gdImageOpenPolygon() has been introduced with líbgd 2.0.29, so we finally
add a PHP binding for it, and port the respective libgd functionality to
PHP's bundled libgd.
gdLayerMultiply() has been introduced in libgd 2.1.1, and as such would have
been already available for imagelayereffect() with a system libgd. We port
the respective code to the bundled libgd, and also make IMG_EFFECT_MULTIPLY
available to userland.
Instead of rolling our own in the bundled libgd, we use libgd's anti-aliased
drawing API. This way imageantialias() is also available, when built against
a system libgd.
We apply the law `(b**r)**s == b**(r*s)` which holds for all non-negative b
and positive r,s, so a single pow() suffices. Furthermore, we precompute the
gamma, so the refactored code is simpler and faster.
The GD image format is able to handle truecolor images as of libgd 2.0.12
(<https://github.com/libgd/libgd/blob/gd-2.2.3/src/gd_gd.c#L31-L33>).
Therefore we don't need the potentially lossy and time consuming palette
conversion.
This way, imagegd() can also be used to export raw truecolor image data.
As of PHP 5.4.0 the second parameter of all image writer functions (except
imagexbm) accepts also a stream resource. Therefore the parameter name
`filename` is inappropriate. We change it to `to` according to what it's
already called in _php_image_output_ctx().
We consider the reflection only related BC break acceptable for a minor version.
These functions may be used in tight loops to do image manipulation in
userland. Using FAST_ZPP is supposed to bring considerable performance
improvements in this case; we've been able to measure up to 25%.
GD:
- PrintWindow() is available as of Windows XP, it requires linking to User32.lib, which config.w32 for ext/gd already.
CLI:
- The borrowed functions from PostgreSQL to set the titles of the console window uses SetConsoleTitle() and GetConsoleTitle(), both are available as of Windows 2000 from Kernel32.lib which we already are linking against.
Standard:
- The disk space utility functions uses GetDiskFreeSpaceExA() which is available as of Windows XP, again links to Kernel32.lib.
- The symlink() PHP function uses CreateSymbolicLinkA() which is available from Windows Vista, again from Kernel32.lib.
- php_get_windows_name() in info.c uses GetNativeSystemInfo() which is available as of Windows XP and GetProductInfo() which is available as of Windows Vista, both are again from Kernel32.lib.
Notes:
- ext/interbase & ext/pdo_firebird uses GetProcAddress(), I'm not entirely sure how to handle this one.
- ext/sqlite3, this is apart of the bundled libsqlite3, I don't really wanna play around with our bundled libs and make it a bigger issue for those who maintain and upgrade them.
- ext/readline, the call to GetProcAddress() here does not do any system calls, so it is left as is.
- win32/ioutil.c uses GetProcAddress(), but the function it attempts to load (PathCchCanonicalizeEx()) is only available from Windows 8 and greater (Pathcch.lib linkage).
- win32/time.c uses GetSystemTimePreciseAsFileTime() which is available from Windows 8 and greater to get the current system date and time which the highest possible precision and falls back to GetSystemTimeAsFileTime() (available as of Windows 2000), again Kernel32.lib, the GetSystemTimePreciseAsFileTime() is left in a GetProcAddress().
Calling imagesetstyle() with an empty $styles array caused gdImageSetStyle()
to be called with `noOfPixels==0`, what could have lead to OOB reads.
Actually, this issue will be fixed in libgd, but to avoid issues when older
libgd is in use, we simply disallow passing an empty $styles array to
imagesetstyle(), what wouldn't serve a useful purpose anyway.
We add the necessary PHP bindings for both functions which are available
as of GD_2_0_12 (released 2006-04-05). The API of imagegetclip() is modelled
according to imageftbbox().
* PHP-7.0:
#72482, Ilegal write/read access caused by gdImageAALine overflow
fix#72494, improve input color check and prevent issues when old gd are used, done before gd call
improve fix#72558, free contribRow as well
That happens because the external libgd uses other error codes than PHP
(and the bundled libgd), but the libgd error codes are simply forwarded
to php_verror(). We fix that by properly mapping libgd errors to PHP errors.
