class WeilerAthertonClipping:
def __init__(self, v_list: Vlist):
self.v_list = v_list
self.new_polygon = Polygon()
def exec_clipping(self):
if self.v_list is None:
return
while True:
if len(self.v_list.crossing_list) > 0:
current_node = self.v_list.crossing_list[0]
flag = current_node.type
if flag == 1:
current_node = current_node.mutual_link
start_node = current_node
self.new_polygon.add_vertex(current_node.x, current_node.y)
else:
break
while True:
current_node = current_node.next
if current_node.id == start_node.id:
self.v_list.delete_crossing_by_id(current_node.id)
break
self.new_polygon.add_vertex(current_node.x, current_node.y)
if current_node.id < 0: # polygon vertex
continue
self.v_list.delete_crossing_by_id(current_node.id)
current_node = current_node.mutual_link # crossing
self.new_polygon.close_ring()
return
class Application(Frame):
def __init__(self, master=None):
super().__init__(master)
self.last_x, self.last_y = -1, -1
self.first_x, self.first_y = -1, -1
self.color = 'red'
self.operation_flag = 0
self.master = master
self.pack()
self.main_polygon = Polygon()
self.clipping_polygon = Polygon()
self.current_polygon = -1
self.vertex_list = None
self.clipping = None
self.create_widget()
def create_widget(self):
self.canvas = Canvas(self, width=720, height=540, bg='#FFFFFF')
self.canvas.bind('<Button-3>', self.draw_last_edge)
self.canvas.pack()
self.btn_object = Button(self, name='object', text='主多边形')
self.btn_object.pack(side='left', padx=10)
self.btn_window = Button(self, name='window', text='裁剪多边形')
self.btn_window.pack(side='left', padx=10)
self.btn_reset = Button(self, name='reset', text='重置')
self.btn_reset.pack(side='left', padx=10)
self.btn_clipping = Button(self, name='clipping', text='裁剪')
self.btn_clipping.pack(side='right', padx=10)
self.btn_object.bind('<Button-1>', self.event_manager)
self.btn_window.bind('<Button-1>', self.event_manager)
self.btn_reset.bind('<Button-1>', self.event_manager)
self.btn_clipping.bind('<Button-1>', self.event_manager)
def event_manager(self, event):
name = event.widget.winfo_name()
if name == 'object':
self.current_polygon = 0
self.color = 'red'
self.reset_last_coord()
self.canvas.bind('<Button-1>', self.draw_new_vertex)
elif name == 'window':
self.current_polygon = 1
self.color = 'blue'
self.reset_last_coord()
self.canvas.bind('<Button-1>', self.draw_new_vertex)
elif name == 'reset':
self.reset_everything()
elif name == 'clipping':
if self.operation_flag == 0:
self.vertex_list = Vlist(self.main_polygon,
self.clipping_polygon)
self.draw_crossings(self.vertex_list.crossing_list)
self.clipping = WAclip(self.vertex_list)
self.operation_flag = self.operation_flag + 1
elif self.operation_flag == 1:
self.clipping.exec_clipping() # Operate polygon clipping
self.draw_polygon(self.clipping.new_polygon, line_width=2)
self.operation_flag = self.operation_flag + 1
elif self.operation_flag == 2:
new_polygon = self.clipping.new_polygon
self.reset_everything()
self.main_polygon = new_polygon
self.draw_polygon(self.main_polygon, color='red')
def reset_last_coord(self):
self.last_x = -1
self.last_y = -1
def reset_first_coord(self):
self.first_x = -1
self.first_y = -1
def reset_everything(self):
self.canvas.delete('all')
self.operation_flag = 0
self.reset_last_coord()
self.reset_first_coord()
self.main_polygon = Polygon()
self.clipping_polygon = Polygon()
self.vertex_list = None
self.clipping = None
def draw_new_vertex(self, event):
if self.operation_flag != 0:
return
if self.first_x == -1: # Store the ring's 1st vertex
self.first_x, self.first_y = event.x, event.y
if self.current_polygon == 0:
self.main_polygon.add_vertex(event.x, event.y)
elif self.current_polygon == 1:
self.clipping_polygon.add_vertex(event.x, event.y)
self.canvas.create_oval(event.x - 5,
event.y - 5,
event.x + 5,
event.y + 5,
fill=self.color)
if self.last_x != -1:
self.canvas.create_line(self.last_x,
self.last_y,
event.x,
event.y,
fill=self.color)
self.last_x, self.last_y = event.x, event.y
def draw_crossings(self, crossing_list: list):
for node in crossing_list:
if node.type == 1:
self.canvas.create_oval(node.x - 5,
node.y - 5,
node.x + 5,
node.y + 5,
fill='black')
else:
self.canvas.create_oval(node.x - 5,
node.y - 5,
node.x + 5,
node.y + 5,
fill='green')
def draw_last_edge(self, event):
if self.first_x == -1:
return
if self.current_polygon == 0:
self.main_polygon.close_ring()
elif self.current_polygon == 1:
self.clipping_polygon.close_ring()
self.canvas.create_line(self.last_x,
self.last_y,
self.first_x,
self.first_y,
fill=self.color)
self.reset_last_coord()
self.reset_first_coord()
def draw_polygon(self, polygon: Polygon, line_width=1, color='black'):
for ring in polygon.all_rings:
if len(ring) == 0:
continue
old_node = None
for node in ring:
self.canvas.create_oval(node[0] - 5,
node[1] - 5,
node[0] + 5,
node[1] + 5,
fill=color)
if old_node is not None:
self.canvas.create_line(old_node[0],
old_node[1],
node[0],
node[1],
fill=color,
width=line_width)
old_node = node
self.canvas.create_line(old_node[0],
old_node[1],
ring[0][0],
ring[0][1],
fill=color,
width=line_width)
