{
    "mode": "man",
    "parameter": "ppmdither",
    "section": "1",
    "url": "https://www.chedong.com/phpMan.php/man/ppmdither/1/json",
    "generated": "2026-06-16T10:47:54Z",
    "synopsis": "ppmdither [-dim power] [-red shades] [-green shades] [-blue shades] [ppmfile]",
    "sections": {
        "NAME": {
            "content": "ppmdither - ordered dither for color images\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "ppmdither [-dim power] [-red shades] [-green shades] [-blue shades] [ppmfile]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "Reads  a portable pixmap as input, and applies dithering to it to reduce the number of colors\nused down to the specified number of shades for each primary.  The default number  of  shades\nis  red=5,  green=9, blue=5, for a total of 225 colors.  To convert the image to a binary rgb\nformat suitable for color printers, use -red 2 -green 2 -blue 2.\n",
            "subsections": []
        },
        "OPTIONS": {
            "content": "-dim power    The size of the dithering matrix.  The dithering matrix is a square  whose  di-\nmension is a power of 2.  power is that power of 2.  The default is 4, for a 16\nby 16 matrix.\n\n-red shades   The number of red shades to be used, including black; minimum of 2.\n\n-green shades The number of green shades to be used, including black; minimum of 2.\n\n-blue shades  The number of blue shades to be used, including black; minimum of 2.\n",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "pnmdepth(1), ppmquant(1), ppm(5)\n",
            "subsections": []
        },
        "AUTHOR": {
            "content": "Copyright (C) 1991 by Christos Zoulas.\n\n14 July 1991                              ppmdither(1)",
            "subsections": []
        }
    },
    "summary": "ppmdither - ordered dither for color images",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "pnmdepth",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/pnmdepth/1/json"
        },
        {
            "name": "ppmquant",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/ppmquant/1/json"
        },
        {
            "name": "ppm",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/ppm/5/json"
        }
    ],
    "tldr": {
        "source": "official",
        "description": "Reduce the number of colors in an image by applying dithering.",
        "examples": [
            {
                "description": "Read a PPM image, apply dithering, and save it to a file",
                "command": "ppmdither {{path/to/image.ppm}} > {{path/to/file.ppm}}"
            },
            {
                "description": "Specify the desired number of shades for each primary color",
                "command": "ppmdither {{-r|-red}} {{2}} {{-g|-green}} {{3}} {{-b|-blue}} {{2}} {{path/to/image.ppm}} > {{path/to/file.ppm}}"
            },
            {
                "description": "Specify the dimensions of the dithering matrix",
                "command": "ppmdither {{-d|-dim}} {{2}} {{path/to/image.ppm}} > {{path/to/file.ppm}}"
            }
        ]
    }
}