Crocodile touchscreen keyboard with triangular buttons

From The Register:

A British inventor has submitted a patent application for a wacky touchscreen keyboard design which, he claims, could spell the end for accidental key presses.

Baker told Register Hardware today that each triangular key has significantly more dead space around it than you’d find on a standard Qwerty layout. Consequently, users are more likely to press the correct key each time they tap.

Link: Triangular buttons key to touchscreen typing success — inventor.


Hmm. The hexagonal grid design is useful, I think (see previous post) but I'm not sure that the extra dead space is always going to be so helpful, especially if you were to shrink that keyboard down to regular iPhone size so that it covers only half the screen (or, worse, to its size in portrait orientation).

There are (at least) two important aspects of soft keyboard buttons. There's the displayed button shape, and it may be true that drawing them smaller makes people more accurate, and there's also the active area's shape. The active area is the region where a touch gets accepted as that particular key. The two areas are typically not the same, and the iPhone actually resizes the active areas dynamically so that more likely letters are easier to press. (e.g. if you type 't', 'h', then the active area for 'e' will be expanded in expectation that you'll type that next.)

It gets even more complicated when you consider that there isn't just a single xy location associated with a keypress. There is a touch-down position, a lift-off position, and a stream of positions in-between. The key event is triggered when lift-off happens (typically — because this works best for capacitive touch). But you don't want to just take that single lift-off position. It needs to be filtered somewhat to account for the fact that the trailing end of position data may be a little skewed when people lift their fingers. That filtering and other tricks mean that effectively there is not even a simple fixed "active area" for the button — it's really dynamic and determined by the whole interaction.

All of which is to say that designing good touchscreen keyboards is a heck of a lot more complicated than creating the shape of the keys. (I'm sure this inventor knows all this — I'm not trying to pick on him, just on the impression that this news story gives. And I haven't read his patent application.)

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