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LibWeb: Add partial implementation of border conflict resolution

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Fix handling of border style specified per column as well.
This commit is contained in:
Andi Gallo 2023-06-04 14:21:20 +00:00 • committed by Andreas Kling
parent 6c2712764d
commit 8090adf268
9 changed files with 282 additions and 16 deletions
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151
Userland/Libraries/LibWeb/Layout/TableFormattingContext.cpp
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@ -7,6 +7,7 @@
#include <LibWeb/DOM/Node.h>
#include <LibWeb/HTML/BrowsingContext.h>
#include <LibWeb/HTML/HTMLTableCellElement.h>
#include <LibWeb/HTML/HTMLTableColElement.h>
#include <LibWeb/Layout/BlockFormattingContext.h>
#include <LibWeb/Layout/Box.h>
#include <LibWeb/Layout/InlineFormattingContext.h>
@ -161,11 +162,10 @@ void TableFormattingContext::compute_table_measures()
CSSPixels padding_left = computed_values.padding().left().to_px(cell.box, width_of_containing_block);
CSSPixels padding_right = computed_values.padding().right().to_px(cell.box, width_of_containing_block);
auto is_left_most_cell = cell.column_index == 0;
auto is_right_most_cell = cell.column_index == m_columns.size() - 1;
auto should_hide_borders = cell.box->computed_values().border_collapse() == CSS::BorderCollapse::Collapse;
CSSPixels border_left = should_hide_borders && !is_left_most_cell ? 0 : computed_values.border_left().width;
CSSPixels border_right = should_hide_borders && !is_right_most_cell ? 0 : computed_values.border_right().width;
auto const& cell_state = m_state.get(cell.box);
auto is_collapse = cell.box->computed_values().border_collapse() == CSS::BorderCollapse::Collapse;
CSSPixels border_left = is_collapse ? cell_state.border_left : computed_values.border_left().width;
CSSPixels border_right = is_collapse ? cell_state.border_right : computed_values.border_right().width;
CSSPixels width = computed_values.width().to_px(cell.box, width_of_containing_block);
auto cell_intrinsic_offsets = padding_left + padding_right + border_left + border_right;
@ -499,16 +499,12 @@ void TableFormattingContext::compute_table_height(LayoutMode layout_mode)
cell_state.padding_left = cell.box->computed_values().padding().left().to_px(cell.box, width_of_containing_block);
cell_state.padding_right = cell.box->computed_values().padding().right().to_px(cell.box, width_of_containing_block);
auto is_top_most_cell = cell.row_index == 0;
auto is_left_most_cell = cell.column_index == 0;
auto is_right_most_cell = cell.column_index == m_columns.size() - 1;
auto is_bottom_most_cell = cell.row_index == m_rows.size() - 1;
auto should_hide_borders = cell.box->computed_values().border_collapse() == CSS::BorderCollapse::Collapse;
cell_state.border_top = (should_hide_borders && is_top_most_cell) ? 0 : cell.box->computed_values().border_top().width;
cell_state.border_bottom = (should_hide_borders && is_bottom_most_cell) ? 0 : cell.box->computed_values().border_bottom().width;
cell_state.border_left = (should_hide_borders && is_left_most_cell) ? 0 : cell.box->computed_values().border_left().width;
cell_state.border_right = (should_hide_borders && is_right_most_cell) ? 0 : cell.box->computed_values().border_right().width;
if (cell.box->computed_values().border_collapse() == CSS::BorderCollapse::Separate) {
cell_state.border_top = cell.box->computed_values().border_top().width;
cell_state.border_bottom = cell.box->computed_values().border_bottom().width;
cell_state.border_left = cell.box->computed_values().border_left().width;
cell_state.border_right = cell.box->computed_values().border_right().width;
}
auto cell_computed_height = cell.box->computed_values().height();
if (cell_computed_height.is_length()) {
@ -744,6 +740,84 @@ void TableFormattingContext::position_cell_boxes()
}
}
static const CSS::BorderData& winning_border_style(const CSS::BorderData& a, const CSS::BorderData& b)
{
// Implements steps 1, 2 and 3 of border conflict resolution algorithm.
static HashMap<CSS::LineStyle, unsigned> const line_style_score = {
{ CSS::LineStyle::Inset, 0 },
{ CSS::LineStyle::Groove, 1 },
{ CSS::LineStyle::Outset, 2 },
{ CSS::LineStyle::Ridge, 3 },
{ CSS::LineStyle::Dotted, 4 },
{ CSS::LineStyle::Dashed, 5 },
{ CSS::LineStyle::Solid, 6 },
{ CSS::LineStyle::Double, 7 },
};
if (a.line_style == CSS::LineStyle::Hidden) {
return a;
}
if (b.line_style == CSS::LineStyle::Hidden) {
return b;
}
if (a.line_style == CSS::LineStyle::None) {
return b;
}
if (b.line_style == CSS::LineStyle::None) {
return a;
}
if (a.width > b.width) {
return a;
} else if (a.width < b.width) {
return b;
}
if (*line_style_score.get(a.line_style) > *line_style_score.get(b.line_style)) {
return a;
} else if (*line_style_score.get(a.line_style) < *line_style_score.get(b.line_style)) {
return b;
}
return a;
}
void TableFormattingContext::border_conflict_resolution()
{
// Partially implements border conflict resolution, as described in
// https://www.w3.org/TR/CSS22/tables.html#border-conflict-resolution
BorderConflictFinder finder(this);
for (auto& cell : m_cells) {
if (cell.box->computed_values().border_collapse() == CSS::BorderCollapse::Separate) {
continue;
}
// Execute steps 1, 2 and 3 of the algorithm for each edge.
Painting::BordersData override_borders_data;
auto const& cell_style = cell.box->computed_values();
auto& cell_state = m_state.get_mutable(cell.box);
for (auto const conflicting_element : finder.conflicting_elements(cell, ConflictingEdge::Left)) {
auto const& other_style = conflicting_element->computed_values();
override_borders_data.left = winning_border_style(cell_style.border_left(), other_style.border_left());
cell_state.border_left = override_borders_data.left.width;
}
for (auto const conflicting_element : finder.conflicting_elements(cell, ConflictingEdge::Right)) {
auto const& other_style = conflicting_element->computed_values();
override_borders_data.right = winning_border_style(cell_style.border_right(), other_style.border_right());
cell_state.border_right = override_borders_data.right.width;
}
for (auto const conflicting_element : finder.conflicting_elements(cell, ConflictingEdge::Top)) {
auto const& other_style = conflicting_element->computed_values();
override_borders_data.top = winning_border_style(cell_style.border_top(), other_style.border_top());
cell_state.border_top = override_borders_data.top.width;
}
for (auto const conflicting_element : finder.conflicting_elements(cell, ConflictingEdge::Bottom)) {
auto const& other_style = conflicting_element->computed_values();
override_borders_data.bottom = winning_border_style(cell_style.border_bottom(), other_style.border_bottom());
cell_state.border_bottom = override_borders_data.bottom.width;
}
// FIXME: 4. If border styles differ only in color, then a style set on a cell wins over one on a row, which wins over a
// row group, column, column group and, lastly, table. When two elements of the same type conflict, then the one
// further to the left (if the table's 'direction' is 'ltr'; right, if it is 'rtl') and further to the top wins.
cell_state.set_override_borders_data(override_borders_data);
}
}
CSSPixels TableFormattingContext::compute_row_content_height(Cell const& cell) const
{
auto& row_state = m_state.get(m_rows[cell.row_index].box);
@ -771,6 +845,51 @@ CSSPixels TableFormattingContext::compute_row_content_height(Cell const& cell) c
return span_height;
}
TableFormattingContext::BorderConflictFinder::BorderConflictFinder(TableFormattingContext const* context)
: m_context(context)
{
collect_conflicting_col_elements();
}
void TableFormattingContext::BorderConflictFinder::collect_conflicting_col_elements()
{
m_col_elements_by_index.resize(m_context->m_columns.size());
for (auto* child = m_context->table_box().first_child(); child; child = child->next_sibling()) {
if (!child->display().is_table_column_group()) {
continue;
}
size_t column_index = 0;
for (auto* child_of_column_group = child->first_child(); child_of_column_group; child_of_column_group = child_of_column_group->next_sibling()) {
VERIFY(child_of_column_group->display().is_table_column());
auto const& col_node = static_cast<HTML::HTMLTableColElement const&>(*child_of_column_group->dom_node());
unsigned span = col_node.attribute(HTML::AttributeNames::span).to_uint().value_or(1);
for (size_t i = column_index; i < column_index + span; ++i) {
m_col_elements_by_index[i] = child_of_column_group;
}
column_index += span;
}
}
}
Vector<Node const*> TableFormattingContext::BorderConflictFinder::conflicting_elements(Cell const& cell, TableFormattingContext::ConflictingEdge edge) const
{
// FIXME: Conflicting elements can be cells, rows, row groups, columns, column groups, and the table itself,
// but we only consider 'col' elements in a 'colgroup', the table and the cell itself for now.
Vector<Node const*> result = { cell.box };
auto is_top = cell.row_index == 0;
auto is_left = cell.column_index == 0;
auto is_right = cell.column_index == m_context->m_columns.size() - 1;
auto is_bottom = cell.row_index == m_context->m_rows.size() - 1;
auto conflicts_top_or_bottom = (is_top && edge == ConflictingEdge::Top) || (is_bottom && edge == ConflictingEdge::Bottom);
if (conflicts_top_or_bottom || (is_left && edge == ConflictingEdge::Left) || (is_right && edge == ConflictingEdge::Right)) {
result.append(&m_context->table_box());
}
if (m_col_elements_by_index[cell.column_index] && (conflicts_top_or_bottom || edge == ConflictingEdge::Left || edge == ConflictingEdge::Right)) {
result.append(m_col_elements_by_index[cell.column_index]);
}
return result;
}
void TableFormattingContext::run(Box const& box, LayoutMode layout_mode, AvailableSpace const& available_space)
{
m_available_space = available_space;
@ -782,6 +901,8 @@ void TableFormattingContext::run(Box const& box, LayoutMode layout_mode, Availab
// Determine the number of rows/columns the table requires.
calculate_row_column_grid(box);
border_conflict_resolution();
// Compute the minimum width of each column.
compute_table_measures();