Glitch Suite - PNG

Glitch Suite is a series of tools created for the sole purpose of manipulating image data.

This particular tool, created back in 2017, is specifically for modifying PNG images, and consists of a modified libPNG codec to control various aspects of the coding and decoding process.

Building

Should just need to run these commands afaik:

git clone https://github.com/KernelEquinox/glitch_png.git
cd glitch_png
make

Usage

Glitch Suite - PNG

Usage: glitch_png [options] <infile> <outfile>

Options:
    -a <filter>   Filter to use for writing row data
    -d <filter>   Filter to use for decoding row data
    -h            Show this help message
    -i            Interlace the image data
    -p <num>      Interlace pass to stop at (1-7)
    -s            Stop the interlace process mid-pass
    -x <byte>     Byte mask to modify filter with
    -y <byte>     Byte mask for AVG / PAETH output
    -z <num>      Force alpha channel off (0) or on (1)

Filters:
    0:   None
    1:   Sub
    2:   Up
    3:   Average
    4:   Paeth
    5:   Sub (Modified)
    6:   Up (Modified)
    7:   Average (Modified)
    8:   Paeth (Modified)
    255: Random (Output only)

Examples:

    Write with Sub, read with Up:
        glitch_png -a 1 -d 2 in.png out.png

    Write with Up (Modified), AND each pixel with 0xFE, read with Up:
        glitch_png -a 6 -d 2 -x 0xFE in.png out.png

    Write with Up, read with Paeth, interlace up to pass 2 and stop mid-pass:
        glitch_png -a 2 -d 4 -i -p 2 -s in.png out.png

    Write normally, read randomly:
        glitch_png -d 255 in.png out.png

Examples

Base image:

Write raw data without transparency, then read with Up:

glitch_png -a 0 -d 2 -z 0 base.png none_up.png

Write interlaced data using the Up filter, stop in the middle of pass 4, then read with Paeth:

glitch_png -a 2 -d 4 -z 0 -i -p 4 -s base.png interlace.png

Write interlaced data, stop in the middle of pass 7, then read with randomized filters:

glitch_png -d 255 -z 0 -i -p 7 -s base.png random.png

Write data using the Up filter, AND each byte with 0xFE, then read with Up:

glitch_png -a 6 -d 2 -x 0xFE base.png up_mod.png