Hi!
This issue has been filed to our bugtracker years ago[1], but didn't
deserve much attention, so I'm forwarding to the list.
imagepolygon(), imagefilledpolygon() and imageopenpolygon() have the
following signature:
image*polygon(resource $im, array $points, int $num_points, int $col)
Note the third parameter, $num_points, which doesn't make much sense for
PHP, and has most likely being directly ported from the underlying libgd
implementation of gdImage*Polygon[2].
Even worse, while the common implementation[3] checks that $points
(which would better have been called $coordinate, by the way) has at
least 6 elements, $num_points can be smaller than 3, what will cause
gdImagePolygon() to be called with only so many points. That is not an
issue per se, as gdImagePolygon() is capable of handling monogons and
digons, but of course it doesn't make sense to force the programmer to
construct a larger array with unused values to do so. Furthermore the
imagefilledpolygon() man page[4] states that $num_points must be greater
than or equal to 3, but neither of the other man pages document this.
In the long run (i.e. for PHP 8) I'd suggest to purge the $num_points
parameter altogether, relying solely on the number of $points given.
For PHP 7.2 I propose to weaken the constraint on count($points) so that
2 would be sufficient instead of the 6 required now.
Would the proposed change for PHP 7.2 require an RFC, or would a PR suffice?
[1] https://bugs.php.net/bug.php?id=55005
[2] http://libgd.github.io/manuals/2.2.4/files/gd-c.html#gdImagePolygon
[3] https://github.com/php/php-src/blob/PHP-7.1.1/ext/gd/gd.c#L3355-L3413
[4] http://php.net/manual/en/function.imagefilledpolygon.php
--
Christoph M. Becker
In the long run (i.e. for PHP 8) I'd suggest to purge the $num_points
parameter altogether, relying solely on the number of $points given.
Since there's a 4th parameter ($color), what would "purge" mean in this
case? Reducing the number of parameters to 3 would be very confusing,
because existing code passing $num_points would be interpreted as
passing that value as $color.
We could ignore the argument whatever value was provided; or we could
document that it should be passed as null, and raise a warning if it's
anything else; or we could ignore it if it matched the length of
$points, and raise a warning or error if it didn't...
Regards,
--
Rowan Collins
[IMSoP]
In the long run (i.e. for PHP 8) I'd suggest to purge the $num_points
parameter altogether, relying solely on the number of $points given.Since there's a 4th parameter ($color), what would "purge" mean in this
case? Reducing the number of parameters to 3 would be very confusing,
because existing code passing $num_points would be interpreted as
passing that value as $color.We could ignore the argument whatever value was provided; or we could
document that it should be passed as null, and raise a warning if it's
anything else; or we could ignore it if it matched the length of
$points, and raise a warning or error if it didn't...
I haven't really though about how to do that, because PHP 8 is too far
away, and for now I'm interested in a clean solution that can be applied
to PHP 7(.2)
--
Christoph M. Becker