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ladybird/Libraries/LibWeb/Layout/LayoutBlock.cpp
Andreas Kling 9b8464f455 LibWeb: Cache the used CSS 'position' value on LayoutNodeWithStyle 
This avoids having to query the StyleProperties hash map whenever we
need to know if an element is absolutely positioned. This was extremely
hot in interactive window resize profiles.
2020-06-23 23:15:23 +02:00

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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <LibGUI/Painter.h>
#include <LibWeb/CSS/StyleResolver.h>
#include <LibWeb/DOM/Element.h>
#include <LibWeb/Dump.h>
#include <LibWeb/Layout/LayoutBlock.h>
#include <LibWeb/Layout/LayoutDocument.h>
#include <LibWeb/Layout/LayoutInline.h>
#include <LibWeb/Layout/LayoutReplaced.h>
#include <LibWeb/Layout/LayoutText.h>
#include <LibWeb/Layout/LayoutWidget.h>
#include <math.h>
namespace Web {
LayoutBlock::LayoutBlock(const Node* node, NonnullRefPtr<StyleProperties> style)
: LayoutBox(node, move(style))
{
}
LayoutBlock::~LayoutBlock()
{
}
LayoutNode& LayoutBlock::inline_wrapper()
{
if (!last_child() || !last_child()->is_block() || last_child()->node() != nullptr) {
append_child(adopt(*new LayoutBlock(nullptr, style_for_anonymous_block())));
last_child()->set_children_are_inline(true);
}
return *last_child();
}
void LayoutBlock::layout(LayoutMode layout_mode)
{
compute_width();
layout_inside(layout_mode);
compute_height();
layout_absolutely_positioned_descendants();
}
void LayoutBlock::layout_absolutely_positioned_descendant(LayoutBox& box)
{
box.layout(LayoutMode::Default);
auto& box_model = box.box_model();
auto& style = box.style();
auto zero_value = Length(0, Length::Type::Px);
auto specified_width = style.length_or_fallback(CSS::PropertyID::Width, Length(), width());
box_model.margin().top = style.length_or_fallback(CSS::PropertyID::MarginTop, {}, height());
box_model.margin().right = style.length_or_fallback(CSS::PropertyID::MarginRight, {}, width());
box_model.margin().bottom = style.length_or_fallback(CSS::PropertyID::MarginBottom, {}, height());
box_model.margin().left = style.length_or_fallback(CSS::PropertyID::MarginLeft, {}, width());
box_model.offset().top = style.length_or_fallback(CSS::PropertyID::Top, {}, height());
box_model.offset().right = style.length_or_fallback(CSS::PropertyID::Right, {}, width());
box_model.offset().bottom = style.length_or_fallback(CSS::PropertyID::Bottom, {}, height());
box_model.offset().left = style.length_or_fallback(CSS::PropertyID::Left, {}, width());
if (box_model.offset().left.is_auto() && specified_width.is_auto() && box_model.offset().right.is_auto()) {
if (box_model.margin().left.is_auto())
box_model.margin().left = zero_value;
if (box_model.margin().right.is_auto())
box_model.margin().right = zero_value;
}
Gfx::FloatPoint used_offset;
float x_offset = box_model.offset().left.to_px(box)
+ box_model.border_box(box).left
- box_model.offset().right.to_px(box)
- box_model.border_box(box).right;
float y_offset = box_model.offset().top.to_px(box)
+ box_model.border_box(box).top
- box_model.offset().bottom.to_px(box)
- box_model.border_box(box).bottom;
bool has_left_side_constraints = !box_model.offset().left.is_auto() || !box_model.margin().left.is_auto();
bool has_right_side_constraints = !box_model.offset().right.is_auto() || !box_model.margin().right.is_auto();
if (has_left_side_constraints && has_right_side_constraints) {
// If both 'left' and 'right' are set, we will have stretched the width to accomodate both.
x_offset += box_model.offset().right.to_px(box);
}
if (has_left_side_constraints) {
used_offset.set_x(x_offset + box_model.margin().left.to_px(box));
} else if (has_right_side_constraints) {
used_offset.set_x(width() + x_offset - box.width() - box_model.margin().right.to_px(box));
}
if (!box_model.offset().top.is_auto()) {
used_offset.set_y(y_offset + box_model.margin().top.to_px(box));
} else if (!box_model.offset().bottom.is_auto()) {
used_offset.set_y(height() + y_offset - box.height() - box_model.margin().bottom.to_px(box));
}
box.set_offset(used_offset);
}
void LayoutBlock::layout_inside(LayoutMode layout_mode)
{
if (children_are_inline())
layout_inline_children(layout_mode);
else
layout_contained_boxes(layout_mode);
}
void LayoutBlock::layout_absolutely_positioned_descendants()
{
for_each_in_subtree_of_type<LayoutBox>([&](auto& box) {
if (box.is_absolutely_positioned() && box.containing_block() == this) {
layout_absolutely_positioned_descendant(box);
}
return IterationDecision::Continue;
});
}
void LayoutBlock::layout_contained_boxes(LayoutMode layout_mode)
{
float content_height = 0;
float content_width = 0;
for_each_in_subtree_of_type<LayoutBox>([&](auto& box) {
if (box.is_absolutely_positioned() || box.containing_block() != this)
return IterationDecision::Continue;
box.layout(layout_mode);
if (box.is_replaced())
place_block_level_replaced_element_in_normal_flow(to<LayoutReplaced>(box));
else if (box.is_block())
place_block_level_non_replaced_element_in_normal_flow(to<LayoutBlock>(box));
else
dbg() << "FIXME: LayoutBlock::layout_contained_boxes doesn't know how to place a " << box.class_name();
content_height = max(content_height, box.effective_offset().y() + box.height() + box.box_model().margin_box(*this).bottom);
content_width = max(content_width, to<LayoutBox>(box).width());
return IterationDecision::Continue;
});
if (layout_mode != LayoutMode::Default) {
auto specified_width = style().length_or_fallback(CSS::PropertyID::Width, Length(), containing_block()->width());
if (specified_width.is_auto())
set_width(content_width);
}
set_height(content_height);
}
void LayoutBlock::layout_inline_children(LayoutMode layout_mode)
{
ASSERT(children_are_inline());
m_line_boxes.clear();
for_each_child([&](auto& child) {
ASSERT(child.is_inline());
if (child.is_absolutely_positioned())
return;
child.split_into_lines(*this, layout_mode);
});
for (auto& line_box : m_line_boxes) {
line_box.trim_trailing_whitespace();
}
auto text_align = style().text_align();
float min_line_height = style().line_height(*this);
float line_spacing = min_line_height - style().font().glyph_height();
float content_height = 0;
float max_linebox_width = 0;
for (auto& line_box : m_line_boxes) {
float max_height = min_line_height;
for (auto& fragment : line_box.fragments()) {
max_height = max(max_height, fragment.height());
}
float x_offset = 0;
float excess_horizontal_space = (float)width() - line_box.width();
switch (text_align) {
case CSS::ValueID::Center:
case CSS::ValueID::VendorSpecificCenter:
x_offset += excess_horizontal_space / 2;
break;
case CSS::ValueID::Right:
x_offset += excess_horizontal_space;
break;
case CSS::ValueID::Left:
case CSS::ValueID::Justify:
default:
break;
}
float excess_horizontal_space_including_whitespace = excess_horizontal_space;
int whitespace_count = 0;
if (text_align == CSS::ValueID::Justify) {
for (auto& fragment : line_box.fragments()) {
if (fragment.is_justifiable_whitespace()) {
++whitespace_count;
excess_horizontal_space_including_whitespace += fragment.width();
}
}
}
float justified_space_width = whitespace_count ? (excess_horizontal_space_including_whitespace / (float)whitespace_count) : 0;
for (size_t i = 0; i < line_box.fragments().size(); ++i) {
auto& fragment = line_box.fragments()[i];
// Vertically align everyone's bottom to the line.
// FIXME: Support other kinds of vertical alignment.
fragment.set_offset({ roundf(x_offset + fragment.offset().x()), content_height + (max_height - fragment.height()) - (line_spacing / 2) });
if (text_align == CSS::ValueID::Justify) {
if (fragment.is_justifiable_whitespace()) {
if (fragment.width() != justified_space_width) {
float diff = justified_space_width - fragment.width();
fragment.set_width(justified_space_width);
// Shift subsequent sibling fragments to the right to adjust for change in width.
for (size_t j = i + 1; j < line_box.fragments().size(); ++j) {
auto offset = line_box.fragments()[j].offset();
offset.move_by(diff, 0);
line_box.fragments()[j].set_offset(offset);
}
}
}
}
if (fragment.layout_node().is_inline_block()) {
auto& inline_block = const_cast<LayoutBlock&>(to<LayoutBlock>(fragment.layout_node()));
inline_block.set_size(fragment.size());
inline_block.layout(layout_mode);
}
float final_line_box_width = 0;
for (auto& fragment : line_box.fragments())
final_line_box_width += fragment.width();
line_box.m_width = final_line_box_width;
max_linebox_width = max(max_linebox_width, final_line_box_width);
}
content_height += max_height;
}
if (layout_mode != LayoutMode::Default) {
set_width(max_linebox_width);
}
set_height(content_height);
}
void LayoutBlock::compute_width_for_absolutely_positioned_block()
{
auto& style = this->style();
auto& containing_block = *this->containing_block();
auto zero_value = Length(0, Length::Type::Px);
Length margin_left;
Length margin_right;
Length border_left;
Length border_right;
Length padding_left;
Length padding_right;
auto try_compute_width = [&](const auto& a_width) {
margin_left = style.length_or_fallback(CSS::PropertyID::MarginLeft, zero_value, containing_block.width());
margin_right = style.length_or_fallback(CSS::PropertyID::MarginRight, zero_value, containing_block.width());
border_left = style.length_or_fallback(CSS::PropertyID::BorderLeftWidth, zero_value);
border_right = style.length_or_fallback(CSS::PropertyID::BorderRightWidth, zero_value);
padding_left = style.length_or_fallback(CSS::PropertyID::PaddingLeft, zero_value, containing_block.width());
padding_right = style.length_or_fallback(CSS::PropertyID::PaddingRight, zero_value, containing_block.width());
auto left = style.length_or_fallback(CSS::PropertyID::Left, {}, containing_block.width());
auto right = style.length_or_fallback(CSS::PropertyID::Right, {}, containing_block.width());
auto width = a_width;
auto solve_for_left = [&] {
return Length(containing_block.width() - margin_left.to_px(*this) - border_left.to_px(*this) - padding_left.to_px(*this) - width.to_px(*this) - padding_right.to_px(*this) - border_right.to_px(*this) - margin_right.to_px(*this) - right.to_px(*this), Length::Type::Px);
};
auto solve_for_width = [&] {
return Length(containing_block.width() - left.to_px(*this) - margin_left.to_px(*this) - border_left.to_px(*this) - padding_left.to_px(*this) - padding_right.to_px(*this) - border_right.to_px(*this) - margin_right.to_px(*this) - right.to_px(*this), Length::Type::Px);
};
auto solve_for_right = [&] {
return Length(containing_block.width() - left.to_px(*this) - margin_left.to_px(*this) - border_left.to_px(*this) - padding_left.to_px(*this) - width.to_px(*this) - padding_right.to_px(*this) - border_right.to_px(*this) - margin_right.to_px(*this), Length::Type::Px);
};
// If all three of 'left', 'width', and 'right' are 'auto':
if (left.is_auto() && width.is_auto() && right.is_auto()) {
// First set any 'auto' values for 'margin-left' and 'margin-right' to 0.
if (margin_left.is_auto())
margin_left = Length(0, Length::Type::Px);
if (margin_right.is_auto())
margin_right = Length(0, Length::Type::Px);
// Then, if the 'direction' property of the element establishing the static-position containing block
// is 'ltr' set 'left' to the static position and apply rule number three below;
// otherwise, set 'right' to the static position and apply rule number one below.
// FIXME: This is very hackish.
left = Length(0, Length::Type::Px);
goto Rule3;
}
if (!left.is_auto() && !width.is_auto() && !right.is_auto()) {
// FIXME: This should be solved in a more complicated way.
return width;
}
if (margin_left.is_auto())
margin_left = Length(0, Length::Type::Px);
if (margin_right.is_auto())
margin_right = Length(0, Length::Type::Px);
// 1. 'left' and 'width' are 'auto' and 'right' is not 'auto',
// then the width is shrink-to-fit. Then solve for 'left'
if (left.is_auto() && width.is_auto() && !right.is_auto()) {
auto result = calculate_shrink_to_fit_width();
solve_for_left();
auto available_width = solve_for_width();
width = Length(min(max(result.preferred_minimum_width, available_width.to_px(*this)), result.preferred_width), Length::Type::Px);
}
// 2. 'left' and 'right' are 'auto' and 'width' is not 'auto',
// then if the 'direction' property of the element establishing
// the static-position containing block is 'ltr' set 'left'
// to the static position, otherwise set 'right' to the static position.
// Then solve for 'left' (if 'direction is 'rtl') or 'right' (if 'direction' is 'ltr').
else if (left.is_auto() && right.is_auto() && !width.is_auto()) {
// FIXME: Check direction
// FIXME: Use the static-position containing block
left = zero_value;
right = solve_for_right();
}
// 3. 'width' and 'right' are 'auto' and 'left' is not 'auto',
// then the width is shrink-to-fit. Then solve for 'right'
else if (width.is_auto() && right.is_auto() && !left.is_auto()) {
Rule3:
auto result = calculate_shrink_to_fit_width();
right = solve_for_right();
auto available_width = solve_for_width();
width = Length(min(max(result.preferred_minimum_width, available_width.to_px(*this)), result.preferred_width), Length::Type::Px);
}
// 4. 'left' is 'auto', 'width' and 'right' are not 'auto', then solve for 'left'
else if (left.is_auto() && !width.is_auto() && !right.is_auto()) {
left = solve_for_left();
}
// 5. 'width' is 'auto', 'left' and 'right' are not 'auto', then solve for 'width'
else if (width.is_auto() && !left.is_auto() && !right.is_auto()) {
width = solve_for_width();
}
// 6. 'right' is 'auto', 'left' and 'width' are not 'auto', then solve for 'right'
else if (right.is_auto() && !left.is_auto() && !width.is_auto()) {
right = solve_for_right();
}
return width;
};
auto specified_width = style.length_or_fallback(CSS::PropertyID::Width, {}, containing_block.width());
// 1. The tentative used width is calculated (without 'min-width' and 'max-width')
auto used_width = try_compute_width(specified_width);
// 2. The tentative used width is greater than 'max-width', the rules above are applied again,
// but this time using the computed value of 'max-width' as the computed value for 'width'.
auto specified_max_width = style.length_or_fallback(CSS::PropertyID::MaxWidth, {}, containing_block.width());
if (!specified_max_width.is_auto()) {
if (used_width.to_px(*this) > specified_max_width.to_px(*this)) {
used_width = try_compute_width(specified_max_width);
}
}
// 3. If the resulting width is smaller than 'min-width', the rules above are applied again,
// but this time using the value of 'min-width' as the computed value for 'width'.
auto specified_min_width = style.length_or_fallback(CSS::PropertyID::MinWidth, {}, containing_block.width());
if (!specified_min_width.is_auto()) {
if (used_width.to_px(*this) < specified_min_width.to_px(*this)) {
used_width = try_compute_width(specified_min_width);
}
}
set_width(used_width.to_px(*this));
box_model().margin().left = margin_left;
box_model().margin().right = margin_right;
box_model().border().left = border_left;
box_model().border().right = border_right;
box_model().padding().left = padding_left;
box_model().padding().right = padding_right;
}
void LayoutBlock::compute_width()
{
if (is_absolutely_positioned())
return compute_width_for_absolutely_positioned_block();
auto& style = this->style();
auto auto_value = Length();
auto zero_value = Length(0, Length::Type::Px);
Length margin_left;
Length margin_right;
Length border_left;
Length border_right;
Length padding_left;
Length padding_right;
auto& containing_block = *this->containing_block();
auto try_compute_width = [&](const auto& a_width) {
Length width = a_width;
#ifdef HTML_DEBUG
dbg() << " Left: " << margin_left << "+" << border_left << "+" << padding_left;
dbg() << "Right: " << margin_right << "+" << border_right << "+" << padding_right;
#endif
margin_left = style.length_or_fallback(CSS::PropertyID::MarginLeft, zero_value, containing_block.width());
margin_right = style.length_or_fallback(CSS::PropertyID::MarginRight, zero_value, containing_block.width());
border_left = style.length_or_fallback(CSS::PropertyID::BorderLeftWidth, zero_value);
border_right = style.length_or_fallback(CSS::PropertyID::BorderRightWidth, zero_value);
padding_left = style.length_or_fallback(CSS::PropertyID::PaddingLeft, zero_value, containing_block.width());
padding_right = style.length_or_fallback(CSS::PropertyID::PaddingRight, zero_value, containing_block.width());
float total_px = 0;
for (auto& value : { margin_left, border_left, padding_left, width, padding_right, border_right, margin_right }) {
total_px += value.to_px(*this);
}
#ifdef HTML_DEBUG
dbg() << "Total: " << total_px;
#endif
if (!is_replaced() && !is_inline()) {
// 10.3.3 Block-level, non-replaced elements in normal flow
// If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' (plus any of 'margin-left' or 'margin-right' that are not 'auto') is larger than the width of the containing block, then any 'auto' values for 'margin-left' or 'margin-right' are, for the following rules, treated as zero.
if (width.is_auto() && total_px > containing_block.width()) {
if (margin_left.is_auto())
margin_left = zero_value;
if (margin_right.is_auto())
margin_right = zero_value;
}
// 10.3.3 cont'd.
auto underflow_px = containing_block.width() - total_px;
if (width.is_auto()) {
if (margin_left.is_auto())
margin_left = zero_value;
if (margin_right.is_auto())
margin_right = zero_value;
if (underflow_px >= 0) {
width = Length(underflow_px, Length::Type::Px);
} else {
width = zero_value;
margin_right = Length(margin_right.to_px(*this) + underflow_px, Length::Type::Px);
}
} else {
if (!margin_left.is_auto() && !margin_right.is_auto()) {
margin_right = Length(margin_right.to_px(*this) + underflow_px, Length::Type::Px);
} else if (!margin_left.is_auto() && margin_right.is_auto()) {
margin_right = Length(underflow_px, Length::Type::Px);
} else if (margin_left.is_auto() && !margin_right.is_auto()) {
margin_left = Length(underflow_px, Length::Type::Px);
} else { // margin_left.is_auto() && margin_right.is_auto()
auto half_of_the_underflow = Length(underflow_px / 2, Length::Type::Px);
margin_left = half_of_the_underflow;
margin_right = half_of_the_underflow;
}
}
} else if (!is_replaced() && is_inline_block()) {
// 10.3.9 'Inline-block', non-replaced elements in normal flow
// A computed value of 'auto' for 'margin-left' or 'margin-right' becomes a used value of '0'.
if (margin_left.is_auto())
margin_left = zero_value;
if (margin_right.is_auto())
margin_right = zero_value;
// If 'width' is 'auto', the used value is the shrink-to-fit width as for floating elements.
if (width.is_auto()) {
// Find the available width: in this case, this is the width of the containing
// block minus the used values of 'margin-left', 'border-left-width', 'padding-left',
// 'padding-right', 'border-right-width', 'margin-right', and the widths of any relevant scroll bars.
float available_width = containing_block.width()
- margin_left.to_px(*this) - border_left.to_px(*this) - padding_left.to_px(*this)
- padding_right.to_px(*this) - border_right.to_px(*this) - margin_right.to_px(*this);
auto result = calculate_shrink_to_fit_width();
// Then the shrink-to-fit width is: min(max(preferred minimum width, available width), preferred width).
width = Length(min(max(result.preferred_minimum_width, available_width), result.preferred_width), Length::Type::Px);
}
}
return width;
};
auto specified_width = style.length_or_fallback(CSS::PropertyID::Width, auto_value, containing_block.width());
// 1. The tentative used width is calculated (without 'min-width' and 'max-width')
auto used_width = try_compute_width(specified_width);
// 2. The tentative used width is greater than 'max-width', the rules above are applied again,
// but this time using the computed value of 'max-width' as the computed value for 'width'.
auto specified_max_width = style.length_or_fallback(CSS::PropertyID::MaxWidth, auto_value, containing_block.width());
if (!specified_max_width.is_auto()) {
if (used_width.to_px(*this) > specified_max_width.to_px(*this)) {
used_width = try_compute_width(specified_max_width);
}
}
// 3. If the resulting width is smaller than 'min-width', the rules above are applied again,
// but this time using the value of 'min-width' as the computed value for 'width'.
auto specified_min_width = style.length_or_fallback(CSS::PropertyID::MinWidth, auto_value, containing_block.width());
if (!specified_min_width.is_auto()) {
if (used_width.to_px(*this) < specified_min_width.to_px(*this)) {
used_width = try_compute_width(specified_min_width);
}
}
set_width(used_width.to_px(*this));
box_model().margin().left = margin_left;
box_model().margin().right = margin_right;
box_model().border().left = border_left;
box_model().border().right = border_right;
box_model().padding().left = padding_left;
box_model().padding().right = padding_right;
}
void LayoutBlock::place_block_level_replaced_element_in_normal_flow(LayoutReplaced& box)
{
ASSERT(!is_absolutely_positioned());
auto& style = box.style();
auto zero_value = Length(0, Length::Type::Px);
auto& containing_block = *this;
auto& replaced_element_box_model = box.box_model();
replaced_element_box_model.margin().top = style.length_or_fallback(CSS::PropertyID::MarginTop, zero_value, containing_block.width());
replaced_element_box_model.margin().bottom = style.length_or_fallback(CSS::PropertyID::MarginBottom, zero_value, containing_block.width());
replaced_element_box_model.border().top = style.length_or_fallback(CSS::PropertyID::BorderTopWidth, zero_value);
replaced_element_box_model.border().bottom = style.length_or_fallback(CSS::PropertyID::BorderBottomWidth, zero_value);
replaced_element_box_model.padding().top = style.length_or_fallback(CSS::PropertyID::PaddingTop, zero_value, containing_block.width());
replaced_element_box_model.padding().bottom = style.length_or_fallback(CSS::PropertyID::PaddingBottom, zero_value, containing_block.width());
float x = replaced_element_box_model.margin().left.to_px(*this)
+ replaced_element_box_model.border().left.to_px(*this)
+ replaced_element_box_model.padding().left.to_px(*this)
+ replaced_element_box_model.offset().left.to_px(*this);
float y = replaced_element_box_model.margin_box(*this).top + box_model().offset().top.to_px(*this);
box.set_offset(x, y);
}
LayoutBlock::ShrinkToFitResult LayoutBlock::calculate_shrink_to_fit_width()
{
auto greatest_child_width = [&] {
float max_width = 0;
if (children_are_inline()) {
for (auto& box : line_boxes()) {
max_width = max(max_width, box.width());
}
} else {
for_each_child([&](auto& child) {
if (child.is_box())
max_width = max(max_width, to<LayoutBox>(child).width());
});
}
return max_width;
};
// Calculate the preferred width by formatting the content without breaking lines
// other than where explicit line breaks occur.
layout_inside(LayoutMode::OnlyRequiredLineBreaks);
float preferred_width = greatest_child_width();
// Also calculate the preferred minimum width, e.g., by trying all possible line breaks.
// CSS 2.2 does not define the exact algorithm.
layout_inside(LayoutMode::AllPossibleLineBreaks);
float preferred_minimum_width = greatest_child_width();
return { preferred_width, preferred_minimum_width };
}
void LayoutBlock::place_block_level_non_replaced_element_in_normal_flow(LayoutBlock& block)
{
auto& style = block.style();
auto zero_value = Length(0, Length::Type::Px);
auto& containing_block = *this;
auto& box = block.box_model();
box.margin().top = style.length_or_fallback(CSS::PropertyID::MarginTop, zero_value, containing_block.width());
box.margin().bottom = style.length_or_fallback(CSS::PropertyID::MarginBottom, zero_value, containing_block.width());
box.border().top = style.length_or_fallback(CSS::PropertyID::BorderTopWidth, zero_value);
box.border().bottom = style.length_or_fallback(CSS::PropertyID::BorderBottomWidth, zero_value);
box.padding().top = style.length_or_fallback(CSS::PropertyID::PaddingTop, zero_value, containing_block.width());
box.padding().bottom = style.length_or_fallback(CSS::PropertyID::PaddingBottom, zero_value, containing_block.width());
float x = box.margin().left.to_px(*this)
+ box.border().left.to_px(*this)
+ box.padding().left.to_px(*this)
+ box.offset().left.to_px(*this);
if (this->style().text_align() == CSS::ValueID::VendorSpecificCenter) {
x = (containing_block.width() / 2) - block.width() / 2;
}
float y = box.margin_box(*this).top
+ box.offset().top.to_px(*this);
auto* relevant_sibling = block.previous_sibling();
while (relevant_sibling != nullptr) {
if (relevant_sibling->position() != CSS::Position::Absolute)
break;
relevant_sibling = relevant_sibling->previous_sibling();
}
if (relevant_sibling) {
auto& sibling_box = relevant_sibling->box_model();
y += relevant_sibling->effective_offset().y() + relevant_sibling->height();
// Collapse top margin with bottom margin of previous sibling if necessary
float previous_sibling_margin_bottom = sibling_box.margin().bottom.to_px(*relevant_sibling);
float my_margin_top = box.margin().top.to_px(*this);
if (my_margin_top < 0 || previous_sibling_margin_bottom < 0) {
// Negative margins present.
float largest_negative_margin = -min(my_margin_top, previous_sibling_margin_bottom);
float largest_positive_margin = (my_margin_top < 0 && previous_sibling_margin_bottom < 0) ? 0 : max(my_margin_top, previous_sibling_margin_bottom);
float final_margin = largest_positive_margin - largest_negative_margin;
y += final_margin - my_margin_top;
} else if (previous_sibling_margin_bottom > my_margin_top) {
// Sibling's margin is larger than mine, adjust so we use sibling's.
y += previous_sibling_margin_bottom - my_margin_top;
}
}
block.set_offset(x, y);
}
void LayoutBlock::compute_height()
{
auto& style = this->style();
auto specified_height = style.length_or_fallback(CSS::PropertyID::Height, Length(), containing_block()->height());
auto specified_max_height = style.length_or_fallback(CSS::PropertyID::MaxHeight, Length(), containing_block()->height());
auto& containing_block = *this->containing_block();
box_model().margin().top = style.length_or_fallback(CSS::PropertyID::MarginTop, Length(0, Length::Type::Px), containing_block.width());
box_model().margin().bottom = style.length_or_fallback(CSS::PropertyID::MarginBottom, Length(0, Length::Type::Px), containing_block.width());
box_model().border().top = style.length_or_fallback(CSS::PropertyID::BorderTopWidth, Length(0, Length::Type::Px));
box_model().border().bottom = style.length_or_fallback(CSS::PropertyID::BorderBottomWidth, Length(0, Length::Type::Px));
box_model().padding().top = style.length_or_fallback(CSS::PropertyID::PaddingTop, Length(0, Length::Type::Px), containing_block.width());
box_model().padding().bottom = style.length_or_fallback(CSS::PropertyID::PaddingBottom, Length(0, Length::Type::Px), containing_block.width());
if (!specified_height.is_auto()) {
float used_height = specified_height.to_px(*this);
if (!specified_max_height.is_auto())
used_height = min(used_height, specified_max_height.to_px(*this));
set_height(used_height);
}
}
void LayoutBlock::paint(PaintContext& context, PaintPhase phase)
{
if (!is_visible())
return;
LayoutBox::paint(context, phase);
// FIXME: Inline backgrounds etc.
if (phase == PaintPhase::Foreground) {
if (children_are_inline()) {
for (auto& line_box : m_line_boxes) {
for (auto& fragment : line_box.fragments()) {
if (context.should_show_line_box_borders())
context.painter().draw_rect(enclosing_int_rect(fragment.absolute_rect()), Color::Green);
fragment.render(context);
}
}
}
}
}
HitTestResult LayoutBlock::hit_test(const Gfx::IntPoint& position) const
{
if (!children_are_inline())
return LayoutBox::hit_test(position);
HitTestResult result;
for (auto& line_box : m_line_boxes) {
for (auto& fragment : line_box.fragments()) {
if (enclosing_int_rect(fragment.absolute_rect()).contains(position)) {
if (fragment.layout_node().is_block())
return to<LayoutBlock>(fragment.layout_node()).hit_test(position);
return { fragment.layout_node(), fragment.text_index_at(position.x()) };
}
}
}
// FIXME: This should be smarter about the text position if we're hitting a block
// that has text inside it, but `position` is to the right of the text box.
return { absolute_rect().contains(position.x(), position.y()) ? this : nullptr };
}
NonnullRefPtr<StyleProperties> LayoutBlock::style_for_anonymous_block() const
{
auto new_style = StyleProperties::create();
style().for_each_property([&](auto property_id, auto& value) {
if (StyleResolver::is_inherited_property(property_id))
new_style->set_property(property_id, value);
});
return new_style;
}
LineBox& LayoutBlock::ensure_last_line_box()
{
if (m_line_boxes.is_empty())
m_line_boxes.append(LineBox());
return m_line_boxes.last();
}
LineBox& LayoutBlock::add_line_box()
{
m_line_boxes.append(LineBox());
return m_line_boxes.last();
}
void LayoutBlock::split_into_lines(LayoutBlock& container, LayoutMode layout_mode)
{
layout(layout_mode);
auto* line_box = &container.ensure_last_line_box();
if (layout_mode != LayoutMode::OnlyRequiredLineBreaks && line_box->width() > 0 && line_box->width() + width() > container.width()) {
line_box = &container.add_line_box();
}
line_box->add_fragment(*this, 0, 0, width(), height());
}
}
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