CS 3724 Lecture Notes for Sep 25

I. Characteristics of DM systems

• Continuous visibility of the objects and actions of interest
• Rapid, reversible, incremental actions
• Replacement of comman-language syntax by direct manipulation of the object of interest

II. Examples

Text editors

• line-oriented editors (ed)
• full-page display editors (vi, emacs)
• point-and-click editors (xemacs)

WYSIWYG word processors (Word, Word Pro, WordPerfect)

• display a full page of text
• document appears in form it will appear when printed
• cursor shown to user
• cursor controlled with obvious, intuitive means
• labeled icons
• results of actions displayed immediately
• reversible actions (inverse commands, undo)

Electronic spreadsheets

• VisiCalc
• Lotus 1-2-3, Microsoft Excel

Games

Examples

• PONG
• Space Invaders, Missile Command, Centipede
• Maze games (PacMan, Donkey Kong, Castle Wolfenstein)
• 3-D games (Castle Wolfenstein 3D, Doom, Duke Nukem)

Features

• Entertainment and challenge of mastery vs focus on task and limited distractions
• New I/O devices
• Advanced graphical techniques
• User interface advances

III. Problems with direct manipulation

• Wasted screen space
• Difficult to convey some meanings
• Visual representations misleading
• Mouse can be slower than typing
• Not self-explanatory

• Repetition
• History storage and display
• Certain tasks with no manual equivalent
• Macro creation

IV. Advantages of direct manipulation

• Easier to learn and remember
• Direct WYSIWIG
• Flexible, easily reversible actions
• Context and visual feedback
• Exploits human use of visual spatial cues
• Limits types of errors