Add `notcurses_check_pixel_support()` and
`ncdirect_check_pixel_support()` per #1367. Removes
NCOPTION_VERIFY_SIXEL, again per #1367. Adds
`free_terminfo_cache()`, and calls it from both
`notcurses_stop_minimal()` and `ncdirect_stop()`.
Update all documentation. Closes#1371 and #1367.
Looks like the release process used a regex(?) to replace that included some
unintended targets. Microsoft link broke in 2.2.0; CELL_ALPHA_TRANSPARENT
continually replaced since 2.0.1.
Extract Curses differences and adaptation sections, and
move them to doc/CURSES.md. Reference this new document
in README.md. We now have sufficiently few sections that
we can dispense with the ToC. Do so.
Eliminate NCDIRECT_OPTION_NO_READLINE (it was only introduced in
Notcurses 2.1.6). Add a new function, ncdirect_readline(). Upon
first call to this function, initialize libreadline. Destroy
libreadline in ncdirect_stop() iff we initialized it. Add
hilodirect guessing game PoC from #1325. Rename
notcurses_directmode.3 to notcurses_direct.3. Closes#1326.
Implement channels_set_fg_palindex() and channels_set_bg_palindex()
in terms of channel_set_palindex(). Add missing entries to
notcurses_channels.3 man page. Use uint32_t in place of unsigned
when dealing with channels in notcurses.h.
This completes the work for #1068. This addressed a subtle issue.
When we're using pixel->semigraphic art, we want slightly different
rendering. Essentially, imagine that we have two images, each two
pixels tall and one pixel wide. The top image is a transparent pixel
above a white pixel. The bottom image is a white pixel above a black
pixel. We'd expect the result to be two white pixels, but we can
instead get a black pixel above a white pixel. This is because the
*background* color is being merged from the bottom plane, but really
we want the *top* color. Ncvisuals are now blitted along with
information regarding which quadrants they draw over, and when
appropriate, we invert the foreground and background. Closes#1068.
