CHAPTER 6

BEN CARSON

SUNIL D SOUZA

RAJESH GOLLA

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.

ICONS or TEXT

Icons or Text – depends on Users Tasks Quality of the icons or tasks.

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.

6.5 Direct Manipulation

Performing tasks by DM- not the only goal

Programming by DM

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

6.10 RESEARCHERS AGENDA

Better understanding of factors

Better history keeping

Encourage innovation in DM using software tools