CS 115 Lab 1, Part B: Edit a graphical Python program using IDLE

Overview

You're about to copy and modify some code that repeats Part A, but in a very simple graphical window. For example:
Screenshot of basic program

Drawing all of these elements to the screen takes a lot more code than our program from Part A, including lots of things you haven't seen before. Don't panic! We really expect you to get just a few things out of this:

Drawing graphics involves quite a bit more code than text alone, but it is possible.
It's possible to go into a program and make a few targeted changes, even if you don't grasp the entire picture.
Even when you don't fully understand a program, you can learn a lot from just trying different things.
It's OK to make mistakes. Every programmer makes mistakes all the time.

Ready? Let's do this.

Setup

Follow these instructions to start writing graphical programs.

Right-click on this link: http://mcsp.wartburg.edu/zelle/python/graphics.py. Select "Save Link As..." or "Save Target As..." If you are on a Mac, save the file into your Documents directory. If you are on a PC, save it into C:\Python33 or C:\Python34.
In a separate browser tab, open the reference document for the graphics library, just in case you need to refer to it during this lab.

Instructions

In IDLE, go to the File menu and select "New File."

Copy the following text into that file:

"""
Lab 1B: This program graphically prompts you
for your name and greets you by name.
Author: _____________
"""
from graphics import *


def main():
    # Draw the graphics window
    win = GraphWin("Lab 01b", 600, 600)

    ##### CHANGE THIS LINE #####
    prompt_string = "What is your name?"
    ##############################

    # Draw the prompt to the user, centered near the top of the screen
    prompt = Text(Point(300, 50), prompt_string)
    prompt.setSize(18)  # 18-point font
    prompt.setTextColor('black')  # just an example; black is the default
    prompt.draw(win)

    # Draw the text box for the user to type in,
    # centered just under the prompt and 50 characters long
    name_box = Entry(Point(300, 100), 50)
    name_box.draw(win)

    # Draw the button for the user to click
    button = Rectangle(Point(275, 175), Point(325, 225))
    button.setFill('gray')
    button.draw(win)

    # Draw the "OK" in the button
    button_text = Text(Point(300, 200), 'OK')
    button_text.setSize(18)
    button_text.draw(win)

    # Wait for the user to click on the button
    clicked_point = win.getMouse()  # wait for a click
    click_valid = False
    while not click_valid:
        # see if the click was actually on the button
        if 275 <= clicked_point.getX() <= 325 and 175 <= clicked_point.getY() <= 225:
            click_valid = True
        else:
            clicked_point = win.getMouse()
    # Read what the user typed
    name = name_box.getText()

    ##### CHANGE THIS LINE #####
    reply = "Hi there, " + name + "!"
    ##############################

    # Display the reply
    reply_text = Text(Point(300, 350), reply)
    reply_text.setSize(18)
    reply_text.setTextColor('black')  # just an example; black is the default
    reply_text.draw(win)

    # Display message about how to exit
    Text(Point(300, 450), 'Click anywhere in this window to exit.').draw(win)

    # Leave the window open until the user clicks in it, then close
    win.getMouse()
    win.close()


main()

Go to the File menu and then "Save As", and save your file as lab01b.py in the default directory.
Go to the Run menu, then select Run Module.
When you run the program, a graphics window should pop up. It may pop up in the background, so you may need to look in the start bar or dock for it. It will have this icon:
Type your name in the box, and click the 'OK' button. A message should pop up greeting you by name. Click one more time in the window to close the program.
Answer Question 2 in the lab writeup.
There are two lines of code in the program that are blocked off with
```
##### CHANGE THIS LINE #####
```
Change these two lines so that the program ridicules your taste in film, just like in Part B. Notice that, when we're not using the print function, we can use a + to glue together string literals and string variables.
Modify the docstring to include your name and an accurate description of what your program does now.
One final step: skim through the rest of the code, and figure out how to change the background color of the OK button. Any normal color (e.g. 'blue', 'green') will work, but if you're feeling artistic, this page has the full list of acceptable colors.
Call a member of the course staff to demo this part of the lab.
Answer Question 3 in the lab writeup.
Once you have done the demo and are happy with your program, you can exit IDLE and continue to Part C.