Keycap emoji, for example, begin with ASCII digits. Instead, check the
first code point for the Emoji Unicode property.
On a profile of scrolling around on the welcome page in the Browser,
this raises the runtime percentage of Font::glyph_or_emoji_width from
about 0.8% to 1.3%.
On a profile of scrolling around on the welcome page in the Browser,
this drops the runtime percentage of Font::glyph_or_emoji_width from
about 70% to 0.8%.
For example, consider the Pirate Flag emoji, which is the code point
sequence U+1F3F4 U+200D U+2620 U+FE0F. Our current emoji resolution does
not consider U+200D (Zero Width Joiner) as part of an emoji sequence.
Therefore fonts like Katica, which have a glyph for U+1F3F4, will draw
that glyph without checking if we have an emoji bitmap.
This removes some hard-coded code points and consults the UCD's code
point properties for emoji sequence components and variation selectors.
This recognizes the ZWJ code point as part of an emoji sequence.
Currently, we compute the width of text one code point at a time. This
ignores grapheme clusters (emoji in particular). One effect of this is
when highlighting a multi-code point emoji. We will errantly increase
the highlight rect to the sum of all code point widths, rather than
just the width of the resolved emoji bitmap.
In other words: only consider coefficient of the current scan when
adding coefficients to a macroblock. Information about which
coefficients are present in the stream are passed through the spectral
information in the context.
In progressive mode, this functions will need to be called multiple time
on the same macroblocks, so it shouldn't create the vector every
time it's called.
This means that we should read markers in a loop instead of quiting on
the first scan. This is useless for now as `SOF0` frames only have one
scan, but this is a step forward `SOF2` support.
As a JPEG file can contain multiples scans, we should return from
`scan_huffman_stream` on all new markers (except restart markers) and
not only `JPEG_EOI`.
Miscellaneous and tables segments can also be placed between scans,
placing this code in a function will allow us to avoid duplication when
we get there.
While returning the same image is a cute optimization, it violates the
expectation that the returned Bitmap is a new bitmap, not shared with
anyone else.
Rename "reset_marker" to "restart_marker" as described by the spec. It
also concerns disambiguate the situation as the DRI was also called a
reset marker.
It only implements serialization of the 7-bit ASCII string, not yet
serialization of the UCS-2 and Macintosh ScriptCode strings.
With this, matrix-based v2 profiles can be reencoded :^)
The initial signs were wrong for the deltas of f(x), the ellipse
equation. This seemed to be fine for larger circles/ellipses but
broke things at a small scale, this was previously fixed with a
horrible "error = error / 4" hack. With this change, all ellipses
look a little better :^)
This also fixed a signed integer overflow Andreas found with UBSAN,
which happened for circles with a 1px radius.
