simple_mouse_click_ver2.py

#example of mouse input

import simplegui
import math

#Globals
WIDTH = 450
HEIGHT = 300
#ball_pos = [WIDTH / 2, HEIGHT / 2]
#BALL_RADIUS = 15
ball_color = "Blue"
ball_list = []
ball_radius=15

#Helper function
def distance(p, q):
    '''
    The function verifies the distance between the circles
    '''
    return math.sqrt((p[0] - q[0]) ** 2 + (p[1] - q[1]) ** 2)
    
    
#define event handler for mouse click, draw
def click(pos):
    #global ball_pos,ball_color
    #In this way the ball change the position every single
    #click doing a copy of a list of positions
    #ball_pos = list(pos).
    #Change the color if the distance is grather than the radius
    #if distance(pos, ball_pos) < BALL_RADIUS:
    #    ball_color = "Yellow"
    #else:
    #    ball_pos = list(pos)
    #    ball_color = "Blue"
    #ball_list.append(pos)
    #With this append we can draw mane circles in the screen
    #changed = False
    #for ball in ball_list:
    #    if distance([ball[0],ball[1]],pos) < ball_radius:
    #        ball[2]="Yellow"
    #        changed= True
    
    #if not changed:
    #        ball_list.append([pos[0],pos[1],"Blue"])
    #To remove the circles
    remove = []
    for ball in ball_list:
        if distance(ball,pos) < ball_radius:
            remove.append(ball)
    if remove == []:
        ball_list.append(pos)
    else:
        ball_list.pop(ball_list.index(ball))
   
def draw(canvas):
    for ball in ball_list:
        #canvas.draw_circle(ball_pos, BALL_RADIUS, 1, "Black", ball_color)
        canvas.draw_circle([ball[0],ball[1]],ball_radius,1,"Black",ball_color)
#create frame
frame = simplegui.create_frame("Mouse selection", WIDTH, HEIGHT)
frame.set_canvas_background("White")

#register event handler
frame.set_mouseclick_handler(click)
frame.set_draw_handler(draw)

#star frame
frame.start()