CS 2135 (C04) Individual Project
Implementing an Animation Language

Phase 1 due Monday, February 16
Phase 2 due Sunday, February 29

[ Phase 1 | Phase 2 | Grading | Collaboration Policy | FAQ | Interpreter hints ]

Project Description

You must design and implement a language for animating shapes (similar to a limited form of Flash animations). Shapes should be able to move around the screen, resize, bounce, or jump to random locations. Here are three examples of animations in action.

sample animations

Shapes can be circles, rectangles, or polygons (circles and squares have fill colors, but polygons are just outlines). When specifying a shape, a programmer can give "variables" to represent the shape's dimensions (such as a circle with a center at "x" and "y" and radius "r"; a square could be a rectangle with width and height the same length "l") and initial values of those variables. To animate a shape, the programmer specifies how much some of these dimensions will change and over what time (in seconds). For example,

For this project, you will provide:

  1. A language for specifying animations as described above, and

  2. A program (interpreter) that will run an animation written in your language, displaying it on the screen.

Both the language and the program must support three kinds of animations:

Slides and bounces should occur smoothly within the indicated time. For random jumps, the shape should periodically jump throughout the indicated time.

You will do the project in two stages: a language design stage, followed by an implementation stage. Each stage has a separate due date, as described below.

Project Goal

The goal of the project is to make sure each student can define, design, and implement a domain-specific programming language. This is an individual project -- you may not work with your homework partner, or any other students, on this project (see the collaboration policy for more details).

The Design Phase: DUE Monday, February 16 11:59pm

For this phase, you must propose a language design for animations. You must submit both the proposed language and examples showing how to represent the second and third sample animations, plus an animation of your own with random jumps, in your language:

You do not need to be able to run animation programs at the end of this stage. Macros for the language are not needed at this stage either (you can add those in the implementation stage).

What to Turn in

Submit an electronic file design.scm or design.ss (under turnin name project-design) containing your work for this phase.

The Implementation Phase: DUE Sunday, February 29 11:59pm

For this phase, you must provide a function run-animation that takes an animation in your language and runs it (displays the animation on the screen). Your animation should happen in one window over time---you are not trying to produce a sequence of still frames as shown in the samples.

We will use the draw.ss teachpack in DrScheme for the graphics (not the images material that you used for homework 2).

You may decide to revise or enhance your original language design as you try to implement the language. That's fine. Your project report will describe all changes you decided to make.

The Project Report

Provide a text file with answers to the following questions:

  1. What must the TA do to run your program? Provide concrete instructions (such as "execute (run-animation animation1)"), including a list of the animations you defined as your test cases. The TAs won't grade a program that they can't run.

  2. What is the state of your implementation? Explain which features/aspects work and which don't. If you didn't get the random jumps to work, for example, say so. This gives the TAs guidelines on how to test your system.

  3. How have you changed your design since the version you submitted for the design deadline? Explain the changes and why you made them (i.e., I found I couldn't do X because of problem Y with my earlier definition). We're interested in seeing what doing the implementation taught you about the language design.

  4. What, if anything, do you think could be cleaner in your design or implementation? If you are satisfied with your design, say so. If you think certain aspects should really be easier to use, easier to write, etc, explain those aspects and what you'd like to see different. No danger of losing points for honesty here (you'll only lose points for problems that we can detect without reading your report) -- we just want to hear your assessment as we determine our own.

What to Turn in

  1. A file animations.scm or animations.ss containing your work for this phase.

  2. A file report.txt containing your project report. Please submit these in plain text, rather than in Word format.

Submit these via turnin, under the name project-final.


In general, the design phase counts for 25% of your project grade, the implementation phase (including final language design) for 70%, and your project report for 5%.

Design Phase Grading

We will grade your language designs on a 4-grade scale (check+, check, check-, no credit). At this stage, we're looking to see whether you thought out the design phase well -- did you identify appropriate data, control, etc? Does your design adequately support the given examples?

There's no single right answer for this part, and while we will make suggestions on your designs, we won't give you a single right answer to follow when doing your implementation. Part of the exercise is for you to have to work with, and perhaps revise, your initial language design when it comes time to implement your animation system.

Implementation Phase Grading

In the implementation phase, we will be looking at your final language design and its implementation. More specifically:

Some General Notes on Grading

Collaboration Policy

This is an individual project. Collaboration is not permitted on this assignment. The course staff are the only people you may approach for help with this project (but do come to us if you need help). You may not ask anyone outside of the course staff questions on any aspect of this project. This includes:

Violations of this policy follow the general course collaboration policy, and may result in an NR for the course.

Why this policy? Given the fairly open collaboration policy on homeworks, this assignment helps me assess how much each student understands of the course material. Since some students struggle in timed situations such as exams, the project gives you a more open-ended setting in which to demonstrate what you've understood of the course material.