ladybird/Userland/Libraries/LibVT/Line.cpp
Daniel Bertalan 7419569a2b Kernel+LibVT: Add function for deleting a range of characters
Previously, this was done by telling the client to put a space at each
character in the range. This was inefficient, because a large number of
function calls took place and incorrect, as the ANSI standard dictates
that character attributes should be cleared as well.

The newly added `clear_in_line` function solves this issue. It performs
just one bounds check when it's called and can be implemented as a
pretty tight loop.
2021-06-10 17:18:02 +02:00

53 lines
1.2 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibVT/Line.h>
namespace VT {
Line::Line(size_t length)
{
set_length(length);
}
Line::~Line()
{
}
void Line::set_length(size_t new_length)
{
size_t old_length = length();
if (old_length == new_length)
return;
m_cells.resize(new_length);
}
void Line::clear_range(size_t first_column, size_t last_column, const Attribute& attribute)
{
VERIFY(first_column <= last_column);
VERIFY(last_column < m_cells.size());
for (size_t i = first_column; i <= last_column; ++i) {
auto& cell = m_cells[i];
if (!m_dirty)
m_dirty = cell.code_point != ' ' || cell.attribute != attribute;
cell = Cell { .code_point = ' ', .attribute = attribute };
}
}
bool Line::has_only_one_background_color() const
{
if (!length())
return true;
// FIXME: Cache this result?
auto color = attribute_at(0).effective_background_color();
for (size_t i = 1; i < length(); ++i) {
if (attribute_at(i).effective_background_color() != color)
return false;
}
return true;
}
}