Granted by the U.S. Patent and Trademark Office, Apple's U.S. Patent No. 8,407,623 for "Playback control using a touch interface," describes a method of input that registers touch gestures when no content is displayed on the multitouch screen. That is to say, the multitouch panel is activated, but nothing is being displayed on screen.
As noted in the patent language, normal inputs like physical buttons can increase the size of a portable device or require moving parts that may be undesirable. According to the invention, these types of input controls may also require that a user look down at the device to change song tracks, adjust volume or perform other media playback actions. As seen by the example sixth-generation iPod nano, this can be troublesome when using the device during a workout when the display may be facing away from a user.
While the regular inputs are still available for users, such as push-button play and stop or rocker volume controls, the patent also allows for control the unit without having to look at it.
Table of touch input and device operation associations.
From the patent summary:
To allow a user to control media playback using a touch sensing device without requiring the selection of displayed options, the electronic device can include a mode or configuration for which the touch sensing device can sense touch events, but not display any content on a display. For example, an electronic device with a touch screen can have a mode in which no content is displayed on the touch screen (e.g., the touch screen remains dark), but the touch screen is operative to detect touch events of the user.
Apple's system can support any combination of touch events, which are then associated with certain playback actions. Specifically, the method can associate tap events that mimic button presses from a remote control. For example, the device can associate a single tap with the same operations a single button press of an inline remote triggers. Double taps and press-and-hold gestures are also supported, as is the case when skipping tracks or fast-forwarding through songs.
In another embodiment, the method can provide gesture inputs that don't correspond with button press events. In these examples, the user provides a circular touch motion to control the volume, much like legacy click-wheel iPods.
While the above gestures can be performed on a blank screen, or one that is not displaying a graphical user interface, the patent also allows for playback overlays if necessary. These particular embodiments function like usual iPod UIs in that a graphical asset is displayed for an operation, for example a volume bar will pop up when a volume adjustment gesture is recognized.
Without displaying on-screen graphics, the patent saves energy and allows for a more robust interactive experience that doesn't require a user to constantly look down at their device.
Apple's '623 patent was first filed for in 2009 and credits Duncan Kerr and Nick King as its inventors.