如何在Tkinter畫布中爲子字符串着色

Question

我正在編寫一個程序，它涉及在循環內的Tkinter畫布上的create_text()框中顯示一些文本。每個單詞顯示，然後由下一個替換。有點像閃存卡。

我需要爲每個單詞的一個字母上色，靠近單詞的中間，以便當用戶正在閱讀單詞時，他們的注意力集中在單詞的中間。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，並使用

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

結果應打印這樣

exaMple 

來完成（但明顯的「M」將被染成紅色，而不是爲大寫）

Answer 1

我假設你想要類似this？

這是我現在可以得到的最接近的。它創建三個文本框並使用anchor屬性將它們保持在正確的位置。儘管如此，它對於非常寬或窄的字母來說效果不佳。這並不完美，但可能是一個開始。

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，利用Bryan Oakley's comment的鏈接，我提高了一些，以便它可以與任何字體，不僅那些等寬的代碼。代碼將彩色字母的中心保留在相同的位置，並將單詞的正面和背面放置在正確的距離。

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

您無法將格式應用於畫布文本項目中的單個字符。您需要爲紅色字符創建一個不同的項目，然後做一些小算術以將其覆蓋在字符串的頂部。

如果你不有使用畫布，我推薦一個文本小部件，因爲它很容易將格式應用於單個字符。下面是一個完整的工作示例：

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()