Guard against attempts to output glyphs to a sprixelated
plane in ncplane_putc_yx(), the lowest-level common end
of all ncplane_put*() functions. Add unit test #1572.
When we scribble underneath a TRANSPARENT or ANNIHILATED
sprixcell, or even an OPAQUE or MIXED one in Kitty, we
needn't invalidate the sprixel. Perform these checks for
less aggressive invalidation, eliminating the flicker we
were seeing in xray using Kitty. Closes#1522.
Require a known-good TERM heuristic match to enable
quadrants (NCBLIT_2x2); they otherwise decay to halves
(NCBLIT_2x1). The only terminal that supports quadrants
but does not support sextants is the Linux console, where
we program quadrants directly into the font table,
like a beast. Closes#1517, and #1298 if we're lucky.
deprecate ncvisual_geom() in favor of new ncvisual_blitter_geom(), which allows caller to get the blitter used. replace the checks and calculations in ncvisual_render() with a call to ncvisual_blitter_geom(), unifying the two paths (and eliminating several bugs in the unloved ncvisual_geom()).
if we go into ncvisual_render() looking to render a number
of rows not evenly divisible by the scaling factor, we need
to get an extra row (duh). correct ncvisual_render_cell() to
reflect this. the blitters already know to fill this line in
with transparency wherever the image is not defined. fix up
rotation unit tests to reflect this. closes#1513.
this ends up just confusing people more often than it
gets us useful bug reports. indeed, one distribution
disabled our tests because "it says it can't run without
a real tty".
Previously, the quadblitter compared the external two pixels
against the two lerps, and if the closest was closer to the
primary lerp than the secondary, trilerped the closest with
the primary pair. Instead, calculate the total RGB distance,
and for whichever external pixel is closer to the primary
lerp, calculate the trilerp and the new candidate difference.
if the candidate difference is less than the total distance,
select it and perform the trilerp. This improves upon the
"twinkling problem" described in #1354, though it does not
entirely resolve it. Performance change is negligible. Add a
unit test for this change.
nick black
MasFlam