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Human Computer Interface UNIT-4

UNIT-IV



SELECT THE PROPER KINDS OF WINDOWS


A window is an area of the screen that contains a particular view of some area of the computer or some portion of a person’s dialog with the computer.


Navigation Goals:


  • A well designed navigation system facilitates quick & easy navigation between components whose structure & relationship are easily comprehensible.

  • For the user, answers to the following questions must be obvious at all times during an interaction: Where am I now? Where did I come from? Where can I go from here? How can I get there quickly?

  • General system navigation guidelines include the following.

  • Control

For multilevel menus, provide one simple action to:


  • Return to the next higher-level menu.

  • Return to the main menu.

  • Provide multiple pathways through a menu hierarchy whenever possible.

  • Menu Navigation Aids

To aid menu navigation & learning, provide an easily accessible:


  • Menu map or overview of the menu hierarchy.

  • A “look ahead” at the next level of choices, alternatives that will be presented when a currently viewed choice is selected.

  • Navigation history.


  1. Web Site Navigation:

    • In designing a Web Site Navigation scheme there are two things to take in consideration:

      • Never assume that users know as much about a site as the site designers do.

      • Any page can be an entry point into the website.

    • Web site navigational design includes:

      • Web site organization Divide content into logical fragments, units or chunks.


Establish a hierarchy of generality or importance.




  • Components of a Web Navigation System to move between Web site information fragments necessitates the creation of navigation links.


General link guidelines are:

-Sensible

-Available

-Obvious & Distinctive

-Consistent

-Textual

-Provide multiple navigation paths


  • Browser Command Buttons Hide the split between the browser & the Web site application by including navigational controls within the application.

  • Web Site Navigation Bars

    • Provide a global navigation bar at the top of each page.

    • Provide a local category or typical links navigation bar on the left side of a page.

  • Textual Phrases

Provide a mix of textual phrase links: -In explicit menus. -Embedded within page text.


  • Graphical Images or Icons


Graphical images or icons may appear in an array in the form of a navigation bar or be individually located at relevant points in a page.


  • Command Buttons


Command buttons may appear in an array in the form of a navigation bar or be individually located at relevant points in a page.

Selection of Window:

Window Characteristics


  • A name or title, allowing it to be identified.

  • A size in height & width (which can vary).

  • A state, accessible or active or not accessible.

  • Visibility–the portion can be seen.

  • A location relative to the display boundary.

  • Presentation–its arrangement with respect to other windows.

  • Management capabilities.

  • Highlighting.




  • The function, task or application to which it is dedicated.


  1. Attraction of Windows


  • Presentation of Different Levels of Information.

  • Presentation of Multiple Kinds of Information.

  • Sequential Presentation of Levels or Kinds of Information.

  • Access to Different Sources of Information.

  • Combining Multiple Sources of Information.

  • Performing More Than One Task.

  • Reminding.

  • Monitoring.

  • Multiple Representations of the Same Task.


  1. Constraints in Window System Design


  • Historical Considerations

  • Hardware Limitations

  • Human Limitations


  1. Window Management


  • Single-Document Interface


It’s a single primary window with a set of secondary windows.


  • Multiple-Document Interface


It’s a technique for managing a set of windows where documents are opened into windows. Contains:

-A single primary window called the parent.

-A set of related document or child windows, each also essentially a primary window.

  1. Organizing Window Functions


  • Window Organization–organize windows to support user tasks.

  • Number of Windows–minimize the number of windows needed to accomplish an objective.


  1. Window Operations

  1. Active window


  • A window should be made active with as few steps as possible.

  • Visually differentiate the active window from other windows.




  1. Opening a window


  • Provide an iconic representation or textual list of available windows.

  • If more than one object is selected & opened, display each object in a separate window. Designate the last window selected as the active window.


  1. Sizing windows


  • Provide large-enough windows to present all relevant & expected information for the task.


  1. Window placement


  • Position the window so it is entirely visible.


  1. Window separation


  • Crisply, clearly & pleasingly demarcate a window from the background of the screen on which it appears.


  1. Moving a window


  • Permit the user to change the position of all windows.


Vii .Resizing a window


  • Permit the user to change the size of primary windows.



Select the Proper Device-Based Controls


Device-based controls, often called input devices, are the mechanisms through which people communicate their desires to the system.


Identify the characteristics and capabilities of device-based control

  • Trackball

  • Joystick

  • Graphic tablet

  • Light pen

  • Touch screen

  • Voice

  • Mouse

  • Keyboard




Trackball

  • Description

– A ball that rotates freely in all directions in its socket

  • Advantages

    • Direct relationship between hand and pointer movement in terms of direction and speed

    • Does not obscure vision onscreen

    • Does not require additional desk space (if mounted on keyboard)

  • Disadvantage

    • Movement indirect, in plane different from screen

    • Requires hand to be removed from keyboard keys

    • Requires different hand movements

    • May be difficult to control

    • May be fatiguing to use over extended time

Joystick

  • Advantages

    • Direct relationship between hand and pointer movement in terms of direction and speed

    • Does not obscure vision on screen

    • Does not require additional desk space (if mounted on keyboard)

  • Disadvantage

    • Movement indirect, in plane different from screen

    • Requires hand to be removed from keyboard keys

    • Requires different hand movements

    • May be difficult to control

    • May be fatiguing to use over extended time

    • May be slow and inaccurate.


Graphic (Touch) Tablet

  • Description

    • Pressure-, heat-,light-, or light-blockage-sensitive horizontal surfaces that lie on the desktop or keyboard

    • May be operated with fingers, light pen, or objects like pencil

  • Advantages

    • Direct relationship between hand and pointer movement in terms of direction and speed

    • Does not obscure vision of screen

    • More comfortable horizontal operating plane

  • Disadvantage




  • Movement is indirect, in a plane different from screen

  • Requires hand to be removed from keyboard

  • Requires different hand movements to use

  • Finger may be too large for accuracy with small objects


Touch Screen

  • Advantages

    • Direct relationship between hand and pointer movement in terms of direction and speed

    • Movement is direct, in the same plane as screen

    • Requires no additional desk space

  • Disadvantage

    • Finger may obscure part of screen

    • Finger may be too large for accuracy with small objects

    • Requires moving the hand far from the keyboard to use

    • Very fatiguing to use for extended period of time

    • May Damage the screen

Light Pen

  • Description

    • A special surface on a screen sensitive to the touch of a special stylus pen

  • Advantage

    • Direct relationship between hand and pointer movement in terms of direction, distance, and speed

    • Movement is direct, in the same plane as screen

    • Requires minimal additional desk space

    • Stands up well in high-use environments

    • More accurate than finger touching

  • Disadvantage

    • Hand may obscure part of screen

    • Requires picking it to use

    • Requires moving the hand far from the keyboard to use

    • Very fatiguing to use for extended period over time

Voice


  • Description

– Automatic speech recognition by the computer

  • Advantage

    • Simple and direct

    • Useful for people who cannot use a keyboard





  • Useful when the user’s hands are occupied

  • Disadvantage

    • High error rates due to difficulties in

  • Recognizing boundaries between spoken words

  • Blurred word boundaries due to normal speech patterns

    • Slower throughput than with typing

    • Difficult to use in noisy environment

    • Impractical to use in quiet environment



Mouse

  • Advantage


  • Direct relationship between hand and pointer movement in terms of direction, distance, and speed.

  • Permit a comfortable hand resting position

  • Selection mechanisms are included on mouse

  • Does not obscure vision of the screen

  • Disadvantage

    • Movement is indirect, in a plane different from screen

    • Requires hand to be removed from keyboard

    • Requires additional desk space

    • May require long movement distances

    • Requires a degree of eye-hand coordination

Mouse Usage Guidelines

  • Provide a “hot zone” around small or thin objects that might require extremely fine mouse positioning

  • Never use double-clicks or double drags as the only means of carrying out essential operations

  • Do not use mouse plus keystroke combinations

  • Do not require a person to point at a moving target


Keyboard

  • Advantage

    • Familiar

    • Accurate

    • Does not take up additional desk space

    • Very useful for

  • Entering text and alphanumeric data

  • Inserting in text and alphanumeric data

  • Keyed shortcuts accelerators





  • Keyboard mnemonics equivalents


  • Disadvantage

    • Slow for non-touch-typists

    • Slower than other devices in pointing

    • Requires discrete actions to operate

    • No direct relationship between finger or hand movement.



Keyboard Guidelines

  • Provide keyboard accelerators

    • Assign single keys for frequently performed, small-scale tasks

    • Use standard platform accelerators

    • Assign Shift-key combinations for actions that extend or are complementary to the actions of key or key combination used without the Shit-key

    • Assign Ctrl-key combinations for

  • Infrequent actions

  • Tasks that represent larger-scale versions of the task assigned to the unmodified

Key

  • Provide keyboard equivalents

    • Use standard platform equivalents

    • Use the first letter of the item description

    • Provide window navigation through use of keyboard keys



  • Provide keyboard accelerators

    • Assign single keys for frequently performed, small-scale tasks

    • Use standard platform accelerators

    • Assign Shift-key combinations for actions that extend or are complementary to the actions of key or key combination used without the Shit-key

    • Assign Ctrl-key combinations for

  • Infrequent actions

  • Tasks that represent larger-scale versions of the task assigned to the unmodified key

  • Provide keyboard equivalents

    • Use standard platform equivalents

    • Use the first letter of the item description

    • Provide window navigation through use of keyboard keys

  • Provide keyboards for tasks involving





  • Heavy text entry and manipulation

  • Movement through structured arrays consisting of few discrete objects

  • Provide an alternative pointing device for graphical or drawing tasks

    • Mouse: pointing, selecting, drawing, and dragging

    • Joystick: selecting and tracking

    • Trackball: pointing, selecting and tracking

    • Touch screen pointing and electing

    • Graphic tablet pointing selecting, drawing, and dragging

  • Provide touch screens under the following conditions

    • The opportunity for training is minimal

    • Targets are large, discrete and spread out

    • Frequency of use is low

    • Desk space is at premium

    • Little or no text input requirement exists

  • Consider user characteristics and preferences Provide keyboards for touch typists

  • Minimize eye and hand movements between devices

Pointer Guidelines


  • The pointer

    • Should be visible at all times

    • Should contrast well its background

    • Should maintain its size across all screen locations and during movement

  • Shape of pointer

    • Should clearly indicate its purpose and meaning

    • Should be constructed of already defined shapes

    • Should not be used for any other purpose other than its already defined meaning

  • Use only as many shapes as necessary to inform the user about current location and status

  • Animation should not distract









Choose the Proper Screen Based Controls

Screen Based controls, often simply called controls and sometimes called widgets. By definitions, they are graphic objects that represent the properties or operations of other objects.



Operable Controls

  • Operable controls are those that permit the entry, selection, changing, or editing of a particular value, or cause a command to be performed.

    • Buttons

    • Text entry/read-only, selection, combination entry/selection

    • Specialized controls


Buttons

  • Description

    • A square or rectangular-shaped control with a label inside that indicates action to be accomplished

    • The label may consist of text, graphics, or both

  • Command Buttons

  • Toolbars


Command Buttons (Usage and Label)


  • Use to provide fast access to frequently used or critical commands (for windows with a menu bar)

  • Use to provide access to all necessary commands (for windows without a menu bar)

  • Use single-word labels whenever possible (Use two –three words for clarity, if necessary)





  • Use mixed-case letters with the first letter of each significant label word capitalized.

  • Do not number labels

  • Center the label within the button borders

  • Provide consistency in button labeling across all screens

  • Restrict the number of buttons on a window to six or fewer

  • Provide as large as button as feasible and maintain consistent button heights and widths


Command Buttons (Location and Layout)

  • Buttons exiting a dialog, and usually closing the window, should be positioned horizontally and centered across the lower part of the window

  • For a button invokes a dialog or expands the dialog, position it centered and aligned vertically along the right side of the window

  • Do not provide alignment with other screen controls. Maintain alignment and spacing only within the buttons themselves

  • Position the buttons within windows before locating the other window controls




Command Buttons (Location and Layout)


  • If a button has a contingent relationship to another control, position it adjacent to the related control


  • Buttons found on more than one window should be consistently positioned










Command Buttons (Organization)


  • Most frequent actions to the left or top

  • Keep related buttons grouped together

  • Exception: Buttons containing excessively long labels may be wider

  • Windows Recommends

    • An affirmative action the left or above

    • The default first

    • OK and Cancel next to each other

    • Help last


Command Buttons (Intent Indicators)

  • No intent indicator is necessary, when a button causes an action to be immediately performed

  • When a button leads to a cascading dialog, include and ellipsis (…)

  • When a button leads to a menu, include a triangle pointing in the direction the menu will appear after the label

  • When a button leads to and expanding dialog, include a double arrow(>>)



  • When a button has a contingent relationship to another control, include a single arrow







pointing at the control



Command Buttons (Expansion and Defaults)

  • Gray buttons after Expansion or when not applicable

  • When a window is first displayed, provide a default action, If practical

  • A default should be the most likely action:

    • A confirmation

    • An application of the activity being performed

    • A positive action such as OK

    • If a destructive action is performed (such as a deletion) the default should be Cancel

  • Indicate the default action by displaying the buttons with a bold or double border


Command Buttons (Keyboard Equivalents, Accelerators)

  • The mnemonic should be the first character of the button’s label

  • If duplication exists in first characters, use another character in the label

  • Designate the mnemonic character by underlining it

  • Assign a keyboard accelerator to each button to facilitate keyboard selection


Command Buttons (Scrolling and Button Activation)


  • Use buttons to move between multi-page forms, not scroll bars Label buttons Next and Previous

  • Highlight the button in some visually distinctive manner when the point  is resting on it and the button is available for selection


Toolbars (Usage, Structure and size)

  • Provide easy and fast access to most frequently used commands or options across multiple screens

  • Provide buttons of equal size

  • Create a meaningful and unique icon

  • Center the image within the button

  • Create a meaningful label





  • Provide the smaller size as the default size with a user option to change it


Toolbars (Organization and Location)


  • Place the most frequently used actions to the left or the top

  • Keep related buttons grouped together

  • Separate potentially destructive buttons from frequently chosen selections

  • Permit user to reconfigure the button organization

  • Position main features and functions bar horizontally across top of window just below menu bar

  • Position subtask and sub features bars along sides of window

  • Permit the location of the bar to be changed by the user


Toolbars (Active items, Button Activation and Customization)

  • Make only currently available toolbar items available

  • Temporarily not available items by displaying grayed out

  • Highlight the button in some visually distinctive manner when the pointer is resting on it

  • Call attention to the button in another visually distinctive manner when it has been activated or pressed

  • Permit toolbars to be turned off by user

  • Allow the customizing of toolbars

Text Entry/Read-Only Controls (Captions) For entry boxes

  • Place a colon (:) immediately following the caption

  • For single fields, caption can be located in front of upper left corner of the box

  • For multiple fields, position the caption upper left of the box For read-only boxes

  • If the data field is long or  about the same length, center  the caption above  the displayed textbox

  • If the data is alphanumeric, short, or quite variable in length, left-justify the caption above the displayed

  • If the data field is numeric and variable in length, right justify the caption above the displayed







Text Entry/Read-Only Controls (Fields)


  • To visually indicate that it is an enterable field, present the box in a recessed manner

  • Present read-only text boxes on the window background

  • Break up long text boxes through incorporation of slashes(/), dashes (-), spaces, or common delimiters

  • Call attention to text box data through a highlighting technique

  • Gray-out temporarily unavailable textboxes

Selection Controls

  • Radio Buttons

  • Checkboxes

  • Palettes

  • List Boxes

  • List View Controls

  • Drop-down/Pop-up List Boxes

Radio Buttons




  • A two part control consisting of the following

    • Small circles, diamonds, or rectangles

    • Choice descriptions

  • When a choice is selected

    • The option is highlighted

    • Any existing choice is automatically un highlighted and deselected





  • Purpose

    • To set one item from a small set of option (2 to8)

  • For mutually exclusive choices (that is, only can be selected)

  • Most useful for data and choices that are

    • Discrete

    • Small and fixed in number

    • Not easily remembered

    • Most easily understood when the alternatives can be seen together and compared to one another

    • Never change in content

  • Do not use

    • For commands

Radio Buttons (Defaults and Structure)


  • If there is a default selection, designate it as the default and display its button filled in. Else, display all the buttons without setting adopt

  • When a multiple selection includes choices, display the buttons in another unique manner, such as gray shadow

  • Left-align the buttons and choice descriptions

  • A columnar orientation is the preferred unless vertical space on the screen is limited

  • Enclose the buttons in a border to visually strengthen the relationship

Radio Buttons (Organization, Related Control)


  • Arrange selection in expected order or follow other patterns (frequency of occurrence, sequence of use, or importance)

  • Position any control related to a radio button immediately to the right of the choice description. End the label with an arrow


Radio Buttons (Captions)


  • Display full spelled out in mixed-case letters, capitalizing the first letter of all significant words

  • Columnar orientation

    • With a control border, position the caption:



  • Upper-left-justified within the border

  • Alternatively, to the left of the topmost choice description with (:)

    • Without a control border position, the caption:

  • Left-justified above the choice description with (:)

  • Alternatively, the caption may be located to the left of the topmost choice description with (:)

  • Horizontal orientation

    • Position the caption to the left of the choice

    • Alternatively, with a control border, left-justified within the border

Radio Buttons (Keyboard Equivalents and Selection and Indication)


  • Assign a keyboard mnemonic to each choice description by underlining the applicable letter in the choice description

  • Highlight the selection choice in some visually distinctive way when the cursor’s resting on it

  • When a choice is selected, distinguish it visually from the unselected choices

  • If there is a default choice, display the selected choice as set in the control

Radio Buttons




Check Boxes








Each option acts as a switch and can be either “on” or “off”

  • When an option is selected, a mark (X) appears within the square box, or the box is highlighted in some other manner

  • Otherwise the square is unselected or empty(off)

  • Each box can be

    • Switched on or off independently

    • Used alone or grouped insets

!!Other properties are similar to the radio button’s properties!! Palettes



  • Acontrolconsistingofaseriesofgraphicalalternatives.Thechoicesthemselves are descriptive, being composed of colors, patterns, or images

  • To set one of a series of mutually exclusive options presented graphically or pictorially

  • Usually consume less screen space than textual equivalents

  • Do not use

    • Where the alternatives cannot be meaningfully and clearly represented pictorially

    • Where words are clearer than images

    • Where the choices are going to change

  • Create boxes of equalize

  • Position the boxes adjacent to, or butted up against another

  • A columnar orientation is the preferred manner

  • Top to button, Left to right ordering by expected order, frequency of occurrence, sequence of use or alphabetically

  • Display it less brightly than the other choices, if a choice is not available

  • Highlight the choice in some visually distinctive way when the pointer is resting





  • When a choice is selected, distinguish it visually from the unselected choices



List Boxes


  • A permanently displayed box-shaped control containing a list of attributes or objects from which

    • A single selection is made (mutually exclusive),or

    • Multiple selections are made (non-mutually exclusive)

  • Unlimited number of choices

  • If the list content change, items will be hard to find

  • Good for data that are

    • Best represented textually

    • Not frequently selected

    • Large in number

    • Fixed in list length

  • Clearly and meaningfully describe the choices available

  • Present in mixed case

  • Left-align into columns

  • Require no more than 40 page-downs to search a list

    • If more are required, provide a method for using criteria

  • Must be long enough to display 6-8choices

    • If it is the major control within a window, the box may be larger

  • When box can’t made wide enough to display longest entry

    • Break the long entries with an ellipsis (…)





  • Provide horizontally scrolling

  • Order in a logical and meaningful way to permit easy browsing (allow user to change the sort order will be great)

  • If a particular choices is not available in the current context, omit , gray or dimity

  • Enclose the choices in a box with a solid border

  • Use mixed-case

  • Preferred position of the control caption is above upper-left

  • When a list box is disabled, display its caption as gray out

  • Highlight the selection choice when the pointer is resting on


Single-Selection List Boxes


  • If presented with an associated text box control

    • Position the list box below and as close as possible to the textbox

    • The list box caption should be worded similarly to the text box caption

    • If the related text box and the list box are very close, the caption may be omitted from the list box

  • When the list box is first displayed

    • Present the currently active choice highlighted or marked with a circle or diamond to the left of the entry

    • If a choice has not been previously selected, provide a default choice and display it in the same manner that is used in selecting it



Multiple-Selection List Boxes





  • Mark the selected choice with an X or check mark to the left of the entry

  • Consider providing a summary list box

    • Position it to the right of the list box

    • Use the same color for the summary list box

  • Consider providing a display-only text control indicating how many choices have been selected

    • Position it justified upper-right above the list box

  • Provide command buttons for Select All and Deselect All

  • When the list box is first displayed

    • Display the currently active choices

    • Mark with and X or check mark to the left of the entry


Drop-Down/Pop-up List Boxes




  • Unlimited number of choices

  • When displayed, all choices may not always be visible, requiring scrolling

  • Use drop-down/pop-up when

    • Screen space or layout consideration makes radio buttons or single- selection list boxes impractical

    • Do not use a drop-down list if it important that all options be seen together.


  • Provide a visual cue that a box is hidden by including a downward pointing arrow, or other meaningful image

  • ! Other properties are the same as List boxes!

Combination Entry/Selection Controls and Other Operable Controls

  • Spin Boxes

  • Combo Boxes





  • Drop-down/Pop-up Combo Boxes

  • Slider


Spin Boxes


  • A single line field followed by two small, vertically arranged buttons (pointing up and pointing down arrow)

  • Selection/entry is made by

    • Using the mouse to point at one of directional buttons

    • Keying a value directly into field itself

  • Consumes little screen spaces

  • Useful only for certain kinds of data

  • Proper usage for

    • For mutually exclusive choices

    • Where screen is space is limited

    • Small in number

    • Infrequently changed, selected

  • To reduce the size of potentially long lists, break the listing into subcomponents (break a date into ddmmyyyy)

  • When first displayed, present a default choice in the box

  • The spin box should be wide enough to display the longest entry or choice

  • Caption is mixed-case letters

  • Position the caption to the left of the box

    • Alternatively, left-justified above the box

  • For numeric values

    • Show a larger value using the up arrow




Combo Boxes


  • A single rectangular text box entry field, beneath which is a larger rectangular list box (resembling a drop-down list box)

  • The text box permits a choice to be keyed within it

  • As text is typed into the text box, the list scrolls to the nearest match

  • Also, when an item in the list box is selected, that item is placed within the text box


Drop-down/Pop-up combo Boxes




  • A single rectangular text box with a small button to the side and an associated hidden list of options

  • Selection are made by using the mouse or keyboard

  • The information keyed doesn’t not have to match

  • Unlimited number of entries and choices

  • Flexible, permitting selection or typed entry

  • Requiring scrolling





  • Proper usage

    • Where screen is limited

    • For data and choices that are

  • Best represented textually

  • Frequently changed

  • Large in number

Drop-down/Pop-up combo Boxes


  • Provide a visual cue that a list box is hidden by including a downward-pointing


  • Other properties are the same as Drop-down/Pop-up List Box!!


Slider

  • A scale exhibiting degrees of a quality on continuum

  • To make a setting when a continuous qualitative adjustment is acceptable

  • Spatial representation of relative setting

  • Not as precise as an alphanumeric indication

  • Proper usage:

    • When an object has a limited range of possible settings

    • When the range of values discontinuous

    • When graduations are relatively fine





Custom Controls


  • Presentation controls

  • Provide details about other screen elements or controls or assist in giving the screen structure

    • Static Text Fields





  • Group boxes

  • Column Headings

  • ToolTips

  • Balloon Tips

  • Progress indicators

Task Best Control If screen Space Constraints Exist

  • Mutually Exclusive Radio Buttons Drop-down/Pop-up List Box

  • Not Mutually Exclusive Check Boxes Multiple-Selection List Box

  • Select or Type a Value

  • Text Entry Field

  • Radio Buttons with“ Other”

  • Drop-down Combo Box

  • Setting a Value within a Range

  • Spin Button Text Box


Write Clear Text and Message Words


Do not use technical words, made-up words or terms file spec, abed, or spool, Ungroup or dear chive

  • Do not use abbreviations or acronyms

Always use the fully spelled-out form the first time it is encountered in the interface

  • Consider the usage of contradictions or short forms (won’t vs. will not, un- - nests), Complete words is preferred

  • Positive terms (avoid the prefix “ire-” “in-” “dies-” adnoun-”)

  • Simple action words (“Project status listing”  “List”)

  • Consistency

  • Multiple-word phrases are more readable if the entire phrase is on one line

  • Abbreviation, mnemonics, and acronyms should not include punctuation


Sentences and Messages

  • Brief and simple

  • Directly and immediately usable (Should not search through reference)

  • Affirmative statement is easier to understand than negative statements

  • Active voice is usually easier to understand than passive voice

  • Main topic at the beginning





  • Use the same grammatical structure for elements of sentences

  • Imply that the system is awaiting the user’s direction, not that the system is directing the user

  • Negative tones or actions, or threats are not very friendly (“Numbers are illegal” vs.

“Months must be entered by name”)

  • Encouraging message would be better than insulting message

  • Should remain factual and informative, and should not attempt humor or punishment


Messages

  • Screen messages is classified into two categories

    • System messages:

      • Generated by the system to keep the user informed of the system’s state and activities

    • Instructional messages (prompting message):

      • tell the user how to work with, or complete the screen displayed

System Messages

  • Status messages

    • Providing information concerning the progress of a lengthy operation

    • Usually contains a progress indicator and a short message

  • Informational messages (notification messages)

    • This kind of message is usually identified by an “I” icon to the left of the message

  • Warning messages

    • They are usually identified by an“!”

    • The user must determine whether the situation is in fact a problem and may be asked to advise the system whether or not to proceed (A deletion request by a user is any action that commonly generates a warning messages)

System Messages

  • Critical messages (Action messages)

    • Call attention to conditions that require a user action before the system can proceed

    • Some products use a “Do Not” symbol while others use a “Stop” sign. An X in a circle used by Microsoft Windows

  • Question messages

    • A question message asks a question and offers a choice of options for selection

    • It is designated by a “?” icon proceeding the message text

Writing Message Box Text




  • Title bar: Clearly identify the source of the message

    • The name of the object to which it refers

    • The name of the application to which it refers

    • Do not include an indication of message type

    • Use mixed case in the headline style

  • Message box: Provide a clear and concise description of the condition of the condition causing the message box to be displayed

    • Use complete sentences with ending punctuation

    • Show only message box about the cause of condition in single message

    • Make the solution an option offered in the message

    • Use the word “Please “conservatively

  • Do not exceed two or three lines

  • Center the message text in window

  • Include the relevant icon identifying the type of message


Message Box Controls

  • Command Buttons:

    • If a message requires no choices to be made, include an OK button

    • If a message requires a choice to be made

      • OK and Cancel buttons only when the user has the options continue or cancel

      • Yes and No buttons when the user must decide how to continue

      • If these choices are too ambiguous, label with the name of  specific actions

    • If a message describes an interrupted process, provide Stop button

    • If a message offer a chance to cancel a process, provide a Cancel button

    • If more details about a message must be presented, provide a Help button

    • Display only one message box for a specific condition

  • Close Box:

    • Enable the title bar Close only if the message includes a Cancel button

Instructional Messages

  • Provide instructional information at the depth of detail needed by the user

    • Accessing instruction through a Help function is the best solution

  • Location it at strategic position on the screen





  • Display it in a manner that visually differentiates it from other screen elements

  • In writing, follow all relevant writing guideline for words, sentences, and messages




Create Meaningful Graphics, Icons and Images


Creating Images


  • Create familiar and concrete shapes

  • Create visually and conceptually distinct shapes

  • Incorporate unique features of an object

  • Do not display within a border

  • Clearly reflect object represented

  • Simple reflect object represented, avoiding excessive detail

  • Create as a set, communicating relationships to one another through common shapes

  • Provide consistency in icon type

  • Create shapes of the proper emotional tone


Creating Images

  • Create familiar and concrete shapes

  • Create visually and conceptually distinct shapes

  • Incorporate unique features of an object

  • Do not display within a border

  • Clearly reflect object represented

  • Simple reflect object represented, avoiding excessive detail

  • Create as a set, communicating relationships to one another through common shapes

  • Provide consistency in icon type

  • Create shapes of the proper emotional tone


Icons

  • Icons are most often used to represent objects and actions with which users can interact

  • Icons may stand alone on a desktop or in a window, or be grouped together in a toolbar

  • A secondary use of a icon is to reinforce important information, a warning icon in a dialog message box





Characteristics of Icons

  • Syntactic refers to a icon’s physical structure

    • Shape, Color, Size

    • Similar shapes and colors can be used to classify a group of related icons

  • Semantics is the icon’s meaning

    • What does it refer – a file, a waste basket, or some other objects?

  • Pragmatics is how the icons are physically produced and depicted

    • Is the screen resolution enough to illustrate?

  • Syntactic, semantics and pragmatics determine an icon’s effectiveness and usability

Influences on Icon Usability

  • Provide icons that are

    • Familiar

    • Clarity

    • Simple

    • Consistent

    • Directness of the meaning

    • Efficient

    • Discriminate able from others

  • Also consider the

    • Context in which the icon issued

    • Expectancies of users

    • Complexity of task

Choosing Icons

  • A Successful Icon

    • Looks different from all other icons





  • Is obvious what it does or represents

  • Is recognizable when no larger than 16 pixels square

  • Look as good in black and white as in color

  • Size

16x16, 24x24, 26x26, 32x32 pixels 16-and-256 color version

  • Use colors from the system palette

  • Provide as large a hot zone as possible

    • With stylus or pen: 15 pixels square

    • With mouse: 20 pixels square

    • With finger: 40 pixels square

Choosing Images

  • Use existing icons when available

  • Use images for nouns, not verbs

  • Use traditional images

  • Consider user cultural and social norms


Creating Images

  • Create familiar and concrete shapes

  • Create visually and conceptually distinct shapes

    • Incorporate unique features of an object

    • Do not display within a border

  • Clearly reflect object represented

  • Simple reflect object represented, avoiding excessive detail

  • Create as a set, communicating relationships to one another through common shapes

  • Provide consistency in icon type





  • Create shapes of the proper emotional tone

Creating Images

  • Create familiar and concrete shapes

  • Create visually and conceptually distinct shapes

    • Incorporate unique features of an object

    • Do not display within a border

  • Clearly reflect object represented

  • Simple reflect object represented, avoiding excessive detail

  • Create as a set, communicating relationships to one another through common shapes

  • Provide consistency in icon type

  • Create shapes of the proper emotional tone

Drawing Images

  • Providing consistency in shape over varying sizes

  • Do not use triangular arrows in design to avoid confusion with other system symbols

  • When icons are used to reflect varying attributes, express these attributes as meaning meaningfully as possible

  • Provide proper scale and orientation

  • Use perspective and dimension whenever possible

  • Accompany icon with a label to assure intended meaning Icon Animation and

Audition

  • Animation

    • Use

      • To provide feedback

      • For visual interest





  • Make it interruptible or independent of user’s primary interaction

  • Do not use it for decoration

  • Permit it to be turned off by the user

  • For fluid animation, present images at 16++ frames/second

  • Auditions

    • Consider auditory icons

The design Process

  • Define the icon’s purpose and use

  • Collect, evaluate, and sketch ideas

  • Draw in black and white

  • Draw using an icon-editing utility or drawing package

  • Test for users

    • Expectations

    • Recognition

    • Learning

  • Test for clarity

  • Register new icons in the system’s registry

Graphics in Web

  • Use Graphics to

    • Supplements the textual content, not as a substitute for it

    • Convey information that can’t be effectively accomplished using text

    • Enhance navigation through

      • Presenting a site overview

      • Identifying site pages

      • Identifying content areas





Images

  • Limit the use of graphics that take long time to load

  • Coordinate the graphics with all other page elements

  • Use standard images, image internationalization

  • Provide descriptive text or labels with all images

  • Distinguish navigational images from decorative images

  • Minimize

    • The number of presented images

    • The size of presented images

    • Image animation

    • Number of colors

  • GIF, JPEG is preferred

Photographs/Pictures

  • Use when every aspect of the images is relevant

  • Use JPEG format

  • On the initial page

    • Display a small version

      • A thumbnail

      • Zoom-in on most relevant detail

    • Link to larger photos showing as much detail as needed

Video


  • To show the proper way to perform a task

  • To provide a personal message





  • To grab attention

  • Never automatically download a video into a page

  • Provide controls (playing, pausing, and stopping)

  • Considering using

    • Existing video

    • Audio only

    • A slide show with audio

Diagrams

  • To show the structure of objects

  • To show the relationship of objects

  • To show the flow of a process or task

  • To reveal a temporal or spatial order

Animation

  • To explain ideas involving a change in

    • Time

    • Position

  • To illustrate the location or state of a process

  • To show continuity in transitions

  • To enrich graphical representations

  • To aid visualization of 3-Dstructures

  • Provide a freeze frame and stop mode

  • Avoid distracting animation

Audition

Uses as a supplement to text and graphics





  • To establish atmosphere

  • To create a sense of place

  • To teach

  • To sample

  • The content should be simple

  • Provide audio controls

Combining Mediums

  • Use sensory combination that work best together

    • Auditory text with visual graphics

    • Screen text with visual graphics

  • Both the visual and auditory information should be totally relevant to the task being performed

  • Visual and auditory textual narrative should be presented simultaneously

  • Considering downloading times when choosing media

  • Testing

    • Legibility

    • Comprehensibility

    • Acceptance

Choose the Proper Colors


Color Uses

  • Use color to assist in formatting

    • Relating elements into grouping

    • Breaking apart separate groupings of information

    • Highlighting or calling attention to important information

  • Use color as visual code to identify

    • Screen captions and data

    • Information from different sources





  • Status of information

  • Use color to

    • Realistically portray natural objects

    • Increase screen appeal Possible Problems with Color

  • High Attention-Getting Capacity

    • Viewer might associate, tie together, screen elements of same color

    • Result in confusing, slower reading

  • Interference with Use of Other Screens

  • Varying Sensitivity of the Eye to Different Colors

    • Viewing red and blue  Eye fatigue

  • Color-Viewing Deficiencies

  • Cross-Disciplinary and Cross-Cultural Differences

    • For financial mangers - Corporate qualities or reliability

    • For health care professionals –Death

    • For nuclear reactor monitors – Coolness or water

    • For American movie audiences – Tenderness or Pornography Choosing Colors for Categories of Information

  • Color chosen to organize information or data on a screen must aid the transfer of information from the display to the user, Some examples of using color code

    • If decisions are made based on the status of information on the screen, color- code the types of status the information

    • Screen searching is performed to locate information of particular kind, color- code for contrast

    • If the sequence of information use is constrained or ordered, use color to identify the sequence

    • If the information on a screen is crowded, use color to provide visual grouping

  • Never rely on color as the only way of identifying a screen element

  • Always consider how spatial formatting, highlighting, and messages may also be useful


Color in Context













Usage

  • Color are subject to contextual effects

  • Small adjacent colored images may appear to the eye to merge or mix

  • A color on a dark background will look lighter and brighter than the same color on a light background

  • Colors also change as light levels change


  • Design for monochrome first or in shades of black, white and gray

  • Doing this will permit the screen to be effectively used:

    • By people with a color-viewing deficiency

    • On monochrome displays

    • In conditions where ambient lighting distorts the perceived color

    • If the color ever fails

  • Use colors conservatively

    • Do not use color where other identification techniques, such as location, are available


Discrimination and Harmony

  • Select 4-5 colors for best absolute discrimination

    • Red, yellow, green, blue, and brown

  • Select 6-7 colors for best comparative discrimination

    • Orange, yellow-green, cyan, violet, and magenta

  • Choose harmonious colors

    • One color plus two colors on either side of its complement

    • Three colors at equidistant point around the color circle

  • For extended viewing or older viewers, use brighter colors


Emphasis





  • To draw attention or to emphasize elements, use bright or highlighted colors or use less bright colors for deemphasize

    • The perceived brightness of colors from most to least is white, yellow, green, blue, red

  • To emphasize separation, use contrasting colors

    • Red and green, blue and yellow

  • To convey similarity, use similar colors

    • Orange and yellow, blue and violet


Common Meanings

  • To indicate that actions are necessary, use warm colors

    • Red, orange, yellow

  • To provide status or background, use cool colors

    • Green, blue, violet, purple

  • Conform to human expectation

    • Red: Stop, fire, hot, danger

    • Yellow: Caution, slow, test

    • Green: Go, OK, clear, vegetation, safety

    • Blue: Cold, water, calm, sky, neutrality

    • Gray, White: Neutrality

    • Warm colors: Action, response required, spatial closeness

    • Cool colors: Status, background information, spatial remoteness

  • Typical implications of color with dramatic portrayal are

    • High illumination: Hot, active, comic situations

    • Low illumination: Emotional, tense, tragic, romantic situations

    • High saturation: Emotional, tense, hot, comic situations

    • Warm colors: Active, leisure, recreation, comic situations

    • Cool colors: Efficiency, work, tragic and romantic situations


  • Proper use of color also requires consideration of the experiences and expectation of the screen viewers


Location and Ordering

  • In the center of the visual field, use red and green For peripheral viewing, use blue, yellow, black, and white

  • Use adjacent colors that differ by hue and value or lightness for a sharp edge and maximum differentiation


  • Order colors by their spectral position





  • Red, orange, yellow, green, blue, indigo, violet Foregrounds and Backgrounds

  • Foregrounds

    • Use colors that highly contrast with the background color

    • For text or data

      • Black on light-color background of low intensity (no bright white)

      • Desiderated spectrum colors such as white, yellow, or green on dark background

      • Warmer more active colors

    • To emphasize an element, highlight it in a light value of the foreground color, pure white, or yellow

    • To deemphasize and element, lowlight it in a dark value of the foreground color


Foregrounds and Backgrounds

  • Backgrounds

    • Use colors that do not compete with the foreground

    • Use

      • Light-colored backgrounds of low intensity: Off-white or light gray

      • De saturated colors

      • Cool, dark colors such as blue or black

      • Colors on the spectral extreme end

        • Blue, black, gray, brown, red, green, and purple

Foregrounds and Backgrounds

  • Backgrounds

    • Use colors that do not compete with the foreground

    • Use

      • Light-colored backgrounds of low intensity: Off-white or light gray

      • De saturated colors

      • Cool, dark colors such as blue or black

      • Colors on the spectral extreme end

        • Blue, black, gray, brown, red, green, and purple

Gray Scale

  • For fine discrimination use a black-gray-white scale





  • Recommend values

    • White: Screen background, text located in any black area

    • Light gray: Background of a Pushbutton area

    • Medium gray: Icon background area, Menu drop shadow, Window

Drop shadow, inside area of system icons, Filename bar

  • Dark gray: Window boarder

  • Black: Text, Window title bar, Icon border, Icon elements,

Ruled lines


Text in Color

  • Text in color is not as visible as it is in black

  • When switching text from black to color

    • Double the width of lines

    • Use bold or larger type:

      • If originally 8 to 12 points, increase by 1 to 2points

      • If originally 14 to 24 points, increase by 2 to 4points

Text in Color

  • Text in color is not as visible as it is in black

  • When switching text from black to color

    • Double the width of lines

    • Use bold or larger type:

      • If originally 8 to 12 points, increase by 1 to 2points

      • If originally 14 to 24 points, increase by 2 to 4points

  • Check legibility by squinting at text

    • Too-light type will recede or even disappear

Choosing color for web pages

  • Always minimize the number of presented colors for faster downloading

  • Always consider color in context, never in isolation





  • Use similar or same color schemes throughout a Web site  help the user maintain a sense of place

  • Foreground colors should be a different as possible from background colors

  • The most recommended foreground text color is black presented on a light-colored background of low intensity (off white or light gray)

  • Use dark backgrounds when establishing contrast between an area of the screen and the main screen body Choosing color for web pages

  • High intensity colors as back-ground such as red, magenta and bright green) must be avoided

  • When choosing foreground and background colors, ensure that contrasting combinations are selected

  • Use a uniform color in large screen areas

  • Large areas of the same color download faster

  • For smaller element, the more contrast is required

  • Use flat Web-safe colors

  • Select color that can be easily reproduced in black and white


Use of Color to Avoid

  • Relying exclusively on color (Spatial Formatting and component locations)

  • Too many colors at onetime

  • Highly saturated, spectrally extreme colors together

  • Red/blue and yellow/purple

  • Yellow/blue, green/blue and red/green

  • Low-brightness color for extended viewing or older viewer

  • Colors of equal brightness

  • Colors lacking contrast

  • Fully saturated colors for frequently read screen components

  • Use of Color to Avoid

  • Pure blue for text, thin lines, and small shapes

  • Colors in small areas

  • Colors for fine details

  • Black, gray, and white will provide better resolution

  • Other colors for large area or attracting attention

  • Non-opponent colors

  • Red/yellow or green/blue

  • Recommend: Red/green or yellow/blue

  • Red and green in the periphery of large-scale displays

  • Yellow and blue are much better





Use of Color to Avoid

  • Adjacent colors only differing in the amount of blue they posses

  • Single color distinctions for color-deficient user

  • Using colors in unexpected ways

  • Using color to improve readability of densely packed text

Recommend using space lines



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