How to change the color of certain words in a Tkinter text widget?

Tkinter text widgets allow you to create multiline text displays with rich formatting. You can change the color of specific words using the tag_add() and tag_config() methods.

The tag_add(tag_name, start, end) method selects a range of text to format, while tag_config(tag_name, properties) applies styling like color, font, and background.

Basic Example

Here's how to change the color of specific words in a text widget ?

import tkinter as tk

# Create main window
root = tk.Tk()
root.geometry("600x250")
root.title("Colored Text Widget")

# Create text widget
text_widget = tk.Text(root)
text_widget.insert(tk.INSERT, "Hello World!\n")
text_widget.insert(tk.END, "This is a New Line")
text_widget.pack(fill=tk.BOTH, expand=True)

# Configure tag with red color
text_widget.tag_config("red_text", foreground="red")

# Apply tag to "World" (position 1.6 to 1.12)
text_widget.tag_add("red_text", "1.6", "1.12")

root.mainloop()

Multiple Colors Example

You can create multiple tags for different colors ?

import tkinter as tk

root = tk.Tk()
root.geometry("700x300")
root.title("Multiple Colored Words")

text_widget = tk.Text(root, font=("Arial", 12))
text_widget.insert(tk.END, "Python is awesome!\n")
text_widget.insert(tk.END, "Tkinter makes GUI development easy.\n")
text_widget.insert(tk.END, "Colors make text more appealing.")
text_widget.pack(fill=tk.BOTH, expand=True, padx=10, pady=10)

# Configure multiple color tags
text_widget.tag_config("blue", foreground="blue", font=("Arial", 12, "bold"))
text_widget.tag_config("green", foreground="green", font=("Arial", 12, "italic"))
text_widget.tag_config("red", foreground="red", background="yellow")

# Apply colors to different words
text_widget.tag_add("blue", "1.0", "1.6")      # "Python"
text_widget.tag_add("green", "2.0", "2.7")     # "Tkinter"
text_widget.tag_add("red", "3.0", "3.6")       # "Colors"

root.mainloop()

Understanding Text Positions

Text positions in Tkinter use the format "line.column" where:

• Line: Starts from 1 (first line)
• Column: Starts from 0 (first character)
• Example: "1.6" means line 1, character 6

Dynamic Color Changes

You can also change colors dynamically using functions ?

import tkinter as tk

def highlight_word():
    # Clear existing tags
    text_widget.tag_remove("highlight", "1.0", tk.END)
    
    # Get word to highlight
    word = entry.get()
    if word:
        start_pos = "1.0"
        while True:
            start_pos = text_widget.search(word, start_pos, tk.END)
            if not start_pos:
                break
            end_pos = f"{start_pos}+{len(word)}c"
            text_widget.tag_add("highlight", start_pos, end_pos)
            start_pos = end_pos

root = tk.Tk()
root.geometry("600x350")
root.title("Dynamic Text Highlighting")

# Entry for word input
frame = tk.Frame(root)
frame.pack(pady=10)

tk.Label(frame, text="Highlight word:").pack(side=tk.LEFT)
entry = tk.Entry(frame)
entry.pack(side=tk.LEFT, padx=5)
tk.Button(frame, text="Highlight", command=highlight_word).pack(side=tk.LEFT)

# Text widget
text_widget = tk.Text(root, font=("Arial", 11))
text_widget.insert(tk.END, "Python programming is fun.\n")
text_widget.insert(tk.END, "Python is powerful and easy to learn.\n")
text_widget.insert(tk.END, "Many developers love Python.")
text_widget.pack(fill=tk.BOTH, expand=True, padx=10, pady=10)

# Configure highlight tag
text_widget.tag_config("highlight", background="yellow", foreground="blue")

root.mainloop()

Tag Configuration Options

Conclusion

Use tag_add() to select text ranges and tag_config() to apply colors and formatting. Text positions follow the "line.column" format starting from "1.0". Tags provide powerful text styling capabilities for creating rich text interfaces.