Script to control the opacity of the applications window for the blur-my-shell extension

blur-my-shell-opacity.sh

#!/bin/bash

# This script is used to control the opacity of the applications window for the blur-my-shell extension
# Opacity can be controled with a dconf key at location /org/gnome/shell/extensions/blur-my-shell/applications/opacity
# The value of the key is a integer between 25 and 255
# To change value the dconf write /org/gnome/shell/extensions/blur-my-shell/applications/opacity $value can be used
# The first argument of the script defines the action decrease or increase
# Opacity should be changed in the interval defined by the user from second optional argument
# If second argument is not provided the default value is 5

# Pseudo code
# Get the current value of the opacity
# If the argument is not decrease or increase
#   Print the usage of the script
# If the argument is decrease
#   Decrease the value by 5
#   If the value is less than 25
#       Set the value to 25
# If the argument is increase
#   Increase the value by 5
#   If the value is greater than 255
#       Set the value to 255
# If new value is the same as the old value
#   Exit the script
# Set the value to the dconf key

# Function to print the usage of the script
usage() {
    echo "Usage: $0 [decrease|increase] [interval]"
    echo "interval: integer between 1 and 50"
    exit 1
}

# Set default value for the interval
interval=5

# If the number of arguments is greater than 2
if [ $# -gt 2 ]; then
    # Print the usage of the script
    usage
fi

# If the number of arguments is 2
if [ $# -eq 2 ]; then
    # If the second argument is not a number
    if ! [[ $2 =~ ^[0-9]+$ ]]; then
        # Print log message
        echo "The interval should be a number"
        # Print the usage of the script
        usage
    fi
    # If the second argument is less than 1
    if [ $2 -lt 1 ]; then
        # Print log message
        echo "The interval should be greater than 0"
        # Print the usage of the script
        usage
    fi
    # If the second argument is greater than 50
    if [ $2 -gt 50 ]; then
        # Print log message
        echo "Maximum interval value is 50"
        # Print the usage of the script
        usage
    fi
    # Set the interval to the second argument
    interval=$2
fi

# If the first argument is not decrease or increase
if [ $1 != "decrease" ] && [ $1 != "increase" ]; then
    # Print the usage of the script
    usage
fi

# Get the current value of the opacity
current_opacity=$(dconf read /org/gnome/shell/extensions/blur-my-shell/applications/opacity)
new_opacity=$current_opacity

# If the argument is decrease
if [ $1 == "decrease" ]; then
    # Decrease the value by the interval
    new_opacity=$(($current_opacity - $interval))
    # If the value is less than 25
    if [ $new_opacity -lt 25 ]; then
        # Set the value to 25
        new_opacity=25
    fi
fi

# If the argument is increase
if [ $1 == "increase" ]; then
    # Increase the value by the interval
    new_opacity=$(($current_opacity + $interval))
    # If the value is greater than 255
    if [ $new_opacity -gt 255 ]; then
        # Set the value to 255
        new_opacity=255
    fi
fi

# If new value is the same as the old value
if [ $new_opacity -eq $current_opacity ]; then
    # Print log message
    echo "Opacity value didn't change"
    # Exit the script
    exit 0
fi

# Set the value to the dconf key
dconf write /org/gnome/shell/extensions/blur-my-shell/applications/opacity $new_opacity

# Check if command was successful
if [ $? -eq 0 ]; then
    # Print log message
    echo "Opacity changed to $new_opacity"
    exit 0
else
    # Print log message
    echo "Failed to change opacity"
    exit $?
fi

A quick comment on why I made this script. I enjoy the looks of semi-transparent windows, but during screen demonstrations or recordings I need to keep my windows crisp since video compression would ruin the quality and the text will become unreadable. Doing this manually is a bit of a hassle so I made this script and binded it to the keyboard shortcut to make my life easier.

Small demo:

blur-my-shell-opacity.demo.mp4