Auto Layout DemystifiedI was at a local user group recently where the topic of the hot new cross-platform mobile development options out there (doesn’t really matter which) came up. There was the usual UIkit bashing, which was expected since the topic was to propose an alternative programming model.I’m not here to defend UIkit, because I agree that it can use some improvement. However, the speaker did say one thing about Auto Layout that I have heard before and that rubbed me the wrong way.I’ve heard people say things like, “You need a mathematics PhD to understand Auto Layout,” or, “You need to be a rocket scientist to understand Auto Layout.” I’m not going to get into a debate on how hard rocket science actually is—you can see reddit for the answer. Instead, in this blog post, I will show you how easy the calculation for Auto Layout is. In fact, the linear equation is so simple that an elementary child could do the math.So why do people think Auto Layout is hard? Well, I don’t think Xcode’sinterface builder helps the situation.
Xcode has improved since Auto Layout was introduced, but it can still be hard to see how the Auto Layout equation relates to what you see in interface builder. Let’s see if I can demystify Auto Layout a little.Let’s say you have two buttons and you want to know how far apart to place them. How could we express the relationship between the right edge of the Cancel button and the left edge of the Accept button? If I were to describe this to another person, I would probably say something like, “The Accept button is eight points to the right of the Cancel button.”A more precise statement would be, “The left edge of the Accept button is eight points greater than the right edge of the Cancel button.” The equation for this would be:Accept.left = Cancel.right + 8 where 8 is a constantWhat if I wanted to express the width of the Accept button in relation to the width of the Cancel button? Let’s say it’s twice as wide. Then the equation would be the following:Accept.width = Cancel.width * 2 where 2 is a multiplierThe Auto Layout equation combines these two into one to express any kind of relational constraint.
Item1.attribute = Item2.attribute * multiplier + constantTo express the position of the Accept button in relation to the Cancel button, we don’t need the multiplier, so its value is one. The equation would be the following:Accept.left = Cancel.right * 1 + 8To express the width of the Accept button, we don’t need the constant, so that becomes zero.Accept.width = Cancel.width * 2 + 0That’s it! The mystical equation that you need a math PhD to figure out ¯\_(ツ)_/¯. As with any equation, you can reverse it. You can express the relationship between the distance of these two buttons with Item 1 and Item 2 reversed as follows:Cancel.right = Accept.left * 1 + (-8)I think this is where some of the confusion starts with Auto Layout because Xcode’s interface builder doesn’t always show the equation in the order you are expecting. It is not logical to think of the distance between the two buttons as a negative number.If you want to know more about the equation, Apple has a great page explaining the Anatomy of a Constraint.Next, I’ll show you how interface builder uses this equation to build a constraint.
Let’s create the same horizontal constraint between our two buttons. I am not going to go through all the different ways you can create a constraint in interface builder because there are several different ways. My favorite way is to press the control key and drag a constraint from the first item to the second.After I drag UI elements into my view controller, I give them a meaningful name in the document tree. This is very helpful in understanding which control is which when looking at the attributes of a constraint. Xcode will use the the name of the control in the attribute inspector so it is easier to identify your controls.Now let’s look at the attributes of the horizontal constraint and try to find the elements of the equation in interface builder.When you add constraints in Xcode, the order of the equation may not be what you are expecting so the numbers will be reversed. Here you can see that my constant is a negative number and the first and second items are reversed. I believe this trips people up in understanding what is going on.
You can fix this situation by reversing the first and second item. I often do this so that it is clear in my head (even though, from a mathematical standpoint, it is the same). After you reverse it, the negative constant becomes positive again, and the items appear in the order you expect.Hopefully, this is helpful to someone new to Auto Layout. We don’t need to hire mathematicians to lay out our controls. The math is pretty easy, although Xcode doesn’t help the situation sometimes. Want some depth to your design, some discipline to your practice? Stale approaches, and carbon copy compositions will be left in the dust. Design trends are always evolving, and it’s become increasingly important to shake up your style and get an edge on the market.5 Experts Share their Best Practices: From Layout to Motion Design is a compilation of contemporary design essentials used by industry experts to keep it current, and ensure the best work possible.Each chapter has been handpicked for delivering failsafe advice, unconventional knowledge, and above all, results.
Ask the prosWe don’t want to beat a dead horse, but this eBook hits the mark. Just ask developer Trevor Orr, who’s all like:This eBook is beautifully composed, and the content made me look at my design approach differently. It’s full of actionable, innovative articles and strays away from tired industry advice.”Trevor Orr, Lead Developer at Locus InteractiveGet yours now. Design & IllustrationAdobe InDesign20+ InDesign Tutorials for Magazine and Layout DesignEnvato Market has a range of items for sale to help get you started.The world of ebook conversion is mysterious to most of us. It’s difficult to imagine what goes into designing a file that’s versatile enough for display on many different devices. The standard ebook file format is called ePub, and it’s designed to be responsive and to automatically adjust to the screen size of any e-reader, computer, smartphone or tablet. Unlike a PDF file, which preserves the original design of a given page, ePub is designed to allow text and images to dynamically reflow to suit the device.
ePub has evolved to accommodate illustrated books as well: now fixed-layout ePub files will allow the design to remain fixed while still allowing the ebook to be viewed on different kinds of devices. Since ebook sales are such an important part of an author’s publishing strategy, it makes sense to carefully consider how you would like to have your ebook produced. We sent some questions about ebook conversion to a couple of ebook design specialists whose work we admire: Laura Brady of Brady Type and Kaleeg Hainsworth of Bright Wing Books. We found their answers illuminating, so we thought we’d share them with you: Page Two: Some people hire conversion specialists to produce their ebooks, while others simply upload their text files to online conversion tools that convert them automatically to the ePub format. What value can an ebook conversion specialist add to the ebook conversion process that an automated conversion tool can’t provide? “One of the main reasons to hire an ebook developer that often gets lost in the obvious reasons (better design, bespoke, better QA processes) is accessibility.
A professional ebook developer will not just press convert on whatever software they are using. They will convert and then edit the code for semantics, clean coding practices, and simplify the CSS [a style sheet language used for describing the look and formatting of a document]. Even without advanced accessibility practices, the basics of a good ebook development create cleaner code which is more accessible. This is incredibly important and shouldn’t get lost in the shuffle.” “There certainly are a growing number of conversion tools available to authors and publishers. Some of these tools are stand alone applications (such as Calibre, Kindle Kid’s Book Creator, and Adobe’s export to Epub format, to name a few), and some are offered through websites and the ebook distributors themselves. Some of these tools are buggy and some are very good and intuitive to use, however all of them will only get an ebook so far. For instance, an author can upload their Word file to Kindle or Kobo and it will be converted to a mobi or epub file for them, but it will only be useable by Kindle or Kobo and it will come out in a one-size-fits-all format without any opportunity to customize it.
Many of the stand-alone tools present the opposite problem. Calibre will generate an epub or mobi file, and it provides a dizzying array of options to customize the ebook, but there is no guarantee that this book will work on all the devices or be accepted by the stores and distributors. In both cases, the author has very limited ability in the final look and layout of the book and there is no guarantee that their book will be forward compatible (meaning it may not survive the constantly changing ebook code base). What’s more, the ebook that is generated will contain a lot of extraneous proprietary code and if there is any need to make adjustments to the book, the whole process of conversion needs to be undertaken again, often from scratch. Then there are other questions which need some expertise to answer, such as what to include (and where) in the metadata, cover specifications, and if and where to include a table of contents. Another challenge which the conversion tools will not be very helpful with is what to do with books which have footnotes, block quotes, typography, and practically every other kind of layout and formatting.
If all of this seems enough to make a person go crazy, then believe me that ebook specialists know well the crazy-making experience and are here to help. We have faced every imaginable problem and are still discovering new ones.” Page Two: Can you tell me about any innovations in ebook design/development that you’re excited about? Kaleeg Hainsworth: “There are some extraordinary developments happening right now. First of all, Adobe InDesign came out last year with a significant export feature which allows just about anyone to export a fixed layout book (such as children books or cookbooks) with just a few clicks. This feature has taken much agony out of the notoriously difficult process of creating fixed layout books and has freed the market up to anyone wishing to produce great content. So far, only iBooks and some Kobo readers can accept these books, but the market will open up greatly as time goes on. I am also excited about the increasing adoption of the Epub 3 specs by the major ebook distributors.
This will allow much greater control of how ebooks are designed and will allow for a great many possibilities in what content we can present. It has taken a long time and a lot of negotiations and love songs to get us to the stage that we can offer books in the Epub 3 format, but I think the possibilities will open so wide that it will make the work worth it.” Laura Brady: “I am really happy that I can finally produce EPUB3 in earnest for almost everyone with whom I work. I have never been jazzed about multi-media enhancements (which I think readers, for the most part, don’t want), but I do get excited about really full navigation, using ebook landmarks, and easy to use cross-references. I think that the fuller the navigation baked into an ebook, the easier it is for the reader to use. Clean, fulsome reading experiences are where it’s at!” For any book lovers out there who wonder if ebooks inspire as much devotion as their print counterparts, consider this comment from Kaleeg Hainsworth, to whom we give the last word: