Hi everybody! During the discussion of PR 3080[1] the idea to replace our bundled libgd with an (unmodified) upstream libgd[2] has come up again. It seems this issue deserves its own discussion, and probably an RFC.
Our bundled libgd (particularly as found in master) is mostly compatible with upstream libgd 2.2.5 – actually, the API is compatible, but there are several (mostly minor) implementation differences. For instance, the $threshold parameter of imagecropauto($im, IMG_CROP_THRESHOLD) is interpreted differently[3], the result of imagettfbbox() is slightly different[4] and imagetruecolortopalette() uses a completely different algorithm if built with libimagequant (which is not available for the bundled libgd)[5]. Another important difference is that our bundled libgd uses ZendMM, but upstream libgd does not[6]. For most Linux environments PHP is built with an upstream (system) libgd; on Windows usually the bundled libgd is used. Users targeting both platforms likely already have conditional code (using `GD_BUNDLED`) to cater to relevant implementation differences. So, assuming we would not set `GD_BUNDLED` anymore after bundling upstream libgd, most users would not notice a difference. However, the PHP manual explicitly recommends to use the bundled libgd[7], so users heeding this advice would face several minor BC breaks. The main benefit of bundling upstream libgd, though, would be to save time by avoiding the 2-way synchronizations (which often occur on a per commit basis, and may even sometimes be overlooked). Any thoughts are welcome! [1] <https://github.com/php/php-src/pull/3080> [2] <http://libgd.github.io/> [3] <https://bugs.php.net/73291> [4] <https://github.com/php/php-src/pull/1845> [5] <http://libgd.github.io/manuals/2.2.5/files/gd-h.html#gdPaletteQuantizationMethod> [6] <https://github.com/libgd/libgd/issues/335> [7] <http://www.php.net/manual/en/image.installation.php> -- Christoph M. Becker -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
