Toggle Color Theme on Plasma

Plasma introduced a quick settings panel in plasma 6, where you can toggle between Breeze and Breeze Dark themes. However, it will change the entire theme, ruining customizations like icons. You can toggle the color scheme manually by using the following command:

For dark theme:

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plasma-apply-desktoptheme breeze-dark && plasma-apply-colorscheme BreezeDark && plasma-apply-cursortheme Breeze_Light && /usr/lib/plasma-changeicons Papirus-Dark && /usr/bin/sed -i 's/DefaultProfile=Light.profile/DefaultProfile=Dark.profile/' ~/.config/konsolerc

For light theme:

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plasma-apply-desktoptheme breeze && plasma-apply-colorscheme Breeze && plasma-apply-cursortheme Breeze_Dark && /usr/lib/plasma-changeicons Papirus-Light && /usr/bin/sed -i 's/DefaultProfile=Dark.profile/DefaultProfile=Light.profile/' ~/.config/konsolerc

Before running the commands, ensure you have the Papirus icon theme installed and Light and Dark konsole profiles created. It will change the desktop theme, color scheme, cursor theme, icon theme, and konsole profile. Moreover, you can create two scripts and bind them to keyboard shortcuts for easy toggling.

24/10/25 Update

Plasma 6.5 was released, introducing a new feature to automatically switch between light and dark themes based on the time of day. However, it does not support custom icon themes and konsole profiles. A workaround is to run a script that monitors the theme change event and applies the necessary changes.

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#!/bin/bash

# Monitor KDE theme changes and execute commands

# Function to check current color scheme
check_theme() {
    # Query KDE's color scheme setting (KF6 uses kreadconfig6)
    theme=$(kreadconfig6 --file kdeglobals --group General --key ColorScheme)

    # Check if it's a dark theme (common dark themes contain "Dark" in name)
    if [[ $theme == *"Dark"* ]] || [[ $theme == *"Breeze Dark"* ]]; then
        echo "dark"
    else
        echo "light"
    fi
}

# Get initial state
previous_theme=$(check_theme)
echo "Current theme: $previous_theme"

# Monitor D-Bus for KDE settings changes
dbus-monitor --session "type='signal',interface='org.kde.KGlobalSettings',member='notifyChange'" | \
while read -r line; do
    # When we detect a change notification
    if [[ $line == *"notifyChange"* ]]; then
        sleep 0.5  # Small delay to ensure settings are written

        current_theme=$(check_theme)

        # Only act if theme actually changed
        if [[ $current_theme != $previous_theme ]]; then
            echo "Theme changed: $previous_theme -> $current_theme"

            if [[ $current_theme == "dark" ]]; then
                echo "Executing dark theme commands..."
                # Add your dark theme commands here
                notify-send "Dark Mode" "Switched to dark theme"
                /usr/lib/plasma-changeicons Papirus-Dark && /usr/bin/sed -i 's/DefaultProfile=Light.profile/DefaultProfile=Dark.profile/' ~/.config/konsolerc

            elif [[ $current_theme == "light" ]]; then
                echo "Executing light theme commands..."
                # Add your light theme commands here
                notify-send "Light Mode" "Switched to light theme"
                /usr/lib/plasma-changeicons Papirus-Light && /usr/bin/sed -i 's/DefaultProfile=Dark.profile/DefaultProfile=Light.profile/' ~/.config/konsolerc
            fi

            previous_theme=$current_theme
        fi
    fi
done

A user-level systemd service can be created to run this script in the background:

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[Unit]
Description=KDE Theme Monitor
After=graphical-session.target

[Service]
Type=simple
ExecStart=/home/username/.local/bin/theme-monitor.sh
Restart=on-failure

[Install]
WantedBy=default.target

And the commands to enable and start the service:

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systemctl --user enable theme-monitor.service
systemctl --user start theme-monitor.service

Even though this solution works, it’s quite hacky and heavy. Hoping for a better built-in feature in the future Plasma releases.