ladybird/Libraries/LibHTML/Layout/LayoutBlock.cpp

#include <LibHTML/CSS/StyledNode.h>
#include <LibHTML/DOM/Element.h>
#include <LibHTML/Layout/LayoutBlock.h>

LayoutBlock::LayoutBlock(const Node* node, const StyledNode* styled_node)
    : LayoutNode(node, styled_node)
{
}

LayoutBlock::~LayoutBlock()
{
}

LayoutNode& LayoutBlock::inline_wrapper()
{
    if (!last_child() || !last_child()->is_block()) {
        append_child(adopt(*new LayoutBlock(nullptr, nullptr)));
    }
    return *last_child();
}

void LayoutBlock::layout()
{
    compute_width();

    LayoutNode::layout();

    compute_height();
}

void LayoutBlock::compute_width()
{
    if (!styled_node()) {
        // I guess the size is "auto" in this case.
        return;
    }

    auto auto_value= LengthStyleValue::create({});
    auto& styled_node = *this->styled_node();
    auto width = styled_node.property("width").value_or(auto_value);

    auto zero_value = LengthStyleValue::create(Length(0, Length::Type::Absolute));

    auto margin_left = styled_node.property("margin-left").value_or(zero_value);
    auto margin_right = styled_node.property("margin-right").value_or(zero_value);
    auto border_left = styled_node.property("border-left").value_or(zero_value);
    auto border_right = styled_node.property("border-right").value_or(zero_value);
    auto padding_left = styled_node.property("padding-left").value_or(zero_value);
    auto padding_right = styled_node.property("padding-right").value_or(zero_value);

    dbg() << " Left: " << margin_left->to_string() << "+" << border_left->to_string() << "+" << padding_left->to_string();
    dbg() << "Right: " << margin_right->to_string() << "+" << border_right->to_string() << "+" << padding_right->to_string();

    int total_px = 0;
    for (auto& value : { margin_left, border_left, padding_left, width, padding_right, border_right, margin_right }) {
        total_px += value->to_length().to_px();
    }

    dbg() << "Total: " << total_px;

    // 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->to_length().is_auto() && total_px > containing_block()->rect().width()) {
        if (margin_left->to_length().is_auto())
            margin_left = zero_value;
        if (margin_right->to_length().is_auto())
            margin_right = zero_value;
    }
}

void LayoutBlock::compute_height()
{
}