ladybird/Userland/Libraries/LibWeb/Layout/InlineNode.cpp

/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * Copyright (c) 2021, Sam Atkins <atkinssj@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibGfx/Painter.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/DOM/Element.h>
#include <LibWeb/Layout/BlockContainer.h>
#include <LibWeb/Layout/InlineFormattingContext.h>
#include <LibWeb/Layout/InlineNode.h>
#include <LibWeb/Painting/BackgroundPainting.h>
#include <LibWeb/Painting/BorderPainting.h>
#include <LibWeb/Painting/ShadowPainting.h>

namespace Web::Layout {

InlineNode::InlineNode(DOM::Document& document, DOM::Element& element, NonnullRefPtr<CSS::StyleProperties> style)
    : Layout::NodeWithStyleAndBoxModelMetrics(document, &element, move(style))
{
    set_inline(true);
}

InlineNode::~InlineNode()
{
}

void InlineNode::split_into_lines(InlineFormattingContext& context, LayoutMode layout_mode)
{
    auto& containing_block = context.containing_block();

    auto is_not_undefined_or_auto = [](auto const& length_percentage) {
        return !(length_percentage.is_length() && length_percentage.length().is_undefined_or_auto());
    };

    if (is_not_undefined_or_auto(computed_values().padding().left)) {
        float padding_left = computed_values().padding().left.resolved(CSS::Length::make_px(containing_block.width())).resolved(CSS::Length::make_px(0), *this).to_px(*this);
        containing_block.ensure_last_line_box().add_fragment(*this, 0, 0, padding_left, 0, LineBoxFragment::Type::Leading);
    }

    NodeWithStyleAndBoxModelMetrics::split_into_lines(context, layout_mode);

    if (is_not_undefined_or_auto(computed_values().padding().right)) {
        float padding_right = computed_values().padding().right.resolved(CSS::Length::make_px(containing_block.width())).resolved(CSS::Length::make_px(0), *this).to_px(*this);
        containing_block.ensure_last_line_box().add_fragment(*this, 0, 0, padding_right, 0, LineBoxFragment::Type::Trailing);
    }
}

void InlineNode::paint(PaintContext& context, PaintPhase phase)
{
    auto& painter = context.painter();

    if (phase == PaintPhase::Background) {
        auto top_left_border_radius = computed_values().border_top_left_radius();
        auto top_right_border_radius = computed_values().border_top_right_radius();
        auto bottom_right_border_radius = computed_values().border_bottom_right_radius();
        auto bottom_left_border_radius = computed_values().border_bottom_left_radius();

        for_each_fragment([&](auto& fragment) {
            // FIXME: This recalculates our (InlineNode's) absolute_rect() for every single fragment!
            auto rect = fragment.absolute_rect();
            auto border_radius_data = Painting::normalized_border_radius_data(*this, rect, top_left_border_radius, top_right_border_radius, bottom_right_border_radius, bottom_left_border_radius);
            Painting::paint_background(context, *this, enclosing_int_rect(rect), computed_values().background_color(), &computed_values().background_layers(), border_radius_data);

            if (auto computed_box_shadow = computed_values().box_shadow(); computed_box_shadow.has_value()) {
                auto box_shadow_data = Painting::BoxShadowData {
                    .offset_x = (int)computed_box_shadow->offset_x.resolved_or_zero(*this).to_px(*this),
                    .offset_y = (int)computed_box_shadow->offset_y.resolved_or_zero(*this).to_px(*this),
                    .blur_radius = (int)computed_box_shadow->blur_radius.resolved_or_zero(*this).to_px(*this),
                    .color = computed_box_shadow->color
                };
                Painting::paint_box_shadow(context, enclosing_int_rect(rect), box_shadow_data);
            }

            return IterationDecision::Continue;
        });
    }

    if (phase == PaintPhase::Border) {
        auto top_left_border_radius = computed_values().border_top_left_radius();
        auto top_right_border_radius = computed_values().border_top_right_radius();
        auto bottom_right_border_radius = computed_values().border_bottom_right_radius();
        auto bottom_left_border_radius = computed_values().border_bottom_left_radius();

        auto borders_data = Painting::BordersData {
            .top = computed_values().border_top(),
            .right = computed_values().border_right(),
            .bottom = computed_values().border_bottom(),
            .left = computed_values().border_left(),
        };

        for_each_fragment([&](auto& fragment) {
            // FIXME: This recalculates our (InlineNode's) absolute_rect() for every single fragment!
            auto bordered_rect = fragment.absolute_rect();
            bordered_rect.inflate(borders_data.top.width, borders_data.right.width, borders_data.bottom.width, borders_data.left.width);
            auto border_radius_data = Painting::normalized_border_radius_data(*this, bordered_rect, top_left_border_radius, top_right_border_radius, bottom_right_border_radius, bottom_left_border_radius);

            Painting::paint_all_borders(context, bordered_rect, border_radius_data, borders_data);

            return IterationDecision::Continue;
        });
    }

    if (phase == PaintPhase::Foreground && document().inspected_node() == dom_node()) {
        // FIXME: This paints a double-thick border between adjacent fragments, where ideally there
        //        would be none. Once we implement non-rectangular outlines for the `outline` CSS
        //        property, we can use that here instead.
        for_each_fragment([&](auto& fragment) {
            painter.draw_rect(enclosing_int_rect(fragment.absolute_rect()), Color::Magenta);
            return IterationDecision::Continue;
        });
    }
}

template<typename Callback>
void InlineNode::for_each_fragment(Callback callback)
{
    // FIXME: This will be slow if the containing block has a lot of fragments!
    containing_block()->for_each_fragment([&](auto& fragment) {
        if (!is_inclusive_ancestor_of(fragment.layout_node()))
            return IterationDecision::Continue;
        // FIXME: This skips the 0-width fragments at the start and end of the InlineNode.
        //        A better solution would be to not generate them in the first place.
        if (fragment.width() == 0 || fragment.height() == 0)
            return IterationDecision::Continue;
        return callback(fragment);
    });
}

}