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diff --git a/.repos/farbfeld/README b/.repos/farbfeld/README new file mode 100644 index 0000000..1fe1125 --- /dev/null +++ b/.repos/farbfeld/README @@ -0,0 +1,74 @@ + + ███ ███ ██ ██ ███ ███ █ ██ + █ █ █ █ █ █ █ █ █ █ █ █ + ██ ███ ██ ███ ██ ██ █ █ █ + █ █ █ █ █ █ █ █ █ █ █ █ + █ █ █ █ █ ██ █ ███ ███ ██ + + +WHAT IS FARBFELD? + Farbfeld is a lossless image-format designed to be + parsed and piped easily. It is probably the simplest + image-format you can find (see FORMAT). + It does not have integrated compression, but allows + compression algorithms to work with it easily by adding + little entropy to the image data itself. This beats PNG + in many cases. + Given the free choice of compression algorithms, it + is trivial to switch to better and faster ones as they + show up in the future. + +HOW DO I USE THE TOOLS? + encoding: + png2ff < example.png > example.ff + png2ff < example.png | bzip2 > example.ff.bz2 + + decoding: + ff2png < example.ff > example.png + bzcat example.ff.bz2 | ff2png > example.png + + bzip2 is used in this example and a recommended + compression algorithm. Of course you are free + to use something else. + +WHY FARBFELD? + Current image-formats have integrated compression, + making it complicated to read the image data. + One is forced to use complex libraries like libpng, + libjpeg, libjpeg-turbo, giflib and others, read the + documentation and write a lot of boilerplate in order + to get started. + Farbfeld leaves this behind and is designed to be as + simple as possible, leaving the task of compression + to outside tools. + The simple design, which was the primary objective, + implicitly lead to the very good compression + characteristics, as it often happens when you go with + the UNIX philosophy. + Reading farbfeld images doesn't require any special + libraries. The tools in this folder are just a toolbox + to make it easy to convert between common image formats + and farbfeld. + +HOW DOES IT WORK? + In farbfeld, pattern resolution is not done while + converting, but while compressing the image. + For example, farbfeld always stores the alpha-channel, + even if the image doesn't have alpha-variation. + This may sound like a big waste at first, but as + soon as you compress an image of this kind, the + compression-algorithm (e.g. bzip2) recognizes the + pattern that every 48 bits the 16 bits store the + same information. + And the compression-algorithms get better and better + at this. + Same applies to the idea of having 16 bits per channel. + It sounds excessive, but if you for instance only have + a greyscale image, the R, G and B channels will store + the same value, which is recognized by the compression + algorithm easily. + This effectively leads to filesizes you'd normally only + reach with paletted images, and in some cases bzip2 even + beats png's compression, for instance when you're dealing + with grayscale data, line drawings, decals and even + photographs. |