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Pens v. Mice
Some random thoughts on differences between Pens and Mice
I was thinking the other day about pen computers, and the difference between pens and mice. I have owned both an Apple Newton and a Palm Pilot, and have played with a WinCE handheld, and it occurred to me that there are differences between pens and mice, and their respective environments.
Two big differences struck me immediately: 1) A pen acts like a mouse with only one button: ie a Mac Mouse. 2) When a pen isn't touching the screen, ie when the mouse button isn't pressed, a system has no idea where the pointer is.
In the original Mac, the mouse was a good metaphor for a pen. There was only one button, and when the button wasn't pressed, the mouse did nothing except move the cursor around. Windows copied this interface originally, and for a long time (though most WinMice have two buttons) only used one mouse button. Recently, Windows mice appear to have been cross-bred with game controllers, and are growing all sorts or buttons, toggles and little scroll wheels. I recently saw a new mouse with 4 buttons and a wheel to scroll the screen. From the start, Smalltalk used three buttons on the mouse (does anyone know why?). A small number of buttons, where each button does a specific task seems to work well, but how do you translate this into a pen environment? A hack involving keystrokes, etc., seems arbitrary and messy.
When I take my pen off the screen, the system cannot track where it is. Again, in the original Mac the mouse acted as a metaphor for a pen: when the button was up, all that was left was a cursor to mark where the mouse was. The cursor did nothing. Nowdays rollovers, where a button self-highlights when a cursor moves over it, are becoming a staple of web designers and computer programmers. I like rollovers, they look cool and seem intuitive. But they don't work in a simple pen environment. Notably, Smalltalk seems to have had rollovers from the start: scroll bars that jumped out, etc., suggesting that when Smalltalk was designed, the mouse was seen as a unique device and not as a pen metaphor. How should rollovers be translated into PenSqueak?
One last thing. Showing system status by changing a cursor to an hourglass or wristwatch works poorly for pens, because when you take a pen off a screen, the cursor disapears. I'm not as sorry about this as I am about rollovers, because using the cursor to indicate system status is growing confusing in the age of multitasking. My browser, when loading a page, has a different cursor for each part of the screen: the page itself is an hourglass, the scrollbar is a pointer, the buttons are a hand etc. There must be better ways.
Well, here end my thoughts for now. Please add to this: it is a Wiki after all :-)