Image Multisize Resizer

A robust, production-ready Python Command Line Interface (CLI) tool that allows you to resize a single image into multiple widths in one go. It uses Python's built-in argparse library for the CLI and the Pillow library for high-quality image processing.

The tool automatically calculates proportional heights based on your target widths, ensuring the original aspect ratio is perfectly maintained using high-quality LANCZOS resampling.

👥 For Users

Features

• Multiple Sizes at Once: Provide a comma-separated list of widths to generate multiple images simultaneously.
• Aspect Ratio Preservation: Automatically scales the height proportionally to the provided width.
• High-Quality Resampling: Uses Image.Resampling.LANCZOS for the best possible resized image quality.
• Custom Output Directory: Save the generated images in the same directory as the original, or specify a custom output path.
• Descriptive Naming: Automatically appends the generated width to the filename (e.g., photo_800px.jpg).

Installation

You can install the package directly via pip:

pip install image-multisize-resizer

(Note: If installing from source, clone the repository and run pip install .)

Usage

Once installed, the multi-resizer command is available globally.

Arguments:

• -i, --image (Required): Path to the input image file.
• -s, --sizes (Required): Comma-separated list of target widths (e.g., 300,600,1200).
• -o, --output (Optional): Directory to save resized images. Defaults to the input image directory.

Examples:

1. Basic Usage Saves copies directly next to your original file.

multi-resizer -i photo.jpg -s 400,800,1200

Output files generated: photo_400px.jpg, photo_800px.jpg, and photo_1200px.jpg.

2. Custom Output Directory Saves copies into a dedicated folder (the tool will create the directory if it doesn't exist).

multi-resizer --image elements.png --sizes 150,300 --output ./thumbnails

Output files generated: ./thumbnails/elements_150px.png and ./thumbnails/elements_300px.png.

Error Handling

• Gracefully handles missing input files.
• Creates the target output directory if it does not already exist.
• Validates the target sizes argument to ensure it contains a valid list of integers.

💻 For Developers

Local Setup

To set up the project locally for development:

1. Clone the repository:

   git clone https://github.com/ishandutta2007/image-multisize-resizer.git
   cd image-multisize-resizer
   

2. Create and activate a virtual environment (recommended):

   python -m venv venv
   # On Windows use: venv\Scripts\activate
   # On Linux/macOS use: source venv/bin/activate
   

3. Install the package in editable mode along with dependencies:

   pip install -e .
   

Requirements

• Python 3.7+
• Pillow >= 9.5.0

Contributing

Please refer to the CONTRIBUTING.md file for more details on how to contribute to this project. We welcome bug reports, feature requests, and pull requests.

📦 For Package Publishers

The publishing process for this package to PyPI is fully automated using GitHub Actions and PyPI Trusted Publishing (OIDC).

How Automated Publishing Works

Whenever a new git tag starting with v (e.g., v0.1.1) is pushed to the repository, the GitHub Actions workflow (.github/workflows/publish.yml) is triggered.

The workflow will:

1. Checkout the repository.
2. Set up Python.
3. Build the source distribution (sdist) and wheel (bdist_wheel) using the build module.
4. Publish the package securely to PyPI using the pypa/gh-action-pypi-publish action via an OIDC token. The skip-existing: true flag ensures that if the version already exists, the step will simply skip publishing without failing.

How to Release a New Version

To publish a new version of the package to PyPI, follow these steps:

1. Open pyproject.toml.
2. Update the version = "X.Y.Z" field to the new desired version.
3. Commit your changes.
4. Create a new git tag matching the version (with a v prefix) and push it to origin:

   git tag vX.Y.Z
   git push origin vX.Y.Z
   

5. The GitHub Action will trigger on the pushed tag and automatically build and publish the new version to PyPI.

Initial Setup (For Project Owner)

If this is your first time setting up the repository for PyPI publishing via OIDC:

1. Go to your project on PyPI (or create the project if it doesn't exist).
2. Navigate to Manage > Publishing.
3. Add a new GitHub publisher.
4. Provide the GitHub repository owner (ishandutta2007), repository name (image-multisize-resizer), and workflow filename (publish.yml).
5. This grants the GitHub Action permission to publish to PyPI securely without needing to store API tokens as secrets.