How To Draw A Target In Turtle Python

Cartoon Circles with Python Turtle Graphics

Python Turtle Graphics Circles - Archery Target

In this lesson we are going to learn how to depict circles with Python Turtle Graphics. We volition and so modify the default circle method so that we can centre our circles at specific (x, y) coordinates, and then have some fun some with creating an archery target and adding some interactivity.

As you may already know, Python Turtle Graphics is fantastic way to acquire nigh programming and likewise virtually Maths. In full general at that place seems to be trivial integration between these two subjects at school level, which is something I hope to run across modify. Many of my posts on this blog are written to assist further this cause. Run across Computer Maths Category for related posts.

Before we start, please note that there are many ways to achieve the same goal with Python Turtle Graphics. While this can be a proficient affair, it tin also lead to defoliation. For this reason I have washed things is a certain manner which I consider gives the best foundation for making full use of the potential of this module. For case:

I create a screen object and so I can command its colour and title etc.
I apply functions which take an existing turtle equally an argument, to help discourage the use of global variables and provide added flexibility, so the same function tin work for multiple turtles.

Don't worry too much virtually these details if they don't make full sense to you. The code is fairly self explanatory and at that place are comments to help.

Drawing Circles with Python

The default way to create circles in with Python Turtle Graphics is to elementary apply the circle method, as in the following example.

            import turtle  # Prepare up screen screen = turtle.Screen() screen.title("Circle") screen.setup(450, 450) screen.bgcolor("cyan")  # Create a turtle toby = turtle.Turtle() toby.speed(0) toby.width(five) toby.hideturtle() toby.colour("ruby")  # Depict a circle starting at (x, y) radius = 100 toby.circumvolve(radius)  # Arrive all work properly turtle.done()

Python turtle circle

This is fine for many purposes, only it can be frustrating as it doesn't requite you command of where the centre of the circumvolve is. Notice how in the instance in a higher place the circle is not centred at the location of the turtle (chosen toby), which came into existence at the default location of (0, 0). Using the default method, the circle is drawn from the staring point, and then the starting point is on the circumference.

Drawing Circles Centred at `(x, y)`

The next programme demonstrates how to depict circles centred at specific (10, y) coordinates. Information technology does this past use of a part draw_circle() which takes several arguments every bit described in the code.

Using this role, it is relatively easy to describe an archery target. See the program below.

            import turtle   def draw_circle(tur, ten, y, radius, color="black"):     """     Draws a circumvolve with center at (x, y), radius radius and colour colour.     Create your turtle elsewhere and pass it in every bit tur.     """     tur.color(colour)     tur.pu()     tur.goto(x, y - radius)  # -radius because the default circle method starts drawing at the border.     tur.pd()     tur.begin_fill()     tur.circle(radius)     tur.end_fill()   # Ready screen screen = turtle.Screen() screen.title("Archery") screen.setup(450, 450) screen.bgcolor("cyan")  # Draw the target toby = turtle.Turtle() toby.speed(0) toby.width(5) toby.hideturtle()  draw_circle(toby, 0, 0, 160, "black")  # Draw a black circle at coords (0, 0) with radius 160 pixels draw_circle(toby, 0, 0, 120, "bluish") draw_circle(toby, 0, 0, eighty, "red") draw_circle(toby, 0, 0, 40, "yellow")  # Make it all work properly turtle.done()

This program makes utilize of lots of features which you can use in your own programs. You can use as much or as petty as y'all like, but experiment with the ideas. If you don't take many ideas, try just making pocket-size changes, like changing the colours or sizes of the circles. Some of the colours available in Python Turtle Graphics can exist found here.

The Next Level

This department contains some more than advanced Python programming techniques, so if you are a relative beginner, you may want to leave it for subsequently on.

For case information technology includes

Event detection with Python Turtle Graphics
Event callback functions
Passing boosted arguments to a callback using lambda

            import turtle  CROSS_SIZE = 20   def draw_circle(tur, x, y, radius, colour="black"):     """     Draws a circumvolve with center at (x, y), radius radius and color color.     Create your turtle elsewhere and pass information technology in equally tur.     """     tur.color(color)     tur.pu()     tur.begin_fill()     tur.goto(10, y - radius)  # -radius considering the default circle method starts drawing at the border.     tur.pd()     tur.circle(radius)     tur.end_fill()   def draw_plus(tur, x, y, length=CROSS_SIZE):     """     Draws a cantankerous centered at (10, y) with existing turtle tur and length given past CROSS_SIZE.     """     tur.penup()     tur.goto(x, y - (length / 2))     tur.pendown()     tur.goto(x, y + (length / 2))     tur.penup()     tur.goto(x - (length / 2), y)     tur.pendown()     tur.goto(ten + (length / 2), y)     print("Mouse click at", x, ",", y)  # for useful feedback about where you clicked.   screen = turtle.Screen() screen.title("Archery") screen.setup(450, 450) screen.bgcolor("cyan") screen.listen()  # Draw cross when screen is clicked cross_turtle = turtle.Turtle(visible=False) cross_turtle.color("light-green") cross_turtle.width(four) cross_turtle.speed(0) # The lambda hither is a useful trick to enable additional arguments to be passed to the onclick callback. screen.onclick(lambda 10, y, tur=cross_turtle: draw_plus(tur, 10, y)) screen.onkey(lambda: cross_turtle.articulate(), "space")  # Clear crosses on keypress.  # Depict the target toby = turtle.Turtle() toby.speed(0) toby.width(5) toby.hideturtle()  draw_circle(toby, 0, 0, 160, "blackness")  # Draw a black circle at coords (0, 0) with radius 160 pixels draw_circle(toby, 0, 0, 120, "bluish") draw_circle(toby, 0, 0, lxxx, "scarlet") draw_circle(toby, 0, 0, twoscore, "yellow")  # Make it all work properly. turtle.washed()

Python turtle archery

In that location are lots of ingredients here that y'all can use in your ain projects. As before, go alee and edit bits of the program or use $.25 in you own project. The program is not currently a game equally such, merely I expect information technology could exist made into 1. Can you call back of how? I'm thinking some kind of random positioning of the crosses or reflex-testing game. We haven't looked at timers and animation in this article, but for certain they are possible with Python Turtle Graphics. It may be that an idea y'all have might become possible with a scrap more than knowledge, and so maybe make a note and come back to it later. If you have an idea that you want aid with, let me know in the comments and I'll come across if I can help.

This lesson has shown you how to draw circles using Python Turtle Graphics and so how to better the bones functionality and add some interactive features. I promise you found it fun and interesting.

Happy calculating!