Building Windows 8: Touch hardware and Windows 8

Microsoft are really focusing on touch with Windows 8 and with the latest post on the building Windows 8 blog Microsoft go into details about the touch experience in Windows 8 and the hardware requirements. One of the interesting things in the post is that Windows 8 touch screens should be designed to work beyond the edge of the visible screen so that swipe gestures used to show the charm bars in work well. For existing hardware which doesn’t have the edge detection Windows 8 will have a 20 pixel buffer around the edge of the screen to catch the edge gestures, that way existing Windows 7 hardware will work well with Window 8.

As with the other pots on the Building Windows 8 blog there is a ton of detail and if you’re a developer thinking of using touch in your application it’s well worth reading.

New UI concepts in Windows 8 also impact touch hardware design. This is another area where Windows 8 PCs will be more capable than existing Windows 7 PCs. For example, the edge swipe required to reveal the charms and app bars fundamentally changes all the assumptions made on touch hardware. Traditionally, the edges of the screen are where touch sensitivity drops off, and it’s a place that hardware manufacturers have traditionally not placed much emphasis on. The center of the screen received all the innovation, while the edges have suffered. If you have seen or experienced the Windows 8 user experience, the edge swipe is a critical part of using Windows. However, it also has a big role to play in our developer promise, as every pixel used to detect an edge swipe is a pixel taken away from the developer. For Metro style apps, where every pixel belongs to the developer, it is critical that we uphold and deliver on this promise.

We worked closely with our hardware partners to figure out a design that will allow all pixels on a touch screen to be accurate and perform well. There were many challenges here, but we were able to deliver on the promise of Windows 8 PCs that have the ability to trigger the edge swipe without taking any pixels from applications, and with extremely good edge sensitivity using touch—a promise that benefits developers and users alike. To make things work with Windows 7 PCs, we had to go in a different direction. In order to make edge swipe work consistently on Windows 7 PCs, we created a mode where there is a 20-pixel buffer to catch the edge swipe gesture. This allows a majority of PCs to reliably invoke the charms and use Windows 8 effectively. The downside of this buffer is that it takes away some real estate from the application, and from developers.