Dithering

This is a command line tool for converting images to black and white using dithering techniques.

Dither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dither is routinely used in processing of both digital audio and video data, and is often one of the last stages of mastering audio to a CD. A common use of dither is converting a grayscale image to black and white, such that the density of black dots in the new image approximates the average gray level in the original.

See Wikipedia

Usage

go run main.go [image file] -m [dithering method] -f [output format] -o [output name] -q [output quality] -t [threshold value]

The following dithering methods are supported:

• "o4": Ordered 4x4 dithering
• "o9": Ordered 9x9 dithering
• "t": Threshold dithering
• "r": Random dithering
• "a": Apply all dithering methods and save the output with different names

The following output formats are supported:

• "jpg"
• "png"

The output quality parameter should be an integer between 1 and 100.

The threshold value is only used for threshold dithering.

If no arguments are provided, the program will use default values:

• Dithering method: "o4"
• Output format: "jpg"
• Output name: "output"
• Output quality: 100
• Threshold value: 0

The tool checks if the provided image file exists, and exits with an error message if it does not.

Example Usage

go run main.go image.jpg -m o9 -f png -o image_o9 -q 75 -t 128

This will take the image "image.jpg", apply ordered 9x9 dithering, and save the output as a PNG image named "image_o9" with quality 75 and threshold 128.

Acknowledgements

This CLI tool is heavily inspired by sloum/lid