need to know to get started with complex matrix transformations in CoreGraphics and CoreAnimation and take an in-depth look at folding and flipping animations. We’ll also cover related topics such as anti-aliasing, avoiding off-screen render passes, shadows, and rendering retina images. Tons of demos and full open-source source code provided.

I hope to see you in Raleigh at the end of the month – it’s going to be a good time!

CocoaConf PDX 2012

I am proud to announce that I will be presenting at CocoaConf PDX in Portland, OR this October.  I’ll be debuting a new talk on something I can’t talk about quite yet.  But it’ll be about something new and fun to play with for you to create great interfaces for your users.

Update: Now that the NDA on iOS 6 has been dropped, I can reveal that my new talk will be on UICollectionViews.

Title: Introducing Collection Views

Abstract: UICollectionView, introduced in the iOS 6 SDK, is Apple’s new class for visualizing data in a grid or really any format other than a vertical list.  We’ll cover the basics and then explore the intricacies of UICollectionViewLayout,  UICollectionViewFlowLayout and related classes.  Along the way we’ll learn how to make both horizontal and vertical grids, cover flow, iPhoto-like stacks, and other custom layouts.  Apple has provided yet another tool that makes it easier and faster for you to provide rich experiences for your users – come learn how to hit the ground running with UICollectionView.  Plenty of source code will accompany the talk.

I’ll also be giving my matrix transformations talk, which now has even more rotational and graphical goodness.  That one is a longer session, so there will be plenty of time to get into all the minutiae of shadows, timing curves, anti-aliasing, rendering layers as bitmaps, etc.  If you’re interested in either FlipBoard-style page-flipping animations or Clear-style folding animations, then you won’t want to miss this session.

Title: Enter The Matrix: Reloaded

Abstract: Matrix transformations can make your user interfaces come to life: translate, scale, and rotate. Each on its own is relatively simple and straightforward. Yet many developers are daunted when 2 or more operations need to be combined. What if you need to rotate or zoom about an off-center (or even off-screen) point? How do you combine multiple transformations into a single animation? How do you make advanced, polished 3D animations such as folding and flipping views? Learn everything you need to know to get started with complex matrix transformations in CoreGraphics and CoreAnimation and take an in-depth look at folding and flipping animations. We’ll also cover related topics such as anti-aliasing, avoiding off-screen render passes, shadows, and rendering retina images. Tons of demos and full open-source source code provided.

I’m super excited to visit Portland and looking forward to Chris Adamson‘s Core Audio Workshop.  There’s even a place where you can get bacon on maple-frosted pastries.

“Bacon maple goodness – so wrong and yet so right”

Early Bird registration ends Sept 14th.

iOSDevCampDC wrap-up

Last Saturday I had the privilege of speaking at and attending iOSDevCamp DC (which actually took place in Reston, VA).  iOSDevCamp DC is a single day, single track conference that is now in its 4th year.  This was my 2nd year attending.  Unlike most conferences, this one groups all the attendees in a single (large) room for the day (stocked of course with plenty of beverages and snacks as well as breakfast and lunch).  This aspect really helps facilitate the mingling and conversations that make attending conferences so valuable.

I was the 4th of 6 speakers and I gave my matrix transformations talk for the 3rd time in 5 months.  This time I deliberately cut the introductory material somewhat and spent more time on folding and flipping animations plus touched on some general graphics tips like anti-aliasing, rendering retina bitmaps, and avoiding off-screen render passes.  I think it went well.  I forgot to sacrifice to the demo gods beforehand though and got the dreaded bootstrap server error that prevented me from running my demo app in the iOS Simulator.  Fortunately, I had it on my iPad and with the help of the HDMI adapter was able to run Instruments while projecting the iPad screen.

I enjoyed the other 5 talks, but especially Ken Yarmosh‘s talk on gestures and Jonathan Blocksom‘s iOS concurrency talk.  I think I picked up about 3 different nuggets from Jonathan’s talk alone that made attending worthwhile.

Slides from my “Enter The Matrix: Reloaded” talk can be found here (latest version here), and the code can be found on GitHub.

(Presenter tip: If you use a retina MacBook Pro or a new 2012 MacBook Air to present, remember to pack a MagSafe to MagSafe 2 converter so that you can charge your laptop using the power adapter that’s hopefully installed on the podium.)

iOSDevCampDC 2012

I am pleased to announce that I will be speaking at iOSDevCampDC in Reston, VA on August 11.  This is a single track, single day mini-conference (for a mini price, just $50) that brings together a lot of DC-area developers.  It’s on a Saturday, so work conflicts are minimal.  Ticket sales end this Saturday (July 14), so if you’d like to go, act soon.

Update: registration has been extended until July 24.

I will be doing my “Enter The Matrix” presentation on matrix transformations, but I’ll probably fine-tune it to the more advanced audience I expect to quickly review the basics and then spend more time examining flipping and folding animations (and related ephemera such as anti-aliasing, avoiding off-screen render passes, shadows, rendering retina images, etc.)

So if you’re in the area (or will be), I hope to see you there!  (Seriously, for $50 you can’t beat the price for 6 technical sessions plus the opportunity to network with a cadre of local devs.)

CocoaConf DC wrap-up

Last weekend I had a great time at CocoaConf DC on my home turf of northern Virginia.  In many ways CocoaConf is the antithesis of WWDC.  Capped at 100 attendees, it’s small where WWDC is enormous, and intimate where WWDC can be impersonal.  It’s a conference where you can meet (and spend time chatting with) every speaker and every attendee, if you put your mind to it.  And really, although the sessions are the ostensible reason to attend conferences (the way we justify them to our bosses or to ourselves), for me at least it’s the personal connections you make that are the real value.  As developers we tend to spend most of our time isolated in our cubicles (and in some cases our homes), so it’s doubly important to take the time to reach out to the like-minded individuals we encounter at conferences.  CocoaConf is a great venue for that.  And with 3 tracks of 30 sessions over 2 days (preceded by an optional full-day intensive tutorial), there’s plenty of knowledge to be gained as well.  A common theme I heard throughout last weekend was the “which of these sessions should I attend next?  They all sound great” dilemma (trilemma?).

This time I presented two talks.  I debuted a talk on custom container view controllers (using the iOS 5 containment API), which in addition to containment covered the iterative process of designing and refining the UI and API for a page-flipping control (demo app shown above).  The slides are available here and the code (open source and attribution-only licensed) is up on GitHub.

My other talk, “Enter The Matrix”, I gave for the second time.  It’s about using matrix transformations in Quartz drawing, UIKit animations, and CoreAnimation (with obligatory, gratuitous references to the Matrix movies).  Since Chicago in March, I’ve significantly improved the accompanying sample app, completely revised the slides for fold and flip animations, and introduced a section on skew and perspective.  The slides are available here (latest version here) and the code is on GitHub.

I think one new talk is the most I can manage per conference.  A great deal of work goes into each presentation (code, slides, and speech).  I like this picture of Saul Mora, Scott McAlister and me all preparing for our talks on the first day of the conference.  We work on our presentations up until the last minute not because we’re ill-prepared, but rather because we care.

One little touch that I really appreciated as a speaker: a MacBook power adapter installed on the presenter’s table in each of the rooms.  Sometimes, it’s the attention to little details that really stand out.

I hear that CocoaConf may be back in DC next March.  If so, I hope I can be a part of it again, either as speaker or attendee.

Anatomy of a page-flip animation

In this post I would like to do a close examination of my take on the page-flip animation.  As with my foray into folding animations, this started with my desire to come up with some cool examples of real world use for matrix transformations for my Enter The Matrix presentation for CocoaConf Chicago last March (and which I’ll be delivering a new and improved version of at CocoaConf DC next month).

The Basics

Essentially we have two views that we are transitioning between.  Each one is divided in two along either a vertical or horizontal axis and rendered as an image.  If we’re transitioning from A-B to C-D and flipping from right to left, then we will start by flipping up B (while revealing D beneath it).  At the halfway point B will disappear (and D will be fully revealed), and we will begin flipping down C and covering up D.  By the end A & B will be hidden and only C & D will remain.

For my own purposes I refer to the half of the old view that we flip up (B) as the “front page”.  The other half of the old view that remains in place (A) I call the “facing page”.  The half of the new view that we flip down (C) is the “back page” (i.e. it’s on the back side of the page we’re flipping), and the half of the new view that stays in place (D) is the “reveal page”.  Whether one of these halves is on the left or the right (or the top or the bottom) depends of course on the direction of the flip (and its orientation), so I just like to think in terms of which ones are moving and which are not.

As described above, this is a 2-stage animation.  First we flip the front page up until it’s vertical and disappears.  Then we flip the back page down from vertical to flat.

Setting the Stage

Before we execute either stage, we need to prepare our layer hierarchy for the animation.  We will create a view with 4 sublayers where each sublayer’s content is an image rendered from a half each of the new and old views.  The layers for the facing and reveal pages go beneath the layers for the front and back pages (although we won’t add the back page to the hierarchy just yet).

The 2 lower sublayers (facing and reveal) will not need to move.  At this point we can add our animation view and hide (or remove) the old view as we’ve replaced it with a (static) copy.

Stage 1

In a right-to-left page flip, the front page is on the right.  We anchor it on its left side (the “spine” of our imagined book) and rotate it about the y axis from 0° to -90°.

Stage 2

The back page in a right-to-left flip sits on the left and so we need to anchor it on its right side (again forming the spine in the middle of our view).  At the completion of the stage 1 animation we can remove the front page sublayer from the hierarchy and add in the back page sublayer, already pre-rotated to +90°.  (Note: because the 2 layers are anchored on opposite sides, the sign of the angle to which they need to be rotated to appear in the same position is also opposite.)
Then we simply rotate the back page to 0°.

Making it better

What we have so far, serves as a passable page-flip animation, but we can do better in making it more realistic.  By adding a shadow layer (a simple CALayer with background color set to black and opacity set to maybe 0.5) to the reveal page and then animating its opacity, the page beneath can be initially dark (shadowed by the front page) and then get gradually lighter as the front page moves towards vertical.  So let’s animate the opacity of the shadow layer on the reveal page from 0.5 to 0 throughout the stage 1 animation.
During stage 2 we can add a matching shadow layer to the facing page and animate its opacity from 0 to 0.5 as the back page lowers down on top of it to hide it.

Next it would be nice to create the impression of a crease, of a differentiation between the flat facing page and the flipping front page.  This can be achieved using a shadow layer on the front page, although it doesn’t need to be as dark.  We can animate its opacity from 0 to 0.1 during the stage 1 animation.  We’ll add a similar shadow to the back page for stage 2 and animate it from 0.1 back to 0.

Thinking about the shadows

The width of the flipping page during the animation follows a cosine path (although this is slightly distorted by the viewpoint of our perspective, see below).  So for example at 50% completion of the first flip, the page is rotated to 45° but its width is cos(45°) × width, or 70.7% of the width.  If we animate the shadow on the reveal page linearly, that means the shadow would be only at 50% of its maximum even though the page is still 70% covered; i.e. the intensity of the shadow is not proportional to the width of the page covering it.  The reveal page will only be half revealed when the animation is 2/3 completed (cos(60°) = 0.5) but by then a linear shadow would be at 1/3 of its maximum.  So I decided that the shadows on the reveal and facing pages should animate along cosine and sine paths respectively to achieve a more pleasing effect (using CAKeyframeAnimation, see code).  This effectively means the shadows stay darker longer, so I also reduced their maximum opacity to 0.333.  I think it’s ok to leave the front and back page shadows as simple linear animations.

Antialiasing

Did you notice anything wrong with the screenshots above?  There are probably several things, but one of them is the jagged edge of the flipping page.

Because we’re using static images to perform our animation, it’s a simple matter to antialiase the edges in an efficient manner, which gives us this:

Thinking More About the Shadows

But a shadow on the front page doesn’t really make sense and darkening the entire page just to suggest a crease seems like overkill.  Instead we can use a CAGradientLayer to darken the page just near the crease, but leave the bulk of the page unmodified.  We’ll keep the animation on the shadow layer’s opacity to ease the effect in (alternatively, we could animate the gradient’s colors by increasing their alpha).

Timing Curves

Because this is a 2 stage animation, we need to pay some attention to the timing curves.  While we may want an Ease In Ease Out timing curve over the entire animation, that means using an Ease In curve over the first half and an Ease Out curve over the second half.  If we Ease In and Out over each half, we will end up with an uncomfortable pause in the middle of our page flip.  (Ok, it would probably only be uncomfortable to me having to watch such an animation but still.)

Perspective

For our animation to appear 3d at all, we will need to set the m34 component (skew) of the main layer’s transform.  If we don’t, our page flip will be completely flat and rather odd looking.

No perspective: m34 = 0

Skew is defined as – 1 / z where z is the height of the viewer in points above the flat plane of the view.  Choosing the right skew will be dependent upon the dimensions of the views you are animating.  Your skew should be proportional to your page width (horizontal flip) or height (vertical flip).  If z it too low, your page animation will be blown out of proportion.

Too much perspective: m34 = -1/225 or -1/(1.5 × page width)

If z is too high, your page animation won’t have enough “pop” to it.

Too little perspective: m34 = -1/1800 or -1/(12 × page width)

I find that anything in the range of 4-5 × width works pretty well for z, but you can experiment and adjust the animation to your taste.

Inverse perspective

If you invert your perspective (use a positive value instead of the typical negative one), you can get a pretty cool effect.  It doesn’t really make physical sense as a page-flip illusion, but is nonetheless interesting.  (Note:I’ve removed the shadow on the reveal page for this effect.)

Anchor Point

The anchor point of the layer being animated determines the view point of the perspective.  By default the anchor point is {0.5, 0.5} which corresponds to the midpoint of the layer.  That’s why the flipping page sticks out an equal distance above and below.  But if we change our anchor point, we could also change our perspective on our animation and thus alter its look and feel.

View from below – Anchor Point {0.5, 1.5}View from above – Anchor Point {0.5, -0.5}

Room for Improvement

And now we have a fairly decent page-flip animation.  We could probably improve it further by adding realistic shadows for the front and back pages to cast upon the reveal and facing pages respectively (instead of a uniform shadow).  We could just set shadow properties on some of the sublayers, but that would involve a separate off-screen rendering pass, so we would need to also set the shadowPath appropriately and animate that.  A possible compromise improvement might be to use a CAGradientLayer (darkest by the edge of the covering page) for the reveal and facing page shadows and animate locations (or startPoint and endPoint).

Resources

  • MPFlipViewController – a fully touch gesture-enabled, attribution-licensed container controller, that uses all of the techniques discussed above.
  • MPFoldTransition project with demo app and code you are free to use to easily add these same animations to your own iOS apps.
  • Enter The Matrix project with lots of matrix transformation examples, including touch gesture-enabled versions of both flip and fold animations (the project has now been updated to incorporate the shadow techniques described above).
  • Edge Antialiasing post with a discussion of what it is, why you’d want to do it, and how to do it efficiently.  Also with its own sample project.
  • If you’re not doing WWDC this year, come see me speak about these types of things at CocoaConf DC (and learn from a great speaker lineup).

Credits

I’d like to thank Shawn Welch for starting me down the path of investigating page-flip animations at the Voices That Matter iOS conference in Boston last November, and providing a demo project to get me going.

Anatomy of a folding animation

In this post I want to dive into the minutiae of how a good-looking folding animation can be achieved, and also how I was doing it wrong the first time I took a stab at creating one.  Earlier this year I started looking into fold animations as an example of advanced use of matrix transforms to animate views for my Enter The Matrix presentation for CocoaConf Chicago.

(For a similar in-depth look at page-flip animations see Anatomy of a page-flip animation.)

Initial Efforts

It seemed relatively straight-forward.  Given 4 “panels” (A,B,C,D if you will), fold B & C inward until they disappear while sliding A & D together until they meet.  So the first step was rotating B around the x-axis away from the user along its top edge, and the same for C except along its bottom edge.

Of course that leaves a gap between B & C, so you need to move B down and C up by just the right amount and also move A & D to keep pace with them.  I quickly discovered that the height of panels B & C during rotation is a cosine function of the angle of rotation and not linear.  However, due to perspective issues B & C don’t disappear (are completely on edge) at 90° the way you would expect.  Because you are simultaneously translating and rotating the panels, at 90° the panels are actually slightly over rotated relative to the viewer.  To get them to just disappear, you need to rotate them to arctan((z × 2) / y) where z is the height of the viewer (see perspective below) and y is the height of the panel (or roughly 83.9° in my case).  So you have to rotate the panels from 0 to 83.9° while animating the vertical offset of panels A-D from 0 to cos(±90°) × height.  This roughly works, but if you examine the animation closely, you either see a small gap open between 2 of the 4 panels or else an overlap of a few pixels between 2 of the panels.

Enter CATransformLayer

It turns out, I was thinking about this all wrong.  What I needed to use in order to keep all 4 of my panels together was CATransformLayers.  I was pointed in the right direction by this StackOverflow answer.  As Apple’s documentation says, “CATransformLayers are used to create true 3D layer hierarchies”.  Instead of treating all 4 panels as separate UIViews that need to be transformed independently, we will create the panels as 4 sublayers that are organized together along with CATransformLayers into the proper sublayer hierarchy within a single UIView.  The transform layers keep each panel layer properly adjoined to its neighbors.  To follow along with code, see my MPFoldTransition project (which was the culmination of this dive into folding animations), but in this post here I’ll be talking more about the big picture rather than code details.

I ended up building a layer hierarchy with all 4 panels contained within a single view, and panels B & C (the 2 folding panels) contained within the bounds of a single parent layer (the purpose of which will become clear in a bit).  The difference is that now all these layers are connected together relative to one another in a true 3D hierarchy, so when I rotate panel B away from the user, all 4 panels rotate like so:

In order to compensate for this rotation and to keep panel A flat, I need to rotate panel A in the opposite direction along its bottom edge by the same amount.

Then panel C needs to be rotated towards the user by double the angle of rotation of panel B.

And finally in order to remain flat, panel D needs to be rotated away from the user by the angle of rotation of panel B.  Notice how panels A & D need to be rotated just so that they appear to remain flat throughout the entire animation.  This is of course because each panel is being rotated relative to its parent layer and not relative to the plane of the entire view.

Perspective

This gives us all 4 panels well-connected with no gaps or overlaps, but we’re still not finished.  If you look at the last 2 pictures above you may notice a perspective issue; i.e. that panels B & C are not of equal height.  It’s more noticeable the closer you get to 90°.

This is a perspective issue similar to the one I faced in my original design.  To fix it, at the same time we animate the rotation of these 4 panels, we need to also animate the height of the 2 folding panels B & C to 0.  This keeps the 2 panels of equal height throughout the animation.  If you wish for the border between B & C to remain in a fixed position vertically (as I did), then you actually need to animate the height using a cosine curve rather than a simple linear one (see the code for the CAKeyframeAnimation implementation).

Shadows

Now that perspective is tackled, the next issue is one of improving the 3D illusion by dimming the folding panels as they collapse.  This is easily achieved by adding a sublayer to each folding panel layer and animating its opacity.

This helps, but when the 2 folding panels have the same background color (as they usually do), then they seem to be a single panel (morphing into an hourglass shape instead of folding away from us), which detracts from the 3D illusion.  To solve this, I adjusted the maximum opacity of the 2 shadow layers to be slightly different (set one  to be 90% of the other).  This provides a nice contrast between the 2 folding panels as seen here:

The proper (amount of) perspective

The perspective value that you set as the m34 component of your CATransform3D struct is = -1/z where z is the height of the viewer in points from the view’s surface.  Changing this value dramatically affects the illusion of perspective.  If 0 (z approaching infinity), everything is flat.

No perspective: m34 = 0

If too small (viewer still too far away) then the perspective is too subtle.

Too little perspective: m34 = -1/1800 or -1/(12 × height)

If too large (viewer too close) then the perspective is exaggerated and distorted

Too much perspective: m34 = -1/150 or -1/(1 × height)

I prefer to adjust z relative to the dimension of the objects I am animating. In this case I’ve been happy with 4.666667 × height. I think any value in the range from 4 to 5 yields attractive results.

Other Minutiae

Of course being the OCD-type, I just had to antialiase the edges of the folding panels so that they’re not jagged, even though my default animation duration is only 300 ms.

A different cool effect (which I termed “cubic” for wont of a better description) can be achieved if you rotate panels A & D at a fixed 90° angle relative to their neighbors instead of animating them to remain flat.  The effect is akin to rotating a block- one side appears while another disappears.

If the folding panels (B & C) are created by splitting a single view in 2, and that view has an odd height (in pixels, not points) then once again you see flickering of gaps between panels during the animation. To solve this I make both panels of integer pixel height. e.g. when splitting a view 99 pixels tall, I’ll make the panels 50 and 49 pixels tall instead of 49.5. (Note that on a Retina display 49.5 points is just fine because that’s really 99 pixels.)

Update: Gradient Shadows

I recently switched to using CAGradientLayers for the shadows.  I think these look much better than the solid color shadows, and they also create the impression of a crease between the two folding panels (because the light end of one gradient will be juxtaposed with the dark end of the other).

However, if the bottom sleeve (D) has the same background color as the lower folding panel (C), you end up with no crease if the gradient shadow blends all the way to clear.

Fixing this is simple – just set the end color of the lower gradient to around [[UIColor blackColor] colorWithAlphaComponent:0.25] instead of clear.  This will create enough color difference to suggest a crease while not darkening the lower panel overly much.

This isn’t necessary for the cubic effect, because then panels A and D will have their own shadow gradients.

To achieve the proper effect, I animate the opacity of the shadows on panels B & C along a cosine path so that their intensity is (inversely) proportional to the height of the panel.  For the cubic effect, the shadows on panels A & D are similarly animated along a sine path (again so as to be inversely proportional to panel height).  Using a simple linear animation would lead to a discrepancy between the strength of the shadows and the positions of the panels.

Resources

  • MPFoldTransition project with demo app and code you are free to use to easily add these same animations to your own iOS apps.
  • Enter The Matrix project with lots of matrix transformation examples, including both flip and fold animations (the project has now been updated to incorporate the techniques described above).
  • Edge Antialiasing post with a discussion of what it is, why you’d want to do it, and how to do it efficiently.  Also with its own sample project.
  • If you’re going to be on the East coast in June, come see me speak about these types of things at CocoaConf DC (and of course learn from a great lineup of even better speakers).