Allow using shadow offset to adjust size of text background
Text background refers to the libass-only BorderStyle 4, which is
similar to 3, but isn't affected by outline/border size and doesn't
render shadow, so shadow offset can be used.
You can override the horizontal and vertical box size separately
with override tags, just like you can override the color with
shadow color.
Grigori Goronzy [Thu, 1 Jun 2017 09:25:09 +0000 (11:25 +0200)]
directwrite: fix font collections
DirectWrite's FontFileStream does not actually use the data of a specific
font in a collection, which was an expectation of the existing code. It
simply returns a stream to the underlying file, collection or not. So we
need to get the index of the font. This needs to be done lazily as this
information is only available in a FontFace, which is expensive to
initialize.
Add a new optional font provider function for lazy initialization of the
index and use it. This is similar to the check_postscript callback.
Grigori Goronzy [Wed, 10 May 2017 11:39:57 +0000 (13:39 +0200)]
Fix PlayResX/Y calculations
Avoid that PlayResY is set to 0 when only PlayResX is specified and
set to 1. Setting PlayResY to 0 results in divide-by-zero errors.
Also fix PlayResX calculations in case only PlayResY is specified,
for completeness.
Oleg Oshmyan [Sat, 4 Feb 2017 02:02:50 +0000 (04:02 +0200)]
Fix decode_font when size % 4 != 0 or data contains illegal bytes
When given a byte c, decode_chars expects that 0 <= c - 33 <= 63,
i. e. that only the six lowest bits of c - 33 are possibly set.
With this assumption, it shifts and adds together multiple c - 33 values.
When c > 96, c - 33 has high nonzero bits, which interferes with other
shifted terms. c < 33 is even worse: c - 33 is negative (if unsigned char
fits in int), and left-shifting negative numbers has undefined behavior.
Even before the shift, on common platforms with a two's complement
representation of negative integers (or if unsigned char does not fit in
int and is promoted to unsigned int), c - 33 has high nonzero bits, which
again interfere with other shifted terms.
To make matters worse, even perfectly valid encoded data is affected when
size % 4 != 0, as decode_font calls decode_chars with '\0', which leads
decode_chars to shift and add -33, causing undefined behavior and/or
incorrect output.
Take our cue from VSFilter and bit-mask c - 33 to keep only the six
relevant bits. To ensure that we get the same bits as VSFilter when
c < 33 and to avoid the undefined behavior of left-shifting negative
numbers, convert the number to unsigned before masking and shifting.
While we are at it, rewrite decode_chars entirely
to get rid of any GPL code from mkvtoolnix.
Related mkvtoolnix bug: https://github.com/mbunkus/mkvtoolnix/issues/1003
Oleg Oshmyan [Fri, 3 Feb 2017 19:40:19 +0000 (21:40 +0200)]
string2timecode: don't truncate milliseconds to int
Commit 8c8741fe2000d4b4d89a53f894363a42288cec3e attempted to fix this
expression and make it use the full range of long long, but it missed
the millisecond term.
This fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=522.
The entire timestamp can still overflow long long though.
Oleg Oshmyan [Fri, 3 Feb 2017 19:34:13 +0000 (21:34 +0200)]
Fix parsing of unusual Alignment values in ASS style definitions
Handle large and negative values except INT32_MIN like VSFilter.
This avoids both overflow and inconsistent internal state.
This fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=523.
VSFilter handles INT32_MIN like a mix of \an1, \an2 and \an3:
* Vertical alignment is bottom.
* Lines within the event are center-aligned.
* Without \pos or \move, the center of the event is aligned
with the right edge of the screen minus MarginR.
* With \pos or \move, the left edge of the event is aligned
with the position point.
* Without \org, the rotation origin is aligned
with the horizontal center of the event.
* (With \org, the rotation origin is as specified.)
If we wanted to emulate this in libass, the cleanest way would be to
introduce a new horizontal alignment constant for this purpose that
would be used only for ASS style definitions with Alignment INT32_MIN.
This commit makes no attempt to do this and instead arbitrarily picks
\an2 for style definitions with Alignment -INT_MAX-1, which equals
INT32_MIN if int is int32_t. The fact that int is platform-dependent
is one of the reasons for this. We could change Alignment to be int32_t
instead of int for perfect VSFilter compatibility, but the same applies
to many other fields that currently use platform-dependent types.
Oleg Oshmyan [Tue, 7 Feb 2017 12:14:07 +0000 (14:14 +0200)]
Travis CI: remove HarfBuzz and re-remove Fontconfig from OS X builds
Installing HarfBuzz through Homebrew seems to be consistently slow
whether we use the bottles and disable the Fontconfig cache or build
it from source and drop Fontconfig and other dependencies entirely.
To speed up OS X builds, disable both HarfBuzz and Fontconfig.
We build with HarfBuzz and Fontconfig on Linux, and we should
not have any platform-dependent code that depends on them,
so this should not reduce our code coverage.
Oleg Oshmyan [Mon, 6 Feb 2017 16:46:22 +0000 (18:46 +0200)]
Travis CI: re-enable Fontconfig on OS X but force no cache built
Building HarfBuzz from source works to avoid Fontconfig, but it is still
fairly slow. To further speed up the build, try to use only the prebuilt
bottle packages (which inevitably brings in Fontconfig as a dependency)
but hack the Fontconfig formula to avoid building the font cache.
Adding Fontconfig is not the goal of this commit, as we already have it
on Linux and our Fontconfig-related code "should" work equally well on
other platforms. But since we can now afford it, explicitly ask Homebrew
to install Fontconfig even if the dependency that brings it in disappears
from Homebrew in the future, and enjoy the improved code coverage.
Oleg Oshmyan [Sun, 5 Feb 2017 18:47:48 +0000 (20:47 +0200)]
Travis CI: build with HarfBuzz
On OS X, disable some unnecessary HarfBuzz dependencies. This triggers
a source build of HarfBuzz, but it should be fast and avoids bringing
in Fontconfig through a dependency chain, which we want to avoid as it
wastes a lot of time building its cache when installed.
The dependency that brings in Fontconfig is gobject-introspection, but
we don't need icu4c either, so disable that to save a little more time
that would be spent installing icu4c. We could also disable glib, but
the fribidi formula also has it as a dependency and brings it in anyway.
Oleg Oshmyan [Sun, 5 Feb 2017 02:24:54 +0000 (04:24 +0200)]
Travis CI: run Coverity Scan on every master build
We never remember to push to the coverity_scan branch, so currently
Coverity Scan never runs. Our master builds are not very frequent,
so we should be able to afford running Coverity Scan on every build.
Since https://blog.travis-ci.com/2016-10-04-osx-73-default-image-live/,
this libtool comes preinstalled on Travis CI, thus the hack is no longer needed.
Homebrew bug report possibly relevant to the original problem:
https://github.com/Homebrew/legacy-homebrew/issues/43874
Oleg Oshmyan [Sun, 5 Feb 2017 01:44:34 +0000 (03:44 +0200)]
Travis CI: don't require Fontconfig binaries
Only the library is needed.
In fact, `apt-get install fontconfig` didn't even install the library at
all. Luckily, the package we actually want is preinstalled on Travis CI.
We could continue to rely on this fact and completely remove Fontconfig
from the install list, but it's clearer and possibly more future-proof
to explicitly list it there.
Oleg Oshmyan [Sun, 5 Feb 2017 00:05:20 +0000 (02:05 +0200)]
Travis CI: disable Fontconfig on OS X
Homebrew generates the Fontconfig cache when installing Fontconfig,
which delays the build by several minutes. Disable the Fontconfig
font provider on OS X to avoid this.
Oleg Oshmyan [Mon, 30 Jan 2017 22:11:49 +0000 (00:11 +0200)]
Reduce precision of border width in outline cache keys
The value used to generate outline cache values is 26.6, so there
is no point in storing the more precise 16.16 in the cache key.
Indeed, this can only reduce the efficiency of the cache
and provide an extra opportunity for overflow.
Oleg Oshmyan [Mon, 30 Jan 2017 21:45:43 +0000 (23:45 +0200)]
Reflect border_scale in outline cache keys
border_scale can change, e. g. when ass_render_frame is called twice with
the same renderer but different tracks. Glyphs with equal \bord tag values
but different border_scale values produce different border outlines and
hence should be distinguished in outline cache keys. To this end, store
scaled border widths (which are really used when generating the outlines)
in cache keys instead of \bord tag values.
Dr.Smile [Mon, 30 Jan 2017 23:47:58 +0000 (02:47 +0300)]
render: remove redundant has_clips
has_clips was a workaround for the case where a new image reused
the same memory address as another image used in the previous frame.
In case of such reuse, comparison by pointer address failed
to distinguish the different images in ass_detect_change().
After commit dd06ca30ea79ce50116a43cc5521d4eaf60a017e,
images in the previous frame are no longer freed before
the comparison with current frame. Thus no such reuse can occur,
and the workaround is redundant.
wm4 [Fri, 13 Jan 2017 08:19:23 +0000 (09:19 +0100)]
render_api: do not discard old images on reconfiguration
I noticed that when resizing the mpv window while playback is ongoing
and with subtitles, that subtitles could sometimes get "stuck" on the
screen. The stuck subtitle would remain until the next subtitle event,
or until seeking to a position that has subtitles again.
It turned out that this was a libass change detection bug. The following
steps should reproduce the problem:
1. call ass_render_frame() with a time that has subtitles
2. call ass_set_frame_size() with a different size
3. call ass_render_frame() with a time that has no subtitles
The previous call will return with *detect_change==0.
To make this worse, libass will deallocate image data before the next
ass_render_frame() or ass_renderer_done(), which violates the API and
could possibly make some API users crash. (That the user can rely on
this is not documented though.)
There are two possible solutions:
1. Set a flag in ass_reconfigure(), that makes the next
ass_render_frame() call always return *detect_change==2.
2. Do not discard the previous subtitles (images_root), so change
detection can work reliably.
This commit implements 2. - I prefer this in part because it doesn't
clobber the previously returned image list before the next
ass_render_frame() call. (As pointed out above, this might be unexpected
behavior to the API user.)
This is a regression and was possibly broken by commit dd06ca and later.
I did not check whether it actually behaved sanely before that change,
but it probably did to a degree.
wm4 [Wed, 11 Jan 2017 06:10:13 +0000 (07:10 +0100)]
render: clip BorderStyle=4 against screen
ASS_Images returned by libass are guaranteed to be clipped. Not doing
this will cause invalid memory accesses in applications which try to use
this guarantee.
Oleg Oshmyan [Tue, 3 Jan 2017 19:20:20 +0000 (21:20 +0200)]
Bump ABI version and release 0.13.6
sizeof(ASS_Style) is actually part of the ABI, so adding the Justify field
in commit e54c123d5a08b6212533ddcced2cb1a50fa3d2b2 broke the ABI even
though we tried to avoid it by placing the field at the end of the struct.
Oleg Oshmyan [Wed, 28 Dec 2016 19:14:21 +0000 (21:14 +0200)]
Fix buffer overread in parse_tag when end points to a space
When parse_tag is invoked recursively to handle the animated tags inside
a \t tag, the `end` argument is taken from the `end` field of a struct arg
in the enclosing parse_tag. When struct arg is filled by push_arg, this
field is always right-trimmed using rskip_spaces. Ultimately, the inner
parse_tag invokation sees its `end` argument point not to the ')' or '}'
of the \t as it expects but rather to the spaces preceding the ')' or '}'.
At this point, when parse_tag calls skip_spaces, which is ignorant of the
end pointer, it happily skips over the spaces preceding the ')', moving the
pointer past `end`. Subsequent `pointer != end` comparisons in parse_tag
fail (as in fact `pointer > end`), and parse_tag thinks it is still inside
the substring to be parsed.
This is harmless in many cases, but given either of the following inputs,
parse_tag reads past the end of the actual buffer that stores the string:
{\t(\ }
{\t(\ )(}
After this commit, parse_tag knows that `end` can point to a sequence of
spaces and avoids calling skip_spaces on `end`, thus avoiding the overread.
Discovered by OSS-Fuzz.
Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=194.
Oleg Oshmyan [Fri, 4 Nov 2016 14:27:44 +0000 (16:27 +0200)]
ass_strtod: correctly convert large negative exponents
Avoid overflow in dblExp that prevents subnormal numbers from being
generated (or small normal numbers if `double` supports many more
negative exponents than positive): if `10**abs(exp)` would overflow
and we actually want a negative exponent, switch to using precomputed
negative powers of 10 rather than positive.
Also avoid underflow for numbers with a large negative exponent where
the exponent alone underflows but the significand has enough digits to
cancel this out, e. g. in `10e-324` with IEEE 754 double.
Oleg Oshmyan [Sun, 30 Oct 2016 00:26:00 +0000 (03:26 +0300)]
ass_strtod: skip leading zeros in mantissa
ass_strtod reads at most 18 leading digits of the mantissa.
This previously included zeros, even though they are not significant
digits, e. g. 0.000000000000000001e18 was converted to 0.0.
After this commit, leading zeros before and after the decimal point
will be skipped, so the above number will be correctly converted to 1.0.
Dan Oscarsson [Wed, 5 Oct 2016 11:52:47 +0000 (13:52 +0200)]
Add text justification
Subtitle recommendations often include that multi line
subtitles should be left justified as this is easier for
the eyes. This is also the standard used by several television
companies.
This add the possibility to define how subtitles are to
be justified, independently of where they are aligned.
The most common way could be to set justify to left, and have
alignment to center. But you can, for example, have alignment
to left and justify to center, giving subtitles to the left but
justifed on the center (instead of normal left justified).
Using justify right and alignment of center, might be good
choice for Arabic.
If justify is not defined, all works like before.
If justify is defined, subtitles are aligned as defined
by alignment and justified as defined by justify.
ASS is not extended by this, justify can only be defined
by setting Justify to wanted justification.
Grigori Goronzy [Tue, 4 Oct 2016 19:25:41 +0000 (21:25 +0200)]
Fix line wrapping mode 0/3 bugs
This fixes two separate bugs:
a) Don't move a linebreak into the first symbol. This results in a empty
line at the front, which does not help to equalize line lengths at all.
Instead, merge line with the second one.
b) When moving a linebreak into a symbol that already is a break, the
number of lines must be decremented. Otherwise, uninitialized memory
is possibly used for later layout operations.
Found by fuzzer test case
id:000085,sig:11,src:003377+003350,op:splice,rep:8.
This might also affect and hopefully fix libass#229.
Grigori Goronzy [Tue, 4 Oct 2016 00:35:26 +0000 (02:35 +0200)]
shaper: fix reallocation
Update the variable that tracks the allocated size. This potentially
improves performance and avoid some side effects, which lead to
undefined behavior in some cases.
Fixes fuzzer test case id:000051,sig:11,sync:fuzzer3,src:004221.
At some point in the past Travis and homebrew colluded to break the
preinstalled libtool on travis MacOS instances. Forcing brew to
reinstall libtool seems to be the common solution that several other
projects on github have used.
font load from dir: use MSGL_INFO instead of MSGL_WARN
This is a normal course of action and should not generate a warning,
especially for applications which use libass and might notify the user
on such "warnings", while in fact it should be info or even verbose.
Advantages over the old algorithm consist of the following.
* There are no glitches due to full cache clearing.
Items are arranged into linked list ordered by time of last use.
Only the oldest items get deleted at the clearing event.
* Each item now keeps track of number of references.
Referenced cache values are immune to clearing.
* Reduced amount of total cache memory for the same performance.
* Reduced number of memory allocations per cache item.
wm4 [Thu, 31 Dec 2015 16:26:46 +0000 (17:26 +0100)]
ass: add ass_set_check_readorder() API function
Not all API users will keep the event list on seeking. This also gives
the opportunity to API users to handle severely broken files with
duplicate ReadOrder entries. (It is not known whether this is really
needed, however VSFilter does not deduplicate using the ReadOrder
field.)
wm4 [Thu, 31 Dec 2015 15:28:00 +0000 (16:28 +0100)]
ass: declare mixing ass_flush_events() and ass_process_chunk() allowed
This was always the intention, but the wording could be read as if this
is not allowed. There was a bug that broke ass_flush_events() too, which
gives all the more reason to clarify this.
wm4 [Thu, 31 Dec 2015 15:23:44 +0000 (16:23 +0100)]
Changelog: create entry for the next version
It's always such a bother to write the changelog on release. And in
fact, there is no reason why the changelog should be written on release.
It's easier to edit it as we commit fixes or features.
I'm adding the changelog entries for the past two commits, and in the
future, we should add entries as we commit bug fixes or new features.
Oleg Oshmyan [Wed, 4 Nov 2015 13:25:47 +0000 (15:25 +0200)]
fontselect: replace is_postscript flag with check_postscript function
DirectWrite does not provide fast access to the is_postscript flag,
requiring each font to be loaded before its format can be determined.
Eagerly doing this for every installed font can be quite slow,
on the order of seconds.
To improve performance, ask the font provider for this information
only when it is actually needed, i.e. when one of the font's full
names or its PostScript name matches a requested font name and we
need to know whether to accept this match.
The return value of check_postscript is not cached in this commit.
This makes repeated calls slower than accessing is_postscript was.
This should not be a problem, but if it is, the value can be cached
(or precomputed) by font providers in their font private data.
This commit also potentially increases the memory usage of some
font providers by retaining data structures needed to implement
check_postscript in their font private data. This should not be
a problem either, but if it is, the value of check_postscript
can be precomputed by all providers other than DirectWrite.
Oleg Oshmyan [Thu, 29 Oct 2015 23:33:30 +0000 (01:33 +0200)]
directwrite: improve error handling
* Check malloc and calloc return values.
* Abort if a name can't be fetched, rather than supply a NULL
string to fontselect causing it to crash.
* Make sure to free all allocated memory.
* Always check FAILED(hr) before using the value of any output
argument returned by DirectWrite, because it is not clear whether
they are guaranteed to have correct values in case of error.
Oleg Oshmyan [Thu, 29 Oct 2015 23:33:30 +0000 (01:33 +0200)]
directwrite: slightly clean up the code
* Metrics are not used, so don't fetch them.
* All variables except meta are always explicitly set before use,
so don't initialize them.
* Declare variables where they are used.
* Use int loop variables when the loop bound is int.
* Prefer post-increment to pre-increment.
Oleg Oshmyan [Thu, 29 Oct 2015 23:13:59 +0000 (01:13 +0200)]
directwrite: split out the inner loop of scan_fonts as a separate function
This has the side effect that the ASS_FontProviderMetaData instance is now
cleared for every font rather than only once at the start of the search,
which fixes some use-after-free scenarios and prevents the creation of
chimeric fonts using names left over from other fonts processed earlier.
This lays the groundwork for further code simplification and error handling
improvements within this function, which will come in a separate commit.
This commit is transparent to `git blame -w` except for return statements.
Oleg Oshmyan [Wed, 28 Oct 2015 22:19:20 +0000 (00:19 +0200)]
fontselect: silence warnings about discarding const
Fixing this properly involves constifying ASS_FontProviderMetaData
and refactoring code that allocates and frees strings stored in it.
This seems easy on the surface but turns out to be nontrivial when
you actually try to do it. This may still be done at a later date,
but for now, just add explicit casts.