panoviewer

panoviewer is a minimal image viewer made for HDRI panoramas, but supports most image files and camera raw files too.

Controls

• Left or middle mouse drag: pan/rotate view
• Mouse wheel: zoom
• Ctrl + mouse wheel: smooth exposure change
• ,: exposure -1 stop
• .: exposure +1 stop
• Ctrl + ,: gamma -0.1
• Ctrl + .: gamma +0.1
• Move cursor to the left edge: open toolbar overlay (open/reload/view transform/file info)
• P: Toggle 2D projection and equirectangular
• Home: Reset zoom and pan to the image's original opened view
• W: In 2D mode, toggle tiled wrapping on/off (both axes, default: off)
• F: Toggle fisheye and rectilinear lens (rectilinear is default; disabled in 2D mode)
• T: Toggle view transform
• F2: Toggle image metadata overlay (top-left)
• F11 or double-click: Full screen
• Esc: Exit

For panorama images, (2:1 aspect, hdr or exr) the last view transform used persists. For all others, Standard is always loaded by default.

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Development

• Python 3.11+
• PyQt6 windowing
• moderngl renderer
• OpenImageIO loading
• rawpy camera RAW decode
• OpenColorIO v2 display transforms

Setup

python -m venv .venv
# Windows PowerShell
.\.venv\Scripts\Activate.ps1
pip install --upgrade pip
pip install -e .[dev]

Run

panoviewer
# or open directly
panoviewer path/to/file.exr

Tests

pytest

Type checking

mypy hdri_viewer tests

Formatting

black .

OCIO configs

• Default config: hdri_viewer/resources/config.ocio
• Custom config folder: hdri_viewer/resources/ocio_configs

Drop a .ocio file in the custom folder and choose Reload from the left-edge toolbar.