Touchscreen devices that respond not only to regular taps and swipes in two-dimensions, but sheering forces across the display, could open up a new paradigm of tablet and phone control, research has suggested. Rather than conjuring up pop-up toolbars and other screen-dominating UI elements, a press-and-pull gesture could be used to cycle through options, select different colored pens or drawing tools, or perform speedy copy & paste.
The project, handiwork of Chris Harrison and Scott Hudson of Carnegie Mellon University, describes "Using Shear as a Supplemental Input Channel for Rich Touchscreen Interaction." Their prototype uses a moving panel on top of a touchscreen tablet device, which can be pulled in multiple directions if the user presses down and drags their finger across it. That, it's argued, introduces a whole new input method that next-gen platforms could take advantage of.
"Touch input is constrained, typically only providing finger X/Y coordinates. To access and switch between different functions, valuable screen real estate must be allocated to buttons and menus, or users must perform special actions, such as touch-and-hold, double tap, or multi-finger chords. Even still, this only adds a few bits of additional information, leaving touch interaction unwieldy for many tasks. In this work, we suggest using a largely unutilized touch input dimension: shear (force tangential to a screen’s surface). Similar to pressure, shear can be used in concert with conventional finger positional input. However, unlike pressure, shear provides a rich, analog 2D input space, which has many powerful uses" Harrison and Hudson
So, in the researchers' demo apps, by using sheering forces in one of several directions, different options can be selected; a touch and sheer-up gesture can copy text, with a touch and sheer-down then pasting it. A prototype music player controls play/pause and track skip with sheering movements, while circular sheer-dragging motions can be used for scrolling or zooming.
One obvious practical issue is the nature of the hardware: the current prototype, for instance, requires a screen which can move on top of the device itself. However, some touchscreen manufacturers - such as Neonode - are already working on sensors which can pinpoint not only points of touch but angle of touch, pressure and more. That would presumably support the researchers' sheer system, without requiring an awkward panel on top.