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Section 6.1 - Introduction Users of systems incorporating direct
manipulation are enthusiastic supporters
Traits of direct manipulation systems typically include: Easy to learn Competent and efficient use of the system Enjoy using Eager to learn more about the system Visibility of objects and actions
6.2 – Examples
Word Processing Systems Spreadsheets Spatial data management Video games Computer Aided Design Office Automation
Word Processing Progression of word processing systems
Line-oriented Full-page display editors WYSIWYG
Enhancements Inclusion of objects Desktop publishing Slide presentation software Hypermedia environments Improved macros Spell/grammar checkers and thesauri Documents assemblers
Enjoyment from easily designing complex documents versus original command line editors
Spreadsheets Progression of spreadsheets
VisiCalc Lotus 1-2-3 Excel
Enhancements Graphics 3-D representations Multiple sheets Database features
Enjoyment from ease of making many tedious calculations quickly and representing it in many meaningful forms
Spatial Data Management Visual representation of a specific area of interest
Personnel of a company Map with travel information File directories
Enjoyment from interacting with the visual elements of this type of system
Video Games PONG
1st video game Commands are physical actions, results on-
screen Can be entertaining and/or educational Differs from other systems behavior
Game systems challenge the user Non-game systems try not to challenge the user
Enjoyment from user being challenged and entertained
Computer Aided Design (CAD)
“virtually” design products and receive quick feedback
Computer aided manufacturing Aids in improving already existing
processes Enjoyment from ability to manipulate
systems directly and easily view multiple alternatives.
Office Automation
Uses direct manipulation principles hardware and software has evolved to
support more and better graphics, dropdowns, icons, etc.
Enjoyment from easier working environment than with command line based environments
6.3 - Explanations of Direct Manipulation
Nelson Principle of virtuality
Rutkowski Principle of transparency
Hutches Gulf of execution and evaluation
All refer to making the interface as invisible as possible
Problems with Direct Manipulation
Visual representation may not be the best way to represent a particular problem or scenario
Must learn meaning of visuals Can be misleading Using a mouse can be more time-
consuming than a keyboard
Objects-Actions Interface (OAI) model explanation of direct manipulation
D.M. systems usually have the following Consistent and meaningful visual representations and actions Physical actions or labeled button presses replace complex command
syntax Quick reversible changes on objects with immediately visible results
Users report D.M. systems to be Easy to learn Experts are very fast and effective and can expand upon existing
functionality of the system Easy to retain knowledge Error messages rarely needed Less anxiety-inducing because of ease-of-use and reversible actions
D.M. systems operate on a high-level task domain Easy of learning and use is a result of their more intuitive interface,
compared with command syntax based environments
6.4 Visual Thinking and Icons
Concepts of Visual language and visual thinking- promoted by Arnheim (1972)
Computer provides remarkable visual environment
New- WIMP Old -inflexible and stubborn Different people have different cognitive
styles
Issue of Icons
An icon is an image, picture or symbol representing a concept.
For visually oriented tasks- stay visual by using icons
For text document- stay textual by using textual menus
Sometimes use a “mix” of both.
Icon specific guidelines
1. Represent the object in a familiar manner.2. Limit he number of icons.3. Make the icon stand out from its background.4. Consider 3-D icons.5. Single selected icon clearly visible when surrounded by
unselected icons.6. Make each icon distinctive from every other icon.7. Ensure the harmoniousness of each icon as a member of family
of icons.8. Design the movement animation.9. Add detailed information. Ex-shading to show size of file.10. Explore the use of combinations of icons.
Four levels of design
1. Lexical qualities: Machine generated tasks-pixel shape, color, brightness, blinking.
2. Syntactics: Appearance and movement-lines, patterns, size, shape.
3. Semantics: Objects represented- concrete versus abstract, part versus whole.
4. Pragmatics: overall legibility, utility, identifiable, memorable, pleasing.
5. Dynamics: receptivity to clicks.
CHALLENGES
Five challenges of programming in the user interface
1. Access to appropriate date structures.
2. Sufficient computational generality.
3. Ease in programming and editing programs.
4. Simplicity in invocation and assignment of arguments.
5. Low risk.
6.6 Home Automation.
Prediction of larger market in extensive controls in homes- but only if the user interfaces can be made simple.
6.7 Remote Direct Manipulation
Teleoperation/Remote Controlled Environment
E.g.: Home-automation, applications underwater
TELEMEDICINE
Disadvantages Time Delays Incomplete Feedback Cumbersome due to multiple sensors Unanticipated Interferences
6.8 VIRTUAL ENVIRONMENTS
Components Visual display Head position sensing Hand position sensing Force feedback Sound input and output
6.9 SUMMARY
More resources, possibly Some actions cumbersome Tracing difficult? Difficult for visually impaired users
Benefits Concerns
Faster feedbackReduced error ratesFaster learning & retentionEncourages innovation