如何在Tkinter中无需使用图片创建圆角UI元素

要在Tkinter里做出圆角效果，不用图片的话可以试试以下几种方案：

• 用tkinter.Canvas绘制圆角元素
  利用Canvas的绘图功能，通过拼接圆弧和矩形来实现圆角背景，还能封装成自定义控件复用。示例代码：

  import tkinter as tk
  
  class RoundedFrame(tk.Canvas):
      def __init__(self, parent, bg_color, corner_radius, width, height):
          super().__init__(parent, bg=parent["bg"], highlightthickness=0, width=width, height=height)
          self.corner_radius = corner_radius
          self.bg_color = bg_color
          self.draw_rounded_rect()
  
      def draw_rounded_rect(self):
          # 绘制四个圆角弧
          self.create_arc(0, 0, 2*self.corner_radius, 2*self.corner_radius, start=90, extent=90, fill=self.bg_color, outline=self.bg_color)
          self.create_arc(self.winfo_width()-2*self.corner_radius, 0, self.winfo_width(), 2*self.corner_radius, start=0, extent=90, fill=self.bg_color, outline=self.bg_color)
          self.create_arc(0, self.winfo_height()-2*self.corner_radius, 2*self.corner_radius, self.winfo_height(), start=180, extent=90, fill=self.bg_color, outline=self.bg_color)
          self.create_arc(self.winfo_width()-2*self.corner_radius, self.winfo_height()-2*self.corner_radius, self.winfo_width(), self.winfo_height(), start=270, extent=90, fill=self.bg_color, outline=self.bg_color)
          # 填充中间矩形区域
          self.create_rectangle(self.corner_radius, 0, self.winfo_width()-self.corner_radius, self.winfo_height(), fill=self.bg_color, outline=self.bg_color)
          self.create_rectangle(0, self.corner_radius, self.winfo_width(), self.winfo_height()-self.corner_radius, fill=self.bg_color, outline=self.bg_color)
  
  # 使用示例
  root = tk.Tk()
  root.config(bg="#f0f0f0")
  rounded_frame = RoundedFrame(root, bg_color="#ffffff", corner_radius=20, width=300, height=200)
  rounded_frame.pack(pady=20, padx=20)
  
  btn = tk.Button(rounded_frame, text="测试按钮")
  btn.place(relx=0.5, rely=0.5, anchor="center")
  
  root.mainloop()
  

• 自定义ttk.Style实现圆角（限部分控件）
  针对ttk系列控件，切换到支持borderradius属性的主题后，就能直接通过样式设置圆角。注意不同平台兼容性有差异，示例：

  import tkinter as tk
  from tkinter import ttk
  
  root = tk.Tk()
  style = ttk.Style(root)
  style.theme_use("clam")  # 选用支持圆角的主题
  
  # 自定义圆角框架样式
  style.configure("Rounded.TFrame", background="#ffffff", borderwidth=0, borderradius=15)
  # 自定义圆角按钮样式
  style.configure("Rounded.TButton", borderradius=10, padding=10)
  
  frame = ttk.Frame(root, style="Rounded.TFrame", width=300, height=200)
  frame.pack(pady=20, padx=20)
  frame.pack_propagate(False)
  
  btn = ttk.Button(frame, text="圆角按钮", style="Rounded.TButton")
  btn.pack(pady=50)
  
  root.mainloop()
  

• 用PIL动态生成圆角背景
  通过PIL代码生成圆角图片，再作为控件背景，全程无需外部图片文件。示例：

  import tkinter as tk
  from PIL import Image, ImageDraw, ImageTk
  
  def create_rounded_image(width, height, radius, color):
      img = Image.new("RGBA", (width, height), (0,0,0,0))
      draw = ImageDraw.Draw(img)
      draw.rounded_rectangle((0,0,width,height), radius=radius, fill=color)
      return ImageTk.PhotoImage(img)
  
  root = tk.Tk()
  root.config(bg="#f0f0f0")
  
  rounded_img = create_rounded_image(300, 200, 20, "#ffffff")
  label = tk.Label(root, image=rounded_img, bg="#f0f0f0")
  label.pack(pady=20, padx=20)
  
  btn = tk.Button(label, text="测试按钮", bg="#ffffff", borderwidth=0)
  btn.place(relx=0.5, rely=0.5, anchor="center")
  
  root.mainloop()
  

你可以根据自己已有的UI元素，选择适配的方案调整。

内容的提问来源于stack exchange，提问作者user20610117