A Microsoft™ program manager reviewed tablet personal computer (PC) software application program interface (API) considerations and development history with BYU-Hawaii students during the School of Computing's March 14 InForm meeting.
Arin Goldberg, who is currently program manager for MSTV technology in the software company's Redmond, Washington, headquarters, previously worked for about 10 years encouraging other developers to integrate a Microsoft API with their respective products and software. APIs are a set of routines, protocols and tools that programmers use to create consistent product interfaces.
"I'm the guy that designs the API that you get to use when you use things like Windows™," Goldberg said. He added he "evangelized building tablet functionality... It was my job to convince them [the other developers, such as Photoshop™] that they would benefit" by using Wintab technology.
Goldberg explained there are two distinct types of tablet PC input technology: One that uses a "pen" or stylus, and the other a touch-sensitive screen.
The first, which uses an electromagnetic (EM) grid of fine wiring beneath the screen "has been around a long time." The Wacom™ brand slate tablet is one type, he said, noting the devices also come in other forms. The one he was using, for example, looks like a laptop with an attached keyboard; and other slates can be docked with a desktop computer. "There's lots of variety."
The pen or stylus, he continued, contains a "little coil that disrupts the magnetic field [generated by the wiring], and the software can determine where it is." For example, on his own tablet PC he demonstrated how the pen point would actually show up as it drew near but hadn't touched the screen. "As I push down on the pen, the relative frequency of the coil changes." He added that in some devices the screen emits the signal and the pen disrupts it, while vice versa in others.
Goldberg pointed out EM technology "allows for much better quality. We can make it look really good," whereas "touch screens usually do not render at very high resolution." For example, EM resolution is about ten-times that of a mouse "so that the granularity of the pixels is much smaller...so when you start writing with the pen it doesn't look jagged."
Of course, tablet PC handwriting recognition brings its own set of challenges, Goldberg continued. "Handwriting recognition is a very difficult science. Everyone writes differently. It turns out in all the research we did, you can tell where somebody grew up by how they write, and how old they are."
He added that while some software "actually learns from your handwriting," more specifically most users also "learn not to make mistakes. About three-to-six weeks after people got their tablets, they would tell us it's learned a lot. [But] it had nothing to do with their computer."
Goldberg also explained that EM digitizers give "higher throughput" — about 133 samples/second, compared with about 40 samples/second with touch screen technology — which allows tablet PCs the ability to determine such things as the acceleration rate of the pen and how hard your pressing. In the case of the latter, "we don't 'show more ink' [on screen] if you slow down. We show more ink if you press harder."
"The EM digitizer can also detect more than just the X,Y [axis] position — where you are on the screen. Other things that are supported, if the software supports it, is how far above the screen the pen is, or its angle to the screen, or the rotation of the screen."
To demonstrate these characteristics, with just a few lines of programming code Goldberg created a new "ink overlay" on his tablet screen and gave it the ability to display and recognize a "stroke object" or "one instance of when you push the pen down…until you remove it." He said he could have also included programming to recognize "your own properties, such as what time it was when you wrote it, or who wrote it," and other characteristics such as color, width, etc.
"The code only fires when the stroke has been created," Goldberg continued. He then altered the code again to have the computer recognize the handwritten strokes and generate the appropriate alpha-numeric characters on screen. "We have an English recognizer, a German one, a Japanese one — all kinds of languages [which] reflect a great deal of knowledge of how people write words."
As the forum was ending, Goldberg demonstrated an Ultramobile PC, which is about the size of a paperback novel. He explained how on a trip to Hawaii about 18 months ago students at another college told him what they wanted in a tablet PC. He combined their requests with some of his own ideas, and convinced Microsoft to work on the software for the device, which has all the features of a laptop.
