png2wbmp() and jpeg2wbmp() are the only direct image format conversion functions available in ext/gd which makes them rather special, particularly as libgd doesn't offer any such functions 1). Furthermore WBMP 2) has been invented to support WAP 3), which appears to be mostly obsolete nowadays.
Therefore I propose to deprecate the png2wbmp() and jpeg2wbmp() functions as of PHP 7.2, and to remove them as of PHP 8.0. During the deprecation phase calling either function should emit an E_DEPRECATED error.
The main benefit in doing so would be easier maintainance of the libgd bindings (_php_image_convert() alone accounts for rougly 200 lines). An additional benefit would be to have a slightly cleaner and less confusing API (Why are there no other conversion functions? Why don't these functions follow the general “image” prefix rule?)
Obviously, code still using png2wbmp() or jpeg2wbmp() would break. However, fallback functions could easily implemented in userland. The supposedly long deprecation period should give users ample time to cater to the removal.
Currently none.
imagewbmp() and image2wbmp() are not subject of this RFC, and as such their functionality will remain unmodified.
Deprecate and remove the functions: yes or no.
This RFC requires a 50%+1 majority.
Voting ends on 2016-11-13, 22:00 UTC.
PR implementing the deprecation: https://github.com/php/php-src/pull/2164.