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Remove scrolling detection/optimization in terminal output

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Just validate if line changed or not. This should avoid flickering
on terminals such as the linux console that eagerly redraw on line
deletions. Unfortunately this means drawing will use more data and
might add a bit of latency on slow links.

Fixes #4317
Fixes #4320
This commit is contained in:
Maxime Coste 2021-09-09 08:59:26 +10:00
parent 3d8061b975
commit b3a1017a26
1 changed files with 26 additions and 62 deletions
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52
src/terminal_ui.cc
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@ -286,7 +286,7 @@ void TerminalUI::Screen::output(bool force, bool synchronized, Writer& writer)
// iTerm2 "begin synchronized update" sequence // iTerm2 "begin synchronized update" sequence
if (synchronized) if (synchronized)
writer.write("\033P=1s\033\\"); writer.write("\033[?2026h");
if (force) if (force)
{ {
@ -299,52 +299,17 @@ void TerminalUI::Screen::output(bool force, bool synchronized, Writer& writer)
return (hash_value(line.atoms) << 1) | 1; // ensure non-zero return (hash_value(line.atoms) << 1) | 1; // ensure non-zero
}; };
struct Change { int keep; int add; int del; }; for (int line = 0; line < (int)size.line; ++line)
Vector<Change> changes{Change{}};
auto new_hashes = ArrayView{lines.get(), (size_t)size.line} | transform(hash_line);
for_each_diff(hashes.get(), (int)size.line,
new_hashes.begin(), (int)size.line,
[&changes](DiffOp op, int len) mutable {
switch (op)
{ {
case DiffOp::Keep: auto hash = hash_line(lines[line]);
changes.push_back({len, 0, 0}); if (hash == hashes[line])
break; continue;
case DiffOp::Add: hashes[line] = hash;
changes.back().add += len;
break;
case DiffOp::Remove:
changes.back().del += len;
break;
}
});
std::copy(new_hashes.begin(), new_hashes.end(), hashes.get());
int line = 0;
for (auto& change : changes)
{
line += change.keep;
if (int del = change.del - change.add; del > 0)
{
format_with(writer, "\033[{}H\033[{}M", line + 1, del);
line -= del;
}
line += change.del;
}
line = 0;
for (auto& change : changes)
{
line += change.keep;
for (int i = 0; i < change.add; ++i)
{
if (int add = change.add - change.del; i == 0 and add > 0)
format_with(writer, "\033[{}H\033[{}L", line + 1, add);
else
format_with(writer, "\033[{}H", line + 1); format_with(writer, "\033[{}H", line + 1);
ColumnCount pending_move = 0; ColumnCount pending_move = 0;
for (auto& [text, skip, face] : lines[line++].atoms) for (auto& [text, skip, face] : lines[line].atoms)
{ {
if (text.empty() and skip == 0) if (text.empty() and skip == 0)
continue; continue;
@ -365,11 +330,10 @@ void TerminalUI::Screen::output(bool force, bool synchronized, Writer& writer)
writer.write(String{' ', skip}); writer.write(String{' ', skip});
} }
} }
}
// iTerm2 "end synchronized update" sequence // iTerm2 "end synchronized update" sequence
if (synchronized) if (synchronized)
writer.write("\033P=2s\033\\"); writer.write("\033[?2026l");
} }
constexpr int TerminalUI::default_shift_function_key; constexpr int TerminalUI::default_shift_function_key;