CPSC 110: Introduction to Computing Chapter 2: What the Digerati Know: Exploring the Human-Computer Interface Dr. Lonnie E. Cheney Overview What experienced users know: Expect consistent graphical user interfaces (GUI) Expect feedback Nothing will get broken Observe other users (ask questions) Standard GUI & Operations Components Functions Exploration techniques 2 Born to Use Technology? No one has innate technological abilities Users (use devices): Past experience shows us what to expect. Designers (create devices): Know about this experience Design products to match what we already know..the most uncomfortable part part of of being an an inexperienced computer user user is is the the suspicion that that every one one but but you youknows how how to to use use [a [a computer]. (L.Snyder, 2005, p.30) 3 1
Metaphors Analogies for computation The Desktop Image displayed when computers start up. Has a background Has icons (files, folders, applications) Working at PC is like to working at a desk. Work goes in files (documents) Files go in folders (directories) Tools (applications) perform tasks 4 Metaphors Using a CD Player GUI resembles music players (metaphor). Users apply previous knowledge. 5 Understanding Designer s Intent Designers: pick easy-to-understand interfaces. Good software allows us to "brain out" how it works. use existing metaphors. Advantages: Seeing a metaphor, we know how it works. GUI metaphors become standard. 6 2
Similar User Interfaces 7 Expecting Consistent GUIs Buttons 3D rectangles or circles, with a centered icon or text Pressing the button: clicking mouse "presses" the button invokes a command (perform the operation) We receive feedback confirming button was clicked color change, shadow, highlight, or audible click Expecting Consistent GUIs Slide controls Sets a value from a "continuous" range (volume) Move control by placing mouse pointer on it and dragging in the direction of change Scroll bars are a type of slider control 3
Expecting Consistent GUIs Menus (I) List operations the software can perform Grouped by similarity (in menu bar) All operations should be listed in the menu Expecting Consistent GUIs Menus (II) Top bar menus are pull-down or drop-down Sliding mouse down the list highlights items Clicking on highlighted item performs that operation Expecting Consistent GUIs Menus (III) Menus provide information about operations: Whether an operation is available Where more user input is needed Shortcuts (clover or control) 4
Expecting Standard Functionality Common operations Available in most software Needed to process any type of information New Open Close Exit Usually grouped under File and Edit Expecting Standard Functionality File Operations apply to whole instances Word Processor Instance is a document MP3 Player Instance is a song Photo Editor Instance is a picture Common operations: New Creates a blank instance Open Locates and reads file on disk Close Closes current instance but keeps program running Save Writes current instance to disk Print Prints data in current instance Exit Ends execution of program Expecting Standard Functionality Edit Operations apply to within an instance Involve selection or cursor placing Usually performed as part of a sequence Common operations: Copy Copies selected data, ready for pasting Cut Removes & copy selected data, ready for pasting Paste Inserts cut or copied data into current instance Undo Cancels most recent change (not always available) Repeat Applies most recent undone change again 5
Expecting Standard Functionality Edit Operations apply to within an instance Involve selection or cursor placing Usually performed as part of a sequence Common operations: Copy Copies selected data, ready for pasting Cut Removes & copy selected data, ready for pasting Paste Inserts cut or copied data into current instance Undo Cancels most recent change (not always available) Repeat Applies most recent undone change again Standard Shortcuts 17 Expecting Feedback Indication that software: is still working, or has completed an operation proof of editing: new text is visible proof that a button was pressed: change on highlighting, shading, underlining, color, audible click Common feedback: When working on a time-consuming task, cursor drawn as: * hourglass (Windows) * spinner (Mac) 6
Exploration Techniques 1. Clicking around Looking for clues: identify basic GUI features check menus for available operations Helps to figure out what operations are available without being taught It works because: consistent metaphors and interfaces make new software predictable Exploration Techniques 2. Blazing Away Exploring to see what happens: try operations observe results Concentrate on operations related to whatever task needs to be done Nothing will break! Only risk is losing time spent and having to re-start or reboot Exploration Techniques 3.Watch others Look for non-obvious operations: sequence of common steps identify shortcuts Ask questions! Every man is a fool for five minutes every day. Wisdom consists in not exceeding the limit. E.Hubbard 7
Searching Text An illustration of the principle that form follows function GUIs may look different, but two software systems for the same task will have same basic operations and will work similarly Text search, or find, is used in many applications such as word processors, browsers, email readers, and operating systems Tokens are the things to be searched * Single characters like letters, numbers, special symbols * Composite items like date How Searching Works Searching starts at beginning of document or at current cursor position 1. "Slide" the search string along the text 2. At each position, look for token match 3. If there is a match, the process stops and displays the found instance 4. If there is no match, slide the search string one position along 5. If the search string is not found by the end of the text, search stops and is unsuccessful 23 Search Complications Case Sensitivity: Computer stores uppercase and lowercase letters as different characters Match only occurs when both the letters and the case are identical Search tools are case-sensitive in word processors but not necessarily in all applications User has the option to ignore case-sensitive capability 24 8
Search Complications (cont d) Hidden Text: There are two types of characters: keyboard characters typed by user, and formatting information added by the application Search generally ignores application's formatting tags Some systems allow user to search for formatted text such as italic. 25 Search Specifics 26 Search Complications (cont d) Substrings User may be looking for words, but the tokens are the characters in the word Search will turn up words that contain the search string (searching for "you" will turn up "your") Word processors usually have ability to search for whole words Multiword Strings Words are separated by spaces. If the number of spaces in the search string is different from the number in the text being searched, no match is found 27 9
Replacing Text Search and replace combines searching and editing to make corrections to documents Useful for correcting all occurrences of search string Change "west coast" to "West Coast" Eliminate extra spaces Formatting text 28 Replace Options 29 10