Microsoft likes to talk about Windows 8 as being Windows "reimagined," and in many ways it is quite a departure from its predecessors. To allow the operating system's use across a range of touchscreen devices, Microsoft radically redesigned the look and feel of the OS.
This week at the company's Build conference in Redmond, Washington, developers learned some of the techniques they will need to make the most of the new OS. The talks addressed issues such as how to work with live tiles on the start page, how to work with the touch interface, and how to design applications so they look good in the new, simpler, interface.
Windows 8 goes beyond static icons that link to applications. Instead, each app can have a live tile on the start page, one that can be updated with information such as photos, calendar items or news. "The whole purpose of live tiles is to create a system that is alive with activity," said Kraig Brockschmidt, senior program manager for Windows planning, during one talk.
Live updating can take place in three places: on the start page, in pop-up notifications and on the lock screen.
Microsoft designed live updating so that it would not consume an undue amount of power. "We could have a system that is very alive with apps running all the time, but we'd get only one or two hours of battery life," Brockschmidt said. Instead, tiles can issue updates even when the underlying app is not running. Windows will allow a developer to define an external service, through an API (application programming interface), that can deliver updates over the Internet on behalf of the app.
Microsoft limited what can be placed on the start and lock screens. "If you let everybody put what they want on their tiles -- video, interactive controls, motion -- it would be utter chaos eventually," Brockschmidt said. Instead, the company offers 40 templates for tiles and notifications that developers can use. Each image in a tile can be no larger than 200Kb and have no more than 1024 pixels. "By limiting what you can do on the start screen, you get a much more unified view that is much cleaner and more informative," Brockschmidt said.
Another design consideration developers will have to grapple with is a new form of input, namely touch, where users interact with the OS directly through the display. "We really want developers to have a touch-centric approach to their applications," said Jeff Burtoft, a Microsoft HTML5 evangelist, during another talk.
Just as the mouse introduced new ways of interacting with graphical programs, so too does the touch interface offer new possibilities for user interaction. Windows 8 can determine if the device it's runs on accepts touch as an input. If it does, it activates "listeners" for touch-based input.
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