Direct Manipulation and WIMP Environments

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Direct Manipulation and WIMP Environments

• CS 97 Human Computer Interaction
• Lecture 4

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Positive feelings associated with good user
interfaces

• Mastery of the interface
• Competence in performing tasks
• Ease in learning the system originally and in
  assimilating advanced features
• Confidence in the capacity to retain mastery over
  time
• Enjoyment in using the system
• Eagerness to show the system off to novices
• Desire to explore more powerful aspects of the
  system
• Direct manipulation is claimed to be a good
  interface

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Criteria for direct manipulation

• The OAI Model explanation of direct manipulation
• Continuous representation of the object of
  interest
• Physical actions or labeled button presses
  instead of complex syntax
• Rapid incremental reversible operations whose
  impact on the object of interest is immediately
  visible

WIMP - Windows, Icons, Mouse, Pull-Down Menus OAI
Object Action Interaction.
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Direct Manipulation Interface Characteristics

• Screen objects resemble physical objects
• Objects arranged in 2-D space
• Trades perceptual motor operations for linguistic
  operations
• Use of recognition in place of recall
• Expensive to implement

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Direct Manipulation Interface Examples

• Display editors and word processors
• Spreadsheet programs
• Spatial and geographic databases
• Video games and educational simulations
• CAD and paint type applications
• Hypertext
• Office automation software
• Virtual reality

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Advantages of WYSIWYG Word Processors

• Displays full page of text
• Displays document in preview format
• Shows cursor to user
• Control cursor using intuitively obvious moves
• Use labeled icons for actions
• Display results of actions immediately
• Provide rapid display response
• Offers easily reversible actions

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Word Processing Works Spawned Other Developments

• Integration of multimedia and hypermedia with
  text documents
• Desktop publishing tools
• Slide presentation software
• Hypermedia environments
• Improved macro facilities
• Spellcheckers and thesauri
• Grammar checkers
• Document assemblers

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GOMS Model for Direct Manipulation Interfaces

• Basic goal - minimize learning using a metaphoric
  device
• Basic method - find relevant object on screen and
  manipulate
• Step 1. Search screen for an object to operate on
• Step 2. Select it for manipulation
• Step 3. Move object on screen to destination

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GOMS Model for Direct Manipulation Interfaces
(contd)

• Must ensure
• Visual search (steps 1 and 3) works easily to
  find objects and their destinations
• Steps 2 and 3 must be fast consistent and easy to
  learn
• There must be a familiar direct manipulation
  metaphor or analogy (e.g. desktop)

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Problems with Direct Manipulation Interfaces

• Visual representations are more spread out than
  simple text - causing "off page" problems
• Users must learn meaning of components (e.g.
  icons) which are meaningful to designer and not
  user
• Visual representation may be misleading
• Touch typists do better with a keyboard than with
  a mouse

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Direct Manipulation Interfaces Allow

• Novices to learn basic fundamentals quickly
• Experts to carry out new tasks
• Knowledgable intermittent users to retain
  operational concepts
• Error messages are rarely needed
• Users can assess progress to goals and make
  changes instantly
• Users experience less anxiety because systems is
  understood and actions are reversible
• Users gain confidence and mastery through their
  sense of control over the system

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Visual Thinking and Icons

• The visual nature of computers can challenge the
  first generation of hackers
• An icon is an image, picture, or symbol
  representing a concept
• The debate concerning text versus icons is an
  emotional one (depends on how quickly user can
  figure out meaning of icon).

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Icon Design Guidelines

• Represent object/action in recognizable form
• Limit number of icons
• Make icon stand out from background
• Be careful when using 3-D icons
• Selected icons must be easily distinguished from
  unselected icons
• Icons unique from one another
• Ensure harmony with family of icons
• Design animation movement
• Add detailed information if possible
• Explore use of icon combinations to create new
  objects or operations

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Icon Design Considerations (Marcus)

• Lexical qualities (shape, color, brightness)
• Syntactics (appearance and component movement)
• Semantics (concrete vs abstract representation)
• Pragmatics (overall subjective impression)
• Dynamics (e.g. receptivity to mouse operations)

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Direct-Manipulation Programming

• Visual representations of information make
  direct-manipulation programming possible in other
  domains
• Demonstrational programming is when users create
  macros by simply doing their tasks
• The five challenges of programming in the user
  interface
• Sufficient computational generality
• Access to the appropriate data structures and
  operators
• Ease in programming and editing programs
• Simplicity in invocation and assignment of
  arguments
• Low risk

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Growth Areas for Direct Manipulation Interfaces

• Home automation
• Remote direct manipulation
• Virtual reality

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Home Automation

• Remote control of devices is being extended to
• Channel audio and video
• lawn watering
• video surveillance and burglar alarms
• Multiple-zone environmental controls
• Maintenance records
• Providing direct-manipulation with rich feedback
  is vital in these applications
• Many direct-manipulation actions take place on a
  display of the floor plan
• Controlling complex home equipment by direct
  manipulation reshapes how we think of homes and
  residents

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Remote Direct Environments

• Complicating factors in the architecture of
  remote environments
• Time delays
• transmission delays
• operation delays
• Incomplete feedback
• Feedback from multiple sources
• Unanticipated interferences

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Virtual Environments

• Virtual reality breaks the physical limitations
  of space and allow users to act as though they
  were somewhere else
• Augmented reality shows the real world with an
  overlay of additional overlay
• Situational awareness shows information about the
  real world that surrounds you by tracking your
  movements in a computer model

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Components for Successful Virtual Reality
Application

• Visual display
• Head positioning and sensing
• Hand positioning and sensing
• Force feedback
• Sound input and output
• Other sensation
• Cooperative and competitive virtual reality

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Direct Manipulation Program Structure

• Provide header information
• Initialize the program
• Create the interface widgets
• Render the display
• Build an infinite loop
• A direct manipulation program can be viewed as an
  event handler, i.e., waiting for an event to
  happen such as a mouse click or a key press and
  depending on the event calls an appropriate
  procedure or function. At least one event should
  terminate or exit the loop.

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Direct Manipulation and WIMP Interface Widgets
(Generic Set)

• Radio Box
• Paned Window
• Dialog
• Text
• Menu Bar
• Pull-down Menu
• application specific icons and widgets

• Window
• Label
• Form
• List
• Scroll Bar
• Push Button
• Toggle Switch

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Direct Manipulation(Summary)

• Visual representations (metaphor) of the world of
  action
• Objects and actions are shown
• Analogical reasoning is tapped
• Rapid, incremental and reversible actions
• Typing replaced by pointing and selecting
• Results of actions visible immediately

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Direct Manipulation(Summary)

• Benefits
• Control and display compatibility
• Less syntax, resulting in reduced error rates
• More preventable errors
• Faster learning and higher retention
• Exploration environment

• Concerns
• Increase system resources
• Cumbersome actions
• Weak macro techniques
• Difficult history tracing
• Difficult for visually impaired users