I am trying to make a Python program with Turtle Graphics that draws 2 circles overlapping (like a Venn Diagram) within a rectangle, and plots random dots onto the Venn Diagram.
I have successfully done this, but now I want to make the program recognize if a point is in one of the circles or in the intersection of the Venn Diagram. I then want to change the color of the dots depending on which region they're in.
What I have done so far for the program is listed variables, defined the shapes and made a for loop to randomly generate points.
turtle is just a graphics library- it doesn't keep track of the objects you've drawn on screen. So, to calculate if a given point is within one of your Venn diagram circles, you'll need to take the following steps:
- Store each circle's coordinates when you call
circle()
(classes would be helpful, but chances are you haven't learned those yet)
- Call a function to test if the point is in the stored circle coordinate space. This will be a purely mathematical operation on Cartesian coordinates. The link @Tim gave (Equation for testing if a point is inside a circle) will help you achieve this.
A little guidance on step 1:
When you draw a circle, you have its center (current turtle position), and a radius. From there, obtaining all points within that circle is just geometry (if you can't derive the formula, a quick search will help you out). I'd suggest that you make a function that draws a Venn diagram circle, and one that returns the points within a circle. Something like this:
def venn_circle(circle_color, circle_radius):
""" Draws a colored circle, returns the points within. """
turtle.color(circle_color)
# <fill in: code to move, orient the turtle>
center = turtle.position()
# <fill in: code to draw the circle>
return circle_coords(center, circle_radius)
def circle_coords(center, radius):
""" Return the set of pixels within the circle. """
raise NotImplementedError()
And one quick note- you should never do from package import *. It's okay in some cases, but will generally just lead to trouble. In my example code, I've assumed you've substituted this idiom for import turtle.
I had quite similar assignment, tried to solve it the simple way:
import tkinter
import random
canvas = tkinter.Canvas(width = 300, height = 200, bg = "white")
canvas.pack()
n = 500
for i in range(n):
x = random.randrange(0, 300)
y = random.randrange(0, 200)
bod = canvas.create_oval(x+3, y+3, x-3, y-3, fill = "black")
if (x - 100)**2+(y - 100)**2 < 80**2: #for dot in circle1 fill red
canvas.itemconfig(bod, fill = "red")
if (x - 180)**2+(y - 100)**2 < 90**2: #for dot in circle2 fill blue
canvas.itemconfig(bod, fill = "blue")
if (x - 100)**2+(y - 100)**2 < 80**2 and (x - 180)**2+(y - 100)**2 < 90**2:
canvas.itemconfig(bod, fill = "green") #overlapping of circle1 and 2
