TRX Viewer

A cross-platform desktop application for visualizing TRX brain tractography files with NIfTI-1 background volumes.

Built with Rust, egui, and wgpu for GPU-accelerated rendering.

Features

• 4-viewport layout — 3D perspective view with axial, coronal, and sagittal slice views
• GPU-accelerated rendering via wgpu (Metal on macOS, Vulkan/DX12 on Linux/Windows)
• NIfTI-1 volume slices correctly aligned in RAS+ coordinates using the NIfTI affine
• Depth-tested 3D rendering for proper occlusion of streamlines and slices
• Multiple coloring modes — direction RGB, per-vertex (DPV) scalar, per-streamline (DPS) scalar, group color, or uniform
• Group visibility controls — toggle individual streamline groups on/off
• Interactive cameras — orbit/zoom in 3D, pan/zoom/scroll through slices in 2D
• Crosshair overlays on slice views showing the position of the other two slice planes
• Intensity windowing — adjustable center/width for volume display
• Large dataset support — separate position/color GPU buffers for efficient recoloring of 100k+ streamline datasets

Usage

# Run with files as arguments
cargo run --release -- tractogram.trx background.nii.gz

# Or open files from the sidebar after launch
cargo run --release

Building

Requires Rust 1.88+ and the trx-rs library as a sibling directory.

# Build release binary
cargo build --release

# The binary is at target/release/trx-viewer-app

macOS app bundle

cargo build --release

# The .app bundle is at target/release/TRX Viewer.app
# To rebuild after code changes:
cp target/release/trx-viewer-app "target/release/TRX Viewer.app/Contents/MacOS/TRX Viewer"
touch "target/release/TRX Viewer.app"

Controls

Viewport	Action	Input
3D	Orbit	Left-click drag
3D	Zoom	Scroll
Slice	Pan	Left-click drag
Slice	Zoom	Right-click drag
Slice	Change slice	Scroll

Dependencies

• trx-rs — TRX file reading
• eframe / egui — GUI framework
• wgpu — GPU rendering
• nifti — NIfTI-1 volume loading
• rfd — Native file dialogs

License

BSD 2-Clause