ladybird/Libraries/LibWeb/Layout/TableGrid.cpp

108 lines
3.8 KiB
C++

/*
* Copyright (c) 2023, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibWeb/HTML/HTMLTableCellElement.h>
#include <LibWeb/HTML/HTMLTableColElement.h>
#include <LibWeb/Layout/TableGrid.h>
namespace Web::Layout {
TableGrid TableGrid::calculate_row_column_grid(Box const& box, Vector<Cell>& cells, Vector<Row>& rows)
{
// Implements https://html.spec.whatwg.org/multipage/tables.html#forming-a-table
TableGrid table_grid;
size_t x_width = 0, y_height = 0;
size_t x_current = 0, y_current = 0;
size_t max_cell_x = 0, max_cell_y = 0;
// Implements https://html.spec.whatwg.org/multipage/tables.html#algorithm-for-processing-rows
auto process_row = [&](auto& row) {
if (y_height == y_current)
y_height++;
x_current = 0;
for (auto* child = row.first_child(); child; child = child->next_sibling()) {
if (child->display().is_table_cell()) {
// Cells: While x_current is less than x_width and the slot with coordinate (x_current, y_current) already has a cell assigned to it, increase x_current by 1.
while (x_current < x_width && table_grid.m_occupancy_grid.contains(GridPosition { x_current, y_current }))
x_current++;
Box const* box = static_cast<Box const*>(child);
if (x_current == x_width)
x_width++;
size_t colspan = 1, rowspan = 1;
if (box->dom_node() && is<HTML::HTMLTableCellElement>(*box->dom_node())) {
auto const& node = static_cast<HTML::HTMLTableCellElement const&>(*box->dom_node());
colspan = node.col_span();
rowspan = node.row_span();
}
if (x_width < x_current + colspan)
x_width = x_current + colspan;
if (y_height < y_current + rowspan)
y_height = y_current + rowspan;
for (size_t y = y_current; y < y_current + rowspan; y++)
for (size_t x = x_current; x < x_current + colspan; x++)
table_grid.m_occupancy_grid.set(GridPosition { x, y }, true);
cells.append(Cell { *box, x_current, y_current, colspan, rowspan });
max_cell_x = max(x_current, max_cell_x);
max_cell_y = max(y_current, max_cell_y);
x_current += colspan;
}
}
rows.append(Row { row });
y_current++;
};
auto process_col_group = [&](auto& col_group) {
auto dom_node = col_group.dom_node();
dom_node->template for_each_in_subtree_of_type<HTML::HTMLTableColElement>([&](auto&) {
x_width += 1;
return TraversalDecision::Continue;
});
};
for_each_child_box_matching(box, is_table_column_group, [&](auto& column_group_box) {
process_col_group(column_group_box);
});
for_each_child_box_matching(box, is_table_row_group, [&](auto& row_group_box) {
for_each_child_box_matching(row_group_box, is_table_row, [&](auto& row_box) {
process_row(row_box);
return IterationDecision::Continue;
});
});
for_each_child_box_matching(box, is_table_row, [&](auto& row_box) {
process_row(row_box);
return IterationDecision::Continue;
});
table_grid.m_column_count = x_width;
for (auto& cell : cells) {
// Clip spans to the end of the table.
cell.row_span = min(cell.row_span, rows.size() - cell.row_index);
cell.column_span = min(cell.column_span, table_grid.m_column_count - cell.column_index);
}
return table_grid;
}
TableGrid TableGrid::calculate_row_column_grid(Box const& box)
{
Vector<Cell> cells;
Vector<Row> rows;
return calculate_row_column_grid(box, cells, rows);
}
}