Blue Light Filter Script

This Bash script (bluelightfilter.sh) automatically adjusts your screen's warmth (gamma settings) to reduce blue light exposure based on the time of day, local weather conditions, and whether a fullscreen application is running. It uses xrandr to modify screen gamma, making it warmer at night or during cloudy weather to promote better sleep and reduce eye strain.

Features

• Time-Based Adjustment: Warms the screen at night based on local sunrise and sunset times.
• Weather-Based Adjustment: Applies an intermediate gamma setting during cloudy weather to balance visibility and comfort.
• Fullscreen Detection: Reverts to neutral gamma when a fullscreen application (e.g., video player or game) is active to preserve color accuracy.
• Caching: Minimizes API calls by caching location coordinates, sunrise/sunset times, and weather data for 24 hours or 1 hour, respectively.
• Logging: Maintains a log file for debugging and monitoring.
• Multi Screen Support: Added thanks to @dm+ (from PCLOS forum)

Prerequisites

• Operating System: Linux with X11 display server.
• Dependencies:
  • curl: For making API requests.
  • jq: For parsing JSON responses from APIs.
  • xrandr: For adjusting screen gamma settings.
• Optional (for fullscreen detection, at least one of):
  • xdotool (preferred)
  • wmctrl
  • xwininfo
• Internet Connection: Required to fetch location, sunrise/sunset, and weather data.

Install dependencies on Debian/Ubuntu:

sudo apt update
sudo apt install curl jq x11-xserver-utils xdotool wmctrl x11-utils

Installation

Clone or download this repository:

git clone <repository-url>
cd <repository-directory>

Make the script executable:

chmod +x bluelightfilter.sh

Usage

Run the script with the default location (Santiago, Chile) or specify a custom location.

Basic Usage

./bluelightfilter.sh

Specify a Custom Location

./bluelightfilter.sh -location "New York, USA"

Other params:

-nofs # No fullscreen detection
-noweather # Skip weather checks
-sunrise HH:MM # Ignore API sunrise time (24H)
-sunset HH:MM # Ignhore API sunset time (24H)
-cleancache # Clean cache and force query to APIs

Running in the Background

./bluelightfilter.sh -location "Your City, Country" &

Stopping the Script

ps aux | grep bluelightfilter.sh
kill <process-id>

How It Works

Initialization

• Checks for required tools (curl, jq, xrandr) and optional fullscreen detection tools.
• Creates cache (~/.cache/bluelightfilter) and log directories (~/tmp).
• Logs activity to ~/tmp/bluelightfilter.log.

Location and Data Fetching

• Retrieves coordinates for the specified location using the OpenStreetMap API.
• Fetches sunrise and sunset times from the SunriseSunset API.
• Checks local weather using the OpenMeteo API (no API key required).
• Caches data to reduce API calls.

Screen Adjustment Logic

• Night: Applies warm gamma 1.0:0.9:0.8 after sunset or before sunrise.
• Day (Clear Weather): Applies neutral gamma 1.0:1.0:1.0 for accurate colors.
• Day (Cloudy Weather): Applies intermediate gamma 1.0:0.95:0.85 for comfort.
• Fullscreen Mode: Reverts to neutral gamma when a fullscreen application is detected.

Loop

• Checks for fullscreen applications every 3 seconds.
• Updates sunrise/sunset data every 10 minutes.
• Updates weather data every hour during the day.

Configuration

The script uses the following defaults, which can be modified directly in the script:

• Default Location: Santiago, Chile

• Gamma Settings:

  • Neutral: 1.0:1.0:1.0
  • Night: 1.0:0.9:0.8
  • Cloudy: 1.0:0.95:0.85

• Cache TTL:

  • Coordinates and sunrise/sunset: 24 hours
  • Weather: 1 hour

Log File

The script logs its activity to ~/tmp/bluelightfilter.log. Logs are rotated daily to prevent excessive growth. Check the log for debugging:

cat ~/tmp/bluelightfilter.log

Troubleshooting

• "Error: <tool> is not installed": Install the missing tool using your package manager.
• "Failed to fetch coordinates/sunrise/sunset/weather": Check your internet connection or try a different location.
• Gamma not changing: Ensure xrandr is installed and your display supports gamma adjustments.
• Fullscreen detection not working: Install xdotool, wmctrl, or xwininfo, or check if your window manager supports fullscreen detection.

Contributing

Feel free to submit issues or pull requests to improve the script. Suggestions for additional features, such as custom gamma profiles or alternative APIs, are welcome.

License

This project is licensed under the MIT License. See the LICENSE file for details.

Acknowledgments

• APIs used: OpenStreetMap, SunriseSunset, OpenMeteo.
• Tools: xrandr, curl, jq, xdotool, wmctrl, xwininfo.

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