Source/WebCore/layout/integration/InlineIteratorTextBox.cpp

/*
 * Copyright (C) 2019-2021 Apple Inc. All rights reserved.
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#include "config.h"
#include "InlineIteratorTextBox.h"

#include "InlineIteratorLine.h"
#include "LayoutIntegrationLineLayout.h"
#include "RenderCombineText.h"

namespace WebCore {
namespace InlineIterator {

TextBoxIterator TextBox::nextTextBox() const
{
    return TextBoxIterator(*this).traverseNextTextBox();
}

LayoutRect TextBox::selectionRect(unsigned rangeStart, unsigned rangeEnd) const
{
    auto [clampedStart, clampedEnd] = selectableRange().clamp(rangeStart, rangeEnd);

    if (clampedStart >= clampedEnd && !(rangeStart == rangeEnd && rangeStart >= start() && rangeStart <= end()))
        return { };

    auto selectionTop = line()->selectionTop();
    auto selectionHeight = line()->selectionHeight();

    LayoutRect selectionRect { logicalLeft(), selectionTop, logicalWidth(), selectionHeight };

    TextRun textRun = createTextRun();
    if (clampedStart || clampedEnd != textRun.length())
        fontCascade().adjustSelectionRectForText(textRun, selectionRect, clampedStart, clampedEnd);

    return snappedSelectionRect(selectionRect, logicalRight(), selectionTop, selectionHeight, isHorizontal());
}

unsigned TextBox::offsetForPosition(float x, bool includePartialGlyphs) const
{
    if (isLineBreak())
        return 0;
    if (x - logicalLeft() > logicalWidth())
        return isLeftToRightDirection() ? length() : 0;
    if (x - logicalLeft() < 0)
        return isLeftToRightDirection() ? 0 : length();
    return fontCascade().offsetForPosition(createTextRun(CreateTextRunMode::Editing), x - logicalLeft(), includePartialGlyphs);
}

float TextBox::positionForOffset(unsigned offset) const
{
    ASSERT(offset >= start());
    ASSERT(offset <= end());

    if (isLineBreak())
        return logicalLeft();

    auto [startOffset, endOffset] = [&] {
        if (direction() == TextDirection::RTL)
            return std::pair { selectableRange().clamp(offset), length() };
        return std::pair { 0u, selectableRange().clamp(offset) };
    }();

    auto selectionRect = LayoutRect(logicalLeft(), 0, 0, 0);
    
    auto textRun = createTextRun(CreateTextRunMode::Editing);
    fontCascade().adjustSelectionRectForText(textRun, selectionRect, startOffset, endOffset);
    return snapRectToDevicePixelsWithWritingDirection(selectionRect, renderer().document().deviceScaleFactor(), textRun.ltr()).maxX();
}

bool TextBox::isCombinedText() const
{
    auto& renderer = this->renderer();
    return is<RenderCombineText>(renderer) && downcast<RenderCombineText>(renderer).isCombined();
}

const FontCascade& TextBox::fontCascade() const
{
    if (isCombinedText())
        return downcast<RenderCombineText>(renderer()).textCombineFont();

    return style().fontCascade();
}

TextBoxIterator::TextBoxIterator(Box::PathVariant&& pathVariant)
    : LeafBoxIterator(WTFMove(pathVariant))
{
}

TextBoxIterator::TextBoxIterator(const Box& box)
    : LeafBoxIterator(box)
{
}

TextBoxIterator& TextBoxIterator::traverseNextTextBox()
{
    WTF::switchOn(m_box.m_pathVariant, [](auto& path) {
        path.traverseNextTextBox();
    });
    return *this;
}

TextBoxIterator firstTextBoxFor(const RenderText& text)
{
#if ENABLE(LAYOUT_FORMATTING_CONTEXT)
    if (auto* lineLayout = LayoutIntegration::LineLayout::containing(text))
        return lineLayout->textBoxesFor(text);
#endif

    return { BoxLegacyPath { text.firstTextBox() } };
}

TextBoxIterator textBoxFor(const LegacyInlineTextBox* legacyInlineTextBox)
{
    return { BoxLegacyPath { legacyInlineTextBox } };
}

#if ENABLE(LAYOUT_FORMATTING_CONTEXT)
TextBoxIterator textBoxFor(const LayoutIntegration::InlineContent& content, const InlineDisplay::Box& box)
{
    return textBoxFor(content, content.indexForBox(box));
}

TextBoxIterator textBoxFor(const LayoutIntegration::InlineContent& content, size_t boxIndex)
{
    ASSERT(content.boxes[boxIndex].text());
    return { BoxModernPath { content, boxIndex } };
}
#endif

TextBoxRange textBoxesFor(const RenderText& text)
{
    return { firstTextBoxFor(text) };
}

}
}