Graion 📐

A fast, modern, and private offline engineering calculator and wire drawing schedule toolbox for Android, built 100% with Jetpack Compose, Kotlin Coroutines, Room, and Material 3.

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✨ Features

• Scientific Calculator:

  • High-precision arithmetic backed by Java BigDecimal (MathContext.DECIMAL128).
  • Trigonometric functions (sin, cos, tan) with clean degree conversions and undefined angle handling.
  • Natural logarithm (ln), base-10 logarithm (log), square root (√), power (^), and constants ($\pi$, $e$).
  • Percentage arithmetic adhering to calculator conventions (e.g. 200 + 10% = 220).
  • Memory registers ($M+$, $M-$, $MR$, $MC$) and repeated equals operations.
  • Live preview of expression evaluations as you type.

• Wire Drawing Tool:

  • Area reduction, elongation, and reduction ratio calculations across die passes.
  • Automatic intermediate die sequence generation for target elongations.
  • Quality and consistency rating based on pass-to-pass deviation.
  • CSV export and persistent saved schedules.

• Unit Converter:

  • Comprehensive conversions across 6 categories: Length, Mass, Area, Volume, Temperature, and Speed.

• Privacy First & 100% Offline:

  • Zero internet permission (android.permission.INTERNET is not requested).
  • All history and preferences stored locally via Room and Jetpack DataStore.

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🛠 Tech Stack & Architecture

• Language: Kotlin 2.3
• UI Framework: Jetpack Compose (Material 3)
• Navigation: AndroidX Navigation 3 (NavDisplay, type-safe NavKey)
• Persistence: AndroidX Room 2.8 (CalculationDao, WireDrawScheduleDao) & Jetpack DataStore Preferences
• Architecture: Clean Architecture with pure domain engines (CalculatorEngine, ExpressionParser, ExpressionTokenizer, WireDrawingCalculatorEngine, UnitConverterEngine) decoupled from Android framework APIs.

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🚀 Building & Running

Prerequisites

• Android Studio Ladybug / Meerkat or newer
• JDK 17+
• Android SDK (API 36 compileSdk, minSdk 26)

Command Line

# Run unit tests
./gradlew test

# Build debug APK
./gradlew assembleDebug

# Install on connected device
./gradlew installDebug

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📄 License & Privacy

See PRIVACY_POLICY.md for data privacy practices.