# CS 151: Project 9

Project 9
Spring 2019

### Project 9: Unique Trees and Shapes

The project this week is to continue to make shape classes, making use of inheritance, starting with a tree class.

1. The first task is to make a Tree shape class, similar to the Square and Triangle classes. The difference between a Tree and a Square, though, is that the Tree generates its string dynamically using an L-system. The string for a Square is always the same, so it can set the string field once and then use the parent Shape class' draw method. However, every time we draw a tree, we first must build a string using an L-system. Then it can use the Shape draw method.

Because we use an L-system to generate the string to draw, a Tree object must contain an L-system, which means it must have a field that holds an L-system object.

Because a Tree is a Shape, it must be a child of the Shape class. That lets it use the parent methods for setting color, distance, and angle, among other things.

To make our Tree class, start by creating a file called tree.py. Import your lsystem and shape modules. The Tree class should be derived from the Shape class, but you'll need to override some of the methods because of the special nature of a Tree: it needs more fields than a simple Shape, and it has to dynamically create the string it will draw using an L-system.

The methods you'll need to override or create for the Tree class include:

• def __init__(self, distance=5, angle=22.5, color=(0.5, 0.4, 0.3), iterations=3, filename=None): - The init method should call the parent (Shape) init method with self, distance, angle, and color, store the iterations number in an iterations field, then create an Lsystem object (passing in the filename) and store it in an lsystem field.
• Create a setIterations(self, iterations) mutator method for the iterations field of the Tree object.
• Create a read(self, filename) method that calls the lsystem object's read method with the specified filename. Use the Lsystem object you created and stored in the lsystem field to call the read method.
• Override the draw method--but keep the same parameter list--so it uses the Lsystem to build the string, assigns the string to the string field of self, and then calls the parent draw method. You may want to change the default orientation for this function to 90 so the trees grow up.

Once you've written the tree class, make a test method for the class and try it out. The test method should take in an Lsystem filename, create a Tree object, and then use the Tree object's draw method to draw at least 3 trees. Use an L-system with multiple replacements for at least one rule (e.g. systemJ.txt and show the three trees are different.

The output of your tree.py test method is required image 1.

2. In shapes.py, create at least three classes--other than Square and Triangle--that are derived from the Shape class and define different shapes using strings. One of them should make a filled shape using curly brackets { and } to turn on and off the fill. Make a test function for your shapes.py file that generates an image that incorporates all of the shapes you created. The function should test all of the capabilities of the different shape classes.

The output of your shapes.py test method is required image 2.

3. In a file named home.py, Create a new scene representing a scene near your home (or favorite place that isn't Colby). Give your scene a title in your report. Use your various shape classes and include at least one tree in the scene. Use only the Tree and shape classes from this assignment to create the scene, not your turtle code from prior assignments. Only the TurtleInterpreter class should execute turtle commands.

The home scene is required image 3.

4. In a file named mosaic.py, create a function tile(x, y, scale) that draws a set of shapes inside a square that is scale by scale in size with the lower left corner of the tile at location (x, y). If scale is 10, then the tile should be 10x10.

Then make a function mosaic(x, y, scale, Nx, Ny) that draws a 2D array of tiles Nx by Ny, where each tile is of size scale by scale, and the lower left corner of the mosaic is at (x, y). So if scale is 10, Nx is 3 and Ny is 4, the function should draw twelve 10x10 tiles three across and four down.

Just like in the previous task, use only the Tree and shape classes from this assignment to create the scene, not your turtle code from prior assignments. Only the TurtleInterpreter class should execute turtle commands.

An image of at least 20 tiles (5 x 4) in a non-square arrangement is required image 4.

### Extensions

Congratulations on completing the core tasks! Between the code (and comments) that you’ve already written and the report (below), you’ve already earned up to 26/30 points for this project. The remaining 4/30 are a chance for you to earn credit for exploring parts of this project and digging deeper to express your creativity! If you’re exhausted or running out of time, this is a perfectly respectable place to stop. If you’re up for it, you have the option to design your own extension or pick one of the following examples. To earn all 4 extension points, concentrate on one design challenge, and really dig into it both computationally and creatively. What will you create?

Here are some example extensions:

• Make non-square tiles. Rectangles are easy, hexagons, triangles, or n-gons are a real extension.
• Make new L-systems and add characters to the vocabulary that do interesting things.
• Modify drawString so that when drawing a tree the branches droop down like gravity is pulling at them.
• Create a sequence of images to build an animation.
• Make more tile functions and mix them around in the mosaic function.
• Make more shape classes that do interesting things. Making a fixed sequence of characters is easy. Make a shape class where the strings are the result of executing a function. L-systems are one example of a dynamically created string, but there are many other ways to do that.
• Develop your own extension. If you choose to do this, explain what you are trying to accomplish and then how you implemented your solution. Show the result.

Remember: We award extension points based on the depth of your computational exploration. A good extension should interest you and show us that you can apply this week's material in creative ways.

### Hand-in and Report

1. Put the python files you wrote on the Courses server in your private directory in a folder named Project9.