Write a program that draws a wall of circles one at a time using a timer. Every DELAY milliseconds, it should draw one circle.
Start by drawing one in the top left corner and then draw circles to its right until you finish one row. Then draw circles on the next row. The circles should alternate between the colors red and black.
When you have drawn circles covering the entire screen, stop your timer.
Hint: You can’t use a for loop or while loop here, since you need to draw on a timer.
// Set up canvas
let canvas = document.createElement('canvas');
let ctx = canvas.getContext('2d');
document.body.appendChild(canvas);
// Set up variables
let DELAY = 1000; // milliseconds
let x = 0;
let y = 0;
let color = 'red';
// Draw the first circle
ctx.fillStyle = color;
ctx.beginPath();
ctx.arc(x, y, 10, 0, Math.PI * 2);
ctx.fill();
// Set up timer
let timer = setInterval(drawCircle, DELAY);
// Draw circle function
function drawCircle() {
// Change color
if (color === 'red') {
color = 'black';
} else {
color = 'red';
}
ctx.fillStyle = color;
// Draw circle
ctx.beginPath();
ctx.arc(x, y, 10, 0, Math.PI * 2);
ctx.fill();
// Move to next position
x += 20;
if (x > canvas.width) {
x = 0;
y += 20;
}
// Stop timer when done
if (y > canvas.height) {
clearInterval(timer);
}
}
To create a program that draws a wall of circles one at a time using a timer, you can use the following steps:
1. Set up the graphical environment:
- Create a window or canvas where you can draw the circles.
- Define the size of the window to cover the entire screen.
2. Create a timer:
- Set a delay interval (DELAY) in milliseconds between each circle drawing.
- Connect the timer to a callback function that will draw one circle each time it is triggered.
3. Implement the drawing logic inside the callback function:
- Define a variable to keep track of the current row and column position of the circles. Start with row 0 and column 0.
- Create a variable to track the color of the circles, starting with red.
- In the callback function, draw a circle based on the current row and column position using an appropriate graphics library.
- After drawing a circle, update the row and column position:
- If the column is at the far right, move to the next row and reset the column to 0.
- If the column is not at the far right, move to the next column.
- Switch the color between red and black for each circle drawn.
4. Stop the timer:
- After drawing circles covering the entire screen, stop the timer to prevent further circle drawings.
Here's a sample Python code using the tkinter library to implement this program:
```python
import tkinter as tk
DELAY = 100 # Delay in milliseconds
ROW_COUNT = 10
COLUMN_COUNT = 10
CIRCLE_RADIUS = 20
WINDOW_WIDTH = COLUMN_COUNT * 2 * CIRCLE_RADIUS
WINDOW_HEIGHT = ROW_COUNT * 2 * CIRCLE_RADIUS
def draw_circle():
global row, column, color
canvas.create_oval(
column * 2 * CIRCLE_RADIUS, row * 2 * CIRCLE_RADIUS,
(column + 1) * 2 * CIRCLE_RADIUS, (row + 1) * 2 * CIRCLE_RADIUS,
fill=color
)
column += 1
if column >= COLUMN_COUNT:
row += 1
column = 0
color = "black" if color == "red" else "red"
if row >= ROW_COUNT:
root.after_cancel(timer) # Stop the timer
root = tk.Tk()
canvas = tk.Canvas(root, width=WINDOW_WIDTH, height=WINDOW_HEIGHT)
canvas.pack()
row = 0
column = 0
color = "red"
timer = root.after(DELAY, draw_circle)
root.mainloop()
```
This code sets up a tkinter window of size `WINDOW_WIDTH` by `WINDOW_HEIGHT` and creates a `canvas` object to draw the circles. It then defines the `draw_circle` function as the callback for the timer.
The `draw_circle` function uses the `create_oval` method of the canvas object to draw a circle based on the current `row` and `column` position. It then updates the `row` and `column` variables and switches the color between red and black.
The timer is initialized using the `after` method of the `root` object, which triggers the `draw_circle` function every `DELAY` milliseconds. Finally, the main event loop is started with `root.mainloop()`, allowing the program to respond to user interactions and timed events.
To draw a wall of circles one at a time using a timer, you can make use of the `turtle` module in Python. Follow the steps below:
1. Import the necessary modules:
```python
import turtle
import time
```
2. Initialize the turtle screen and set up the parameters:
```python
screen = turtle.Screen()
screen.setup(600, 600)
screen.bgcolor("white")
```
3. Define the circle drawing function:
```python
def draw_circle(x, y, color):
turtle.penup()
turtle.goto(x, y)
turtle.pendown()
turtle.color(color)
turtle.begin_fill()
turtle.circle(20)
turtle.end_fill()
```
4. Define the main function to draw the wall of circles:
```python
def draw_wall():
colors = ["red", "black"]
x = -280
y = 280
rows = 10
cols = 12
delay = 100 # milliseconds
for row in range(rows):
for col in range(cols):
index = (row + col) % 2
color = colors[index]
draw_circle(x, y, color)
x += 50
time.sleep(delay / 1000)
y -= 50
x = -280
```
5. Start the drawing by calling the `draw_wall` function and then exit the turtle program:
```python
draw_wall()
turtle.done()
```
Putting it all together, here's the complete code:
```python
import turtle
import time
screen = turtle.Screen()
screen.setup(600, 600)
screen.bgcolor("white")
def draw_circle(x, y, color):
turtle.penup()
turtle.goto(x, y)
turtle.pendown()
turtle.color(color)
turtle.begin_fill()
turtle.circle(20)
turtle.end_fill()
def draw_wall():
colors = ["red", "black"]
x = -280
y = 280
rows = 10
cols = 12
delay = 100 # milliseconds
for row in range(rows):
for col in range(cols):
index = (row + col) % 2
color = colors[index]
draw_circle(x, y, color)
x += 50
time.sleep(delay / 1000)
y -= 50
x = -280
draw_wall()
turtle.done()
```
When you run this code, you should see a wall of circles being drawn one at a time with alternating red and black colors. The drawing will start in the top left corner and proceed row by row until the entire screen is covered.