# -*- mode: org -*-

* [[http://www.youtube.com/watch%3Fv%3DMu5FCQmtdJU][Video: Stroke Dialer For Eyes-Free Keypad Input]]


The /stroke dialer/ enables one-handed keypad input using the
touch-screen --- and that without having to even look at the
screen. Here is how it works --- we start with a brief
description of the problem  that asks the /right/
question. The answer becomes self-evident as you follow this
video.

** The Problem

On-screen keyboards typically show some buttons on the screen
that you activate by touching the screen. To activate such
buttons, one needs to look at the screen, because the buttons are
placed at specific points on the screen, i.e., they are
/absolutely/ positioned. So what if you want to activate such
buttons /without/ looking at the screen?
From the foregoing description, it's clear that the only reason
one is forced to  look at  an on-screen keyboard  is because the
buttons are /absolutely/ positioned. So let's relax that
constraint, let's use /relative/ positioning to place the
buttons.

We'll start with a keyboard we're all familiar with, the
telephone keypad. Since we're using relative positioning,
let's place  the center of the keypad  /wherever/ you  first
touch the screen.
So, to dial a _5_, you just touch the screen.

Now, you know where _5_ is --- it's where you first touch
down. But look, since you know the layout of a phone keypad, you
can now find all the other digits /relative/ to the _5_. So for
example, _2_ is directly above _5_ --- so to    press _2_, you
touch down on the screen, and stroke up before lifting your
finger.
similarly, you stroke down for an _8_, or diagonally up for a
_1_.

In real life, we both /hear/ and /feel/ as we press physical
buttons. This form of synchronized auditory and tactile feedback
is essential for creating user interfaces that /feel/
realistic. The stroke dialer produces a slight vibration as  the
finger moves over the various buttons that is synchronized with
an auditory /tick/ to achieve this effect. It also produces
spoken feedback to indicate the button that was pressed.

To conclude this video, let's dial a few numbers.

#+TITLE: Video: Stroke Dialer For Android
#+AUTHOR: T.V Raman
#+EMAIL: raman@google.com
#+DATE: 2009-03-30 Mon
#+LANGUAGE: en
#+OPTIONS: H:3 num:t toc:nil \n:nil @:t ::t |:t ^:t -:t f:t *:t
#TeX:t LaTeX:nil skip:nil d:nil tags:not-in-toc +LINK_UP:
#http://eyes-free.googlecode.com/svn/trunk/documentation/videos/index.html
#+LINK_HOME: http://eyes-free.googlecode.com/