Groups for Lab Classes

1http://img.cs.man.ac.uk/stevens

Groups for Lab Classes

• http://www.cs.man.ac.uk/~alanw/LABS/2352-groups.html


Interaction Styles

CS2352 Lecture 9

Robert Stevens

http://www.cs.man.ac.uk/~stevensr


Introduction

• A dialogue between human and computer• Interaction style influences nature of dialogue• Command line• WIMPS• Natural language• Form fill-in


Command Line

• Textual, keystroke driven dialogue with computer• @Words, part-words, function keys etc used to talk to computer• Direct access to system functionality, rather than indirection

through hierarchical menus• Combined together into scripts• Flexibility through options (counterpart in dialogue boxes)• Can be applied to many items at once• Good for repetitive tasks


Costs of Command Line

• Difficulty in use and learning• No cues for recognition• Alleviate with memorable and consistent terminology• Commands should be terms from the task language (remove,

copy, move, make directory, etc.)• Commands often obscure and vary across systems: grep, awk,

sed, bif, rm, del, etc.


Command Line: The Find Command

$find –name cs2352*

$find –name cs2352* -print

Cs2352-exam.doc

Cs2352-script.doc

Cs2352-model-ans.doc

$


Natural Language

• Natural to use• Problems are myriad – Pragmatics, context, anaphora,

ambiguity• “Robert does his research on drugs”• “The business man leant on the bank”• Real natural language unlikely and perhaps not desireable• Restricted forms of language possible• These still have to be learnt• User should be aware of their limitations• Can be successful


Question/Answer or Query Dialogue

• Narrow domain, precise questions with limited answers• Install Wizards – Ask limited questions, offer choices, allow

movement back and forth, choices determine further questions• Narrow range of applications• User led through task• Also general query interfaces e.g. SQL• Specific syntax, choice of values for attributes & complexity of

Boolean expressions


Form Fill-In

• Form-based question & answer• User guided to fill out question• Offered values• Can change mind etc.• Spreadsheet an extreme version


Body Mass Index Form Fill-In


Windowing Systems

• Most common form of interaction• Language of Menus, buttons, text fields, pick lists, check boxes,

etc.• Windows, icons, menus & pointers• Web uses a variant – “point and click”• Elements of the WIMP interface are “widgets”• Different WIMP interfaces display and use widgets in their own

manner• Gives Look and Feel


Three Dimensional Effects


Elements of the WIMP Interface


Windows

• Bounded areas of screen• Act as a thread of dialogue• Act as separate terminals• Multiple windows on a screen• Multiple tasks accessible• Moveable, re-sizeable, scrollable (Window small view on large

world)• Title bar, maximise, minimise and close


Icons

• Windows closed and lost or iconised• Small picture representing the task• Allows increased availability of tasks• Act as reminder• Icons for many attributes of UI: Waste bin, drives, tasks,

programmes, etc.• Images real world, styalised, abstract• Need to be easy to recognise


Pointers

• Used to point and select• Different pointer shapes indicate mode of use• Also display system activity• Pointer has hot-spot where click acts• Lack of visible hot-spot is a design flaw


Menus• Offer choice of tasks to be performed• Offer recognition rather than recall• Thus meaningful, consistent naming• Pointer indicates which option is to be selected• Further task, such as clicking, activates option• Long menus inefficient (Fitt’s law), so casscading menus used• Top-level options often always available; sometimes as tool-

bars for frequent tasks• Pop-up menus give contextual or global tasks • Pull-down, fall-down pin-up menus• Keystroke accelarators and shortcuts to short-cut menus for

experts (should be usable in menu to reinforce learning)


Grouping in Menus

• Menus group tasks together• Should not be too long• Should not be too many menus• Some items could come in more than one place• In pull-down style, name should reflect overall functions of

options (“exit” in /file menu• Consistent across applications to aid learning• Ordered by importance, frequency and task sequence?)• Opposing functions kept apart


Buttons

• Isolated & individual regions of screen selected to invoke task• Resemble mechanical push-button• Meaning related by icon and/or textual label• Toggle buttons for alternative states (bold/italic)• Radio buttons for range of mutually exclusive options

(bold/italic,regular;point sizes)• Toggle buttons sometimes checkboxes


Tool Bars

• Applications have rows of buttons offering commonly used functions

• Editing, drawing and formatting tools• Similar to menu, but icons allow more to be displayed• Contents of icons fixed, but contents of tool-bar can customised


Modes

• A mode places interpretation upon an action• VI has command mode and edit mode• “:wq” is “write and quit” in command mode• Writes “:wq” in edit mode• IN file menu, “s” saves a file, writes “s” in edit window• Mode must be visible to user – not shown in VI• Explicit, clumsy modes seen as bad, but modes are ubiquitous


Palattes

• Palattes make mode apparent• Offer collections of icons, button, etc that make mode apparent

to user• Drawing mode offers collections of drawing tools• Palattes often customisable• Tear-off menus form palattes• Common in graphical tasks• Mode is part of system state


Dialogue Boxes

• Information windows to draw user’s attention to some change of state – “file not saved”

• Sub-dialogue of larger task – “save as” dialogue• Windows provide separation of task threads• Dialogue boxes are separations of sub-tasks etc.• Often have variety of interaction styles vbia various widgets:

Text fields, menus, buttons, checkboxes, etc.


Screen Design

• The way widgets are put together• Ergonomics, cognition via graphical design• Presents tasks and promotes correct dialogue with system• Kinds of information: Text, numbers, maps, pictures, etc.• Technology: Characters, graphical displays, size, etc.• Purpose: File displays by name, type, date, thumbnails, etc.• Much knowledge from graphic design for static material –

transfers well• Interactive systems choice of presentation is possible –

Windows “view” menu arranges file windows


Presentation

• Colour used to reinforce information• Aligned colums: Text aligned left Integers aligned right Reals aligned on decimal point• Shape of column then gives indication of size• Data emtry layout as import as data presentation• Text entry fields should be aligned: Not jagged due to labels!• Remember task analysis for order, dependencies and values• Cultural dependence of viewing order for labels• Beauty and utility

Groups for Lab Classes

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