This commit annotates fonts with a boolean that indicates whether
we think it contains glyphs with emoji presentation, and then
passes the cluster.presentation field down to the shaper.
If the presentation doesn't match the current font in the fallback,
then it will be skipped until we exhaust its options.
`wezterm ls-fonts` also shows whether we think a font has emoji
presentation.
refs: #997
This isn't complete; many of the placement options are not supported,
and the status reporting is missing in a number of cases, including
querying/probing, and shared memory objects are not supported yet.
However, this commit is sufficient to allow the kitty-png.py script
(that was copied from
https://sw.kovidgoyal.net/kitty/graphics-protocol/#a-minimal-example)
to render a PNG in the terminal.
This implementation routes the basic image display via the same
code that we use for iterm2 and sixel protocols, but it isn't
sufficient to support the rest of the placement options allowed
by the spec.
Notably, we'll need to add the concept of image placements to
the data model maintained by the terminal state and find a way
to efficiently manage placements both by id and by a viewport
range.
The renderer will need to manage separate quads for placements
and order them by z-index, and adjust the render phases so that
images can appear in the correct plane.
refs: #986
Also fixes an issue where only the first frame schedule would
take effect! Surprised this didn't bubble up as a bug with
animated gifs already.
refs: #133
This commit introduces the knowledge about whether a font is
scalable or was using bitmap strikes (eg: color emoji bitmaps).
Then that information is used to help figure out whether and
how to scale a glyph.
refs: https://github.com/wez/wezterm/issues/685
As explained in the docs included in this commit, ideally this
wouldn't be needed, but due to a long-standing hinting bug in
freetype <https://gitlab.freedesktop.org/freetype/freetype/-/issues/761>
it seems most expedient to just render our own block glyphs,
so that's what this does!
refs: #433
This is one of those massive time sinks that I almost regret...
As part of recent changes to dust-off the allsorts shaper, I noticed
that the harfbuzz shaper wasn't shaping as well as the allsorts one.
This commit:
* Adds emoji-test.txt, a text file you can `cat` to see how well
the emoji are shaped and rendered.
* Fixes (or at least, improves) the column width calculation for
combining sequences such as "deaf man" which was previously calculated
at 3 cells in width when it should have just been 2 cells wide, which
resulted in a weird "prismatic" effect during rendering where the
glyph would be rendered with an extra RHS portion of the glyph across
3 cells.
* Improved/simplified the clustering logic used to compute fallbacks.
Previously we could end up with some wonky/disjoint sequence of
undefined glyphs which wouldn't be successfully resolved from a
fallback font. We now make a better effort to consolidate runs of
undefined glyphs for fallback.
* For sequences such as "woman with veil: dark skin tone" that occupy a
single cell, the shaper may return 3 clusters with 3 glyphs in the
case that the font doesn't fully support this grapheme. At render
time we'd just take the last glyph from that sequence and render it,
resulting in eg: a female symbol in this particular case. It is
generally a bit more useful to show the first glyph in the sequence
(eg: person with veil) rather than the gender or skin tone, so the
renderer now checks for this kind of overlapping sequence and renders
only the first glyph from the sequence.
