Two bugs:
- There was an extra `* 4` that caused panic when the Text was clipped
- There was a bug in glyph handling when the text is being split in
several runs
Remove platform glyph abstraction, just use non-zero u16 as glyph index
like everyone else. As a bonus, this reduces the memory consumption of
the glyph buffers per glyph from a size of a pointer to the size of the
u16.
This change makes the test pass without the unicode feature.
Note that it is not possible to run the test without the unicode feature
unless one changes the Cargo.toml, so I did that locally to run the
tests
Separate the text shaping functionality from font metrics by having a
FontMetrics trait next to the TextShaper. AbstractFont is the combining
super trait. This allows eliminating the font height member from
TextParagraphLayout and improving the overall naming of fields and
types.
Finally, this prepares the API for composability of TextShaper for font
fallback handling.
Replace the abstract glyph trait with a glyph struct. That way the text
layout code can operate properly on a struct with fields, instead of on
functions on a trait (some of which returning a mutable reference). The
input is a glyph with offset, advance, etc. - everything needed for the
layout and the output is a position along with the platform specific
glyph data.
Remove the font reference field anymore as it's not needed anymore and
remove the manual clone implementations. Those were needed because
otherwise the TextShaper trait would have to also support clone - as
[derive(Clone)] imposes that. Now we can impose that just on Glyph and
that's easy and makes sense.
