Question

Program using Python.

This program will draw a user-defined grid on the screen. When run the program will prompt the user for a positive (not 0) number to use for the grid spacing. Make sure to provide a reasonable default, and reasonable max value.

Demo1 Demo1 Grid Grid Grid Enter grid spacing Cance 00:03 1I 00:03

Answer 1

#!/usr/bin/python

import Tkinter
import turtle


def draw(grid_spacing):
    grid_spacing = int(grid_spacing)  # User defined grid spacing
    grid_window = turtle.Screen()  # Turtle screen
    grid_window.title('Grid')
    # Getting screen width and height
    windowWidth = grid_window.window_width()
    windowHeight = grid_window.window_height()
    if not grid_spacing > 0 and windowHeight / grid_spacing < 2:  # Validating
        grid_spacing = 20
    # Setting coordinates for window
    turtle.setworldcoordinates(-1, -1, windowWidth, windowHeight)
    grid_turtle = turtle.Turtle()  # turtle
    height_of_grid = 0
    width_of_grid = 0
    # Calculating total width of the grids
    for i in range(0, windowWidth - grid_spacing, grid_spacing):
        width_of_grid += grid_spacing
    # Drawing lines horizontally
    for i in range(0, windowHeight - grid_spacing, grid_spacing * 2):
        """In each iteration, the turtle draws a line from left to right
            and then draws the next line from right to left and stops
            at the position to draw the third line from left to right
            again"""
        grid_turtle.forward(width_of_grid)  # Drawing from left to right
        grid_turtle.left(90)  # Turning left
        grid_turtle.forward(grid_spacing)  # Moving spacing distance upwards
        grid_turtle.left(90)  # Again turning left
        grid_turtle.forward(width_of_grid)  # Drawing 2nd line from right to left
        height_of_grid += grid_spacing  # Calculating grid's total height
        """Checking so that turtle stops at the boundary and don't move
            upwards crossing the boundary."""
        if grid_turtle.distance(0, windowHeight) > grid_spacing:
            # Drawing vertical line of spacing length after second line
            grid_turtle.right(90)
            grid_turtle.forward(grid_spacing)
            grid_turtle.right(90)
            height_of_grid += grid_spacing
    # Drawing vertical lines
    grid_turtle.left(90)
    for i in range(0, width_of_grid + grid_spacing, grid_spacing * 2):
        """In each iteration, turtle draws a line from top to bottom
        and then moves it's left to maintain grid distance and then draws
        the next line from bottom to top and then  moves it's right
        again to maintain grid distance for next line."""
        grid_turtle.forward(height_of_grid)  # Moving downwards
        # Checking so that turtle does not cross boundary from the bottom portion
        if grid_turtle.distance(width_of_grid, 0) >= grid_spacing - 1:
            grid_turtle.left(90)
            grid_turtle.forward(grid_spacing)
            grid_turtle.left(90)
            grid_turtle.forward(height_of_grid)
            # Checking do that turtle does not cross boundary from the top line
            if grid_turtle.distance(width_of_grid, height_of_grid) > 1:
                grid_turtle.right(90)
                grid_turtle.forward(grid_spacing)
                grid_turtle.right(90)
    turtle.mainloop()


def main():
    main_window = Tkinter.Tk()  # Creating main window
    main_window.title("Grid")
    user_prompt = Tkinter.Label(main_window, text='Enter grid spacing:')  # Creating label
    user_prompt.pack()  # Placing on main_window
    text_field = Tkinter.Entry(main_window, text="")  # Creating text field
    text_field.pack()
    # Creating buttons
    # command binds a button to a function which will get invoked on click
    buttonOk = Tkinter.Button(main_window, text='OK', command=lambda: draw(text_field.get()))
    buttonOk.pack(side='left', fill='both', expand=True)
    buttonCancel = Tkinter.Button(main_window, text='Cancel', command=lambda: main_window.quit())
    buttonCancel.pack(side='right', fill='both', expand=True)
    main_window.mainloop()  # Running the application


if __name__ == '__main__':
    main()

Output: