gesture.py

import sys

import math
import pygame
from itertools import combinations

pygame.init()

maxfps = 30

size = width, height = 320, 240
black = 0, 0, 0

screen = pygame.display.set_mode(size)
pygame.display.set_caption('Click and drag to create a gesture')

dont_burn_my_cpu = pygame.time.Clock()


def square_distance(p1, p2):
    ((x1, y1), (x2, y2)) = (p1, p2)
    return math.hypot(x2 - x1, y2 - y1)


def max_distance_pair(points):
    if len(points) <= 1:
        raise ValueError("Expects iterable with multiple values")
    max_pair = points[:2]
    max_square_distance = 0
    for pair in combinations(points, 2):
        if square_distance(*pair) > max_square_distance:
            max_square_distance = square_distance(*pair)
            max_pair = pair
    return max_pair


def get_angle(p1, p2):
    """ The angle between two points where north is 0 degrees """
    ((x1, y1), (x2, y2)) = (p1, p2)
    x = x2 - x1
    y = y2 - y1
    angle = math.degrees(math.atan2(y, x))
    angle += 90
    if angle < 0:
        angle += 360
    return angle


class GestureFactory:
    bodies = []
    points = None

    def add_body(self, body):
        self.bodies.append(body)
        if len(self.bodies) > 10:
            self.bodies.pop(0)a
        self.find_gestures()

    def clear_bodies(self):
        self.bodies = []

    def find_gestures(self):
        if len(self.bodies) >= 3:
            p1, p2 = max_distance_pair(self.bodies)
            distance = square_distance(p1, p2)
            if distance > 100:
                angle = get_angle(p1, p2)
                print("{}'".format(angle))
                self.points = (p1, p2)
                self.clear_bodies()


gesture_factory = GestureFactory()

pygame.mouse.set_visible(True)

while 1:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()

        # Somehow Pygame doesn't update the mouse pos. Only on drag.
        if event.type == pygame.MOUSEBUTTONDOWN:
            gesture_factory.clear_bodies()
        elif event.type == pygame.MOUSEBUTTONUP:
            gesture_factory.clear_bodies()
        else:
            pos = pygame.mouse.get_pos()
            print("pos", pos)
            gesture_factory.add_body(pos)

    screen.fill(black)

    if gesture_factory.points:
        pygame.draw.line(screen, (255, 255, 255), gesture_factory.points[0], gesture_factory.points[1], 18)
        pygame.draw.circle(screen, (255, 0, 0), gesture_factory.points[1], 24, 0)

    pygame.display.flip()
    dont_burn_my_cpu.tick(maxfps)