Increases code reuse between encoder and decoder a tiny bit.
No behavior change.
(We should use the vectorized version in the future! But first,
we should learn to do the prediction in-place.)
The differencing predictor is a different way to encode pixels in TIFF
images. Every pixel is encoded as a difference with the previous column
of the image, except the first column, obviously.
This parameter is materialized by a new tag for which reading was also
implemented.
Previously, it was possible for a `TextDescriptionTagData` object with
an incorrect Macintosh ScriptCode description length to cause a buffer
overflow.
Add two new members to Font::AllowInexactMatch: Larger and Smaller.
This allows callers of FontDatabase::get to specify if they want to
prefer a larger or smaller font in the event of a tie.
Read the basic lists as spans, and use those when looking for kerning.
Kerning lookup still does bit-casting for now. As for CBLC, the data is
a bit complicated.
A few closely-related changes:
- Move our definitions of the OpenType spec's "data types" into their
own header file.
- Add definitions for the integer types there too, for completeness.
(Plus Uint16 matches the spec term, and is less verbose than
BigEndian<u16>.)
- Include Traits for the non-BigEndian types so that we can read them
from Streams. (BigEndian<integer-type> already has this.)
- Use the integer types in our struct definitions.
As a bonus, this fixes a bug in Hmtx, which read the left-side bearings
as i16 instead of BigEndian<i16>.
Do more checks at load time, including categorizing the subtables and
producing our own directory of them.
The format for Kern is a little complicated, so use a Stream instead of
manual offsets.
Maxp had the shared fields duplicated, and OS2 embedded each version's
struct in the next. Instead, let's use inheritance to avoid duplicating
shared fields while still allowing them to be directly accessed.
While I'm at it, rename the Maxp and GPOS table structs to just be
VersionX_Y, because they're not ambiguous with anything else.
LibGfx: Rename GPOSHeader to HeaderVersion1_0
Because there's a version 1.1 as well, which we'll eventually want to
support.
At first glance this looks like it holds the memory that the various
slices point into... but it actually doesn't own that memory. Nobody
uses m_buffer, so it serves no purpose.
Some of these are odd sizes. We managed not to insert padding because
BigEndian is itself marked as packed, but let's be explicit instead of
relying on that. :^)
