Allow cloning of GdImage from gd 2.2.3

[blar]

From version 2.2.3 gd supports cloning https://libgd.github.io/manuals/2.2.3/files/gd-c.html#gdImageClone

The bundled version of gd is at version 2.0.35 so cloning is only supported with --with-external-gd

[iluuu1994]

LGTM, but maybe @cmb69 wants to have a look?

[cmb69]

Thank you for the PR!

I fully agree that it makes sense to expose gdImageClone() to userland, but not 100% sure about whether via clone or a new function (imageclone()). Since we're having objects now, the former probably makes most sense.

Regarding the libgd version requirements: there are several known bugs in that function, and some have not even been fixed yet (albeit quite serious). Maybe we should require a newer version right away? On the other hand, bugs in external libraries are not uncommon, so we can stick with libgd ≥ 2.2.

The bundled version of gd is at version 2.0.35 so cloning is only supported with --with-external-gd

ext/gd is lying. :) There have been several updates (bugfixes and features), but the bundled gd never conformed to any particular libgd version. We might update these version numbers, although the long term goal is still to unbundle libgd (what is still blocked by libgd/libgd#335).

Anyhow, we could port gdImageClone() from libgd right away, so more users could use the new feature. This could alternatively be done via a separate follow-up PR.

[blar]

I fully agree that it makes sense to expose gdImageClone() to userland, but not 100% sure about whether via clone or a new function (imageclone()). Since we're having objects now, the former probably makes most sense.

The function imageclone() only make sense if you want to backport it to a version of php before 8.0.0, which don't had the GdImage class. Additionally developers may question why every other (clonable) class can be cloned with clone, but GdImage requires imageclone().

[cmb69]

Additionally developers may question why every other (clonable) class can be cloned with clone, but GdImage requires imageclone().

I agree (although devs also may wonder why there are no methods for this class). :)

[TimWolla]

With #10225, I agree that the clone operator is the right choice.

[pierrejoye]

see #22532