8 Commits

Author SHA1 Message Date
Qwerasd
c66042d6e0 font/sprite: address PR review feedback
- Make canvas geometry primitives generic, use `Rect(u32)` for `rect`
function, so that we don't have to worry about negatives or rounding.
- Make `Quads` struct packed just in case it gets non-comptime use in
the future.
- Clarify comment on why we're discarding out of range pixels + runtime
unreachable for any other type of error which we shouldn't ever see.
- Move z2d import above in-tree imports.
2024-10-15 12:00:11 -04:00
Qwerasd
d38d0f30c4 font/sprite: replace pixman with z2d, extend Box coverage
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.
2024-10-14 17:50:49 -04:00
Qwerasd
10b8ca3c69 spelling: normalize grey -> gray 2024-08-11 18:31:01 -04:00
Chris Marchesi
dfefe953fc Powerline: add trapezoid rendering
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.
2023-12-19 11:36:05 -08:00
Chris Marchesi
c03ae47a27 Powerline: add references for the ellipse algorithm
Further to the additional comments in #1055, this adds some references
to the comments in the ellipse algorithm (including the original
reference for the circle algorithm).
2023-12-12 00:10:40 -08:00
Chris Marchesi
4aa56ab8dd Powerline: Change half-circle algorithm to ellipse
This changes the half-circle drawing algorithm for glyphs E0B4 and E0B6
to an ellipse algorithm.

This fixes a shortcoming in the circle approach - how do you handle
drawing for a box that is not a typical 2:1 H*W? We were trying to
anticipate this by taking the smaller of the two axes and using that for
the radius. This works when there's some error in the zoom and the x
radius somehow becomes larger than the y radius (in observation, this
happens occasionally in some zoom steps, but only slightly).

However, turns out a more realistic anticipation is for fonts that have
a much *larger* height-to-width ratio. Iosevka, for example, has an
approx. 2.6:1 ratio (observed in the inspector). In this instance, this
approach does nothing except lock the circle to an extremely small
radius. For this instance, we need an ellipse, which will handle all
cases in an expected fashion.

Fixes #1050.
2023-12-11 21:01:11 -08:00
Chris Marchesi
d34b5571d8 Powerline: Add half-circle rendering
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).
2023-12-07 22:29:59 -08:00
Chris Marchesi
e0d458004f font/sprite: add Powerline face
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.
2023-11-23 01:29:12 -08:00