TerminalDX12

A GPU-accelerated terminal emulator for Windows using DirectX 12.

Features

• GPU-Accelerated Rendering - DirectX 12 instanced rendering with glyph atlas
• VT100/ANSI Support - Colors (16, 256, true color), bold, underline, inverse
• ConPTY Integration - Native Windows pseudo console for shell processes
• Win32 Input Mode - Full support for ConPTY's Win32 input mode for proper key handling
• Copy/Paste - Mouse text selection with Ctrl+C/V clipboard support
• Scrollback Buffer - 10,000 lines of history with mouse wheel scrolling
• Unicode Support - Full UTF-8/UTF-32 character handling via FreeType
• Multi-Shell Support - Works with PowerShell, cmd.exe, and WSL/Ubuntu

Screenshots

The terminal features GPU-accelerated rendering with full color and attribute support:

Feature	Description
True Color	Full 24-bit RGB color support (16.7M colors)
Text Styles	Bold, italic, underline, strikethrough, dim
Selection	Mouse text selection with blue highlight
Tabs	Multiple terminal sessions in a single window
Split Panes	Horizontal and vertical pane splitting
Scrollback	10,000 lines of history with smooth scrolling

Requirements

• Windows 10 1809 or later (for ConPTY support)
• DirectX 12 capable GPU
• Visual Studio 2026 or later with C++20 support
• CMake 3.20+
• vcpkg package manager

Building

1. Install vcpkg

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.bat

2. Set environment variable

set VCPKG_ROOT=C:\path\to\vcpkg

3. Build the project

cd TerminalDX12
mkdir build && cd build
cmake .. -DCMAKE_TOOLCHAIN_FILE=%VCPKG_ROOT%/scripts/buildsystems/vcpkg.cmake
cmake --build . --config Release

4. Run

bin\Release\TerminalDX12.exe

By default, PowerShell is used. To run a different shell:

bin\Release\TerminalDX12.exe cmd.exe
bin\Release\TerminalDX12.exe wsl.exe

Usage

Keyboard Shortcuts

Shortcut	Action
Ctrl+C	Copy selected text (or send SIGINT if nothing selected)
Ctrl+V	Paste from clipboard
Ctrl+T	Open new tab
Ctrl+W	Close current tab
Ctrl+Shift+D	Split pane horizontally (left/right)
Ctrl+Shift+E	Split pane vertically (top/bottom)
Ctrl+Shift+W	Close focused pane
Ctrl+Shift+F	Open in-terminal search
Ctrl+Shift+Z	Toggle pane zoom
Ctrl+,	Open settings dialog
Ctrl+Plus	Zoom in (increase font size)
Ctrl+Minus	Zoom out (decrease font size)
Ctrl+0	Reset zoom
Shift+Page Up	Scroll up in history
Shift+Page Down	Scroll down in history

Mouse

Action	Result
Click and drag	Select text
Double-click	Select word
Triple-click	Select line
Alt+drag	Rectangle selection
Single click	Clear selection
Mouse wheel	Scroll through buffer
Drag divider	Resize split panes
Click in pane	Focus that pane
Right-click	Context menu (copy, paste, split, settings)

Project Structure

TerminalDX12/
├── include/          # Header files
│   ├── core/         # Application, Window
│   ├── pty/          # ConPTY integration
│   ├── terminal/     # VT parser, screen buffer
│   ├── rendering/    # DirectX 12 renderer
│   └── ui/           # Input handling
├── src/              # Implementation files
├── shaders/          # HLSL shaders for text rendering
├── tests/            # Test suites
│   ├── unit/         # C++ unit tests (GTest)
│   ├── *.py          # Python integration tests
│   └── README.md     # Test documentation
└── run_tests.bat     # Test runner script

Architecture

Rendering Pipeline

1. Glyph Atlas - FreeType rasterizes glyphs into 2048x2048 RGBA texture
2. Instance Buffer - Per-glyph position, UV, and color data
3. GPU Rendering - Single instanced draw call renders all visible glyphs
4. Selection Highlight - Blue overlay for selected text regions

Terminal Emulation

1. ConPTY - Native Windows pseudo console spawns cmd.exe/powershell
2. VT Parser - State machine processes ANSI/VT escape sequences
3. Screen Buffer - 80x24 grid of cells with Unicode + attributes
4. Scrollback - Circular buffer storing 10,000 lines of history

Testing

C++ Unit Tests

Build with tests enabled:

cmake .. -DCMAKE_TOOLCHAIN_FILE=%VCPKG_ROOT%/scripts/buildsystems/vcpkg.cmake -DBUILD_TESTS=ON
cmake --build . --config Release

Run tests using the helper script:

run_tests.bat

Or run the test executable directly:

build\tests\Release\TerminalDX12Tests.exe

Test Coverage: 333 unit tests covering VT parser, screen buffer, tab management, ConPTY contracts, configuration, Unicode handling, and performance benchmarks.

Python Integration Tests

Visual validation tests using screenshots and OCR:

python -m pytest tests/ -v

Requirements: Python 3.x, Pillow, pywin32, numpy, winocr

Test Coverage: 72 integration tests covering clipboard, keyboard shortcuts, ANSI colors, text attributes, Unicode rendering, mouse input, scrolling, window resize, E2E workflows, and stress testing.

Contract Tests

Verify ConPTY interface behavior:

build\tests\Release\TerminalDX12ContractTests.exe

Test Coverage: 31 contract tests covering session lifecycle, input/output handling, resize operations, and process management.

PowerShell Smoke Tests

Quick validation of build artifacts and stability:

powershell -ExecutionPolicy Bypass -File tests/test_basic.ps1

Test Coverage: 4 smoke tests covering executable existence, dependencies, multiple instances, and rapid start/stop.

For detailed test documentation, see tests/README.md.

Feature Specification

See SPECIFICATION.md for a complete list of supported VT escape sequences, text attributes, and planned features with implementation status.

Dependencies (via vcpkg)

Runtime:

• directx-headers
• freetype
• spdlog
• nlohmann-json

Testing (optional):

• gtest

Known Issues

• Alternate buffer resize content loss - When resizing the terminal while in alternate screen buffer mode (used by TUI applications like vim, htop), content may not be fully preserved. Test: ScreenBufferTest.AlternateBufferResizePreservesContent.

License

GPL v2 License - See LICENSE.md

Contributing

Contributions and suggestions are welcome! See CONTRIBUTING.md for guidelines.