How to draw Android lock screen patterns using Python-CodePudding

This may seem trivial but I Googled it and found no relevant results. And I don't have access to ChatGPT because unfortunately I was born in China.

I want to find out all the ways a polyline can pass through n*n evenly spaced lattice points without crossing itself.

Basically like a typical Android lock screen pattern, in which there are 9 points situated at the vertices of 4 adjacent congruent squares. And you can draw polylines that goes from vertices to other vertices.

I want to programmatically generate all such polylines that passes through all n*n (n >= 3 and n is integer) lattice points without intersecting itself, but to do that I need to first manually draw such polylines to find the mathematical pattern.

I can handle all the logics but I really don't know how to code GUI, basically I want a window that displays n*n lattice points arranged in a square, and you use mouse pointer to draw the polyline, the pointer auto-snaps to the grid, and you click and hold from one lattice to another to draw the lines.

How can I do that?

CodePudding user response：

If you just need to use it for visualization, you can just use PyGame. Here I just created a way to draw lines between points, which should be enough to get a better understanding.

Create window

import pygame

size = 500

pygame.init()
window = pygame.display.set_mode((size, size))

Create grid

n = 3

grid = []
for i in range(n):
    for j in range(n):
        grid.append((i*size//n   size//n//2, j*size//n size//n//2))

Create and draw the lines

start_point = None
end_point = None
line_points = []

running = True

while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.MOUSEBUTTONDOWN:
            mouse_pos = pygame.mouse.get_pos()
            closest_point = min(grid, key=lambda x: ((x[0]-mouse_pos[0])**2   (x[1]-mouse_pos[1])**2)**0.5)
            start_point = closest_point
        elif event.type == pygame.MOUSEBUTTONUP:
            mouse_pos = pygame.mouse.get_pos()
            closest_point = min(grid, key=lambda x: ((x[0]-mouse_pos[0])**2   (x[1]-mouse_pos[1])**2)**0.5)
            end_point = closest_point
            line_points.append((start_point, end_point))
            start_point = None
            end_point = None

    for point in grid:
        pygame.draw.circle(window, (0, 0, 255), point, 10)

    for start, end in line_points:
        pygame.draw.line(window, (255, 0, 0), start, end, 5)

    pygame.display.update()

pygame.quit()

Good luck with your project!