If empty text is rendered, the bounding box is empty. Instead of
continuing with a bogus bounding box that would result in garbage
being rendered on screen, make the OSD image invisible.
This happened when playing demuxer SRT subtitles (e.g. SRT embedded in
MKV) with -no-ass at the moment a subtitle line disappeared.
Unrelated to this issue, fix libass API usage. Delete the event with
libass_flush_events(), instead of trying to reuse the previous event.
Based on a patch by uau.
Commit 7484ae8e2e attempted to introduce two ass_library handles
(as it was needed to deal with how ass_library manages fonts), but the
commit was completely bogus: it assumed osd_state->ass_library would be
used by osd_libass.c only, which is not the case. As result, some of the
subtitle code used the wrong ass_library handle.
We need two ass_library handles in osd_state. The one from the mplayer
core for subtitles (osd_state->ass_library), and one for OSD rendering
(osd_state->osd_ass_library).
osd_libass.c used the same ASS_Library object as the player core. This
caused a problem: when playing a new file, all fonts loaded by the
ASS_Library object were unloaded, including the OSD font. Parts of the
OSD would stop being rendered correctly.
Solve this by creating a separate ASS_Library, with its own set of
fonts.
Teletext requires special OSD support. Because I can't even test
teletext, I can't restore support for it. Since teletext can be
considered ancient and obscure, and since it doesn't make sense to keep
the remaining teletext code without being able to use it, I'm removing
it.
The previous commit made libass the default OSD renderer. This commit
removes the disabled freetype renderer completely. The commits were
done separately to make rolling back easier, because using libass for
OSD rendering is a risky choice.
Also remove freetype/fontconfig/fribidi code. This is all done by
libass now.
If mplayer is compiled without libass, no OSD is displayed.
The OSD will now be rendered with libass. The old rendering code, which
used freetype/fontconfig and did text layout manually, is disabled. To
re-enable the old code, use the --disable-libass-osd configure switch.
Some switches do nothing with the new code enabled, such as -subalign,
-sub-bg-alpha, -sub-bg-color, and many more. (The reason is mostly that
the code for rendering unstyled subtitles with libass doesn't make any
attempts to support them. Some of them could be supported in theory.)
Teletext rendering is not implemented in the new OSD rendering code. I
don't have any teletext sources for testing, and since teletext is
being phased out world-wide, the need for this is questionable.
Note that rendering is extremely inefficient, mostly because the libass
output is blended with the extremely strange mplayer OSD format. This
could be improved at a later point.
Remove most OSD rendering from vo_aa.c, because that was extremely
hacky, can't be made work with osd_libass, and didn't work anyway in
my tests.
Internally, some cleanup is done. Subtitle and OSD related variable
declarations were literally all over the place. Move them to sub.h and
sub.c, which were hoarding most of these declarations already. Make the
player core in mplayer.c free of concerns like bitmap font loading.
The old OSD rendering code has been moved to osd_ft.c. The font_load.c
and font_load_ft.c are only needed and compiled if the old OSD
rendering code is configured.
