Decide whether to highlight the visual-selected character under the
cursor, depending on 'guicursor' style:
- Highlight if cursor is blinking or non-block (vertical, horiz).
- Do NOT highlight if cursor is non-blinking block.
Traditionally Vim's visual selection does "reverse mode", which perhaps
conflicts with the non-blinking block cursor. But 'guicursor' defaults
to a vertical bar for selection=exclusive, and this confuses users who
expect to see the text highlighted.
closes#8983
Note about shada.c:
- shada_read_next_item_start was intentionally shadowing `unpacked` and
`i` because many of the macros (e.g. ADDITIONAL_KEY) implicitly
depended on those variable names.
- Macros were changed to parameterize `unpacked` (but not `i`). Macros
like CLEAR_GA_AND_ERROR_OUT do control-flow (goto), so any other
approach is messy.
Problem: Segfault when pattern with \z() is very slow.
Solution: Check for NULL regprog. Add "nfa_fail" to test_override() to be
able to test this. Fix that 'searchhl' resets called_emsg.
bcf9442307closes#8788
- TUI: _never_ rely on BCE for implicit clearing, only explicit commands.
- TUI: use unibi_erase_chars when possible.
- TUI: use end-exclusive ranges for invalid and cleared areas
- screen: scrolling leaves scrolled in aree undefined. This is a
conservative change, a client assuming the old semantics will still
behave correctly.
- screen: factor out vsep handling from line drawing. This is needed
anyway for the multigrid refactor.
- screen: simplifications of win_do_lines
Avoid clearing the screen in most situations. NOT_VALID should be
equivalent to CLEAR unless some external force messed up the terminal,
for these situations <c-l> and :mode will still clear the screen.
Also eliminate some obsolete code in screen.c, that dealt with that in
vim drawing window 1 can mess up window 2, but this never happens in
nvim.
But what about slow terminals? There is two common meanings in which
a terminal is said to be "slow":
Most commonly (and in the sense of vim:s nottyfast) it means low
bandwidth for sending bytes from nvim to the terminal. If the screen is
very similar before and after the update_screen(CLEAR) this change
should reduce bandwidth. If the screen is quite different, but there is
no new regions of contiguous whitespace, clearing doesn't reduce
bandwidth significantly. If the new screen contains a lot of whitespace,
it will depend of if vsplits are used or not: as long as there is no
vsplits, ce is used to cheaply clear the rest of the line, so
full-screen clear is not needed to reduce bandwith. However a left
vsplit currently needs to be padded with whitespace all the way to the
separator. It is possible ec (clear N chars) can be used to reduce
bandwidth here if this is a problem. (All of this assumes that one
doesn't set Normal guibg=... on a non-BCE terminal, if you do you are
doomed regardless of this change).
Slow can also mean that drawing pixels on the screen is slow. E-ink
screens is a recent example. Avoiding clearing and redrawing the
unchanged part of the screen will always improve performance in these
cases.
The statusline may incorporate b:term_title, so redraw it when that
title changes.
Introduce a new function status_redraw_buf to redraw windows associated
with the current buffer.
Vim :! may "mess up the screen" because of e.g. switching between cooked
mode, but Nvim just uses pipes. So maybe we can avoid these
redraw_later_clear() CYA calls.
