John Bowler

Hum: `../configure --with-libpng-prefix=conf; make -j; make -j check` works and symbols are prefixed with `conf` `cmake .. -DPNG_PREFIX=cmake; make; make test` works and the symbols are prefixed with `cmake` `cmake...

Exactly, and @LucasChollet stepped up. Even better his pull request demonstrates an ability to deal with the actual build process and an understanding of the basic architecture. His patch was...

Please comment on this @ProgramMax https://github.com/ProgramMax/ProgramMax is the current chair of the W3C PNG specification working group, so far as I am aware no one involved with libpng is currently...

> we see this image emitted millions of times to the logs when training on large web-scale datasets. there's no way to modify how middleware interacts with libpng, eg. cv2...

@ctruta: by design. Can be switched off when building libpng using the extensively documented setting `sRGB_PROFILE_CHECKS`. (See scripts/pnglibconf.dfa.) Can be disabled by the png_set_option Glenn described. The specific problem is...

There are more than enough controls to allow this or, indeed, any warning to be turned off. Indeed this warning has its own run-time png_set_option setting and there is a...

> yes but the pre-packaged options are not doing this. and instead of making it a cv2 issue, we make it a libpng one, since this is the common denominator...

For those who don't know how to find the code in the simplified API do this: ``` png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER, NULL, -1); png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT, "eXIf\0", 1); ``` The code in pngread.c...

I investigated the optimum filtering for a range of PNG images I had spidered off the web many years ago. The conclusion was that the spec recommendations and the actual...

The history of ISO-JPEG is salutary. The JPEG did exactly the same thing; they chose a filter method (the Discrete Cosine Transformation) which was determined by a lot of factors...