| # Spectral Terminal Emulator |
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| A next-generation terminal emulator written in Rust, designed to be **faster than Ghostty** while solving its biggest user frustration: **font rendering that looks too thin**. |
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| ## What Makes Spectral Different |
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| ### 1. Cross-Platform Font Thickening (Finally!) |
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| Ghostty's #1 user complaint is that fonts look thinner than other terminals — and on Linux there's no fix. Spectral solves this with a **shader-based thickening system** that works identically on **macOS, Linux, and Windows**. |
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| ```ini |
| # Spectral config (works on ALL platforms) |
| font-thicken = true |
| font-thicken-strength = 0.5 # 0.0 = thin, 1.0 = bold |
| ``` |
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| The MSDF (Multi-Channel Signed Distance Field) renderer allows per-pixel threshold adjustment in the GPU fragment shader. No platform-specific hacks — just one clean cross-platform solution. |
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| ### 2. True Cross-Platform Native GPU Backend |
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| | Platform | Graphics API | Why | |
| |----------|-------------|-----| |
| | macOS | **Metal** (via wgpu) | Unified memory, triple buffering | |
| | Linux | **Vulkan** (via wgpu) | Low overhead, explicit control | |
| | Windows | **DirectX 12** (via wgpu) | Native Windows compositor | |
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| One wgpu codebase renders everywhere. No separate Metal/OpenGL backends like Ghostty. |
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| ### 3. SIMD-Optimized ANSI Parser |
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| The VT100/ANSI parser uses `memchr` for bulk ESC byte scanning — a SIMD-accelerated search that skips large text runs without per-byte dispatch. |
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| ### 4. GPU-First Architecture |
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| | Component | Traditional Terminal | Spectral | |
| |-----------|---------------------|----------| |
| | Font rasterization | CPU (FreeType) | CPU initial cache, GPU rendering | |
| | Text rendering | Per-glyph draw calls | Single instanced draw (6 vertices × N cells) | |
| | Background | CPU compositing | GPU instanced colored quads | |
| | Frame pacing | VSync blocked | `PresentMode::AutoNoVsync`, 1-frame latency | |
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| ### 5. Zero System Dependencies for Font Discovery |
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| Unlike Ghostty/Alacritty which require `fontconfig`/`pkg-config` on Linux, Spectral uses `fontdue` (pure Rust) + manual font file scanning. No `apt install fontconfig-dev` needed. |
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| ## Architecture |
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| ``` |
| spectral/ |
| ├── spectral-core/ # Terminal grid, ANSI parser, damage tracking |
| ├── spectral-font/ # Font loading, MSDF atlas, metrics |
| ├── spectral-render/ # wgpu GPU renderer |
| ├── spectral-pty/ # PTY abstraction |
| └── src/main.rs # winit window + event loop |
| ``` |
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| ## Build |
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| ```bash |
| # Requires: Rust 1.75+, a Vulkan/Metal/DX12 capable GPU |
| cargo build --release |
| ``` |
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| ## Performance Targets |
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| | Benchmark | Kitty | Ghostty | Alacritty | **Spectral Target** | |
| |-----------|-------|---------|-----------|-------------------| |
| | `cat /dev/urandom` | 121 MB/s | ~90 MB/s | 43 MB/s | **>150 MB/s** | |
| | Key-to-screen latency | ~8ms | ~8ms | ~10ms | **<8ms** | |
| | Startup time | ~200ms | ~150ms | ~120ms | **<100ms** | |
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| ## License |
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| MIT/Apache-2.0 dual license. |
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