How to Use the Command 'cjxl' (with Examples)

The cjxl command is a powerful tool used to compress images into the JPEG XL format. JPEG XL is a next-generation image compression format designed to supersede older formats like JPEG, PNG, and GIF, by offering better compression and higher-quality image output. The cjxl command-line tool provides various options to optimize the process of converting images into this new format. Accepted input extensions include PNG, JPEG, GIF, and other commonly used image formats, making it a versatile tool for image compression tasks.

Use Case 1: Convert an Image to JPEG XL

Code:

cjxl path/to/image.ext path/to/output.jxl

Motivation:

Converting images to the JPEG XL format can significantly reduce file size while maintaining high image quality, making it an excellent option for web developers and photographers looking to optimize image delivery without sacrificing visual fidelity. JPEG XL supports high-quality compression, efficient encoding, and decoding, which is highly beneficial for reducing storage and bandwidth use.

Explanation:

• cjxl: The command-line tool used for compressing images into the JPEG XL format.
• path/to/image.ext: This placeholder represents the path and file extension of the image you want to convert. For example, this could be images/picture.png or photos/photo.jpg.
• path/to/output.jxl: This specifies the path and file name where the compressed JPEG XL image will be saved. By defining this path, you ensure the compression result is properly stored.

Example Output:

Upon successful execution of the command, the terminal will display information about the compression process, including the original and compressed file sizes. The resulting .jxl file will be created in the specified location, confirming that the image has been successfully converted and compressed into the JPEG XL format.

Use Case 2: Set Quality to Lossless and Maximize Compression of the Resulting Image

Code:

cjxl --distance 0 --effort 9 path/to/image.ext path/to/output.jxl

Motivation:

For projects requiring absolute preservation of image quality—such as archival purposes, professional photography, or medical imaging—it’s critical to maintain the original quality of images while reducing their file size. Using the --distance 0 setting ensures lossless compression, meaning no quality is lost from the original image, while the --effort 9 maximally compresses the file size without altering the image data integrity.

Explanation:

• --distance 0: This option sets the compression to lossless mode. A distance of zero indicates that the resulting image will retain all the original data, ensuring that there is zero loss in quality.
• --effort 9: This indicates the highest level of compression effort. A higher effort level means the tool will spend more time optimizing the compression to achieve the smallest possible file size, maximizing storage savings.
• path/to/image.ext: Here is the path to the source image you wish to compress.
• path/to/output.jxl: This shows where the compressed image file will be saved.

Example Output:

After running this command, you’ll receive detailed output about the conversion process, affirming that a lossless JPEG XL image has been generated. The terminal output will include information such as compression ratio and the size difference between the original and output files. The generated .jxl file will be stored as specified, reflecting optimal compression performance without compromising image quality.

Use Case 3: Display an Extremely Detailed Help Page

Code:

cjxl --help --verbose --verbose --verbose --verbose

Motivation:

For users who want to take full advantage of the cjxl tool, understanding all available options and configurations is crucial. Accessing a very detailed help page allows users to learn about advanced options and settings that could be utilized for specific needs. This ensures users can leverage all features available in cjxl, customizing image conversion operations to match particular requirements.

Explanation:

• --help: This option requests the help page for cjxl, providing a list of possible commands and options available with the tool.
• --verbose: Using the verbose flag multiple times increases the level of detail in the help page’s output. Each additional --verbose flag adds more layers of descriptive information, delivering comprehensive and exhaustive command documentation.

Example Output:

When executing this command, the terminal will display a full and detailed help page, shedding light on the extensive features and options available in cjxl. The information will include all possible parameters, options for image compression, supported file formats, and advanced usage scenarios. This output serves as a helpful reference for understanding how to utilize all capabilities of the cjxl tool effectively.

Conclusion:

The cjxl command is a highly valuable utility for anyone looking to optimize image compression using the advanced JPEG XL format. Through these three use cases, we explored the basics of converting images to JPEG XL, achieving lossless quality, and maximizing compression, and learning extensively about the command’s features. By understanding and utilizing these different command options, users can enhance their image processing workflows, improve storage efficiency, and ultimately support high-quality media delivery across a variety of platforms.