Source/WebCore/layout/RenderBlockFlowLineLayout.cpp

/*
 * Copyright (C) 2019 Apple Inc. All rights reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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 *    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 APPLE INC. AND ITS 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 APPLE INC. OR ITS CONTRIBUTORS
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#include "config.h"
#include "RenderBlockFlowLineLayout.h"

#if ENABLE(LAYOUT_FORMATTING_CONTEXT)

#include "DisplayBox.h"
#include "DisplayPainter.h"
#include "InlineFormattingState.h"
#include "InvalidationState.h"
#include "LayoutContext.h"
#include "LayoutTreeBuilder.h"
#include "PaintInfo.h"
#include "RenderBlockFlow.h"
#include "RenderLineBreak.h"
#include "RuntimeEnabledFeatures.h"
#include "SimpleLineLayout.h"

namespace WebCore {
namespace Layout {

RenderBlockFlowLineLayout::RenderBlockFlowLineLayout(const RenderBlockFlow& flow)
    : m_flow(flow)
{
    m_treeContent = TreeBuilder::buildLayoutTree(flow);
}

RenderBlockFlowLineLayout::~RenderBlockFlowLineLayout() = default;

bool RenderBlockFlowLineLayout::canUseFor(const RenderBlockFlow& flow)
{
    if (!RuntimeEnabledFeatures::sharedFeatures().layoutFormattingContextRenderTreeIntegrationEnabled())
        return false;

    // Initially only a subset of SLL features is supported.
    if (!SimpleLineLayout::canUseFor(flow))
        return false;

    if (flow.style().textTransform() == TextTransform::Capitalize)
        return false;

    if (flow.fragmentedFlowState() != RenderObject::NotInsideFragmentedFlow)
        return false;

    return true;
}

void RenderBlockFlowLineLayout::layout()
{
    if (!m_layoutState)
        m_layoutState = makeUnique<LayoutState>(*m_treeContent);

    auto& rootContainer = m_layoutState->root();
    auto layoutContext = LayoutContext { *m_layoutState };
    auto invalidationState = InvalidationState { };
    layoutContext.layout(m_flow.contentSize(), invalidationState);

    auto& lineBoxes = downcast<InlineFormattingState>(m_layoutState->establishedFormattingState(rootContainer)).displayInlineContent()->lineBoxes;
    auto height = lineBoxes.last().logicalBottom();

    auto& displayBox = m_layoutState->displayBoxForLayoutBox(rootContainer);
    displayBox.setContentBoxHeight(height);
}

LayoutUnit RenderBlockFlowLineLayout::contentBoxHeight() const
{
    return m_layoutState ? m_layoutState->displayBoxForLayoutBox(m_layoutState->root()).contentBoxHeight() : 0_lu;
}

const Display::InlineContent* RenderBlockFlowLineLayout::displayInlineContent() const
{
    return downcast<InlineFormattingState>(m_layoutState->establishedFormattingState(m_treeContent->rootLayoutBox())).displayInlineContent();
}

void RenderBlockFlowLineLayout::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    auto& graphicsContext = paintInfo.context();

    graphicsContext.save();
    graphicsContext.translate(paintOffset);

    Display::Painter::paintInlineFlow(*m_layoutState, paintInfo.context());

    graphicsContext.restore();
}

LineLayoutTraversal::TextBoxIterator RenderBlockFlowLineLayout::textBoxesFor(const RenderText& renderText) const
{
    auto* inlineContent = displayInlineContent();
    if (!inlineContent)
        return { };
    auto* layoutBox = m_treeContent->layoutBoxForRenderer(renderText);
    ASSERT(layoutBox);

    Optional<size_t> firstIndex = 0;
    size_t lastIndex = 0;
    for (size_t i = 0; i < inlineContent->runs.size(); ++i) {
        auto& run =  inlineContent->runs[i];
        if (&run.layoutBox() == layoutBox) {
            if (!firstIndex)
                firstIndex = i;
            lastIndex = i;
        }
    }
    if (!firstIndex)
        return { };

    return { LineLayoutTraversal::DisplayRunPath(*inlineContent, *firstIndex, lastIndex + 1) };
}

LineLayoutTraversal::ElementBoxIterator RenderBlockFlowLineLayout::elementBoxFor(const RenderLineBreak& renderLineBreak) const
{
    auto* inlineContent = displayInlineContent();
    if (!inlineContent)
        return { };
    auto* layoutBox = m_treeContent->layoutBoxForRenderer(renderLineBreak);
    ASSERT(layoutBox);

    for (size_t i = 0; i < inlineContent->runs.size(); ++i) {
        auto& run =  inlineContent->runs[i];
        if (&run.layoutBox() == layoutBox)
            return { LineLayoutTraversal::DisplayRunPath(*inlineContent, i, i + 1) };
    }

    return { };
}

}
}

#endif