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LibWeb: Account for absolutely positioned table wrappers

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Table wrappers don't quite behave the same as most elements, in that
their computed height and width are not meant to be used for layout.
Instead, we now calculate suitable widths and heights based on the
contents of the table wrapper when performing absolute layout.

Fixes the layout of
http://wpt.live/css/css-position/position-absolute-center-007.html
This commit is contained in:
implicitfield 2024-03-04 22:11:04 +04:00 • committed by Andreas Kling
parent 096ddb0021
commit 0243278587
6 changed files with 333 additions and 188 deletions
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384
Userland/Libraries/LibWeb/Layout/FormattingContext.cpp
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@ -381,6 +381,93 @@ CSSPixels FormattingContext::compute_auto_height_for_block_formatting_context_ro
return max(CSSPixels(0.0f), bottom.value_or(0) - top.value_or(0));
}
// 17.5.2 Table width algorithms: the 'table-layout' property
// https://www.w3.org/TR/CSS22/tables.html#width-layout
CSSPixels FormattingContext::compute_table_box_width_inside_table_wrapper(Box const& box, AvailableSpace const& available_space)
{
// Table wrapper width should be equal to width of table box it contains
auto const& computed_values = box.computed_values();
auto width_of_containing_block = available_space.width.to_px_or_zero();
auto zero_value = CSS::Length::make_px(0);
auto margin_left = computed_values.margin().left().resolved(box, width_of_containing_block);
auto margin_right = computed_values.margin().right().resolved(box, width_of_containing_block);
// If 'margin-left', or 'margin-right' are computed as 'auto', their used value is '0'.
if (margin_left.is_auto())
margin_left = zero_value;
if (margin_right.is_auto())
margin_right = zero_value;
// table-wrapper can't have borders or paddings but it might have margin taken from table-root.
auto available_width = width_of_containing_block - margin_left.to_px(box) - margin_right.to_px(box);
LayoutState throwaway_state(&m_state);
auto context = create_independent_formatting_context_if_needed(throwaway_state, box);
VERIFY(context);
context->run(box, LayoutMode::IntrinsicSizing, m_state.get(box).available_inner_space_or_constraints_from(available_space));
Optional<Box const&> table_box;
box.for_each_in_subtree_of_type<Box>([&](Box const& child_box) {
if (child_box.display().is_table_inside()) {
table_box = child_box;
return IterationDecision::Break;
}
return IterationDecision::Continue;
});
VERIFY(table_box.has_value());
auto table_used_width = throwaway_state.get(*table_box).border_box_width();
return available_space.width.is_definite() ? min(table_used_width, available_width) : table_used_width;
}
// 17.5.3 Table height algorithms
// https://www.w3.org/TR/CSS22/tables.html#height-layout
CSSPixels FormattingContext::compute_table_box_height_inside_table_wrapper(Box const& box, AvailableSpace const& available_space)
{
// Table wrapper height should be equal to height of table box it contains
auto const& computed_values = box.computed_values();
auto width_of_containing_block = available_space.width.to_px_or_zero();
auto height_of_containing_block = available_space.height.to_px_or_zero();
auto zero_value = CSS::Length::make_px(0);
auto margin_top = computed_values.margin().top().resolved(box, width_of_containing_block);
auto margin_bottom = computed_values.margin().bottom().resolved(box, width_of_containing_block);
// If 'margin-top', or 'margin-top' are computed as 'auto', their used value is '0'.
if (margin_top.is_auto())
margin_top = zero_value;
if (margin_bottom.is_auto())
margin_bottom = zero_value;
// table-wrapper can't have borders or paddings but it might have margin taken from table-root.
auto available_height = height_of_containing_block - margin_top.to_px(box) - margin_bottom.to_px(box);
LayoutState throwaway_state(&m_state);
auto context = create_independent_formatting_context_if_needed(throwaway_state, box);
VERIFY(context);
context->run(box, LayoutMode::IntrinsicSizing, m_state.get(box).available_inner_space_or_constraints_from(available_space));
Optional<Box const&> table_box;
box.for_each_in_subtree_of_type<Box>([&](Box const& child_box) {
if (child_box.display().is_table_inside()) {
table_box = child_box;
return IterationDecision::Break;
}
return IterationDecision::Continue;
});
VERIFY(table_box.has_value());
auto table_used_height = throwaway_state.get(*table_box).border_box_height();
return available_space.height.is_definite() ? min(table_used_height, available_height) : table_used_height;
}
// 10.3.2 Inline, replaced elements, https://www.w3.org/TR/CSS22/visudet.html#inline-replaced-width
CSSPixels FormattingContext::tentative_width_for_replaced_element(Box const& box, CSS::Size const& computed_width, AvailableSpace const& available_space) const
{
@ -705,6 +792,8 @@ void FormattingContext::compute_width_for_absolutely_positioned_non_replaced_ele
// 1. The tentative used width is calculated (without 'min-width' and 'max-width')
auto used_width = try_compute_width([&] {
if (is<TableWrapper>(box))
return CSS::Length::make_px(compute_table_box_width_inside_table_wrapper(box, available_space));
if (computed_values.width().is_auto())
return CSS::Length::make_auto();
return CSS::Length::make_px(calculate_inner_width(box, available_space.width, computed_values.width()));
@ -833,17 +922,19 @@ void FormattingContext::compute_height_for_absolutely_positioned_non_replaced_el
// In the before pass, if it turns out we need the automatic height of the box, we abort these steps.
// This allows the box to retain an indefinite height from the perspective of inside layout.
auto apply_min_max_height_constraints = [this, &box, &available_space](CSSPixels unconstrained_height) -> CSSPixels {
auto apply_min_max_height_constraints = [this, &box, &available_space](CSS::Length unconstrained_height) -> CSS::Length {
auto const& computed_min_height = box.computed_values().min_height();
auto const& computed_max_height = box.computed_values().max_height();
auto constrained_height = unconstrained_height;
if (!computed_max_height.is_none()) {
auto inner_max_height = calculate_inner_height(box, available_space.height, computed_max_height);
constrained_height = min(constrained_height, inner_max_height);
if (inner_max_height < constrained_height.to_px(box))
constrained_height = CSS::Length::make_px(inner_max_height);
}
if (!computed_min_height.is_auto()) {
auto inner_min_height = calculate_inner_height(box, available_space.height, computed_min_height);
constrained_height = max(constrained_height, inner_min_height);
if (inner_min_height > constrained_height.to_px(box))
constrained_height = CSS::Length::make_px(inner_min_height);
}
return constrained_height;
};
@ -852,7 +943,6 @@ void FormattingContext::compute_height_for_absolutely_positioned_non_replaced_el
auto margin_bottom = box.computed_values().margin().bottom();
auto top = box.computed_values().inset().top();
auto bottom = box.computed_values().inset().bottom();
auto height = box.computed_values().height();
auto width_of_containing_block = containing_block_width_for(box);
auto height_of_containing_block = available_space.height.to_px_or_zero();
@ -861,171 +951,177 @@ void FormattingContext::compute_height_for_absolutely_positioned_non_replaced_el
No,
Yes,
};
auto solve_for = [&](CSS::Length length, ClampToZero clamp_to_zero = ClampToZero::No) {
auto unclamped_value = height_of_containing_block
- top.to_px(box, height_of_containing_block)
- margin_top.to_px(box, width_of_containing_block)
- box.computed_values().border_top().width
- box.computed_values().padding().top().to_px(box, width_of_containing_block)
- height.to_px(box, height_of_containing_block)
- box.computed_values().padding().bottom().to_px(box, width_of_containing_block)
- box.computed_values().border_bottom().width
- margin_bottom.to_px(box, width_of_containing_block)
- bottom.to_px(box, height_of_containing_block)
+ length.to_px(box);
if (clamp_to_zero == ClampToZero::Yes)
return CSS::Length::make_px(max(CSSPixels(0), unclamped_value));
return CSS::Length::make_px(unclamped_value);
};
auto solve_for_top = [&] {
top = solve_for(top.resolved(box, height_of_containing_block));
};
auto try_compute_height = [&](CSS::Length height) -> CSS::Length {
auto solve_for = [&](CSS::Length length, ClampToZero clamp_to_zero = ClampToZero::No) {
auto unclamped_value = height_of_containing_block
- top.to_px(box, height_of_containing_block)
- margin_top.to_px(box, width_of_containing_block)
- box.computed_values().border_top().width
- box.computed_values().padding().top().to_px(box, width_of_containing_block)
- height.to_px(box)
- box.computed_values().padding().bottom().to_px(box, width_of_containing_block)
- box.computed_values().border_bottom().width
- margin_bottom.to_px(box, width_of_containing_block)
- bottom.to_px(box, height_of_containing_block)
+ length.to_px(box);
if (clamp_to_zero == ClampToZero::Yes)
return CSS::Length::make_px(max(CSSPixels(0), unclamped_value));
return CSS::Length::make_px(unclamped_value);
};
auto solve_for_bottom = [&] {
bottom = solve_for(bottom.resolved(box, height_of_containing_block));
};
auto solve_for_top = [&] {
top = solve_for(top.resolved(box, height_of_containing_block));
};
auto solve_for_height = [&] {
height = CSS::Size::make_length(solve_for(height.resolved(box, height_of_containing_block), ClampToZero::Yes));
};
auto solve_for_bottom = [&] {
bottom = solve_for(bottom.resolved(box, height_of_containing_block));
};
auto solve_for_margin_top = [&] {
margin_top = solve_for(margin_top.resolved(box, width_of_containing_block));
};
auto solve_for_height = [&] {
height = solve_for(height, ClampToZero::Yes);
};
auto solve_for_margin_bottom = [&] {
margin_bottom = solve_for(margin_bottom.resolved(box, width_of_containing_block));
};
auto solve_for_margin_top = [&] {
margin_top = solve_for(margin_top.resolved(box, width_of_containing_block));
};
auto solve_for_margin_top_and_margin_bottom = [&] {
auto remainder = solve_for(CSS::Length::make_px(margin_top.to_px(box, width_of_containing_block) + margin_bottom.to_px(box, width_of_containing_block))).to_px(box);
margin_top = CSS::Length::make_px(remainder / 2);
margin_bottom = CSS::Length::make_px(remainder / 2);
};
auto solve_for_margin_bottom = [&] {
margin_bottom = solve_for(margin_bottom.resolved(box, width_of_containing_block));
};
// If all three of top, height, and bottom are auto:
if (top.is_auto() && should_treat_height_as_auto(box, available_space) && bottom.is_auto()) {
// First set any auto values for margin-top and margin-bottom to 0,
if (margin_top.is_auto())
margin_top = CSS::Length::make_px(0);
if (margin_bottom.is_auto())
margin_bottom = CSS::Length::make_px(0);
auto solve_for_margin_top_and_margin_bottom = [&] {
auto remainder = solve_for(CSS::Length::make_px(margin_top.to_px(box, width_of_containing_block) + margin_bottom.to_px(box, width_of_containing_block))).to_px(box);
margin_top = CSS::Length::make_px(remainder / 2);
margin_bottom = CSS::Length::make_px(remainder / 2);
};
// then set top to the static position,
// and finally apply rule number three below.
// NOTE: We actually perform these two steps in the opposite order,
// because the static position may depend on the height of the box (due to alignment properties).
auto maybe_height = compute_auto_height_for_absolutely_positioned_element(box, available_space, before_or_after_inside_layout);
if (!maybe_height.has_value())
return;
height = CSS::Size::make_px(maybe_height.value());
auto constrained_height = apply_min_max_height_constraints(maybe_height.value());
m_state.get_mutable(box).set_content_height(constrained_height);
auto static_position = calculate_static_position(box);
top = CSS::Length::make_px(static_position.y());
solve_for_bottom();
}
// If none of the three are auto:
else if (!top.is_auto() && !should_treat_height_as_auto(box, available_space) && !bottom.is_auto()) {
// If both margin-top and margin-bottom are auto,
if (margin_top.is_auto() && margin_bottom.is_auto()) {
// solve the equation under the extra constraint that the two margins get equal values.
solve_for_margin_top_and_margin_bottom();
}
// If one of margin-top or margin-bottom is auto,
else if (margin_top.is_auto() || margin_bottom.is_auto()) {
// solve the equation for that value.
// If all three of top, height, and bottom are auto:
if (top.is_auto() && height.is_auto() && bottom.is_auto()) {
// First set any auto values for margin-top and margin-bottom to 0,
if (margin_top.is_auto())
solve_for_margin_top();
else
solve_for_margin_bottom();
}
margin_top = CSS::Length::make_px(0);
if (margin_bottom.is_auto())
margin_bottom = CSS::Length::make_px(0);
// If the values are over-constrained,
else {
// ignore the value for bottom and solve for that value.
solve_for_bottom();
}
}
// Otherwise,
else {
// set auto values for margin-top and margin-bottom to 0,
if (margin_top.is_auto())
margin_top = CSS::Length::make_px(0);
if (margin_bottom.is_auto())
margin_bottom = CSS::Length::make_px(0);
// and pick one of the following six rules that apply.
// 1. If top and height are auto and bottom is not auto,
if (top.is_auto() && should_treat_height_as_auto(box, available_space) && !bottom.is_auto()) {
// then the height is based on the Auto heights for block formatting context roots,
auto maybe_height = compute_auto_height_for_absolutely_positioned_element(box, available_space, before_or_after_inside_layout);
if (!maybe_height.has_value())
return;
height = CSS::Size::make_px(maybe_height.value());
// and solve for top.
solve_for_top();
}
// 2. If top and bottom are auto and height is not auto,
else if (top.is_auto() && bottom.is_auto() && !should_treat_height_as_auto(box, available_space)) {
// then set top to the static position,
top = CSS::Length::make_px(calculate_static_position(box).y());
// and finally apply rule number three below.
// then solve for bottom.
solve_for_bottom();
}
// NOTE: We actually perform these two steps in the opposite order,
// because the static position may depend on the height of the box (due to alignment properties).
// 3. If height and bottom are auto and top is not auto,
else if (should_treat_height_as_auto(box, available_space) && bottom.is_auto() && !top.is_auto()) {
// then the height is based on the Auto heights for block formatting context roots,
auto maybe_height = compute_auto_height_for_absolutely_positioned_element(box, available_space, before_or_after_inside_layout);
if (!maybe_height.has_value())
return;
height = CSS::Size::make_px(maybe_height.value());
return height;
height = CSS::Length::make_px(maybe_height.value());
auto constrained_height = apply_min_max_height_constraints(height);
m_state.get_mutable(box).set_content_height(constrained_height.to_px(box));
auto static_position = calculate_static_position(box);
top = CSS::Length::make_px(static_position.y());
// and solve for bottom.
solve_for_bottom();
}
// 4. If top is auto, height and bottom are not auto,
else if (top.is_auto() && !should_treat_height_as_auto(box, available_space) && !bottom.is_auto()) {
// then solve for top.
solve_for_top();
// If none of the three are auto:
else if (!top.is_auto() && !height.is_auto() && !bottom.is_auto()) {
// If both margin-top and margin-bottom are auto,
if (margin_top.is_auto() && margin_bottom.is_auto()) {
// solve the equation under the extra constraint that the two margins get equal values.
solve_for_margin_top_and_margin_bottom();
}
// If one of margin-top or margin-bottom is auto,
else if (margin_top.is_auto() || margin_bottom.is_auto()) {
// solve the equation for that value.
if (margin_top.is_auto())
solve_for_margin_top();
else
solve_for_margin_bottom();
}
// If the values are over-constrained,
else {
// ignore the value for bottom and solve for that value.
solve_for_bottom();
}
}
// 5. If height is auto, top and bottom are not auto,
else if (should_treat_height_as_auto(box, available_space) && !top.is_auto() && !bottom.is_auto()) {
// then solve for height.
solve_for_height();
// Otherwise,
else {
// set auto values for margin-top and margin-bottom to 0,
if (margin_top.is_auto())
margin_top = CSS::Length::make_px(0);
if (margin_bottom.is_auto())
margin_bottom = CSS::Length::make_px(0);
// and pick one of the following six rules that apply.
// 1. If top and height are auto and bottom is not auto,
if (top.is_auto() && height.is_auto() && !bottom.is_auto()) {
// then the height is based on the Auto heights for block formatting context roots,
auto maybe_height = compute_auto_height_for_absolutely_positioned_element(box, available_space, before_or_after_inside_layout);
if (!maybe_height.has_value())
return height;
height = CSS::Length::make_px(maybe_height.value());
// and solve for top.
solve_for_top();
}
// 2. If top and bottom are auto and height is not auto,
else if (top.is_auto() && bottom.is_auto() && !height.is_auto()) {
// then set top to the static position,
top = CSS::Length::make_px(calculate_static_position(box).y());
// then solve for bottom.
solve_for_bottom();
}
// 3. If height and bottom are auto and top is not auto,
else if (height.is_auto() && bottom.is_auto() && !top.is_auto()) {
// then the height is based on the Auto heights for block formatting context roots,
auto maybe_height = compute_auto_height_for_absolutely_positioned_element(box, available_space, before_or_after_inside_layout);
if (!maybe_height.has_value())
return height;
height = CSS::Length::make_px(maybe_height.value());
// and solve for bottom.
solve_for_bottom();
}
// 4. If top is auto, height and bottom are not auto,
else if (top.is_auto() && !height.is_auto() && !bottom.is_auto()) {
// then solve for top.
solve_for_top();
}
// 5. If height is auto, top and bottom are not auto,
else if (height.is_auto() && !top.is_auto() && !bottom.is_auto()) {
// then solve for height.
solve_for_height();
}
// 6. If bottom is auto, top and height are not auto,
else if (bottom.is_auto() && !top.is_auto() && !height.is_auto()) {
// then solve for bottom.
solve_for_bottom();
}
}
// 6. If bottom is auto, top and height are not auto,
else if (bottom.is_auto() && !top.is_auto() && !should_treat_height_as_auto(box, available_space)) {
// then solve for bottom.
solve_for_bottom();
}
}
return height;
};
// Compute the height based on box type and CSS properties:
// https://www.w3.org/TR/css-sizing-3/#box-sizing
CSSPixels used_height = 0;
if (should_treat_height_as_auto(box, available_space)) {
used_height = height.to_px(box, height_of_containing_block);
} else {
used_height = calculate_inner_height(box, available_space.height, height);
}
auto used_height = try_compute_height([&] {
if (is<TableWrapper>(box))
return CSS::Length::make_px(compute_table_box_height_inside_table_wrapper(box, available_space));
if (should_treat_height_as_auto(box, available_space))
return CSS::Length::make_auto();
return CSS::Length::make_px(calculate_inner_height(box, available_space.height, box.computed_values().height()));
}());
used_height = apply_min_max_height_constraints(used_height);
@ -1033,7 +1129,7 @@ void FormattingContext::compute_height_for_absolutely_positioned_non_replaced_el
// the final used values for vertical margin/border/padding.
auto& box_state = m_state.get_mutable(box);
box_state.set_content_height(used_height);
box_state.set_content_height(used_height.to_px(box));
// do not set calculated insets or margins on the first pass, there will be a second pass
if (before_or_after_inside_layout == BeforeOrAfterInsideLayout::Before)