Draw lines at the respective positions clicked by the mouse using Turtle

In this article, we will learn how to draw lines at any position which is clicked by the mouse using a turtle module.

Turtle graphics: 

• turtle.listen(): Using this then we can give keyboard inputs
• turtle.onscreenclick(func,1 or 3): This function is used to bind function to a mouse-click event on canvas. 1 means left click and 3 means to right-click.
• pen.goto(x coordinate , y coordinate): Moves the turtle from the current position to the location x, y along the shortest linear path between the two locations (i.e. a direct line between the current position and (x,y))
• pen.color( colour ): This method is used to change the color of the turtle
• pen.shape(shape): This method is used to give the shape to the turtle
• head.penup: Picks the pen up so the turtle does not draw a line as it moves
• head.hideturtle: This method is used to make the turtle invisible. It’s a good idea to do this while you’re in the middle of a complicated drawing because hiding the turtle speeds up the drawing observably. This method does not require any argument.
• head.clear: This function is used to delete the turtle's drawings from the screen
• head.write: This function is used to write text at the current turtle position.

Approach:

• Import the turtle modules.
• Define two instances for the turtle pen and head.
• Head is to tell currently at which coordinate mouse is clicked.
• Give shape and color to the instance
• Define the function btnclick which takes two parameters x and y coordinates, now use the function goto() inside this function to take the turtle to x and y coordinates passed in the parameter.
• Use onscreenclick to bind btnclick function with the mouse click on the screen.
• Use function listens to perform the above specified task.

Below is the Python implementation of the above approach:

# python program
# import for turtle module
import turtle

# defining instance of turtle
pen=turtle.Turtle()
head=turtle.Turtle()
head.penup()
head.hideturtle()
head.goto(0, 260)
head.write("This is to display the coordinates of the position where mouse is clicked",
           align = "center", 
           font = ("courier", 12, "normal"))

# giving circle shape to pen i.e. instance of turtle
pen.shape("circle")

# giving colour to turtle
pen.color("red")

# define function to make the turtle move 
# to the position which is clicked by the mouse
def btnclick(x, y):
    pen.goto(x, y)
    head.clear()    
    head.write(f"x coordinate = {x}, y coordinate = {y}",
               align = "center", font = ("courier", 24, "normal"))
    
# this function will call btnclick whenever mouse is clicked    
turtle.onscreenclick(btnclick, 1)
turtle.listen()
turtle.mainloop()

Output: