如何在 Tkinter 画布中为子字符串着色

Question

我正在编写一个程序，该程序涉及在循环中在 Tkinter 画布上的 create_text() 框中显示一些文本。显示每个单词，然后替换为下一个单词。有点像闪存卡。

我需要给每个单词的一个字母上色，靠近单词的中间，这样当用户阅读单词时，他们的眼睛就会集中在单词的中间。所以if len(i)=1, color i[0], if len(i)>= 2 and <= 5, color i[1]，等等。它需要使用 Canvas 完成，并使用

canvas.create_text(text = i[focus_index],fill = 'red') 

结果应该是这样打印出来的

exaMple

（但显然“m”会被涂成红色，而不是大写）

Answer 1

我假设你想要this 之类的东西？

这是我目前能得到的最接近的。它创建三个文本框并使用anchor 属性将它们保持在正确的位置。不过，对于真正宽或窄的字母来说，它并不是那么好。这并不完美，但它可能是一个开始。

import Tkinter as tk

root = tk.Tk()

c = tk.Canvas(root)
c.pack(expand=1, fill=tk.BOTH)

words = '''I am writing a program that involves displaying some text in a create_text() box on a Tkinter canvas, within a loop. Each word is displayed, then replaced by the next. Sort of like flash cards. I need to color one letter of each word, close to the middle of the word, so that when the user is reading the words their eyes focus on the middle of the word. So if len(i)=1, color i[0], if len(i)>= 2 and <= 5, color i[1], and so on. It needs to be done using the Canvas, and using canvas.create_text(text = i[focus_index],fill = 'red') The result should print like this exaMple (but obviously "m" would be colored red, not be uppercase)'''
words = words.split()

def new_word(i):
    if i == len(words):
        i = 0

    word = words[i]
    middle = (len(word)+1)//2
    c.itemconfigure(t1, text=word[:middle-1]+' ')
    c.itemconfigure(t2, text=word[middle-1:middle])
    c.itemconfigure(t3, text=word[middle:])

    root.after(100, lambda: new_word(i+1))


t1 = c.create_text(200,100,text='', anchor='e', font=("Courier", 25))
t2 = c.create_text(200,100,text='', anchor='e', font=("Courier", 25), fill='red')
t3 = c.create_text(200,100,text='', anchor='w', font=("Courier", 25))
new_word(0)

root.geometry('400x200+200+200')
root.mainloop()

---

好的，使用来自Bryan Oakley's comment 的链接，我进一步改进了代码，使其适用于任何字体，而不仅仅是等宽字体。代码将彩色字母的中心保持在同一位置，并将单词的前后放置在正确的距离周围。

import Tkinter as tk
import tkFont

root = tk.Tk()
c = tk.Canvas(root)
c.pack(expand=1, fill=tk.BOTH)

fn = "Helvetica"
fs = 24
font = tkFont.Font(family=fn, size=fs)

words = '''I am writing a program that involves displaying some text in a create_text() box on a Tkinter canvas, within a loop. Each word is displayed, then replaced by the next. Sort of like flash cards. I need to color one letter of each word, close to the middle of the word, so that when the user is reading the words their eyes focus on the middle of the word. So if len(i)=1, color i[0], if len(i)>= 2 and <= 5, color i[1], and so on. It needs to be done using the Canvas, and using canvas.create_text(text = i[focus_index],fill = 'red') The result should print like this exaMple (but obviously "m" would be colored red, not be uppercase)'''
words = words.split()

def new_word(i):
    if i == len(words):
        i = 0

    word = words[i]
    middle = (len(word)+1)//2

    front = word[:middle-1]
    letter = word[middle-1:middle]
    back = word[middle:]

    c.itemconfigure(t1, text=front)
    c.itemconfigure(t2, text=letter)
    c.itemconfigure(t3, text=back)
    c.coords(t1, 200-font.measure(letter)/2, 100)
    c.coords(t3, 200+font.measure(letter)/2, 100)

    root.after(100, lambda: new_word(i+1))


t1 = c.create_text(200,100,text='', anchor='e', font=font)
t2 = c.create_text(200,100,text='', anchor='c', font=font, fill='red')
t3 = c.create_text(200,100,text='', anchor='w', font=font)
new_word(0)

root.geometry('400x200+200+200')
root.mainloop()

Answer 2

您不能将格式应用于画布文本项中的单个字符。您需要为红色字符创建一个不同的项目，并进行一些数学运算以将其覆盖在字符串之上。

如果您没有 使用画布，我推荐使用文本小部件，因为它可以轻松地将格式应用于单个字符。这是一个完整的工作示例：

import Tkinter as tk

words = '''
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Morbi mi leo, vulputate a consectetur in, congue sit amet elit. Fusce lacinia placerat mi, vitae maximus leo congue sed. Donec non diam dapibus, fringilla risus at, interdum sem. Interdum et malesuada fames ac ante ipsum primis in faucibus. 
'''.strip().split()

class Example(tk.Frame):
   def __init__(self, parent):
      tk.Frame.__init__(self, parent)
      self.text = tk.Text(self, wrap=None, font="Helvetica 24",
                          highlightthickness=0)
      self.text.pack(side="top", fill="x")

      self.text.tag_configure("center", justify="center")
      self.text.tag_configure("red", foreground="red")

      self.show_words(0)

   def show_words(self, index):
      self.show_word(words[index])
      next = index + 1 if index < len(words)-1 else 0
      self.after(200, self.show_words, next)

   def show_word(self, word):
      self.text.configure(state="normal")
      self.text.delete("1.0", "end")
      self.text.insert("1.0", word, "center")
      offset = len(word)/2
      self.text.tag_add("red", "1.0 + %sc" % offset)
      self.text.configure(state="disabled")

if __name__ == "__main__":
   root = tk.Tk()
   Example(root).pack(fill="both", expand=True)
   root.mainloop()