together instead of handling them one by one. This is significantly
faster. Sequences are terminated when we reach the end of the line, fill
the internal buffer, or a different character is seen by the input
parser (an escape sequence, or UTF-8).
Rather than writing collected sequences out immediately, hold them until
it is necessary (another screen modification, or we consume all
available data). This means we can discard changes that would have no
effect (for example, lines that would just be scrolled off the screen or
cleared). This reduces the total amount of data we write out to the
terminal - not important for fast terminals, but a big help with slow
(like xterm).
sequences (notable EL and ED but also IL, DL, ICH, DCH) create blank
cells using the current background colour rather than the default
colour.
On modern systems BCE doesn't really have many benefits, but most other
terminals now support it, some (lazy) applications rely on it, and it is
not hard to include now that we have pane background colours anyway.
Mostly written by Sean Haugh.
the end of the source, but it was wrong and causes problems that are
only showing up now we are more aggressive about skipping redundant
screen updates. Remove the optimization entirely as more trouble than it
is worth to fix (and it'll have to go when BCE is done anyway).
instead track them as change (dirty) and update them once at the end,
saves much time if repeatedly writing the same cell. Also fix comparison
of cells being equal in a few places (memcmp is not enough).
poor idea that was fairly quickly replaced by SGR mouse input (which is
now widespread). It is impossible to tell the difference between UTF-8
and non-UTF-8 mouse input; since the mouse-utf8 option was removed tmux
has not handled it correctly in any case; and it is ridiculous to have
three different forms of mouse input.
of storing a full grid_cell with UTF-8 data and everything, store a new
type grid_cell_entry. This can either be the cell itself (for ASCII
cells), or an offset into an extended array (per line) for UTF-8
data.
This avoid a large (8 byte) overhead on non-UTF-8 cells (by far the
majority for most users) without the complexity of the shadow array we
had before. Grid memory without any UTF-8 is about half.
The disadvantage that cells can no longer be modified in place and need
to be copied out of the grid and back but it turned out to be lot less
complicated than I expected.
