imagepng("file", $comp_mode, $filter_mode);
The filters are defined in the libpng docs for png_set_filter
allow to divide the size of png images by more than 2. Constants
will be added later
BC kept, by default no filter are set
Fine to MFH? With the constants?
used to return "" and not bool(false). It's not worth keeping it because
STR_FREE() and zval_dtor() always have to check for it and it slows down
the general case. In addition, it seems that empty_string has been abused
quite a lot, and was used not only for setting zval's but generally in
PHP code instead of "", which wasn't the intention. Last but not least,
nuking empty_string should improve stability as I doubt every place
correctly checked if they are not mistakenly erealloc()'ing it or
calling efree() on it.
NOTE: Some code is probably broken. Each extension maintainer should
check and see that my changes are OK. Also, I haven't had time to touch
PECL yet. Will try and do it tomorrow.
i nuked all unneded calls to php_header() - i'm not too sure how we do
handle HEAD Requests as they were only detected via php_header(). but calling
php_header from a module makes output-buffering unusable.
NOTICE: there is some EBSDIC stuff in gd.c - i think it's obsolete.
