Design, prototyping and construction

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Design, prototyping and construction
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The Task-Centered Design Process

• figure out who's going to use the system to do
  what
• choose representative tasks for task-centered
  design
• plagiarize
• rough out a design
• think about it
• create a mock-up or prototype

• test it with users
• iterate
• build it
• track it
• change it

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Overview

• Prototyping and construction
• Conceptual design
• Physical design
• Tool support

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Two guidelines for design

• 1. Provide a good conceptual model
• allows user to predict the effects of our actions
• problem
• designers conceptual model communicated to user
  through system image
• appearance, written instructions, system
  behaviour through interaction,
• transfer, idioms and stereotypes
• if system image does not make model clear and
  consistent, user will develop wrong conceptual
  model

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Two guidelines for design (continued)

• 2. Make things visible
• relations between users intentions, required
  actions, and results are
• sensible
• non arbitrary
• meaningful
• visible affordances, mappings, and constraints
• use visible cultural idioms
• reminds person of what can be done and how to do
  it

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Prototyping and construction

• What is a prototype?
• Why prototype?
• Different kinds of prototyping low
  fidelity high fidelity
• Compromises in prototyping vertical horizontal
• Construction

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What is a prototype?
In other design fields a prototype is a
small-scale model a miniature car a miniature
building or town
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What is a prototype?

• In interaction design it can be (among other
  things)
• a series of screen sketchesa storyboard, i.e. a
  cartoon-like series of scenes a Powerpoint slide
  showa video simulating the use of a systema
  lump of wood (e.g. iphone)a cardboard mock-upa
  piece of software with limited functionality
  written in the target language or in another
  language

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Why prototype?

• Evaluation and feedback are central to
  interaction design
• Stakeholders can see, hold, interact with a
  prototype more easily than a document or a
  drawing
• Team members can communicate effectively
• You can test out ideas for yourself
• It encourages reflection very important aspect
  of design
• Prototypes answer questions, and support
  designers in choosing between alternatives

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What to prototype?

• Technical issues
• Work flow, task design
• Screen layouts and information display
• Difficult, controversial, critical areas

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Low-fidelity Prototyping

• Uses a medium which is unlike the final medium,
  e.g. paper, cardboard
• Is quick, cheap and easily changed
• Examples sketches of screens, task sequences,
  etc Post-it notes storyboards Wizard-of-Oz
  

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Storyboards

• Often used with scenarios, bringing more detail,
  and a chance to role play
• It is a series of sketches showing how a user
  might progress through a task using the device
• Used early in design

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Sketching

• Sketching is important to low-fidelity
  prototyping
• Dont be inhibited about drawing ability.
  Practice simple symbols

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Using index cards

• Index cards (3 X 5 inches)
• Each card represents one screen
• Often used in website development

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Wizard-of-Oz prototyping

• The user thinks they are interacting with a
  computer, but a developer is responding to output
  rather than the system.
• Usually done early in design to understand users
  expectations
• What is wrong with this approach?

User
gtBlurb blurb gtDo this gtWhy?
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High-fidelity prototyping

• Uses materials that you would expect to be in the
  final product.
• Prototype looks more like the final system than a
  low-fidelity version.
• For a high-fidelity software prototype common
  environments include Macromedia Director, Visual
  Basic, and Smalltalk.
• Danger that users think they have a full
  system.see compromises

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Compromises in prototyping

• All prototypes involve compromises
• For software-based prototyping maybe there is a
  slow response? sketchy icons? limited
  functionality?
• Two common types of compromise
• horizontal provide a wide range of functions,
  but with little detail
• vertical provide a lot of detail for only a
  few functions
• Compromises in prototypes mustnt be ignored.
  Product needs engineering

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Construction

• Taking the prototypes (or learning from them) and
  creating a whole
• Quality must be attended to usability (of
  course), reliability, robustness,
  maintainability, integrity, portability,
  efficiency, etc
• Product must be engineered
• Evolutionary prototyping
• Throw-away prototyping

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Conceptual design from requirements to design

• Transform user requirements/needs into a
  conceptual model
• a description of the proposed system in terms of
  a set of integrated ideas and concepts about what
  it should do, behave and look like, that will be
  understandable by the users in the manner
  intended
• Dont move to a solution too quickly. Iterate,
  iterate, iterate
• Consider alternatives prototyping helps

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Three perspectives for a conceptual model

• Which interaction mode?
• How the user invokes actions
• Activity-based instructing, conversing,
  manipulating and navigating, exploring and
  browsing.
• Object-based structured around real-world
  objects

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Three perspectives for a conceptual model

• Which interaction paradigm?
• desktop paradigm, with WIMP interface (windows,
  icons, menus and pointers),
• ubiquitous computing
• pervasive computing
• wearable computing
• mobile devices and so on.
• Is there a suitable metaphor?
• (contd).

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Is there a suitable metaphor?

• Interface metaphors combine familiar knowledge
  with new knowledge in a way that will help the
  user understand the product.
• Three steps understand functionality, identify
  potential problem areas, generate metaphors
• Evaluate metaphors
• How much structure does it provide?
• How much is relevant to the problem?
• Is it easy to represent?
• Will the audience understand it?
• How extensible is it?

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Interface metaphors

• Interface designed to be similar to a physical
  entity but also has own properties
• e.g. desktop metaphor, web portals
• Can be based on activity, object or a combination
  of both
• Exploit users familiar knowledge, helping them
  to understand the unfamiliar
• Conjures up the essence of the unfamiliar
  activity, enabling users to leverage of this to
  understand more aspects of the unfamiliar
  functionality

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Benefits of interface metaphors

• Makes learning new systems easier
• Helps users understand the underlying conceptual
  model
• Can be very innovative and enable the realm of
  computers and their applications to be made more
  accessible to a greater diversity of users

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Problems with interface metaphors

• Break conventional and cultural rules
• e.g. recycle bin placed on desktop
• Can constrain designers in the way they
  conceptualize a problem space
• Conflict with design principles
• Forces users to only understand the system in
  terms of the metaphor
• Designers can inadvertently use bad existing
  designs and transfer the bad parts over
• Limits designers imagination in coming up with
  new conceptual models

http//www.cooper.com/articles/art_myth_of_metapho
r.htm
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Expanding the conceptual model

• What functions will the product perform?
• What will the product do and what will the human
  do (task allocation)?
• How are the functions related to each other?
• sequential or parallel?
• categorisations, e.g. all actions related to
  telephone memory storage
• What information needs to be available?
• What data is required to perform the task?
• How is this data to be transformed by the system?

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Physical design getting concrete

• Considers more concrete, detailed issues of
  designing the interface
• Iteration between physical and conceptual design
• Guidelines for physical design
• Nielsens heuristics
• Coopers About Face 2.0
• Styles guides commercial, corporate
• decide look and feel for you
• widgets prescribed, e.g. icons, toolbar

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Alan Coopers Excise Traps

• Dont force the user to go to another window to
  perform a function that affects this window
• Dont force the user to remember where he put
  things in the hierarchical file system
• Dont force the user to resize windows
  unnecessarily
• Dont force the user to move windows
• Dont force the user to reenter personal settings

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Coopers Excise Traps

• Dont force the user the fill fields to satisfy
  some arbitrary measure of completeness
• Dont force the user to ask permission to make
  changes.
• Dont ask the user to confirm his actions.
• Dont let the users actions result in an error.

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Direct manipulation

• Direct manipulation captures the idea of direct
  manipulation of the object of interest
  (Shneiderman 1983 p. 57), which means that
  objects of interest are represented as
  distinguishable objects in the UI and are
  manipulated in a direct fashion.
• Characteristics
• Visibility of the object of interest.
• Rapid, reversible, incremental actions.
• Replacement of complex command language syntax by
  direct manipulation of the object of interest.

Drag and drop files
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One of the earliest commercially available
direct manipulation interfaces was MacPaint
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Direct Manipulation

• Advantages
• Visually presents task concepts.
• Easy to learn.
• Errors can be avoided more easily.
• Encourages exploration.
• High subjective satisfaction.
• Recognition memory (as opposed to cued or free
  recall memory) 
• Disadvantages
• May be more difficult to program.
• Not suitable for small graphic displays.
• Spatial and visual representation is not always
  preferable.
• Metaphors can be misleading since the the
  essence of metaphor is understanding and
  experiencing one kind of thing in terms of
  another (Lakoff and Johnson 1983 p. 5), which,
  by definition, makes a metaphor different from
  what it represents or points to.
• Compact notations may better suit expert users.

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Dont Mode me in

• UNIX vi is an example of evil modes
• same actions have different meanings depending on
  context
• edit replaces your file with t
• Paint programs are a good example of good
  modes.
• Modes are visible

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Rules for modes

• Use modes consistently
• Do not initiate modes unexpectedly
• Make modes visible
• Make it easy to escape modes
• without consequences.

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Physical design getting concrete

• Different kinds of widget (dialog boxes,
  toolbars, icons, menus etc)
• menu design
• icon design
• screen design
• information display

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Icon design

• Good icon design is difficult
• Meaning of icons is cultural and context
  sensitive
• Some tips
• always draw on existing traditions or standards
• concrete objects or things are easier to
  represent than actions
• From clip art, what do these mean to you?

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Screen design

• Two aspects
• How to split across screens
• moving around within and between screens
• how much interaction per screen?
• Individual screen design
• white space balance between enough
  information/interaction and clarity
• grouping items together separation with boxes?
  lines? colors?

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Screen design individual screen design

• Draw user attention to salient point, e.g.
  colour, motion, boxing
• Animation is very powerful but can be distracting
• Good organization helps grouping, physical
  proximity
• Trade off between sparse population and
  overcrowding

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Principles of Visual interface design

• Avoid visual noise and clutter
• Use contrast, similarity, and layering to
  distinguish and organize elements
• Provide visual structure and flow at each level
  of organization
• Use cohesive, consistent, and contextually
  appropriate imagery
• Integrate style and function comprehensively and
  purposefully
• Alan Cooper, Robert M. Reimann. About Face 2.0
  The Essentials of Interaction Design. Page 227.

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Organization of Screen Elements

• Balance
• Symmetry
• Regularity
• Predictability
• Sequentiality
• Economy
• Unity
• Proportion
• Simplicity
• Groupings

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Balance

• Equal weight of screen elements
• Left to right, top to bottom

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Balance
Unstable
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Balance

• Left column processed - Right column noted as
  same
• Both columns need to be understood by visual
  processing system

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Symmetry

• Replicate elements left and right of the center
  line

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Symmetric
Asymmetric
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Regularity

• Create standard and consistent spacing on
  horizontal and vertical alignment points

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Regularity

• Left column processed - 2 right columns noted as
  same
• Location size of each object processed

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Predictability

• Put things in predictable locations on the screen

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Predictable
Spontaneous
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Predictability

• User expects title menu bar on top of screen
• Visual scene needs to be completely processed -
  objects not in expected places

Icon
Search for Movies
File Edit View Insert Window Help
Enter Keywords
Kung Foo
Grasshopper
Old blind guy
Cancel
OK
Icon
OK
Enter Keywords
Kung Foo
Grasshopper
Old blind guy
File Edit View Insert Window
Help
Search for Movies
Cancel
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Sequentiality

• Guide the eye through the task in an obvious way
• The Eye is attracted to
• bright elements over less bright
• Isolated elements over grouped
• graphics before text
• color before monochrome
• saturated vs. less saturated colors
• dark areas before light
• big vs. small elements
• unusual shapes over usual ones

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Screen design splitting functions across screens

• Task analysis as a starting point
• Each screen contains a single simple step?
• Frustration if too many simple screens
• Keep information available multiple screens open
  at once

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Membership Form
Name
Dues
Address
Pubs
City
Total
State
Zip
OK
Cancel
Sequential
Membership Form
Name
OK
Cancel
Address
Pubs
State
Dues
City
Zip
Total
Random
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Economy

• Use as few styles, fonts, colors, display
  techniques, dialog styles, etc., as possible

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Membership Form
Name
Dues
Address
Pubs
City
Total
State
Zip
OK
Cancel
Economical
Membership Form
Name
Dues
Address
Pubs
City
Total
State
Zip
OK
Cancel
Busy
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Unity

• Make items appear as a unified whole (for visual
  coherence)
• Use similar shapes, sizes, or colors
• Leave less space between screen elements than at
  the margin of the screen

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Unity
Fragmentation
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Proportion

• Create groupings of data or text by using
  aesthetically pleasing proportions

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Pleasing Proportions
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Simplicity

• Minimize the number of aligned points
• Use only a few columns to display screen elements
• Combine elements to minimize the number of screen
  objects
• Within limits of clarity

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Simplicity

• Only four alignments need to be processed
• A total of nine alignments need to be processed

Membership Form
Name
Dues
Address
Pubs
City
Total
State
Zip
OK
Cancel
Membership Form
Name
Address
Pubs
City
Total
State
OK
Zip
Cancel
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Size
Preserve Proportions of original height of
original width
Simple
Size Uniformity Height Width
Preserve Proportions of original of original
Complex
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Groupings

• Use visual arrangements to provide functional
  groupings of screen elements
• Align elements in a group
• Evenly space elements in a group
• Provide separation between groups
• Use additional group elements sparingly
• color borders add complexity

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Simple Grouping

• Similar elements aligned vertically
• Vertical distance between similar objects small

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Boxed Grouping

• Boxes add additional complexity to form
• Spatial arrangement adequate

Membership Form
Name
Dues
Address
Pubs
City
Total
State
Zip
OK
Cancel
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Background Grouping

• Color adds additional visual complexity
• Spatial arrangement adequate

Membership Form
Name
Dues
Address
Pubs
City
Total
State
Zip
OK
Cancel
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Alignment Grids and the Users Logical Path

• Align labels. Labels for controls stacked
  vertically should be aligned with each other
  left-justification is easier for users to scan
  than right justification, although the latter may
  look visually cleaner-if the input forms are the
  same size. (Otherwise, you get a Christmas tree,
  ragged-edge effect on the left and right.)
• Align within a set of controls. A related group
  of check boxes, radio buttons, or text fields
  should be aligned according to a regular grid.
• Align across controls. Aligned controls (as
  described previously) that are grouped together
  with other aligned controls should all follow the
  same grid.
• Follow a regular grid structure for larger-scale
  element groups, panes, and screens, as well as
  for smaller grouping of controls.
• Alan Cooper, Robert M. Reimann. About Face 2.0
  The Essentials of Interaction Design. (Wiley,
  2003). Page 230.

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Aligned grid layout
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Screen-based Controls

• Widgets
• elements of screen displays
• interaction toolkits
• ready-made interaction objects
• predefined behaviors
• customizable properties

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Functions of Widgets

• Selecting options and commands
• Entering and editing data values
• Displaying data

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Kinds of Widgets

• Buttons
• Text entry/read-only
• Selection
• Combination entry/selection
• Specialized or custom
• Presentation

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Design issues

• Labels and graphics
• Layout and organization
• Activation

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Labels and Graphics

• Use labels and captions
• Use standard names when appropriate
• Use regular system font
• Clearly tie the text to the control
• Maintain consistent heights and widths
• Use common shapes (mostly rectangles)
• Pick icons that map to the actions
• Supplement icons with text descriptions

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Layout and Organization

• Provide adequate spacing
• Limit the number of controls on one screen
• Keep related controls together
• Use visual enclosure of groups where appropriate

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Aligning list boxes

• Align list boxes vertically rather than
  horizontally.
• Horizontally aligned list boxes are more
  difficult for the user to use, as the controls
  cannot be scanned easily.

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Aligning radio buttons

This
Not this
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Activation

• Provide keyboard equivalents
• Control activation
• Movement among controls within a screen
• Provide feedback for actions
• Gray out unavailable choices

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Buttons

• Initiates an action
• to activate a command (an alternate to menu
  choice or command line entry).
• to display another window or menu selection
• Always visible
• provides convenient access to frequently-used
  commands
• standard shapes and screen location for similar
  commands.
• Logical organization

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Buttons

• Types
• Command buttons -- text as labels
• Bar buttons (menu buttons)
• -- graphics and/or text as labels
• Radio buttons

Next
Microsofts Button Types
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Which one is better?
Plan Choice
Limited
Basic
Superior
Premium
Plan Choice
Plan Choice
Limited
Limited
Basic
Basic
Superior
Superior
Premium
Premium
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Button Design Issues

• Labels
• Shapes and Graphics
• Location and layout
• Organization
• Activation

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Buttons -- labels

• Use standard button labels when available
• Provide meaningful action description
• Use regular system font
• unless for some special purposes
• Center the label text
• Provide consistency across all screens

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Buttons --shape and graphics

• Use rectangular shape whatever possible
• Maintain consistent button heights and widths
• Design graphics/icons that have natural mapping
  to the actions
• Enhanced graphics with text description

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Buttons -- Organization

• Maintain consistency in button locations across
  screens and windows
• provide adequate spacing between buttons and
  other screen controls
• Restrict the number of buttons on one screen
• Follow standards
• Keep related buttons together

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Buttons -- Activation

• Consider different actions for
• mouse enter/exit .. mouse down/up/
• Consider keyboard equivalents for actions
• Provide feedback for actions
• highlight the button when the button is selected
• Gray out unavailable choices.

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Text Entry/Read-Only Controls

• Text boxes
• Editable/read-only (fields vs. labels)
• single line/multiple lines
• fixed size/resizable
• fixed length/variable lengths
• visual box/non-visual box
• scrollable /non-scrollable
• Properties
• background/foreground colors
• sizes/fonts/styles of text
• alignments

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Text Box Design

• Provide descriptive caption
• Logical arrangement of multiple fields
• Consider the cursor movement from one field to
  another.
• Provide large enough boxes for fixed-length data
• Select reasonable fonts/sizes/colors
• Design highlight to attract attention

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Selection Controls

• Present all options or choices on the screen
• Radio Buttons
• Check Boxes
• Palettes
• List Boxes
• Combo Boxes
• Drop-Down/Pop-Up
• Single Selection/Multiple Selection?

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Selection Design

• Choice Description
• Meaningful and clear description for the value or
  effects of the choice
• Use single line of text whenever possible
• Organization
• Meaningful order of choices
• Consider adding a enclosure box
• Activation
• Provide visual feedback
• Provide default values

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List Box or Combo Box?

• List box
• unlimited number of choices
• possible multiple choices
• consumes screen space
• can be set to different size
• easy to see the choices

• Combo box
• unlimited number of choices
• highlight the selection
• conserves screen space
• Extra step to display all the choices

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More Selection Controls

• Spin Boxes

• Attached Combo Boxes

0.5
Left Margin
Font Style
Regular
Regular
Italic Bold Bold Italic
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Other Controls

• Scroll Bars
• Sliders
• Toggle Switches
• Tab pages
• Contain tabbed divider pages

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Presentation Controls

• Provide additional information to screen elements
• Tooltips
• a small popup window attached to an object
• shows only when the mouse moves over the object
• Static Text Fields -- labels
• Group Boxes
• Combined controls in one box
• Progress Indicators

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Message Design