如何在 tkinter 中平滑椭圆周围的边缘？

Question

我是 tkinter 的新手，我最近了解了 canvas 小部件。在掌握了基础知识之后，我认为我可以使用画布制作一个自定义进度条，并且成功了！真的很棒，然而，在去除形状上的轮廓后，我看到形状的边缘非常粗糙，尤其是椭圆形。我做了一些搜索，发现您只能将 smooth 关键字参数用于多边形。所以我的问题是，有没有办法在 tkinter 中平滑形状的边缘，尤其是椭圆形的边缘，有点像 anti-aliasing？我的代码：

from tkinter import *

root = Tk()
root.geometry("500x500")
percent = 0
progress_done, new_oval = None, None
canvas = Canvas(root, width=400, height=400, bg="white")
canvas.pack(pady=10)
prg_bar = canvas.create_rectangle(50, 140, 350, 160, fill="grey", outline="")
oval_one = canvas.create_oval(40, 140, 60, 160, fill="grey", outline="", )
oval_two = canvas.create_oval(340, 140, 360, 160, fill="grey", outline="")


def add_up():
    global percent, progress_done, new_oval
    if percent < 100:
        percent += 20
        if progress_done is None and new_oval is None:
            canvas.create_oval(40, 140, 60, 160, fill="light blue", outline='')
            canvas.delete(oval_one)
            progress_done = canvas.create_rectangle(50, 140, (percent * 3) + 50, 160, fill="light blue", outline="")
            new_oval = canvas.create_oval((percent * 3) + 40, 140, (percent * 3) + 60, 160, fill="light blue",
                                          outline="")
        else:
            canvas.delete(progress_done)
            canvas.delete(new_oval)
            progress_done = canvas.create_rectangle(50, 140, (percent * 3) + 50, 160, fill="light blue", outline="")
            new_oval = canvas.create_oval((percent * 3) + 40, 140, (percent * 3) + 60, 160, fill="light blue",
                                          outline="")
            if percent == 100:
                canvas.delete(oval_two)


btn = Button(root, text="Add to prg", command=add_up)
btn.pack()
root.mainloop()

Answer 1

使用create_polygon 绘制椭圆形。下面是绘制椭圆和圆形矩形的示例。这两个示例都设置了splinesteps 选项以增强生成曲线的平滑度。 splinesteps 选项默认为 12。

import tkinter as tk
root = tk.Tk()

c = tk.Canvas(root)
c.pack(fill='both', expand=True, anchor='nw')

def poly_oval(x, y, width, height, resolution=32):
    points = [x, y,
              x+width, y,
              x+width, y+height,
              x, y+height,
              x, y]
              
    return c.create_polygon(points, fill='#f00', smooth=True, splinesteps=resolution)   
    
def poly_roundrect(x, y, width, height, radius, resolution=32):
    #this is not a true round rect
    #it's a round rect with the potential to have invisible garbage that cheats
    #it cheats convincingly if you don't use an outline when it is cheating
    radius = min(min(width, height), radius*2)
    points = [x, y,
              x+radius, y,
              x+(width-radius), y,
              x+width, y,
              x+width, y+radius,
              x+width, y+(height-radius),
              x+width, y+height,
              x+(width-radius), y+height,
              x+radius, y+height,
              x, y+height,
              x, y+(height-radius),
              x, y+radius,
              x, y]
              
    rect = c.create_polygon(points, fill='#1f1', smooth=True, splinesteps=resolution) 
    
    #display vertices
    #for i in range(0, len(points), 2):
    #    poly_oval(points[i]-2, points[i+1]-2, 4, 4)
              
    return rect
    
rect = poly_roundrect(10, 10, 300, 50, 10, 64)

root.mainloop()