https://github.com/humbertoschoenwald/auto-theme-solar-engine
A privacy-first, ultra-lightweight Windows tray utility built with .NET 11 Native AOT that automatically syncs your system theme with the local solar cycle using offline astronomical calculations.
https://github.com/humbertoschoenwald/auto-theme-solar-engine
astronomy auto-theme csharp csharp-15 dark-mode dotnet dotnet-11 dpapi light-mode lightweight native-aot no-telemetry offline-first privacy-first solar-cycle sunrise-sunset system-tray theme-switcher win32-api windows
Last synced: 29 days ago
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A privacy-first, ultra-lightweight Windows tray utility built with .NET 11 Native AOT that automatically syncs your system theme with the local solar cycle using offline astronomical calculations.
- Host: GitHub
- URL: https://github.com/humbertoschoenwald/auto-theme-solar-engine
- Owner: humbertoschoenwald
- License: mit
- Created: 2026-05-12T00:32:43.000Z (about 1 month ago)
- Default Branch: main
- Last Pushed: 2026-05-14T05:46:23.000Z (29 days ago)
- Last Synced: 2026-05-14T06:44:38.885Z (29 days ago)
- Topics: astronomy, auto-theme, csharp, csharp-15, dark-mode, dotnet, dotnet-11, dpapi, light-mode, lightweight, native-aot, no-telemetry, offline-first, privacy-first, solar-cycle, sunrise-sunset, system-tray, theme-switcher, win32-api, windows
- Language: C#
- Homepage:
- Size: 183 KB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
Awesome Lists containing this project
README
# Auto Theme Solar Engine
[](https://github.com/humbertoschoenwald/auto-theme-solar-engine/actions/workflows/ci.yml)
[](https://github.com/humbertoschoenwald/auto-theme-solar-engine/releases/latest)
[](https://dotnet.microsoft.com/en-us/download/dotnet/11.0)
[](https://learn.microsoft.com/windows/win32/)
[](https://opensource.org/licenses/MIT)
A high-precision, privacy-first Windows tray utility that automatically synchronizes your system theme with the local solar cycle. No cloud APIs, no telemetry—just your PC following the sun.
---
## ⚡ Quick Start
The recommended installation is a **per-user** setup. This allows the application to update itself seamlessly without requiring Administrator privileges.
Run the following command in a **PowerShell** session:
```powershell
# Create target directory and download the baseline release
New-Item -ItemType Directory -Force -Path "$env:LOCALAPPDATA\AutoThemeSolarEngine"
Set-Location "$env:LOCALAPPDATA\AutoThemeSolarEngine"
# Download the executable
Invoke-WebRequest -Uri "https://github.com/humbertoschoenwald/auto-theme-solar-engine/releases/download/v26.05.00/AutoThemeSolarEngine.exe" -OutFile ".\AutoThemeSolarEngine.exe"
# Launch the engine
Start-Process ".\AutoThemeSolarEngine.exe"
```
---
## 💡 Why use it?
Most theme switchers rely on heavy frameworks or external weather APIs. **Auto Theme Solar Engine** is built for those who value performance, system resources, and data sovereignty.
* **☀️ Astronomical Accuracy:** Uses robust NOAA/Meeus equations to calculate sunrise and sunset locally based on your coordinates.
* **🚀 Ultra-Lightweight:** Written in native **.NET 11** and compiled via **Native AOT**. It leverages raw Win32 interop for the UI to keep idle memory usage near absolute zero.
* **🛡️ Privacy by Design:** * **100% Offline:** Core theme-switching behavior requires zero internet connection.
* **DPAPI Encryption:** Coordinates are securely encrypted at rest using the Windows Data Protection API.
* **Data Minimization:** Coordinates are mathematically obfuscated before being stored to protect your exact location.
* **🌗 Seamless Transitions:** Uses undocumented `uxtheme.dll` hooks to ensure the theme switch is incredibly fluid, completely avoiding the harsh flickering common in standard registry-only toggles.
---
## ✨ Key Features
* **Native Settings UI:** A clean, tabbed interface (Home, Configuration, Updates) that dynamically respects your current system theme.
* **Smart Scheduling:** Intelligently handles edge cases like **Polar Night** and **Midnight Sun** for users in extreme latitudes.
* **Auto-Updates:** A built-in update orchestrator securely checks GitHub Releases and applies updates via a transparent, visible PowerShell helper.
* **Bilingual Support:** Full support for **English** and **Spanish**, selectable directly from the settings menu.
---
## 🛠️ Technical Baseline
| Component | Details |
| --- | --- |
| **Runtime** | .NET 11 (Preview 3) |
| **Language** | C# 15 |
| **Platform** | Windows 10 (Build 19041+) x64 |
| **Deployment** | Single, self-contained Native AOT executable |
---
## 🏗️ Development
This repository follows a strict **ADR-first (Architecture Decision Record)** doctrine. We believe in documenting the "why" just as much as the "how". If you wish to contribute, understand our technical choices, or fork the project, please review the `docs/adr/` directory first.
---
## 📄 License
Distributed under the **MIT License**. See `LICENSE` for more information.