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ladybird/Libraries/LibWeb/Layout/LayoutBlock.cpp
Andreas Kling 5e83a97fa2 LibWeb: Rename LayoutNode::style() => specified_style() 
Let's make way for a slightly-more-cooked style() that will eventually
replace the raw specified_style() for layout and paint purposes.
2020-06-24 13:54:31 +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.specified_style();
auto zero_value = Length::make_px(0);
auto specified_width = style.length_or_fallback(CSS::PropertyID::Width, Length::make_auto(), width());
box_model.margin.top = style.length_or_fallback(CSS::PropertyID::MarginTop, Length::make_auto(), height());
box_model.margin.right = style.length_or_fallback(CSS::PropertyID::MarginRight, Length::make_auto(), width());
box_model.margin.bottom = style.length_or_fallback(CSS::PropertyID::MarginBottom, Length::make_auto(), height());
box_model.margin.left = style.length_or_fallback(CSS::PropertyID::MarginLeft, Length::make_auto(), width());
box_model.offset.top = style.length_or_fallback(CSS::PropertyID::Top, Length::make_auto(), height());
box_model.offset.right = style.length_or_fallback(CSS::PropertyID::Right, Length::make_auto(), width());
box_model.offset.bottom = style.length_or_fallback(CSS::PropertyID::Bottom, Length::make_auto(), height());
box_model.offset.left = style.length_or_fallback(CSS::PropertyID::Left, Length::make_auto(), 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 = specified_style().length_or_fallback(CSS::PropertyID::Width, Length::make_auto(), 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 = this->text_align();
float min_line_height = specified_style().line_height(*this);
float line_spacing = min_line_height - specified_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::TextAlign::Center:
case CSS::TextAlign::VendorSpecificCenter:
x_offset += excess_horizontal_space / 2;
break;
case CSS::TextAlign::Right:
x_offset += excess_horizontal_space;
break;
case CSS::TextAlign::Left:
case CSS::TextAlign::Justify:
default:
break;
}
float excess_horizontal_space_including_whitespace = excess_horizontal_space;
int whitespace_count = 0;
if (text_align == CSS::TextAlign::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::TextAlign::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->specified_style();
auto& containing_block = *this->containing_block();
auto zero_value = Length::make_px(0);
Length margin_left = Length::make_auto();
Length margin_right = Length::make_auto();
Length border_left = Length::make_auto();
Length border_right = Length::make_auto();
Length padding_left = Length::make_auto();
Length padding_right = Length::make_auto();
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, Length::make_auto(), containing_block.width());
auto right = style.length_or_fallback(CSS::PropertyID::Right, Length::make_auto(), 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::make_px(0);
if (margin_right.is_auto())
margin_right = Length::make_px(0);
// 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::make_px(0);
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::make_px(0);
if (margin_right.is_auto())
margin_right = Length::make_px(0);
// 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, Length::make_auto(), 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, Length::make_auto(), 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, Length::make_auto(), 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->specified_style();
auto auto_value = Length::make_auto();
auto zero_value = Length::make_px(0);
Length margin_left = Length::make_auto();
Length margin_right = Length::make_auto();
Length border_left = Length::make_auto();
Length border_right = Length::make_auto();
Length padding_left = Length::make_auto();
Length padding_right = Length::make_auto();
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.specified_style();
auto zero_value = Length::make_px(0);
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.specified_style();
auto zero_value = Length::make_px(0);
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 (text_align() == CSS::TextAlign::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->specified_style();
auto specified_height = style.length_or_fallback(CSS::PropertyID::Height, Length::make_auto(), containing_block()->height());
auto specified_max_height = style.length_or_fallback(CSS::PropertyID::MaxHeight, Length::make_auto(), containing_block()->height());
auto& containing_block = *this->containing_block();
box_model().margin.top = style.length_or_fallback(CSS::PropertyID::MarginTop, Length::make_px(0), containing_block.width());
box_model().margin.bottom = style.length_or_fallback(CSS::PropertyID::MarginBottom, Length::make_px(0), containing_block.width());
box_model().border.top = style.length_or_fallback(CSS::PropertyID::BorderTopWidth, Length::make_px(0));
box_model().border.bottom = style.length_or_fallback(CSS::PropertyID::BorderBottomWidth, Length::make_px(0));
box_model().padding.top = style.length_or_fallback(CSS::PropertyID::PaddingTop, Length::make_px(0), containing_block.width());
box_model().padding.bottom = style.length_or_fallback(CSS::PropertyID::PaddingBottom, Length::make_px(0), 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();
specified_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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