#+ professor patrick baudisch hci1: designing interactive systems hasso-plattner institute discrete, text, menus

for discrete tasks use discrete controls & techniques (such as buttons for typing or launching app) use pointing controls for pointing tasks

most of you will want 1. one or more types of discrete input (“buttons”) 2. one or more types of continuous input (“pointing”)

discrete input

keypad d-pad/ joystick qwerty keyboard

[PARC Tab] three buttons on the PARC tab

 Scott MacKenzie

text entry using gestures

hand writing reco

anoto

unistroke [Goldberg] reliable tokenization

graffiti more guessable

graffiti 2 Why did they change this?

June 28, 2006 Unistroke Payoff “Palm has agreed to pay Xerox $22.5 million to settle its long-running unistroke patent infringement suit.”

edgewrite [wobbrock] edgewrite works on joysticks, pen, touch, device backside..., is guessable

dasher slow, not intuitive as it may seem (try it out)

quikwriting benefit: concatenate strokes... h=

shark = shapewriter concatenate and leave out strokes...

let’s reflect…

buttons (e.g., keyboards) vs. gestures? pros and cons, when to use what?

tradeoff: buttons require minimum space, visual control gestures can be performed eyes free, but are all but impossible to discover

discoverability is a huge thing. for many applications a show stopper

that said: reminder… discoverable: users figure it out (without a tutorial?) efficient: allows performing tasks quickly robust: minimal error rates; help users recover pleasing/fun: high user satisfaction usability does not mean you always have to design for novices (but know who you design for)

two main usability goals for this tabletop: (1) discoverability (2) fun/pleasing probably no gesture here

most of these are simply gesture training devices

marking menus [Kurtenbach & Buxton, '91] alias sketchbook one that particularly well for 8 of fewer choices

linear menus require visual control marking menus can be used eyes-free

how to handle more than 8 choices?

29 compound marks

limitation: need space NE-E -NE-E

simple marks

limitation of simple marks?

how to abort half way in? forget that I have a mark already  error (they are “modal”)

there is no free lunch

minority

gwindows

[Rekimoto, GestureWrist, ISWC 2001] gesturesWrist uses accelerometers

[Wilson, Flowmouse] gestures observed by camera

[gesture pendant, starner et al ISWC 2000] wearable camera

motion capture system = set of cameras and markers (gold standard, used by film industry)

data glove measures position of hand and angle at finger joins

the term gesture is overloaded: motion vs. posture of the hand

gestures on tiny hardware

“scanners” := devices that users operate by moving their hand across [disappearing mobile devices, Ni & Baudisch, 2009]

1. motion scanner camera (as in mouse) seen as “curve right, curve right” recognized language is unistroke-like

graffiti “a” virtual scroll ring but: motion sensor = camera  requires certain size

2. touch scanner touch sensor seen as “..” recognized language ismorse ~pressing a button [Fukomoto]

one finger = 1 two fingers = 2

3. direction scanner 3 touch sensors seen as “east east” recognized language issimple marks

“west” “south”

touch scanner direction scanner motion scanner entering a “2” “NE” “..” “2”

# errors (out of 96) 5 letters = two thirds of errors error edgewrite works well (~5% error) most of graffiti works

edgewrite is entirely based on recognition of corners users can perform these eyes-free graffiti uses an additional type of feature: whether and where two strokes intersect graffiti error

large gestures (on non-mobile)

menuing

also discrete, not really different from text entry

keypad d-pad/ joystick qwerty keyboard can use same devices…

thumb wheel offers detents eyes-free

no detents 