Intro Graphics Assignment 1

Impressionist Painting

Due: September 9, 2003

Overview

Your assignment is to implement an impressionistic paint system.  Your program will load a full color image, allow the user to create a painting, and then save the resulting image. The painting, unlike the original image, will consist of a set of brush strokes: each stroke will have a color, a shape, a position, a size and an orientation. The strokes will be created by the user, by sweeping the mouse over the image, in the process picking up the color from the original image and laying down a stroke at the cursor location.

Some images to get you started are here.

Skeleton code to get you started is here.

Required Features

• Provide a palette of at least three brush shapes. The following three shapes are required: a circle, a rectangle rotated by 45 degrees, and a scattered collection of lines. 10 points each.
• Provide a control so that the user can set the size of the brush. 5 points.
• Provide at least three methods for controlling the position and orientation of the brush. The first, and simplest, method should be to place the brush at the current cursor location in a fixed orientation. The second method should orient the brush in the direction of mouse motion. The final method should continually jitter (randomly perturb) the position and orientation of the brush about the cursor location. 10 points each.
• Provide a blending mode. This requires that you provide a controller for setting the opacity to a value between 0 and 1. The opacity will control the transparency of the brush stroke. If the stroke is opaque (opacity equals 1), then the stroke will overwrite the current painted colors; if the stroke is transparent, it will be blended into the painting using the "over" operator. 10 points.
• Your program must generally work. It should not crash under any circumstances. It should behave reasonably when the window is resized (see the sample program for a definition of "reasonable"). It should not be comically slow (again, see the sample program). 25 points.

Getting Started

To help you get started, and to help you concentrate on the more interesting aspects of this assignment, we will provide a sample program and a collection of images. The sample program will read in a full color image, and store the image in a 2D array. This program will also implement a clear button that erases the canvas, and a save button (that saves the painting in a file).  Here is some documentation on the sample program.

Here is a link to a sample implementation for Windows.

Your program should have the same user interface as the example program.  Your program will be tested semi automatically, so deviations from that user interface will break the testing process and will make everyone involved very unhappy.

Extra Credit

Up to 25 points of extra credit are available for implementing novel, and unique extensions to the base assignment. To apply for extra credit, write a one paragraph description of what you have come up with, and why you think it is interesting. Only highly original ideas will be awarded extra credit.

Here are a few suggestions:

• Add brushes that are substantially different from those you are required to implement. Explain how your brushes are different and the types of effects they allow you to create.
• It can be time-consuming to paint an image manually. Add a feature so that a whole painting can be created automatically. Describe your algorithm for choosing the brush attributes in this automatic painting mode.
• One problem with the base system is that you can not see which part of the image you are painting while you paint. Solve this problem by showing a dimmed version of the original image while you paint. Add controls to show/remove the dimmed image from the canvas.
• Add methods for orienting the brush to the x,y color gradient or the edges in the original image.
• Automatically find edges in the original image and clip long brush stokes to those edges.

Note that some of these suggestions are much more difficult to implement than others. We will judge the amount of extra credit you receive accordingly.

Here is a link to an implementation of some of the extra credit features (again, for Windows).

Submitting

Write a web page describing what you did including your entry for the art contest. Your web page should provide a link to a .zip file containing all the source code required to compile your program

It is your responsibility to make sure that the .zip file you submit is complete.  No credit will be given for programs that fail to compile.

E-mail a link to your submission to the TA.  Never, NEVER e-mail the TA anything but a URL for your submission.  In particular, do not mail your .zip file or any images as an attachment.

Results of the art contest can be found here.