Building Windows 8 - Touch Hardware

Description :

While Windows 7 has some touch screen features built in, few of the Windows 7-based PCs have used it. Windows 8, with its Metro UI, offers up a more full featured touch interface. In the latest post on Microsoft's official Windows 8 developer blog, team members Jerry Koh and Jeff Piira give an update on the efforts to make Windows 8 work on both existing and upcoming touch-based hardware products.



Microsoft first revealed how different touch interactions will work with Windows 8 back in September during the BUILD conference. You can see which touch movements correspond to Windows 8 command in the figure above. While Windows 8's touch interface will work on PCs made for Windows 7, PCs and tablets made especially for Windows 8 will have some extra features.


The blog post states that Windows 8 hardware will require that the digitizers support at least five fingers. Koh and Piira write :

"The reason we went in this direction is a response to developer feedback. Developers do not want their creativity to be limited, and in particular, they let us know that they want to be free to use whichever multi-finger gestures or controls are useful. They do not want requirements for a minimum number of fingers that may not make sense for their application. As such, we focused on a minimum of 5 fingers to enable scenarios like whole hand interactions (all 5 fingers) or multi-finger/multi-hand scenarios. This will address the feedback, and unlocks opportunities for developers to push the envelope with multi-touch applications."


There also have been a number of issues in getting the Windows 8 touch screen experience to work well on Windows 7 PCs. The blog post states :

"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."

Some of the touch interactions in Windows 8 on PCs made first for Windows 7 won't work as well. The blog post cites a few of them, including individual taps not working every time, having swipe and slide being misinterpreted as a tap command on some hardware, and swiping from the edge not always working. The blog post says that users of older Windows 7 hardware can sometimes get around these limitations. It states, "For example, if the charms don’t appear after an edge swipe, you can try again, but swipe more slowly."

Chart showing test results for Right Edge Swipe (no mitigations) on Windows 7 touch screens, Success rate is distributed between 0% and 100%, with a few data points around 55%.

Microsoft has been testing 64 Windows 7-based touch screens with Windows 8 running inside. The final results show that the vast majority of them will be able to handle at least the basic Windows 8 touch screen commands. However, some will work better than others. As the above chart shows, using the right edge swipe touch command on Windows 7 touch screens show that many of the attempts did not succeed at all.
PCs and tablets made especially for Windows 8 should be far more capable of handling its touch screen language. The blog post states, "Microsoft tests and certifies each new touch device before it can enter the market as a Windows 8 PC. This is how we will ensure consistency and quality in touch hardware for Windows 8."


*by andreascy*