Image Viewer

A minimalistic Rust image viewer with advanced features for scientific and technical image analysis. Built with eframe/egui for a responsive GUI experience.

Features

Image Format Support

• Standard formats: PNG, JPG, JPEG, BMP, TIF, TIFF, WebP, GIF, AVIF, HDR, EXR, Farbfeld, QOI, DDS, TGA, PNM, FF, ICO
• Floating point TIFF: Special support for 32-bit floating point TIFF files (Gray, RGB, RGBA)
• Drag & drop: Drop image files directly onto the window
• Command line: Load images by passing file path as argument

Image Analysis Tools

Normalization Types

• None: Display original image data
• Min-Max: Normalize pixel values to 0-255 range
• Log Min-Max: Logarithmic normalization for better visualization of wide dynamic range
• Standard: Standardization using mean and standard deviation
• FFT: Fast Fourier Transform visualization with windowing function

Channel Viewing

• RGB: View all channels combined
• Red: View only the red channel
• Green: View only the green channel
• Blue: View only the blue channel

Histogram Analysis

• Multi-channel histogram: Separate histograms for Red, Green, and Blue channels
• Hover information: Displays bin number, count, and percentage when hovering
• Floating point support: Calculates histograms from original data when available

Pixel Information Tool

• Coordinate display: Shows (x, y) coordinates of clicked pixel
• Value display: Shows RGB values for regular images or floating point values for FP images
• Channel-aware: Displays appropriate format based on image type (Grayscale vs RGB)

Drawing and Annotation Tools

Drawing Modes

• Free Draw: Freehand drawing with mouse
• Rectangle: Draw rectangular shapes (filled or outline)
• Line: Draw straight lines
• Arrow: Draw arrows for annotations
• Text: Add text labels to images

Drawing Features

• Color picker: Choose any color for drawings
• Stroke thickness: Adjustable line width (1-20 pixels)
• Fill option: Toggle filled/outline for rectangles
• Font size: Adjustable text size (8-72 points)
• Undo/Redo: Full undo/redo support (Ctrl/Cmd+Z, Ctrl/Cmd+Y)
• Clear all: Remove all annotations at once

Annotation Persistence

• Save annotations: Save drawings as separate .annotations.json files
• Auto-load: Annotations automatically load with images
• Export: Bake annotations into new image files (PNG/JPEG)
• Non-destructive: Original images remain untouched

Controls

Mouse Interaction

• Zoom: CTRL + Mouse wheel to zoom in/out (0.1x to 20x magnification)
• Pan: Left mouse button drag to pan the image (when not in drawing mode)
• Draw: Click and drag to draw when drawing mode is enabled
• Pixel sampling: Left click to sample pixel values (when pixel tool is enabled)

Keyboard Shortcuts

• Arrow Left/Right: Navigate to previous/next image in folder
• Ctrl/Cmd + Z: Undo last drawing action
• Ctrl/Cmd + Shift + Z or Ctrl/Cmd + Y: Redo drawing action

UI Controls

• Open Image: Button to open file dialog
• Scale slider: Manual zoom control
• Normalization: Radio buttons to select normalization type
• Channel dropdown: Select which channels to display
• Pixel Info checkbox: Toggle pixel inspection mode
• Histogram button: Toggle histogram window
• Drawing Mode checkbox: Enable/disable annotation tools

Loading Images

• File dialog: Use "Open Image" button
• Drag & drop: Drop image files onto the window
• Command line: ./image_viewer path/to/image.jpg

Advanced Features

Floating Point Image Support

• Direct TIFF decoder for 32-bit floating point formats
• Preserves original floating point values for accurate analysis
• Proper normalization handling for floating point ranges
• Shows true floating point values in pixel sampling

Performance Optimizations

• Texture caching to avoid unnecessary regeneration
• Smart scaling that only resizes when displaying smaller than original
• Lazy histogram calculation only when window is opened
• Efficient GPU-based image rendering

Installation

Quick Install (macOS/Linux)

git clone https://github.com/branislavhesko/image_viewer.git
cd image_viewer
./install.sh

This will:

• Build the release version
• Create a system application
• Install to /Applications (macOS) or system/user bin (Linux)

Manual Installation

See INSTALL.md for detailed installation instructions including:

• macOS app bundle creation
• Linux system-wide or user installation
• Windows installation
• Uninstallation steps

From Source (Development)

git clone https://github.com/branislavhesko/image_viewer.git
cd image_viewer
cargo build --release
cargo run --release

From Releases

Download precompiled binaries from the Releases page:

• Linux (x86_64): image_viewer-linux-x86_64
• Windows (x86_64): image_viewer-windows-x86_64.exe
• macOS (Apple Silicon/ARM64): ImageViewer-macos-arm64.app.zip

Note: macOS Intel (x86_64) is not supported. Only Apple Silicon Macs (M1, M2, M3, etc.) are supported.

Usage Examples

# Open file dialog
./image_viewer

# Load specific image
./image_viewer path/to/image.tiff

# Load floating point TIFF for scientific analysis
./image_viewer scientific_data.tiff

Requirements

Linux

• OpenGL support
• GTK development libraries (for file dialogs)

Windows

• Windows 7 or later
• OpenGL support

Feature requests and bug reports are welcome!