Source code GIF and/or PNG

[morulis]

Hello,

Do you know where can I find source code to create my own encoder/decoder? I need to read from a known uncompressed file e.g BMP or PGM or PPM etc and to compress to GIF and/or PNG. I 've heard that the patent of LZW has expired and maybe there is code out there to make compressed GIF. The encoder/decoder will be used for academic purposes. I want to make a benchmark between known lossless compression techniques that used for images.

Thank you

 

[notfred]

If you use someone else's code you're not really creating your own encoder, are you?

regardless, imagemagick is open source and can creat those files, as is the gimp, and GD.

 

[KB]

What language are you looking to use? Imagemagick has commandline utilities to this too so your code only has to run the EXEs with the right command switches.

 

[morulis]

The LZW or LZ77 does not belong to me intellectually. So the encoder/decoder does not belong to me either or to anyone else. All the other things are just "details of the implementation" as we the programmers say. Thank you for your answer

 

[CTho9305]

This is the PNG encoder Gecko uses (i.e. Firefox, SeaMonkey).

The .h