We port the upstream fix[1], and also revert commit a3383ac3d7[2] which
is now obsolete, and also not part of libgd. Especially the change to
gd.png.c was at best a half-baked optimization.
[1] <a24e96f019>
[2] <a3383ac3d7>
Closes GH-7402.
The function accepts a bool since PHP 8.0, so it should also return
a bool to keep things consistent.
Furthermore a null return from this functions is not possible.
If the string is too short, we should treat this the same way as
an unrecognized image type. This function should be usable to
determine whether something is a valid image without doing any
checks beforehand.
Currently we treat paths with null bytes as a TypeError, which is
incorrect, and rather inconsistent, as we treat empty paths as
ValueError. We do this because the error is generated by zpp and
it's easier to always throw TypeError there.
This changes the zpp implementation to throw a TypeError only if
the type is actually wrong and throw ValueError for null bytes.
The error message is also split accordingly, to be more precise.
Closes GH-6094.
The color resolution is expected in bits 4-6 of the packed fields byte
of the logical screen descriptor (byte 10 of the GIF data stream),
according to the specification[1], section 18.
[1] <https://www.w3.org/Graphics/GIF/spec-gif89a.txt>
While `imagesetinterpolation()` is available as of PHP 5.5.0,
there is no according getter function, so users would have to track the
current interpolation method manually.
To remedy this, we introduce `imagegetinterpolation()` as thin wrapper
for `gdImageGetInterpolationMethod()` (which has been introduced with
libgd 2.1.1), and use `im->interpolation_id` as fallback for older
libgd. Since our bundled libgd does not yet have this function, we add
it.
We also simplify the recently introduced bug79068.phpt, where it is
sufficient to check that the interpolation method has not been changed.
That parameter is mostly useless in practise, and likely has been
directly ported from the underlying `gdImagePolygon()` and friends,
which require that parameter since the number of elements of the point
array would otherwise be unknown. Typical usages of `imagepolygon()`,
`imageopenpolygon()` and `imagefilledpolygon()` pass `count($points)/2`
or hard-code this value as literal. Since explicitly specifying this
parameter is annoying and error-prone, we offer the possibility to omit
it, in which case the `$points` array must have an even number of
elements, and the number of points is calculated as `count($points)/2`.
We actually have to check `$num_points` instead of `2*count($points)`,
because the latter may be greater than the former, but not all elements
of `$points` are guaranteed to be used. This allowed to pass arrays
with excess elements to draw polygons with less than three vertices.
While the current implementation of `gdImagePolygon()` and friends
would allow us to draw monogons and digons, we don't allow that
anymore, because the respective drawing primitives work slightly
different (e.g. drawing lines support anti-aliasing, but drawing
general polygons does not).
To minimize the BC break, we do not fix this longstanding issue for PHP
7, but target PHP 8 only.
