ladybird/Libraries/LibHTML/Layout/LayoutBlock.cpp
Andreas Kling ee567cdc3d LibHTML: Implement basic layout for inline <img alt>
LayoutReplaced objects can now participate in inline layout.

It's very hackish, but basically LayoutReplaced will just add itself to
the last line in the containing block.

This patch gets rid of the idea that only LayoutInline subclasses can
be split into lines, by moving the split_into_lines() virtual up to
LayoutNode and overriding it in LayoutReplaced.
2019-10-05 23:29:01 +02:00

238 lines
8.4 KiB
C++

#include <LibGUI/GPainter.h>
#include <LibHTML/DOM/Element.h>
#include <LibHTML/Layout/LayoutBlock.h>
#include <LibHTML/Layout/LayoutInline.h>
LayoutBlock::LayoutBlock(const Node* node, NonnullRefPtr<StyleProperties> style_properties)
: LayoutNode(node, move(style_properties))
{
}
LayoutBlock::~LayoutBlock()
{
}
LayoutNode& LayoutBlock::inline_wrapper()
{
if (!last_child() || !last_child()->is_block() || last_child()->node() != nullptr) {
append_child(adopt(*new LayoutBlock(nullptr, style())));
}
return *last_child();
}
void LayoutBlock::layout()
{
compute_width();
compute_position();
if (children_are_inline())
layout_inline_children();
else
layout_block_children();
compute_height();
}
void LayoutBlock::layout_block_children()
{
ASSERT(!children_are_inline());
int content_height = 0;
for_each_child([&](auto& child) {
child.layout();
content_height = child.rect().bottom() + child.box_model().full_margin().bottom - rect().top();
});
rect().set_height(content_height);
}
void LayoutBlock::layout_inline_children()
{
ASSERT(children_are_inline());
m_line_boxes.clear();
for_each_child([&](auto& child) {
ASSERT(child.is_inline());
child.split_into_lines(*this);
});
int content_height = 0;
for (auto& line_box : m_line_boxes) {
int max_height = 0;
for (auto& fragment : line_box.fragments()) {
max_height = max(max_height, fragment.rect().height());
}
for (auto& fragment : line_box.fragments()) {
// Vertically align everyone's bottom to the line.
// FIXME: Support other kinds of vertical alignment.
fragment.rect().set_x(rect().x() + fragment.rect().x());
fragment.rect().set_y(rect().y() + content_height + (max_height - fragment.rect().height()));
if (fragment.layout_node().is_replaced())
const_cast<LayoutNode&>(fragment.layout_node()).set_rect(fragment.rect());
}
content_height += max_height;
}
rect().set_height(content_height);
}
void LayoutBlock::compute_width()
{
auto& style_properties = this->style();
auto auto_value = Length();
auto zero_value = Length(0, Length::Type::Absolute);
auto width = style_properties.length_or_fallback("width", auto_value);
auto margin_left = style_properties.length_or_fallback("margin-left", zero_value);
auto margin_right = style_properties.length_or_fallback("margin-right", zero_value);
auto border_left = style_properties.length_or_fallback("border-left", zero_value);
auto border_right = style_properties.length_or_fallback("border-right", zero_value);
auto padding_left = style_properties.length_or_fallback("padding-left", zero_value);
auto padding_right = style_properties.length_or_fallback("padding-right", zero_value);
#ifdef HTML_DEBUG
dbg() << " Left: " << margin_left << "+" << border_left << "+" << padding_left;
dbg() << "Right: " << margin_right << "+" << border_right << "+" << padding_right;
#endif
int total_px = 0;
for (auto& value : { margin_left, border_left, padding_left, width, padding_right, border_right, margin_right }) {
total_px += value.to_px();
}
#ifdef HTML_DEBUG
dbg() << "Total: " << total_px;
#endif
// 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()->rect().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()->rect().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::Absolute);
} else {
width = zero_value;
margin_right = Length(margin_right.to_px() + underflow_px, Length::Type::Absolute);
}
} else {
if (!margin_left.is_auto() && !margin_right.is_auto()) {
margin_right = Length(margin_right.to_px() + underflow_px, Length::Type::Absolute);
} else if (!margin_left.is_auto() && margin_right.is_auto()) {
margin_right = Length(underflow_px, Length::Type::Absolute);
} else if (margin_left.is_auto() && !margin_right.is_auto()) {
margin_left = Length(underflow_px, Length::Type::Absolute);
} else { // margin_left.is_auto() && margin_right.is_auto()
auto half_of_the_underflow = Length(underflow_px / 2, Length::Type::Absolute);
margin_left = half_of_the_underflow;
margin_right = half_of_the_underflow;
}
}
rect().set_width(width.to_px());
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_position()
{
auto& style_properties = this->style();
auto auto_value = Length();
auto zero_value = Length(0, Length::Type::Absolute);
auto width = style_properties.length_or_fallback("width", auto_value);
box_model().margin().top = style_properties.length_or_fallback("margin-top", zero_value);
box_model().margin().bottom = style_properties.length_or_fallback("margin-bottom", zero_value);
box_model().border().top = style_properties.length_or_fallback("border-top", zero_value);
box_model().border().bottom = style_properties.length_or_fallback("border-bottom", zero_value);
box_model().padding().top = style_properties.length_or_fallback("padding-top", zero_value);
box_model().padding().bottom = style_properties.length_or_fallback("padding-bottom", zero_value);
rect().set_x(containing_block()->rect().x() + box_model().margin().left.to_px() + box_model().border().left.to_px() + box_model().padding().left.to_px());
int top_border = -1;
if (previous_sibling() != nullptr) {
auto& previous_sibling_rect = previous_sibling()->rect();
auto& previous_sibling_style = previous_sibling()->box_model();
top_border = previous_sibling_rect.y() + previous_sibling_rect.height();
top_border += previous_sibling_style.full_margin().bottom;
} else {
top_border = containing_block()->rect().y();
}
rect().set_y(top_border + box_model().full_margin().top);
}
void LayoutBlock::compute_height()
{
auto& style_properties = this->style();
auto height_property = style_properties.property("height");
if (!height_property.has_value())
return;
auto height_length = height_property.value()->to_length();
if (height_length.is_absolute())
rect().set_height(height_length.to_px());
}
void LayoutBlock::render(RenderingContext& context)
{
LayoutNode::render(context);
// FIXME: position this properly
if (style().string_or_fallback("display", "block") == "list-item") {
Rect bullet_rect {
rect().x() - 8,
rect().y() + 4,
3,
3
};
context.painter().fill_rect(bullet_rect, style().color_or_fallback("color", Color::Black));
}
if (children_are_inline()) {
for (auto& line_box : m_line_boxes) {
for (auto& fragment : line_box.fragments()) {
fragment.render(context);
}
}
}
}
bool LayoutBlock::children_are_inline() const
{
return first_child() && !first_child()->is_block();
}
HitTestResult LayoutBlock::hit_test(const Point& position) const
{
if (!children_are_inline())
return LayoutNode::hit_test(position);
HitTestResult result;
for (auto& line_box : m_line_boxes) {
for (auto& fragment : line_box.fragments()) {
if (fragment.rect().contains(position)) {
return { fragment.layout_node() };
}
}
}
return {};
}