Previous implementation would draw dashes to the edge of the character
cell, which would result in double-wide dashes at the point where they
tiled. This fixes that, and also generally implements it in a cleaner
way than before.
Fixes#1618
Font sizes in configuration were always a u8, but the keybinding and
internal state was a u16 so it allowed for an ever-growing font size. At
a certain point, there is an integer overflow which causes it to wrap
around. This is all silly, 255 should be large enough for anyone[1]
[1]: Ready to be super wrong about this
Up to this point, every font I've experienced with ligatures has
replaced the codepoints that were replaced for combining with a space.
For example, if a font has a ligature for "!=" to turn it into a glyph,
it'd shape to `[not equal glyph, space]`, so it'd still take up two
cells, allowing us to style both.
Monaspace, however, does not do this. It turns "!=" into `[not equal
glyph]` so styles like backgrounds, underlines, etc. were not extending.
This commit detects multi-cell glyphs and inserts synthetic blank cells
so that styling returns. I decided to do this via synthetic blank cells
instead of introducing a `cell_width` to the shaper result because this
simplifies the renderers to assume each shaper cell is one cell. We can
change this later if we need to.
Annoyingly, this does make the shaper slightly slower for EVERYONE to
accomodate one known font that behaves this way. I haven't benchmarked
it but my belief is that the performance impact will be negligible
because to figure out cell width we're only accessing subsequent cells
so they're likely to be in the CPU cache and also 99% of cells are going
to be width 1.
Rather than immediately converting a color palette index into an RGB
value for a cell color, when a palette color is used track the palette
color directly in the cell state and convert to an RGB value in the
renderer.
This causes palette color changes to take effect immediately instead of
only for newly drawn cells.
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.
