ladybird/Userland/Libraries/LibVT/Line.cpp
2022-04-01 21:24:45 +01:00

146 lines
4.8 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibVT/Line.h>
namespace VT {
Line::Line(size_t length)
{
set_length(length);
}
void Line::rewrap(size_t new_length, Line* next_line, CursorPosition* cursor, bool cursor_is_on_next_line)
{
size_t old_length = length();
if (old_length == new_length)
return;
// Drop the empty cells
if (m_terminated_at.has_value() && m_cells.size() > m_terminated_at.value())
m_cells.remove(m_terminated_at.value(), m_cells.size() - m_terminated_at.value());
if (!next_line)
return set_length(new_length);
if (old_length < new_length)
take_cells_from_next_line(new_length, next_line, cursor_is_on_next_line, cursor);
else
push_cells_into_next_line(new_length, next_line, cursor_is_on_next_line, cursor);
}
void Line::set_length(size_t new_length)
{
m_cells.resize(new_length);
if (m_terminated_at.has_value())
m_terminated_at = min(*m_terminated_at, new_length);
}
void Line::push_cells_into_next_line(size_t new_length, Line* next_line, bool cursor_is_on_next_line, CursorPosition* cursor)
{
if (is_empty())
return;
if (length() <= new_length)
return;
// Push as many cells as _wouldn't_ fit into the next line.
auto cells_to_preserve = !next_line->m_terminated_at.has_value() && next_line->is_empty() ? 0 : m_terminated_at.value_or(0);
auto preserved_cells = max(new_length, cells_to_preserve);
auto cells_to_push_into_next_line = length() - preserved_cells;
if (!cells_to_push_into_next_line)
return;
if (next_line->m_terminated_at.has_value())
next_line->m_terminated_at = next_line->m_terminated_at.value() + cells_to_push_into_next_line;
if (m_terminated_at.has_value() && cells_to_preserve == 0) {
m_terminated_at.clear();
if (!next_line->m_terminated_at.has_value())
next_line->m_terminated_at = cells_to_push_into_next_line;
}
if (cursor) {
if (cursor_is_on_next_line) {
cursor->column += cells_to_push_into_next_line;
} else if (cursor->column >= preserved_cells) {
cursor->row++;
cursor->column = cursor->column - preserved_cells;
}
}
MUST(next_line->m_cells.try_prepend(m_cells.span().slice_from_end(cells_to_push_into_next_line).data(), cells_to_push_into_next_line));
m_cells.remove(m_cells.size() - cells_to_push_into_next_line, cells_to_push_into_next_line);
if (m_terminated_at.has_value())
m_terminated_at = m_terminated_at.value() - cells_to_push_into_next_line;
}
void Line::take_cells_from_next_line(size_t new_length, Line* next_line, bool cursor_is_on_next_line, CursorPosition* cursor)
{
// Take as many cells as would fit from the next line
if (m_terminated_at.has_value())
return;
if (length() >= new_length)
return;
auto cells_to_grab_from_next_line = min(new_length - length(), next_line->length());
auto clear_next_line = false;
if (next_line->m_terminated_at.has_value()) {
if (cells_to_grab_from_next_line >= *next_line->m_terminated_at) {
m_terminated_at = length() + *next_line->m_terminated_at;
next_line->m_terminated_at.clear();
clear_next_line = true;
} else {
next_line->m_terminated_at = next_line->m_terminated_at.value() - cells_to_grab_from_next_line;
}
}
if (cells_to_grab_from_next_line) {
if (cursor && cursor_is_on_next_line) {
if (cursor->column <= cells_to_grab_from_next_line) {
cursor->row--;
cursor->column += m_cells.size();
} else {
cursor->column -= cells_to_grab_from_next_line;
}
}
MUST(m_cells.try_append(next_line->m_cells.data(), cells_to_grab_from_next_line));
next_line->m_cells.remove(0, cells_to_grab_from_next_line);
}
if (clear_next_line)
next_line->m_cells.clear();
}
void Line::clear_range(size_t first_column, size_t last_column, Attribute const& 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;
}
}