Vintage Calculator - Retro VFD

Experience the authentic feel and tactile precision of classic scientific handheld calculators directly on your mobile device.

Vintage Calculator combines true retro display physics, algebraic order of operations, interactive function graphing, and mechanical audio feedback into a clean, 100% offline scientific tool.

### 🔬 Comprehensive Scientific Math Engine
- **Algebraic Order of Operations**: Full operator precedence with automatic parentheses closure and implicit multiplication (2π, 2(3), (2)(3)).
- **Trigonometry & Hyperbolics**: sin, cos, tan, arcsin, arccos, arctan, hyperbolic functions (sinh, cosh, tanh), and exact angle modes (DEG, RAD, GRAD).
- **Logarithms & Powers**: Natural logs (ln), base-10 (log10), base-2 (log2), powers (y^x), roots (x√y), and factorials (x!).
- **Scientific Notation**: Real-time exponent formatting for high-precision scientific and engineering calculations.

### 📟 3 Authentic Retro Display Modes
- **1976 Crimson LED Display**: Authentic 9-digit 7-segment display simulation with unlit background segment contrast and warm glow.
- **1996 Dot-Matrix LCD**: Classic green-tinted 96x64 LCD matrix simulation with annunciator mode indicators (DEG, RAD, 2nd, M).
- **Modern High-Contrast LCD**: Clean multi-line display with real-time expression and result preview.

### 📈 Cartesian Function Graphing Engine
- Plot f(x) mathematical curves on a 2D grid.
- Interactive zoom presets (Standard, Trig, Decimal, Square), pan, and coordinate trace cursor readout.

### 💾 Multi-Register Memory & History Paper Tape
- **10 Memory Storage Registers (M0–M9)**: Full support for STO, RCL, M+, M-, and Last Answer (Ans).
- **Scrollable Paper Tape**: Calculation history log with instant tap-to-recall.

### 🔊 Procedural Audio & Tactile Haptics
- Real-time synthesized mechanical switch clicks, relay clacks, and error beeps.
- Customizable vibration feedback profiles for authentic physical key feel.

### 🔒 100% Offline & Private
- **Zero Internet Permission**: The app contains zero network code and operates completely offline.
- **Zero Tracking**: No analytics, no advertising SDKs, no tracking pixels, and no data collection. Your calculations never leave your device.