ladybird/Libraries/LibHTML/Frame.cpp

#include <AK/Function.h>
#include <LibHTML/CSS/StyleResolver.h>
#include <LibHTML/CSS/StyledNode.h>
#include <LibHTML/DOM/Element.h>
#include <LibHTML/Dump.h>
#include <LibHTML/Frame.h>
#include <LibHTML/Layout/LayoutBlock.h>
#include <LibHTML/Layout/LayoutDocument.h>
#include <LibHTML/Layout/LayoutInline.h>
#include <stdio.h>

Frame::Frame()
    : m_size(800, 600)
{
}

Frame::~Frame()
{
}

void Frame::set_document(Document* document)
{
    m_document = document;
}

RefPtr<StyledNode> Frame::generate_style_tree()
{
    if (!m_document)
        return nullptr;

    auto& resolver = m_document->style_resolver();
    Function<RefPtr<StyledNode>(const Node&, StyledNode*)> resolve_style = [&](const Node& node, StyledNode* parent_styled_node) -> RefPtr<StyledNode> {
        RefPtr<StyledNode> styled_node;
        if (node.is_element())
            styled_node = resolver.create_styled_node(static_cast<const Element&>(node));
        else if (node.is_document())
            styled_node = resolver.create_styled_node(static_cast<const Document&>(node));
        if (!styled_node)
            return nullptr;
        if (parent_styled_node)
            parent_styled_node->append_child(*styled_node);
        static_cast<const ParentNode&>(node).for_each_child([&](const Node& child) {
            if (!child.is_element())
                return;
            auto styled_child_node = resolve_style(static_cast<const Element&>(child), styled_node.ptr());
            printf("Created StyledNode{%p} for Element{%p}\n", styled_child_node.ptr(), &node);
        });
        return styled_node;
    };
    auto styled_root = resolve_style(*m_document, nullptr);
    dump_tree(*styled_root);
    return styled_root;
}

RefPtr<LayoutNode> Frame::generate_layout_tree(const StyledNode& styled_root)
{
    auto create_layout_node = [](const StyledNode& styled_node) -> RefPtr<LayoutNode> {
        if (styled_node.node() && styled_node.node()->is_document())
            return adopt(*new LayoutDocument(static_cast<const Document&>(*styled_node.node()), styled_node));
        switch (styled_node.display()) {
        case Display::None:
            return nullptr;
        case Display::Block:
            return adopt(*new LayoutBlock(styled_node.node(), &styled_node));
        case Display::Inline:
            return adopt(*new LayoutInline(*styled_node.node(), styled_node));
        default:
            ASSERT_NOT_REACHED();
        }
    };

    Function<RefPtr<LayoutNode>(const StyledNode&)> build_layout_tree;
    build_layout_tree = [&](const StyledNode& styled_node) -> RefPtr<LayoutNode> {
        auto layout_node = create_layout_node(styled_node);
        if (!layout_node)
            return nullptr;
        if (!styled_node.has_children())
            return layout_node;
        for (auto* styled_child = styled_node.first_child(); styled_child; styled_child = styled_child->next_sibling()) {
            auto layout_child = build_layout_tree(*styled_child);
            if (!layout_child)
                continue;
            if (layout_child->is_inline())
                layout_node->inline_wrapper().append_child(*layout_child);
            else
                layout_node->append_child(*layout_child);
        }
        return layout_node;
    };
    return build_layout_tree(styled_root);
}

void Frame::layout()
{
    if (!m_document)
        return;

    auto styled_root = generate_style_tree();
    auto layout_root = generate_layout_tree(*styled_root);

    layout_root->style().size().set_width(m_size.width());

    printf("\033[33;1mLayout tree before layout:\033[0m\n");
    dump_tree(*layout_root);

    layout_root->layout();

    printf("\033[33;1mLayout tree after layout:\033[0m\n");
    dump_tree(*layout_root);
}