The ncvisual can't own the sprixel -- we could very well
blit it twice to two different planes, wipe cells from one
and not the other, and not want those shared. Instead, it's
owned by the plane. This clears up the ownership/lifetime
story quite a bit, and closes#1548, where only the most
recent of several blittings of a sprixel was visible.
* [bitmap] on move, clear old OPAQUE cells #1527
* update ncvisual_blitter_geom() documentation #1547
* replace some ncvisual_blitter_geom with NCVISUAL_OPTION_VERALIGNED
* [normal] replace ncvisual_blitter_geom with NCVISUAL_OPTION_VERALIGNED
* [intro] use ncvisual_blitter_geom() correctly #1547
* ncvisual_blitter_geom: only set *blitter on success
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.
In Sixel, we map the alpha value to either 0 or 255, as
it has no alpha concept. Kitty can freely reproduce eight
bits of alpha, so go ahead and use them. Improves image
quality of translucent bitmaps in Kitty at the expense of
some behavioral divergence depending on bitmap backend.
Sixel: detect SPRIXCELL_TRANSPARENT cells and mark them as such.
sprixel_invalidate: fix copy-and-paste, want both TRANSPARENT and
ANNIHILATED to block progression to INVALIDATED. add gigantic
comment detailing the state machine. #1537, #1522, #1527, #1483.
When the damaged cell of a sprixel is actually entirely
transparent (or annihilated), there's no need to invalidate
it. Check for this in the TAM in sprixel_invalidate(). Good
optimization, and eliminates a lot of the flicker in `xray`
on Kitty described in #1522.
joseLuís
nick black