How to change menu active item text color in GTK2?

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04-10-2024

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Dynamically Change Menu Item Text Color with GTK2: A Guide

Tired of static menu colors in your GTK2 applications? Want to create a more visually appealing and informative user experience? This article will guide you through the process of dynamically changing the text color of active menu items in your GTK2 applications.

The Problem: In GTK2, menu items typically have a static text color, making it difficult to highlight the currently selected option. This can be confusing for users, especially when navigating through complex menus.

The Solution: By leveraging the power of GTK2's signals and CSS styling, we can dynamically change the text color of an active menu item, providing a more intuitive and visually appealing user interface.

Understanding the Process:

1. Identifying the Active Item: We need a way to determine which menu item is currently selected. GTK2 offers the selection_changed signal for menus, which is emitted whenever the user interacts with the menu and a different item is selected.
2. CSS Styling: GTK2 allows us to apply CSS styles to widgets, including menus and menu items. We can use CSS to specify different text colors for active and inactive menu items.
3. Signal Handler: We'll create a signal handler function that will be triggered when the selection_changed signal is emitted. This function will then update the CSS style of the menu item, changing its text color.

Here's an example code snippet showcasing the implementation:

import gtk

def on_menu_selection_changed(menu, new_item):
    """
    This function handles the selection changed signal for the menu.
    It dynamically changes the text color of the active menu item.
    """
    # Iterate through all the items in the menu
    for item in menu.get_children():
        # Reset text color for inactive items
        if item != new_item:
            item.modify_fg(gtk.STATE_NORMAL, gtk.gdk.color_parse("black"))
        # Set active text color for the selected item
        else:
            item.modify_fg(gtk.STATE_NORMAL, gtk.gdk.color_parse("blue"))

# Create a menu bar
menubar = gtk.MenuBar()

# Create a menu and add items
menu = gtk.Menu()
item1 = gtk.MenuItem("Item 1")
item2 = gtk.MenuItem("Item 2")
menu.append(item1)
menu.append(item2)

# Connect selection changed signal to the handler function
menu.connect("selection_changed", on_menu_selection_changed)

# Attach the menu to the menu bar
menubar.append(menu)

# Create a window and show the menu bar
window = gtk.Window(gtk.WINDOW_TOPLEVEL)
window.add(menubar)
window.show_all()
gtk.main()

Explanation:

1. We define a function on_menu_selection_changed that takes the menu and the newly selected item as arguments.
2. The function iterates through all the menu items.
3. For each item, we check if it's the currently selected item. If not, we reset its text color to black using modify_fg.
4. If the item is the selected one, we set its text color to blue using modify_fg.
5. We connect the selection_changed signal of the menu to the on_menu_selection_changed function.
6. This ensures that whenever a new menu item is selected, the signal is emitted and the function is called, dynamically updating the text color of the active item.

Enhancements:

• Custom Colors: You can easily customize the colors used in this example by changing the gtk.gdk.color_parse parameters to your desired colors.
• CSS Styles: Instead of using modify_fg, you can leverage GTK2's CSS capabilities to define separate styles for active and inactive menu items. This offers a more flexible and maintainable approach.

Additional Notes:

• This technique is applicable to other GTK2 widgets as well, such as buttons, toolbars, and lists.
• You can extend this approach to incorporate additional visual cues, such as background color changes or font styles, to further enhance the user experience.

By applying these techniques, you can elevate your GTK2 applications with dynamic and visually engaging menu interactions, making them more user-friendly and enjoyable to use.