LibWeb: Add border box top/bottom metrics to line box fragments

This will allow us to support more kinds of vertical alignment.

Userland/Libraries/LibWeb/Layout/FormattingContext.cpp

@@ -219,8 +219,12 @@ float FormattingContext::compute_auto_height_for_block_level_element(FormattingS
  top = 0;
  if (!line_boxes.is_empty()) {
  for (auto& fragment : line_boxes.last().fragments()) {
- if (!bottom.has_value() || (fragment.offset().y() + fragment.height()) > bottom.value())
- bottom = fragment.offset().y() + fragment.height();
+ float fragment_top = fragment.offset().y() - fragment.border_box_top();
+ if (!top.has_value() || fragment_top < *top)
+ top = fragment_top;
+ float fragment_bottom = fragment.offset().y() + fragment.height() + fragment.border_box_bottom();
+ if (!bottom.has_value() || fragment_bottom > *bottom)
+ bottom = fragment_bottom;
  }
  }
  } else {

Userland/Libraries/LibWeb/Layout/InlineFormattingContext.cpp

@@ -90,7 +90,7 @@ void InlineFormattingContext::run(Box const&, LayoutMode layout_mode)
  for (auto& line_box : m_state.get(containing_block()).line_boxes) {
  float max_height = min_line_height;
  for (auto& fragment : line_box.fragments()) {
- max_height = max(max_height, fragment.height());
+ max_height = max(max_height, fragment.border_box_height());
  }
  max_line_width = max(max_line_width, line_box.width());
  content_height += max_height;

Userland/Libraries/LibWeb/Layout/LineBox.cpp

@@ -15,7 +15,7 @@
 
 namespace Web::Layout {
 
-void LineBox::add_fragment(Node const& layout_node, int start, int length, float leading_size, float trailing_size, float content_width, float content_height, LineBoxFragment::Type fragment_type)
+void LineBox::add_fragment(Node const& layout_node, int start, int length, float leading_size, float trailing_size, float content_width, float content_height, float border_box_top, float border_box_bottom, LineBoxFragment::Type fragment_type)
 {
  bool text_align_is_justify = layout_node.computed_values().text_align() == CSS::TextAlign::Justify;
  if (!text_align_is_justify && !m_fragments.is_empty() && &m_fragments.last().layout_node() == &layout_node) {
@@ -24,7 +24,7 @@ void LineBox::add_fragment(Node const& layout_node, int start, int length, float
  m_fragments.last().m_length = (start - m_fragments.last().m_start) + length;
  m_fragments.last().set_width(m_fragments.last().width() + content_width);
  } else {
- m_fragments.append(make<LineBoxFragment>(layout_node, start, length, Gfx::FloatPoint(m_width + leading_size, 0.0f), Gfx::FloatSize(content_width, content_height), fragment_type));
+ m_fragments.append(make<LineBoxFragment>(layout_node, start, length, Gfx::FloatPoint(m_width + leading_size, 0.0f), Gfx::FloatSize(content_width, content_height), border_box_top, border_box_bottom, fragment_type));
  }
  m_width += content_width + leading_size + trailing_size;
 

Userland/Libraries/LibWeb/Layout/LineBox.h

@@ -18,7 +18,7 @@ class LineBox {
 
  float width() const { return m_width; }
 
- void add_fragment(Node const& layout_node, int start, int length, float leading_size, float trailing_size, float content_width, float content_height, LineBoxFragment::Type = LineBoxFragment::Type::Normal);
+ void add_fragment(Node const& layout_node, int start, int length, float leading_size, float trailing_size, float content_width, float content_height, float border_box_top, float border_box_bottom, LineBoxFragment::Type = LineBoxFragment::Type::Normal);
 
  const NonnullOwnPtrVector<LineBoxFragment>& fragments() const { return m_fragments; }
  NonnullOwnPtrVector<LineBoxFragment>& fragments() { return m_fragments; }

Userland/Libraries/LibWeb/Layout/LineBoxFragment.h

@@ -23,12 +23,14 @@ class LineBoxFragment : public Weakable<LineBoxFragment> {
  Trailing,
  };
 
- LineBoxFragment(Node const& layout_node, int start, int length, const Gfx::FloatPoint& offset, const Gfx::FloatSize& size, Type type)
+ LineBoxFragment(Node const& layout_node, int start, int length, Gfx::FloatPoint const& offset, Gfx::FloatSize const& size, float border_box_top, float border_box_bottom, Type type)
  : m_layout_node(layout_node)
  , m_start(start)
  , m_length(length)
  , m_offset(offset)
  , m_size(size)
+ , m_border_box_top(border_box_top)
+ , m_border_box_bottom(border_box_bottom)
  , m_type(type)
  {
  }
@@ -48,6 +50,10 @@ class LineBoxFragment : public Weakable<LineBoxFragment> {
  float width() const { return m_size.width(); }
  float height() const { return m_size.height(); }
 
+ float border_box_height() const { return m_border_box_top + height() + m_border_box_bottom; }
+ float border_box_top() const { return m_border_box_top; }
+ float border_box_bottom() const { return m_border_box_bottom; }
+
  float absolute_x() const { return absolute_rect().x(); }
 
  void paint(PaintContext&, PaintPhase);
@@ -66,6 +72,8 @@ class LineBoxFragment : public Weakable<LineBoxFragment> {
  int m_length { 0 };
  Gfx::FloatPoint m_offset;
  Gfx::FloatSize m_size;
+ float m_border_box_top { 0 };
+ float m_border_box_bottom { 0 };
  Type m_type { Type::Normal };
 };
 

Userland/Libraries/LibWeb/Layout/LineBuilder.cpp

@@ -52,13 +52,13 @@ LineBox& LineBuilder::ensure_last_line_box()
 void LineBuilder::append_box(Box const& box, float leading_size, float trailing_size)
 {
  auto const& box_state = m_formatting_state.get(box);
- ensure_last_line_box().add_fragment(box, 0, 0, leading_size, trailing_size, box_state.content_width, box_state.content_height);
+ ensure_last_line_box().add_fragment(box, 0, 0, leading_size, trailing_size, box_state.content_width, box_state.content_height, box_state.border_box_top(), box_state.border_box_bottom());
  m_max_height_on_current_line = max(m_max_height_on_current_line, box_state.content_height);
 }
 
 void LineBuilder::append_text_chunk(TextNode const& text_node, size_t offset_in_node, size_t length_in_node, float leading_size, float trailing_size, float content_width, float content_height)
 {
- ensure_last_line_box().add_fragment(text_node, offset_in_node, length_in_node, leading_size, trailing_size, content_width, content_height);
+ ensure_last_line_box().add_fragment(text_node, offset_in_node, length_in_node, leading_size, trailing_size, content_width, content_height, 0, 0);
  m_max_height_on_current_line = max(m_max_height_on_current_line, content_height);
 }
 
@@ -127,7 +127,7 @@ void LineBuilder::update_last_line()
  for (auto& fragment : line_box.fragments()) {
  float fragment_baseline;
  if (fragment.layout_node().is_box()) {
- fragment_baseline = m_formatting_state.get(static_cast<Box const&>(fragment.layout_node())).content_height;
+ fragment_baseline = m_formatting_state.get(static_cast<Box const&>(fragment.layout_node())).border_box_height();
  } else {
  float font_baseline = fragment.layout_node().font().baseline();
  fragment_baseline = (max_height / 2.0f) + (font_baseline / 2.0f);