testsAndMisc/C/imageViewer

JPG Image Viewer

A simple, lightweight image viewer written in C using SDL2. Supports JPG, PNG, BMP, GIF, and TIF formats with zooming, panning, and basic image navigation features.

Features

• Multi-format support: JPG, JPEG, PNG, BMP, GIF, TIF
• Zoom functionality: Mouse wheel or keyboard controls
• Pan support: Click and drag to move around zoomed images
• Auto-fit: Automatically fits large images to window
• Responsive: Resizable window with real-time updates
• Keyboard shortcuts: Quick controls for common operations

Dependencies

The image viewer requires SDL2 and SDL2_image libraries.

Ubuntu/Debian

sudo apt-get update
sudo apt-get install libsdl2-dev libsdl2-image-dev

Fedora/RHEL/CentOS

sudo dnf install SDL2-devel SDL2_image-devel

Arch Linux

sudo pacman -S sdl2 sdl2_image

macOS (with Homebrew)

brew install sdl2 sdl2_image

Installation

Arch Linux (Automated)

For Arch Linux users, there's an automated installation script that handles everything:

./install_arch.sh

This script will:

• Install SDL2 dependencies via pacman
• Build the imageviewer from source
• Install the binary to /usr/local/bin
• Create a desktop entry for GUI access
• Set up file associations

To uninstall:

./uninstall_arch.sh

Manual Building

1. Install dependencies (see above)
2. Build the project:

make

Or use the dependency helper:

make deps-debian  # For Ubuntu/Debian
make deps-fedora  # For Fedora/RHEL/CentOS  
make deps-arch    # For Arch Linux
make

Usage

./imageviewer <image_file>

Example:

./imageviewer photo.jpg
./imageviewer ../misc/randomJPG/14k/bloated_image_1.jpg

Controls

Control	Action
Mouse wheel	Zoom in/out
+ / -	Zoom in/out (keyboard)
Mouse drag	Pan around the image
R	Reset zoom and position to default
F	Fit image to window
H	Show help in console
ESC / Q	Quit the application

Features in Detail

Zooming

• Use mouse wheel to zoom in/out at the mouse cursor position
• Keyboard shortcuts: + to zoom in, - to zoom out
• Zoom range: 0.1x to 10x
• Smart zoom behavior focuses on mouse position

Panning

• Click and drag with left mouse button to move around zoomed images
• Smooth panning for precise positioning
• Works at any zoom level

Auto-fit

• Large images are automatically scaled to fit the window when first loaded
• Press F to manually fit the current image to window
• Maintains aspect ratio

Window Management

• Resizable window that adapts to content
• Real-time rendering updates
• Dark background for better image contrast

Technical Details

• Language: C (C99 standard)
• Graphics: SDL2 for window management and rendering
• Image loading: SDL2_image for multi-format support
• Performance: Hardware-accelerated rendering when available
• Memory: Efficient texture management with proper cleanup

Makefile Targets

• make or make all - Build the image viewer
• make clean - Remove built files
• make test - Run with a test image (if available in randomJPG folder)
• make deps-debian - Install dependencies on Ubuntu/Debian
• make deps-fedora - Install dependencies on Fedora/RHEL/CentOS
• make deps-arch - Install dependencies on Arch Linux
• make help - Show available targets and usage

Troubleshooting

"SDL could not initialize" Error

Make sure SDL2 development libraries are installed:

# Ubuntu/Debian
sudo apt-get install libsdl2-dev libsdl2-image-dev

# Check if libraries are found
pkg-config --libs sdl2

"Unable to load image" Error

• Check that the image file exists and is readable
• Verify the image format is supported (JPG, PNG, BMP, GIF, TIF)
• Try with a different image file to isolate the issue

Compilation Errors

• Ensure you have a C compiler installed (gcc or clang)
• Check that SDL2 headers are available
• Try rebuilding with make clean && make

License

This project is open source. See the LICENSE file for details.

Contributing

Feel free to submit issues and enhancement requests. The code is designed to be simple and educational while being fully functional.