Touch screen and pen input (like Wacom or tablet PC) are two ceompletely different technologies.
A digitizer (Wacom or tabler PC) does not actually respond to touch (the sensor to detect this is in the pen) and does not require mechanical contact with the pen, so it can be easily integrated in a tablet behind the screen. This is done on tablet PCs and on Watcom devices with integrated display.
A touch surface that responds to a finger is a thin and transparent layer on top of the screen.
So it is possible to integrate both in a single product (digitzer behind the screen and touch sensitive layer in front of it). It could even detect both simultanously.
But there are a few problems: When using the electronic pen, the device would be able to track position even if the pen is a few millimeters above the screen. On a Wacom the pointer follows the pen in this case and you can "hover" without pressing the "mouse button" like you can with a mouse. This is not possible when using finger input. Pen input is much more precise (smaller buttons!), but finger input allows for multi touch. It would be hard to create a user interface that makes optimal of both....
If you look at the prices for Wacoms there is another question: The costs.
Christian
I agree... kind of!
I haven't used a graphics tablet for a few years, so I am not current with their "state of the art" capabilities.
However, I have done some experimentation with using styli on the iPhone multitouch surface.
Long story, short: I think that a multitouch surface can work quite well with either a stylus or fingers. Consider:
1) input method UI:
-- currently the iPhone only responds to touches from capacitive devices like a finger.
-- the device's driver could be enhanced to detect a BlueTooth signal emitted by a capacitive pen stylus in close proximity
-- the UI could adjust itself to allow: pen only; finger only; both.
2) precision:
-- the iPhone software driver is set to detect a touch to an area of about 10-pixel radius, anything less is rejected/ignored
-- with the presence of the BT stylus, the driver could adjust to accept capacitive touches of, say, 1-2 pixels for greater precision
3) pressure:
-- pressure recognition is not particularly meaningful in current iPhone finger touches (though, it could be)
-- the stylus would be responsible for detecting the amount of pressure and including that in its signal the the device
4) pointing:
-- with finger touch, the device provides little/no pointing capability (though it could). The closest thing to built-in "pointing" is sliding to an adjacent key when using the on-display kb.
-- with a pressure-sensitive stylus, the device driver could detect a stylus touch with no (low) pressure as a pointer and display an arrow, crosshairs, brush, etc. ala a mouse or graphics tablet
5) tapping/clicking/dragging/flicking:
-- the device can currently respond to these gestures from any capacitive pointer, be it a finger or a stylus.
6) drawing/painting:
-- with finger input, the user selects a line width or brush size then: press/hold/drags to draw a line of consistent thickness
-- with a pressure-sensitive BT stylus the stylus detects varying pressure and sends that (along with the xy coordinates) to the device. The device draws the line of varying width, accordingly
-- the precision of the stylus will facilitate selecting/drawing/resizing shapes, masks, bezier curves.
Now, consider what the device can be programmed to do with the input described above:
-- handwriting and hand printing recognition
-- shape recognition with optional alignment, straightening and smoothing.
-- layers
-- annotation
-- shading/color/opacity/intensity variations
-- 3D paint thickness and build-up (finger painting)
-- interactive compositing, rotoscoping, rendering
Some of the above will, likely, not be possible with the hardware (CPU/GPU/RAM) of a small, mobile, tablet. But, there is no reason that a larger, beefier, tablet couldn't be used as I/O to, or as replacement for a desktop computer.
And, yes, I believe that every Mac computer (or whatever Apple replaces them with) will have touch screen I/O by 2011.
Let's face it! We're on the cusp of a revolution in the way man and machine interface. Apple is the only company in a position to pull this off & deliver the whole enchilada!
