Use z2d to draw the undercurl instead of the manual raster code we had
before- the code was cool but unnecessarily complicated. Plus z2d lets
us have rounded caps on the undercurl which is neat.
Also make sure we won't draw off the canvas with our underlines-- the
canvas has padding but it's not infinite.
Move size adjustment logic out of `Entry`, I understand the impulse to
put it there but it results in passing a lot of stuff around which isn't
great.
Rework `add(...)` in to `add(...)` and `addDeferred(...)`, faces are
passed directly now instead of passing an entry, and an options struct
is used instead of positional arguments for things like style, fallback,
and size adjustment.
Change size adjustment test back to a half pixel tolerance instead of 5%
because the previous commit (allowing fractional pixel sizes) fixed the
root cause of large differences.
We can reintroduce `advance` if we ever want to do proportional string
drawing, but we don't use it anywhere right now. And we also don't need
`sprite` anymore since that was just there to disable constraints for
sprites back when we did them on the GPU.
This was creating problems with the branch drawing glyphs at some sizes.
In the future the whole "foreground modes" thing needs to be reworked,
so this is just a stopgap until that gets turned in to something nicer.
This is a fairly large rework of how we handle the sprite font drawing.
Drawing routines are now context-less, provided only a canvas and some
metrics. There is now a separate file per unicode block / PUA area.
Sprites are now drawn on canvases with an extra quarter-cell of padding
on each edge, and automatically cropped when sent to the atlas, this
allows sprites to extend past cell boundaries which makes it possible to
have, for example, diagonal box drawing characters that connect across
cell diagonals instead of being pinched in.
Most of the sprites the code is just directly ported from the old code,
but I've rewritten a handful. Moving forward, I'd like to rewrite more
of these since the way they're currently written isn't ideal.
This rework, in addition to improving the packing efficiency of sprites
on the atlas, and allowing for out-of-cell drawing, will make it a lot
easier to add new sprites in the future, since all it takes now is to
add a single function and an import (if it's a new file).
I reworked the regression/change testing to be more robust as well, it
now covers all sprite glyphs (except non-codepoint ones) and does so at
4 different sizes. Addition/removal of glyphs will no longer create diff
noise in the generated diff image, since the position in the image of
each glyph is now fixed.
This sets the stage for dynamically adjusting the sizes of fallback
fonts based on the primary font's face metrics. It also removes a lot of
unnecessary work when loading fallback fonts, since we only actually use
the metrics based on the parimary font.
Subsumes #2580 (which has multiple conflicts with main due to recent
changes to metrics); I figured it'd be easier to just implement it this
way.
#2580 claimed to solve #2487 but I don't think it really does- ideally
we can think of a good way to configure each individual cursor type, but
I don't wanna just do something ad hoc and add a bunch of config keys
blindly so I limited the scope of this.
Unify grid metrics calculations by relying on shared logic mostly based
on values directly from the font tables, this deduplicates a lot of code
and gives us more control over how we interpret various metrics.
Also separate metrics for underlined, strikethrough, and overline
thickness and position, and box drawing thickness, so that they can
individually be adjusted as the user desires.
addresses #2561 - adds support for most Git branch drawing characters as
specified in 
except for fading vertical and horizontal lines.
Adds git_draw_node function and a new Git node type.
Add this range (0xf5d0...0xf60d) for Git branch characters, to tests.
adds vline_middle_xy and hline_middle_xy for node connections.
add git characters to Face.zig.
More complete coverage of the Symbols For Legacy Computing block,
including characters from Unicode 16.0.
Pixman and the web canvas impl for Canvas have been removed in favor of
z2d for drawing, since it has a nicer API with more powerful methods,
and is in Zig with no specific platform optimizations so should compile
to wasm no problem.
This adds Powerline rendering for the trapezoid characters (E0D2 and
E0D4).
This is the last of the Powerline additions for now. These are the
shapes that 1) render the most egregiously with stock fonts (off-center,
bleeding background, visible gaps), and 2) are simple enough to be
rendered without resorting to more complex measures like embedding SVG.
Some box codepoints (the cursor) want to use the original font metrics
height but others (corners) want to use the full grid height. I can't
see a better way to do this than manually maintaining a switch here. We
can add codepoints as needed.
This adds in-terminal rendering for the powerline glyphs E0B4 and E0B6,
similar to how we are rendering the triangle shapes currently.
The circle glyphs use a much more complex rendering due to the nuances
of drawing them: we use a midpoint algorithm for drawing on a 4x
supersampled matrix, fill, and then downsample. We use the same
downsampling approach as is done in the arc box drawing code.
The midpoint variant we're using here is described by Dennis Yurichev:
https://yurichev.com/news/20220322_circle/, although there are similar
variants elsewhere (some cited at the bottom of his article).
This adds the Powerline face to our set of built-in faces, which
represents glyphs that are used to draw Powerline-style shell prompts
and status lines.
Since these are used similar to box-drawing characters, alignment is
important, and this gives us the most control in preventing related
artifacts.
This initial commit is scaffolding and support for the various solid
triangles - additional glyphs will come in other commits.
Fixes#675.
