Gerador de estêncil (desenhe linhas interrompidas com o mouse)

stecil-generator-tabajara.py

import py5
from shapely.geometry import Polygon, MultiPolygon, GeometryCollection, LineString, Point
from shapely.ops import unary_union

MIN_GAP = 10
MIN_LT = 5 # minimum line thickness
SVG_SUFIX = 'output.svg'

save_svg = False
line_thickness = 10

polilinhas = [[]]   # lista com uma lista vazia dentro

def setup():
    py5.size(600, 600)
    
def draw():
    global save_svg
    py5.background(0, 0, 200)  # R G B 0-255 (azul)
    py5.stroke('#FFFFFF')   # cor hexadecimal #RRGGBB
    py5.fill(0, 100)
    
    if save_svg:
        out = py5.create_graphics(py5.width, py5.height, py5.SVG, f'{py5.frame_count}-{SVG_SUFIX}')
        py5.begin_record(out)
    
    poligonos = []
    for polilinha in polilinhas:
        for i, pt in enumerate(polilinha[:-1]):
            x, y = pt
            px, py = polilinha[i + 1]
            poligonos.extend(linha_interrompida(x, y, px, py))
    
    draw_shapely_objs(unary_union(poligonos))
    
    if save_svg:
        save_svg = False
        py5.end_record()
        print(f'saved {py5.frame_count}-{SVG_SUFIX}.')
    
    if polilinhas[-1]:
        x, y = polilinhas[-1][-1]
        py5.stroke(0)
        draw_shapely_objs(linha_interrompida(x, y, py5.mouse_x, py5.mouse_y))

def mouse_pressed():
    if py5.mouse_button == py5.LEFT:
        polilinhas[-1].append((py5.mouse_x, py5.mouse_y))
    elif py5.mouse_button == py5.RIGHT:
        polilinhas[-1].append((py5.mouse_x, py5.mouse_y))
        polilinhas.append([])
        
def key_pressed():
    global save_svg
    if py5.key == py5.BACKSPACE:
      #print('Backspace')
      if polilinhas[-1]:
          polilinhas[-1].pop()
      elif len(polilinhas) > 1:
          polilinhas.pop()
    elif py5.key == 's':
        save_svg = True
    elif py5.key == 'e':
        polilinhas[:] = [[]]


def mouse_wheel(e):
    global line_thickness 
    line_thickness += e.get_count()
    line_thickness = max(MIN_LT, line_thickness)
    
def linha_interrompida(x1, y1, x2, y2):
    resultado = []
    gap = max(MIN_GAP, line_thickness * 2) # tamanho da interrupção da linha
    d = py5.dist(x1, y1, x2, y2)
    if d > 0:
        ux, uy = (x2 - x1) / d, (y2 - y1) / d  # vetor unitario
    else:
        return []
    if d < gap * 2:
        pass
    elif d < gap * 3:
        x1g = x1 + ux * gap
        y1g = y1 + uy * gap
        x2g = x2 - ux * gap
        y2g = y2 - uy * gap
        resultado.append(LineString([(x1g, y1g), (x2g, y2g)]))
    elif d < 5 * gap:  # else if 
        mx, my = (x2 - x1) / 2, (y2 - y1) / 2  # vetor do meio
        x1g = x1 + mx - ux * gap / 2
        y1g = y1 + my - uy * gap / 2
        x2g = x1 + mx + ux * gap / 2
        y2g = y1 + my + uy * gap / 2
        resultado.append(LineString([(x1, y1), (x1g, y1g)]))
        resultado.append(LineString([(x2g, y2g), (x2, y2)]))
    else:
        tx, ty = (x2 - x1) / 3, (y2 - y1) / 3  # vetor de 1 terço
        x1g = x1 + tx - ux * gap / 2
        y1g = y1 + ty - uy * gap / 2
        x2g = x1 + tx + ux * gap / 2
        y2g = y1 + ty + uy * gap / 2
        x3g = x1 + 2 * tx - ux * gap / 2
        y3g = y1 + 2 * ty - uy * gap / 2
        x4g = x1 + 2 * tx + ux * gap / 2
        y4g = y1 + 2 * ty + uy * gap / 2
        
        resultado.append(LineString([(x1, y1), (x1g, y1g)]))
        resultado.append(LineString([(x2g, y2g), (x3g, y3g)]))
        resultado.append(LineString([(x4g, y4g), (x2, y2)]))
    
    resultado_final = [lin.buffer(line_thickness / 2) for lin in resultado]
    return resultado_final

def draw_shapely_objs(element):
    """
    With py5, draw some shapely object (or a list of objects).
    """
    if isinstance(element, (MultiPolygon, GeometryCollection)):
        for p in element.geoms:
            draw_shapely_objs(p)
    elif isinstance(element, Polygon):
        with py5.begin_closed_shape():
            if element.exterior.coords:
                py5.vertices(element.exterior.coords)
            for hole in element.interiors:
                with py5.begin_contour():
                    py5.vertices(hole.coords)
    elif isinstance(element, list):
        for i, p in enumerate(element):
            draw_shapely_objs(p)
    elif isinstance(element, LineString):
        (xa, ya), (xb, yb) = element.coords
        py5.line(xa, ya, xb, yb)
    elif isinstance(element, Point):
        with push_style():
            x, y = element.coords[0]
            py5.point(x, y)
    else:
        print(f"I can't draw {element}.")
        
py5.run_sketch()