Geometric Objects

To get a better feeling for the object-oriented approach to programming we implement classes for geometric objects, like roughly sketched in Everything is an Object. How to draw lines can be guessed from Library Code. Generally, you should have completed the Crash Course chapter before starting with this project.

We’ll need Matplotlib for this project. So we should import it. In principle, imports can be placed anywhere in the code, but it’s considered good practice to have them in the first lines of a file.

import matplotlib.pyplot as plt

Points

Task: Create a class Point with two member variables x and y. To create a Point object we want to call Point(3, 4), for instance.

Solution:

# your solution

Triangles

Task: Create a class Triangle. For creating a Triangle object we want to pass three Point objects.

Solution:

# your solution

Task: Add a draw member function to Triangle which draws the triangle on screen using Matplotlib. Keep the whole class definition in one code cell, because class definitions cannot be scattered over multiple cells.

Task: Create four points and draw two triangles between them (two points are used by both triangles). Remember to call plt.show() to show the plot on screen. Without plt.show() the plot will show up, too, due to some Jupyter magic. In plain Python you won’t see the plot.

Solution:

# your solution

Rectangles

Task: Create a class Rectangle representing an paraxial rectangle. For creating a Rectangle object we want to pass two Point objects, the lower left corner and the upper right corner. Each of the rectangle’s four points should be accessible as a member variable.

Solution:

# your solution

Task: Add a draw member function to Rectangle (use same code cell as before).

Task: Draw a series of 20 squares centered at the origin and growing from edge length 2 to 40. Call plt.axis('equal') before plt.show() to make the squares look like squares.

Solution:

# your solution

Houses

Task: Create a class House representing a house made of a rectangular body and a triangular roof. The roof has one third of the body’s height and is 20 per cent wider than the body. For creation we want to provide the lower left corner as well as width of the body and total height of the house. Add a draw method.

Solution:

# your solution

Task: Draw three houses.

Solution:

# your solution

Moving Objects

Task: Add a move method to Point which takes two numbers and moves the point paraxially by the specified amounts. Then add move methods to Triangle, Rectangle and House, which call Point’s move method.

Task: Write a function row_of_houses for drawing a row of identical houses. Arguments are width and height of the houses as well as start and end coordinates of the row on the x axis. Create one House object inside the function. Draw and move the house in a while loop until the house leaves the specified interval.

Solution:

# your solution

Task: Draw a row of houses.

Solution:

# your solution