CIS525 - Lecture#13 - October 18, 2000
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CIS 525 10/18/00
We get 2 DILBERT's today!! (we were Dilbert-less on Monday)
Interfaces: an overview
Direct manipulation interfaces:
=> menus
=> forms
=> command language
=> direct manipulation, (GUI, and WIMP's - Windows Icons Menus Pulldowns)
characteristics of direct manipulation interface;
1) screen objects resemble real objects
2) objects are arranged in 2d
3) trade a perceptual motor operation for a linguistic one
4) use of recognition in place of recall
5) expensive to implement (i.e. takes more time to program)
user model:
goal - to minimize learning using metaphoric device
basic method - find screen object and manipulate it
1) search screen for object to operate
2) select object for manipulation
3) move object on screen to destination
problems with direct manipulation
1) visual representations more 'spread out', so 'off-page' problems are common
2) users learn meaning of components which are meaningful to the designer, not user
3) visual misrepresentation can be misleading
4) touch typists do better with keyboard than with mouse
Icon design guidlines:
1) object/action is represented in a recognizable form
2) limit the number of icons, (7 + or - 2)
3) make icon distinct from background
4) be careful using 3d icons, they can be deceiving
5) selected icons easily distinguishable from unselected ones
6) icons need to be unique from one another
7) ensure 'harmony' within family of icons, (desktop, pen, scissors)
8) design animation movement, as opposed to letting it happen
9) added detailed info if possible, (mouse-overs)
10) explore creative combinations of icons to create new objects or new operations
interaction devices:
Java
-keyboard
-mice
-trackball, touch pad, (both must act like mice)
pointing device tasks:
1) selection
2) positioning objects
3) orienting objects on screen
4) path tracing
5) quantify, (i.e. slide bars)
menus: architectures
1) single
2) linear sequence
3) tree
4) acyclic networks, (does not return to top)
5) cyclic network, (returns to top - preffered)
screen display types:
1)text - keys
- pointing devices <= icons
2)radio buttons - single selection
3)checkboxes - multiple selections
4)pulldown/pop-up menus
5)command bars
user model:
1) search screen for item matching part of task
2) if match, then choose menu item
else, go to appropriate place in menu structure
3) if task accomplished, then stop
4) go to step 1
maintain task/event consistancy
try to use 'breadth' over 'depth'
possibly provide 'hot-key' shortcuts
menu SCREEN design guidelines
1) use task semantics to organize menu
2) again, prefer 'breadth' over 'depth'
3) show position using graphic, number, or title
4) use menu titles in trees
5) use meaningful groupings
6) use meaningful item sequencing/grouping
7) brief items beginning with keywords\
8) consistent grammar layout terminology
9) allow type ahead/shortcut options
10) allow jumps to main menu
11) consider online help
12) menu matches natural language experiences
form fill-in user model:
1) search screen for next field to fill in
2) move cursor to field
3) user figures out what to type and type it in
4) if all fields are correct, then indicate finished
else, move cursor to incorrect field and change
5) go to step 1
guidlines:
1) preserve similarities to paper forms
2) do not force entry order
3) on screen navigation instruction
4) good graphic layout
5) describe special data entry formats
6) apply validity checks and clear feedback on errors
dialog boxes are basically composite of above items
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