CS 349 Midterm Exam Spring 2014

Transcription

1 Course Title: User Interfaces Sections: All Instructor: Byron Weber Becker Exam Date: 19-June-2014 Time: 7:00-9:00p.m. Duration: 2 hours Pages: 10 CS 349 Midterm Exam Exam Type: Closed Book Permitted Aids: None Cheating is an academic offense. Your signature on this exam indicates that you understand and agree to the University s policies regarding cheating on exams. Signature: Last Name: Given Name: Student ID: Instructions: 1. Place answers in this booklet. Use the back of the last page if more space is required. 2. Before you begin, make certain that you have 10 pages. 3. There are 10 questions on the exam. Answer all questions and each part of each question. The marks assigned to each question are shown at the beginning of the question. Use this information to organize your time effectively. 4. Questions will not be interpreted. Proctors will confirm or deny errors only. If you consider the wording of a question to be ambiguous, state your assumptions clearly and proceed to answer the question to the best of your ability. 5. Documentation is always appreciated, but is not required unless explicitly requested. Q # Marks Available Marks Earned Grader Initials Total 85

2 Name: 1. [08] Direct Manipulation and Instrumental Interaction My favourite graphics editor allows lines to attach to shapes at magnetized points. When drawing a line the magnet appears as a small circle as the mouse approaches and the line snaps to the magnet. If the shapes are later moved, the lines attached to magnets move with the shape. a. [02] Are the magnet instruments activated temporally or spatially (circle one)? Explain. Temporal Spatial b. [02] Analyze the magnet instrument in terms of the degree of indirection. The degree of indirection relates two offsets. c. [02] Analyze the magnet instrument in terms of the degree of integration. The degree of integration relates the input device and the instrument. d. [02] Analyze the magnet instrument in terms of the degree of compatibility. The degree of compatibility relates the physical motions to the instrument. Page 2 of 10

3 Name: 2. [10] X Event Loop Construct an event loop that animates a scene smoothly, responds to events on a timely basis, and does not use more CPU time than necessary. In addition to the standard Xlib functions, you may assume the following are available. Threads are not available. handleanimation(): Advances the animation by one step. handleevent(xevent e): Handles one event (ie: contains the switch statement); does not repaint. repaint(): Repaints the entire interface to reflect the current state of the model. now(): Returns the current time, in milliseconds. sleep(int n): Sleeps for n milliseconds. Page 3 of 10

4 3. [09] XLib Programming Name: a. [03] Explain the basic X architecture, including the client and the server. b. [02] What does XSelectInput do? Why is using it a good idea? c. [02] What is the Base Window System (BWS) responsible for? d. [02] What is the Window Manager responsible for? 4. [05] Model-View-Controller a. [03] What is the essential infrastructure (data structures, methods) that every MVC model will have? b. [01] Slide 16 in the MVC lecture says that the model is very loosely coupled with the UI. What does that mean? Page 4 of 10

5 Name: c. [01] Was the creator of the MVC architecture Ivan Sutherland, Alan Kay, Trygve Reenskaug, or Douglas Engelbart? 5. [11] Listeners a. [05] Explain how Java s listeners are used to connect a mouse click event on a JButton with the appropriate code in the application s model. Include an explanation of what happens inside the JButton class. This question can be successfully answered with UML, pseudo-code, or prose. b. [06] Explain the similarities and/or differences between Java s listeners, the observer design pattern, and the model-view-controller UI design pattern. Page 5 of 10

6 6. [11] Layout Name: a. [10] The images on the right show the same interface at two different sizes. Draw an interactor tree showing the widgets (both visible and invisible) included in the interface. Annotate each widget with the text it displays (if visible) or type (if not visible) and each JPanel with the name of the layout manager it uses. The layout managers we studied are the null layout, GridLayout, BoxLayout, BorderLayout, GridBagLayout, SpringLayout, FlowLayout, and RandomLayout. Hint: It doesn t use SpringLayout or GridBagLayout. b. [01] Layout managers are an example of which design pattern? Page 6 of 10

7 7. [11] Gestalt Principles Name: a. [02] Why are Gestalt principles relevant to designing user interfaces? b. [09] We studied seven of the Gestalt principles. Give the name and a brief description of three of them. Sketch an interface that illustrates all three principles. Annotate the interface to show where each of the principles is being used. Page 7 of 10

8 8. [08] Event Dispatch Name: a. [02] Briefly explain the differences between heavyweight and lightweight widgets. b. [03] What is positional dispatch? Why do we also need another kind of dispatch? What s that other kind of dispatch called? c. [03] Name and briefly explain the two variations of positional dispatch. 9. [06] Vision and Colour a. [04] What is the name of the colour model associated with the colour wheel on the right? Yeah, I know it s printed in black and white. Use your imagination. Label each of the three axes with the appropriate term from the colour model. Colour Model Name: A: B: C: Page 8 of 10

9 Name: b. [01] Define Critical Flicker Frequency c. [01] In LCD and LED displays there are two polarizing filters. What must happen to the light between those two filters in order for us to see it? 10. [06] Perception and Cognition Term Give a brief overview of three of the following five concepts: absorption, automatic action, cognitive unconscious, locus of attention, cognetics. Overview Page 9 of 10

10 Extra room for rough work or continued answers. Name: Page 10 of 10