Apple's Worldwide Developers Conference (WWDC) is over for another year - with the developers now leaving San Francisco and digesting what they learnt there. If you agree with Stefan Constantine that there are only two important events in the annual technology calendar - Apple's WWDC and Google's I/O - then the first half is done.

The first big question people have asked: where were the gadgets? Apple has released hardware at WWDC in the past - notably, iPhones, during the device's early years. This year? Nothing.

On the big screen

Make no mistake - Apple is clearly working on phones with larger screens. It's part of a drive to close every gap with Android for users and developers, while retaining the differences that have attracted existing users and business users, who demand complete security.

Apple's wants to make iOS hugely attractive to developers, while not particularly helping those developers to write for Android. It wants to make iOS attractive for users, offering apps and features that people can't get on Android or don't want to forsake from Android, and extra features so that people will stay with the iOS ecosystem.

A bigger phone

The clues were right there in a functionality called "adaptive display" - which appeared for a moment in a slide, but isn't mentioned in the public details about what's new in iOS 8 for developers. Hidden a little deeper is the "UIAdaptivePresentationControllerDelegate" which "works with a presentation controller to determine how to respond to size changes in your app". If it sounds abstruse, it's meant to - it's the key to a bigger display.

Developers at WWDC told me that adaptive display is new this year, and that it does just what Android does: scales up vector assets so that they will fit a screen of undetermined size. That should mean that when Apple introduces one or more phones with larger screens, there won't be a long pause while developers resize icons and so on to take advantage of it, as happened with the introduction of the iPhone 5 in 2012.

The mood music from Apple's executives is slightly different too. Early last year questions about screen size (which even then seemed like something where Android was beginning to split away) drew responses like "we're quite happy with our screen sizes" (which doesn't preclude a change, but doesn't exactly presage one either). Now it's "we've never said we're against larger screens, but we don't want to compromise on quality."

Apple has always been picky about what's called the "white point" of its screens - which is how true on-screen colours are to real life. It has also fretted about the effects on a larger screen on battery life (though a larger screen should mean longer battery life, because proportionally more of the phone can be devoted to the battery while the chips to provide the phone and computing functionality don't change in size.)

The "swipe" functionality introduced in iOS 7 - which always suggested larger screens were on the way, and that this was a training ground for them - seems a clear signal of larger iPhones in the autumn. There's no consensus on how large. A 4.7in screen seems likely as it's a popular size in the Android market.

But a 5.5in device, which would be classed as a "phablet" by analysts, seems possible. Ben Bajarin of Creative Strategies points out that Apple will struggle to compete effectively for sales in China unless it has a device tailored to that market - and Chinese phone users really like phablets. He thinks that a China-only launch for a phablet-sized iPhone is possible; the fact that it would create a grey market (in which those would be unofficially exported from China to other countries) is just a neat irony, given how many iPhones were brought to China by grey imports.

With a bigger iPhone, Apple would be able to close one of the gaps that has been a key advantage for Android - that some people like larger screens, and that using one tends to have a ratchet effect: once you've done it, you don't go back.

Coming attractions: keyboards, extensions and widgets

A year ago, the British company Swiftkey was quietly confident that third-party keyboards would be allowed into iOS 7 - the first time that Apple had allowed another product to replace a system-wide one.

It didn't happen, and Apple indicated to me last year that it had concerns about security. But this week, Apple said that third-party keyboards will be allowed in iOS 8 - subject to the proviso that they can't send data to the cloud without first getting the user's explicit permission.

That's only the half of it. As Swiftkey's Joe Braidwood pointed out to me, Apple's preliminary support documentation (which, it should be noted, could change) on third-party keyboards has all sorts of spaces where they can't play.

For instance, the section "System Keyboard Features Unavailable to Custom Keyboards" includes password text fields, and phone number fields in the Contacts app. (Apple says its system keyboard will pop up for those.) Nor can they access the clipboard with its contents from Cut, Copy or Paste actions. And third-party keyboards can't show "key artworks" - which seems to mean word suggestions - in the top line above the keyboard, unlike the iOS 8 keyboard.

Taken together, that's maximum security. Braidwood is hopeful that things will relax as the release comes closer in the autumn. But it's clear from that document that Apple definitely hasn't gotten over its concerns about security. I'm told that there are extra protections built into iOS 8 - and the bans on password (officially, "secure text") fields may be part of it.

How big will third-party keyboards be? There's an assumption by some people that because they use one, everyone else in the world is desperate to. But the evidence from the Google Play Store is less clear. Here are some third-party keyboards and their download numbers:

Add these together and third-party keyboards seem a significant business, yet an examination of the reviews suggests that many people try out multiple keyboards before settling on one - so many of these downloads aren't active. The aggregate of the figures above is between 43m and 211m downloads (taking the upper and lower limits of each figure); the higher figure would suggest that 1 in every 5 Android devices has a third-party keyboard on it - which seems unlikely. Given the propensity to download multiple different ones, a more realistic market on Android is somewhere between 50m and 60m devices.

That's nothing to sneeze at - but forecasting the size on iOS is harder, because Apple is simultaneously upgrading its keyboard in iOS 8 to give it a prediction system.

Extensibility

Apple is finally allowing different apps to communicate their ability to deal with data from other apps. While Android has had "intents" forever, so that apps can indicate that they deal with text, or photos, or video, and offer to take output from other apps that generate those sorts of content, or let you direct that content to them, Apple has always bound apps more tightly.

The capability to do this has been around in iOS for a couple of years now, but Apple held back from implementing it - perhaps last year because there was enough upheaval for developers in the swipe-based redesign of iOS 7.



With extensions, apps will be able to indicate that they can perform certain functions, such as adding a filter to a photo. That will be registered with the system, and those extensions will then show up via iOS's "sharing" button. So if you take a photo and then want to apply a filter or effect from one app, and then share that photo on Instagram and/or Twitter and/or Facebook, you'll call up the filter/effect extension, apply it, and then call up the Instagram/Twitter/Facebook extensions, and use those to send the modified photo - all while staying in the Photos app.

It's a lot simpler than the multi-app dance that Apple has forced on people so far.

Yet - security! - those apps applying the effects and sending the data will be sandboxed from the ones they're interacting with: the filter/effect app won't get access to all of your photos, only the one being handled.

Again, Apple's closing the gap with what Android has offered - providing a way to tempt people over from Android so that they aren't frustrated by what they can't do on iOS. Or, alternatively, it's a way to win back iOS users who might have left the platform.

Widgets

Widgets on iOS aren't quite the same as on Android, where they are mini-apps such as the weather or clock which reside on the home screen and update in real time. On iOS, they are mini-apps, but they run in the slide-down Notifications panel, and specifically in the "Today" part (which also contains the calendar).

One difference from Android widgets is that iOS won't let them update all the time. Instead, it will only update the widget when the Today view is opened - that's because of the concern about draining battery life again. (Widgets on Android are notorious juice-suckers.) But they're a "nice to have", and part of the way in which the Notifications panel is becoming ever more complex - and yet useful.



Cloud

Google's cloud powers the back end of Android. Now Apple is going all-in on cloud features in iOS 8, with explicit features like iCloud Drive (which offers file system navigation for people who can't get enough of file trees) but also background data transfer. Developers can now store data directly into iCloud, and photos and changes will be stored too. Charges for users are minimal; charges for developers are fractional. Apple is making cloud storage (including photos and edits of photos) part of what it does naturally.

As to whether Apple's iCloud is really Apple's storage and processing, or whether it's just rented from another company, I was told by authoritative sources that Apple doesn't "white label" or buy in any of iCloud: it's all Apple's own equipment running it.



As Benedict Evans of Andreessen Horowitz comments:

The whole of WWDC is full of cloud. A very large proportion of the new user-facing features touch the cloud in some way, as a conduit or as storage. And the ones that don’t use what you might call the personal cloud - the Bluetooth LE/Wifi mesh around you (such as HealthKit or HomeKit). So edit a photo and the edits are on all your devices, run out of room and your photos stay on the cloud but all but the previews are cleared off your phone, tap a phone number on a web page on your Mac and your phone dials it. But none of this says ‘CLOUD™’ and none of it is done in a web browser. Web browsers are for web pages, not for apps. Hence one could suggest that Apple loves the cloud, just not the web (or, not URLs). This is obviously a contrast with Google, which has pretty much the opposite approach.

iMessage

According to Craig Federighi, Apple's software chief, the Messages app is the one that people spend the most time in per day. Apple is thus enhancing it to tie people more closely to it by allowing users to:

• send self-destructing voice and video messages (they are wiped once consumed, unless the receiver chooses to keep them)

• see a quick view of photos exchanged during a conversation

• name conversations

• silence a multi-person conversation

• temporarily share present location with the people you're messaging

• permanently share location with others in a conversation

None of those is going to immediately stop people using Snapchat, WhatsApp, voicemail or location-sharing apps such as Glympse. But that's not the idea, as Jan Dawson of Jackdaw Research points out. The idea is to make the iOS Messages app more attractive than those on other platforms, so that people who are on iOS are held to it, and those who aren't are bugged by their iOS-using friends to switch. (Peer pressure matters to the iMessage-using demographic, one guesses.)



That's something Samsung has recognised with its own ChatOn messaging service, which had 100m users last September: if you can tie people to your platform with your messaging app, they're likely to stay there.

That gives the broad shape of Apple's battle plan in the software and services side of the smartphone market, which is approaching saturation (and hence the point where further growth has to be won from rival platforms).

The desktop computer stuff

Most of the changes coming to OS X, codenamed "Yosemite", won't affect most computer users - because there are only 80m Mac OS X users, and only half of those are on the latest version of OS X ("Mavericks"). But Apple's strategy is clear here too: encourage people who have an iPhone (a far larger number than Mac owners) to get a Mac too, because there are useful things it can do.

The most notable is "Handoff" and "Connectivity", which lets you route phone calls and text messages (not just iMessages) to your OS X computer. For some people, that's going to be invaluable - apart from anything, it's faster typing on a dedicated keyboard than a phone keyboard.

Yes, you can do the SMS-routing between Android and Windows with MightySMS phone to PC and Mac - but not many people have as yet; it has between 1m and 5m downloads. Its terms of service also say that "MightyText may need to store message content on its servers to facilitate the transmission of the messages to your devices" - which might give some pause for thought.



Data protection

A theme - never made explicit, but alluded to many times - was that Apple is pushing its data privacy angle in comparison to Google and Facebook. Yes, they are there as services on iOS - but it's also introducing DuckDuckGo, which doesn't store any user data at all, as an optional search engine on both iOS and OS X. It's the first time DuckDuckGo has had any mobile presence, and a big win for it. Apple is slowly but surely pushing Google away from iOS: Siri search doesn't use Google, but Bing and Wolfram Alpha. Google+ isn't an option anywhere. You get to decide app permissions, rather than having to accept them in a lump.

This is just the consumer-facing stuff - we haven't touched on Apple's new computer language, Swift, developed in complete secrecy since 2010, or its Metal API for faster graphics performance.

So now we await Google I/O. It should be interesting.

• Apple previews new mobile software at WWDC 2014