H5 Lens — Elegant HDF5 Viewer

A lightweight, fast desktop application for exploring .h5 / .hdf5 files with a clean GUI.

H5Lens/
├── launch.py          ← Entry point (becomes the .exe)
├── config.json        ← User-editable configuration
├── requirements.txt   ← Python dependencies
├── build.py           ← PyInstaller build script
├── lib/               ← Core library
│   ├── __init__.py
│   ├── app.py         ← pywebview ↔ frontend bridge
│   ├── h5engine.py    ← HDF5 reading engine (h5py + numpy)
│   └── viewer.html    ← Frontend GUI
└── README.md

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Quick Start

1. Install dependencies

pip install -r requirements.txt

2. Run

python launch.py                # Opens with file picker
python launch.py mydata.h5      # Opens a specific file directly

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Features

Feature	Description
Tree Explorer	Hierarchical view of all groups and datasets with search/filter
Data Table	Tabular preview of 1D, 2D, and N-D datasets with row indices
Attributes	View HDF5 attributes on any group or dataset
Dataset Details	dtype, shape, compression, chunks, fill value, max shape
Statistics	Min, max, mean, std, median, NaN count, unique values
Image Preview	Auto-renders 2D/3D numeric arrays as images (grayscale/RGB/RGBA)
CSV Export	Export any dataset to CSV via native save dialog
Recent Files	Remembers last 10 opened files
Keyboard Shortcuts	Ctrl+O open, / search, Ctrl+E export, Esc clear
Resizable Sidebar	Drag to resize the tree panel
Native Window	Proper desktop app via pywebview (no browser chrome)

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Build as Standalone .exe

pip install pyinstaller
python build.py            # Single-file .exe (slower startup, portable)
python build.py --onedir   # Directory bundle (faster startup)

The output goes to dist/H5Lens.exe (or dist/H5Lens/ for onedir). Place config.json next to the exe for user-editable settings.

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Configuration

Edit config.json to customize:

{
  "window": {
    "title": "H5 Lens",       // Window title
    "width": 1280,             // Initial width
    "height": 800,             // Initial height
    "on_top": false            // Always-on-top
  },
  "viewer": {
    "max_preview_rows": 5000,  // Max rows shown in data table
    "max_preview_cols": 200,   // Max columns shown for 2D data
    "max_image_pixels": 4000000, // Max pixels for image preview
    "float_precision": 8       // Decimal places for floats
  },
  "export": {
    "csv_separator": ","       // CSV delimiter
  }
}

---

Requirements

• Python 3.10+
• h5py ≥ 3.8
• numpy ≥ 1.24
• pywebview ≥ 5.0
• Pillow ≥ 10.0 (optional, for image preview)