Move painting code from InlineTextBox to InlineTextBoxPainter.

Source/core/paint/InlineTextBoxPainter.cpp

Index: Source/core/paint/InlineTextBoxPainter.cpp
diff --git a/Source/core/paint/InlineTextBoxPainter.cpp b/Source/core/paint/InlineTextBoxPainter.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..4a8540bc812838f73f63b47af585db4712b12a78
--- /dev/null
+++ b/Source/core/paint/InlineTextBoxPainter.cpp
@@ -0,0 +1,791 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/paint/InlineTextBoxPainter.h"
+
+#include "core/dom/DocumentMarkerController.h"
+#include "core/dom/RenderedDocumentMarker.h"
+#include "core/editing/CompositionUnderline.h"
+#include "core/editing/CompositionUnderlineRangeFilter.h"
+#include "core/editing/Editor.h"
+#include "core/editing/InputMethodController.h"
+#include "core/frame/LocalFrame.h"
+#include "core/paint/BoxPainter.h"
+#include "core/rendering/InlineTextBox.h"
+#include "core/rendering/PaintInfo.h"
+#include "core/rendering/RenderBlock.h"
+#include "core/rendering/RenderCombineText.h"
+#include "core/rendering/RenderTheme.h"
+#include "core/rendering/TextPainter.h"
+
+namespace blink {
+
+typedef WTF::HashMap<const InlineTextBox*, TextBlobPtr> InlineTextBoxBlobCacheMap;
+static InlineTextBoxBlobCacheMap* gTextBlobCache;
+
+static const int misspellingLineThickness = 3;
+
+void InlineTextBoxPainter::removeFromTextBlobCache(InlineTextBox& inlineTextBox)
+{
+    if (gTextBlobCache)
+        gTextBlobCache->remove(&inlineTextBox);
+}
+
+void InlineTextBoxPainter::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
+{
+    if (m_inlineTextBox.isLineBreak() || !paintInfo.shouldPaintWithinRoot(&m_inlineTextBox.renderer()) || m_inlineTextBox.renderer().style()->visibility() != VISIBLE
+        || m_inlineTextBox.truncation() == cFullTruncation || paintInfo.phase == PaintPhaseOutline || !m_inlineTextBox.len())
+        return;
+
+    ASSERT(paintInfo.phase != PaintPhaseSelfOutline && paintInfo.phase != PaintPhaseChildOutlines);
+
+    LayoutRect logicalVisualOverflow = m_inlineTextBox.logicalOverflowRect();
+    LayoutUnit logicalStart = logicalVisualOverflow.x() + (m_inlineTextBox.isHorizontal() ? paintOffset.x() : paintOffset.y());
+    LayoutUnit logicalExtent = logicalVisualOverflow.width();
+
+    LayoutUnit paintEnd = m_inlineTextBox.isHorizontal() ? paintInfo.rect.maxX() : paintInfo.rect.maxY();
+    LayoutUnit paintStart = m_inlineTextBox.isHorizontal() ? paintInfo.rect.x() : paintInfo.rect.y();
+
+    // When subpixel font scaling is enabled text runs are positioned at
+    // subpixel boundaries on the x-axis and thus there is no reason to
+    // snap the x value. We still round the y-axis to ensure consistent
+    // line heights.
+    LayoutPoint adjustedPaintOffset = RuntimeEnabledFeatures::subpixelFontScalingEnabled()
+        ? LayoutPoint(paintOffset.x(), paintOffset.y().round())
+        : roundedIntPoint(paintOffset);
+
+    if (logicalStart >= paintEnd || logicalStart + logicalExtent <= paintStart)
+        return;
+
+    bool isPrinting = m_inlineTextBox.renderer().document().printing();
+
+    // Determine whether or not we're selected.
+    bool haveSelection = !isPrinting && paintInfo.phase != PaintPhaseTextClip && m_inlineTextBox.selectionState() != RenderObject::SelectionNone;
+    if (!haveSelection && paintInfo.phase == PaintPhaseSelection) {
+        // When only painting the selection, don't bother to paint if there is none.
+        return;
+    }
+
+    if (m_inlineTextBox.truncation() != cNoTruncation) {
+        if (m_inlineTextBox.renderer().containingBlock()->style()->isLeftToRightDirection() != m_inlineTextBox.isLeftToRightDirection()) {
+            // Make the visible fragment of text hug the edge closest to the rest of the run by moving the origin
+            // at which we start drawing text.
+            // e.g. In the case of LTR text truncated in an RTL Context, the correct behavior is:
+            // |Hello|CBA| -> |...He|CBA|
+            // In order to draw the fragment "He" aligned to the right edge of it's box, we need to start drawing
+            // farther to the right.
+            // NOTE: WebKit's behavior differs from that of IE which appears to just overlay the ellipsis on top of the
+            // truncated string i.e.  |Hello|CBA| -> |...lo|CBA|
+            LayoutUnit widthOfVisibleText = m_inlineTextBox.renderer().width(m_inlineTextBox.start(), m_inlineTextBox.truncation(), m_inlineTextBox.textPos(), m_inlineTextBox.isLeftToRightDirection() ? LTR : RTL, m_inlineTextBox.isFirstLineStyle());
+            LayoutUnit widthOfHiddenText = m_inlineTextBox.logicalWidth() - widthOfVisibleText;
+            // FIXME: The hit testing logic also needs to take this translation into account.
+            LayoutSize truncationOffset(m_inlineTextBox.isLeftToRightDirection() ? widthOfHiddenText : -widthOfHiddenText, 0);
+            adjustedPaintOffset.move(m_inlineTextBox.isHorizontal() ? truncationOffset : truncationOffset.transposedSize());
+        }
+    }
+
+    GraphicsContext* context = paintInfo.context;
+    RenderStyle* styleToUse = m_inlineTextBox.renderer().style(m_inlineTextBox.isFirstLineStyle());
+
+    adjustedPaintOffset.move(0, styleToUse->isHorizontalWritingMode() ? 0 : -m_inlineTextBox.logicalHeight());
+
+    FloatPoint boxOrigin = m_inlineTextBox.locationIncludingFlipping();
+    boxOrigin.move(adjustedPaintOffset.x().toFloat(), adjustedPaintOffset.y().toFloat());
+    FloatRect boxRect(boxOrigin, LayoutSize(m_inlineTextBox.logicalWidth(), m_inlineTextBox.logicalHeight()));
+
+    RenderCombineText* combinedText = styleToUse->hasTextCombine() && m_inlineTextBox.renderer().isCombineText() && toRenderCombineText(m_inlineTextBox.renderer()).isCombined() ? &toRenderCombineText(m_inlineTextBox.renderer()) : 0;
+
+    bool shouldRotate = !m_inlineTextBox.isHorizontal() && !combinedText;
+    if (shouldRotate)
+        context->concatCTM(InlineTextBox::rotation(boxRect, InlineTextBox::Clockwise));
+
+    // Determine whether or not we have composition underlines to draw.
+    bool containsComposition = m_inlineTextBox.renderer().node() && m_inlineTextBox.renderer().frame()->inputMethodController().compositionNode() == m_inlineTextBox.renderer().node();
+    bool useCustomUnderlines = containsComposition && m_inlineTextBox.renderer().frame()->inputMethodController().compositionUsesCustomUnderlines();
+
+    // Determine text colors.
+    TextPainter::Style textStyle = TextPainter::textPaintingStyle(m_inlineTextBox.renderer(), styleToUse, paintInfo.forceBlackText(), isPrinting);
+    TextPainter::Style selectionStyle = TextPainter::selectionPaintingStyle(m_inlineTextBox.renderer(), haveSelection, paintInfo.forceBlackText(), isPrinting, textStyle);
+    bool paintSelectedTextOnly = (paintInfo.phase == PaintPhaseSelection);
+    bool paintSelectedTextSeparately = !paintSelectedTextOnly && textStyle != selectionStyle;
+
+    // Set our font.
+    const Font& font = styleToUse->font();
+
+    FloatPoint textOrigin = FloatPoint(boxOrigin.x(), boxOrigin.y() + font.fontMetrics().ascent());
+    if (combinedText)
+        combinedText->adjustTextOrigin(textOrigin, boxRect);
+
+    // 1. Paint backgrounds behind text if needed. Examples of such backgrounds include selection
+    // and composition highlights.
+    if (paintInfo.phase != PaintPhaseSelection && paintInfo.phase != PaintPhaseTextClip && !isPrinting) {
+        if (containsComposition) {
+            paintCompositionBackgrounds(context, boxOrigin, styleToUse, font, useCustomUnderlines);
+        }
+
+        paintDocumentMarkers(context, boxOrigin, styleToUse, font, true);
+
+        if (haveSelection && !useCustomUnderlines)
+            paintSelection(context, boxOrigin, styleToUse, font, selectionStyle.fillColor);
+    }
+
+    // 2. Now paint the foreground, including text and decorations like underline/overline (in quirks mode only).
+    int length = m_inlineTextBox.len();
+    int maximumLength;
+    StringView string;
+    if (!combinedText) {
+        string = m_inlineTextBox.renderer().text().createView();
+        if (static_cast<unsigned>(length) != string.length() || m_inlineTextBox.start())
+            string.narrow(m_inlineTextBox.start(), length);
+        maximumLength = m_inlineTextBox.renderer().textLength() - m_inlineTextBox.start();
+    } else {
+        combinedText->getStringToRender(m_inlineTextBox.start(), string, length);
+        maximumLength = length;
+    }
+
+    StringBuilder charactersWithHyphen;
+    TextRun textRun = m_inlineTextBox.constructTextRun(styleToUse, font, string, maximumLength, m_inlineTextBox.hasHyphen() ? &charactersWithHyphen : 0);
+    if (m_inlineTextBox.hasHyphen())
+        length = textRun.length();
+
+    int selectionStart = 0;
+    int selectionEnd = 0;
+    if (paintSelectedTextOnly || paintSelectedTextSeparately)
+        m_inlineTextBox.selectionStartEnd(selectionStart, selectionEnd);
+
+    bool respectHyphen = selectionEnd == static_cast<int>(m_inlineTextBox.len()) && m_inlineTextBox.hasHyphen();
+    if (respectHyphen)
+        selectionEnd = textRun.length();
+
+    if (m_inlineTextBox.truncation() != cNoTruncation) {
+        selectionStart = std::min<int>(selectionStart, m_inlineTextBox.truncation());
+        selectionEnd = std::min<int>(selectionEnd, m_inlineTextBox.truncation());
+        length = m_inlineTextBox.truncation();
+    }
+
+    TextPainter textPainter(context, font, textRun, textOrigin, boxRect, m_inlineTextBox.isHorizontal());
+    TextEmphasisPosition emphasisMarkPosition;
+    bool hasTextEmphasis = m_inlineTextBox.getEmphasisMarkPosition(styleToUse, emphasisMarkPosition);
+    if (hasTextEmphasis)
+        textPainter.setEmphasisMark(styleToUse->textEmphasisMarkString(), emphasisMarkPosition);
+    if (combinedText)
+        textPainter.setCombinedText(combinedText);
+
+    if (!paintSelectedTextOnly) {
+        // FIXME: Truncate right-to-left text correctly.
+        int startOffset = 0;
+        int endOffset = length;
+        if (paintSelectedTextSeparately && selectionStart < selectionEnd) {
+            startOffset = selectionEnd;
+            endOffset = selectionStart;
+        }
+
+        // FIXME: This cache should probably ultimately be held somewhere else.
+        // A hashmap is convenient to avoid a memory hit when the
+        // RuntimeEnabledFeature is off.
+        bool textBlobIsCacheable = RuntimeEnabledFeatures::textBlobEnabled() && startOffset == 0 && endOffset == length;
+        TextBlobPtr* cachedTextBlob = 0;
+        if (textBlobIsCacheable) {
+            if (!gTextBlobCache)
+                gTextBlobCache = new InlineTextBoxBlobCacheMap;
+            cachedTextBlob = &gTextBlobCache->add(&m_inlineTextBox, nullptr).storedValue->value;
+        }
+        textPainter.paint(startOffset, endOffset, length, textStyle, cachedTextBlob);
+    }
+
+    if ((paintSelectedTextOnly || paintSelectedTextSeparately) && selectionStart < selectionEnd) {
+        // paint only the text that is selected
+        textPainter.paint(selectionStart, selectionEnd, length, selectionStyle);
+    }
+
+    // Paint decorations
+    TextDecoration textDecorations = styleToUse->textDecorationsInEffect();
+    if (textDecorations != TextDecorationNone && !paintSelectedTextOnly) {
+        GraphicsContextStateSaver stateSaver(*context, false);
+        TextPainter::updateGraphicsContext(context, textStyle, m_inlineTextBox.isHorizontal(), stateSaver);
+        if (combinedText)
+            context->concatCTM(InlineTextBox::rotation(boxRect, InlineTextBox::Clockwise));
+        paintDecoration(context, boxOrigin, textDecorations);
+        if (combinedText)
+            context->concatCTM(InlineTextBox::rotation(boxRect, InlineTextBox::Counterclockwise));
+    }
+
+    if (paintInfo.phase == PaintPhaseForeground) {
+        paintDocumentMarkers(context, boxOrigin, styleToUse, font, false);
+
+        // Paint custom underlines for compositions.
+        if (useCustomUnderlines) {
+            const Vector<CompositionUnderline>& underlines = m_inlineTextBox.renderer().frame()->inputMethodController().customCompositionUnderlines();
+            CompositionUnderlineRangeFilter filter(underlines, m_inlineTextBox.start(), m_inlineTextBox.end());
+            for (CompositionUnderlineRangeFilter::ConstIterator it = filter.begin(); it != filter.end(); ++it) {
+                if (it->color == Color::transparent)
+                    continue;
+                paintCompositionUnderline(context, boxOrigin, *it);
+            }
+        }
+    }
+
+    if (shouldRotate)
+        context->concatCTM(InlineTextBox::rotation(boxRect, InlineTextBox::Counterclockwise));
+}
+
+unsigned InlineTextBoxPainter::underlinePaintStart(const CompositionUnderline& underline)
+{
+    return std::max(static_cast<unsigned>(m_inlineTextBox.start()), underline.startOffset);
+}
+
+unsigned InlineTextBoxPainter::underlinePaintEnd(const CompositionUnderline& underline)
+{
+    unsigned paintEnd = std::min(m_inlineTextBox.end() + 1, underline.endOffset); // end() points at the last char, not past it.
+    if (m_inlineTextBox.truncation() != cNoTruncation)
+        paintEnd = std::min(paintEnd, static_cast<unsigned>(m_inlineTextBox.start() + m_inlineTextBox.truncation()));
+    return paintEnd;
+}
+
+void InlineTextBoxPainter::paintCompositionBackgrounds(GraphicsContext* pt, const FloatPoint& boxOrigin, RenderStyle* style, const Font& font, bool useCustomUnderlines)
+{
+    if (useCustomUnderlines) {
+        // Paint custom background highlights for compositions.
+        const Vector<CompositionUnderline>& underlines = m_inlineTextBox.renderer().frame()->inputMethodController().customCompositionUnderlines();
+        CompositionUnderlineRangeFilter filter(underlines, m_inlineTextBox.start(), m_inlineTextBox.end());
+        for (CompositionUnderlineRangeFilter::ConstIterator it = filter.begin(); it != filter.end(); ++it) {
+            if (it->backgroundColor == Color::transparent)
+                continue;
+            paintSingleCompositionBackgroundRun(pt, boxOrigin, style, font, it->backgroundColor, underlinePaintStart(*it), underlinePaintEnd(*it));
+        }
+
+    } else {
+        paintSingleCompositionBackgroundRun(pt, boxOrigin, style, font, RenderTheme::theme().platformDefaultCompositionBackgroundColor(),
+            m_inlineTextBox.renderer().frame()->inputMethodController().compositionStart(),
+            m_inlineTextBox.renderer().frame()->inputMethodController().compositionEnd());
+    }
+}
+
+void InlineTextBoxPainter::paintSingleCompositionBackgroundRun(GraphicsContext* context, const FloatPoint& boxOrigin, RenderStyle* style, const Font& font, Color backgroundColor, int startPos, int endPos)
+{
+    int sPos = std::max(startPos - static_cast<int>(m_inlineTextBox.start()), 0);
+    int ePos = std::min(endPos - static_cast<int>(m_inlineTextBox.start()), static_cast<int>(m_inlineTextBox.len()));
+    if (sPos >= ePos)
+        return;
+
+    int deltaY = m_inlineTextBox.renderer().style()->isFlippedLinesWritingMode() ? m_inlineTextBox.root().selectionBottom() - m_inlineTextBox.logicalBottom() : m_inlineTextBox.logicalTop() - m_inlineTextBox.root().selectionTop();
+    int selHeight = m_inlineTextBox.root().selectionHeight();
+    FloatPoint localOrigin(boxOrigin.x(), boxOrigin.y() - deltaY);
+    context->drawHighlightForText(font, m_inlineTextBox.constructTextRun(style, font), localOrigin, selHeight, backgroundColor, sPos, ePos);
+}
+
+void InlineTextBoxPainter::paintDocumentMarkers(GraphicsContext* pt, const FloatPoint& boxOrigin, RenderStyle* style, const Font& font, bool background)
+{
+    if (!m_inlineTextBox.renderer().node())
+        return;
+
+    DocumentMarkerVector markers = m_inlineTextBox.renderer().document().markers().markersFor(m_inlineTextBox.renderer().node());
+    DocumentMarkerVector::const_iterator markerIt = markers.begin();
+
+    // Give any document markers that touch this run a chance to draw before the text has been drawn.
+    // Note end() points at the last char, not one past it like endOffset and ranges do.
+    for ( ; markerIt != markers.end(); ++markerIt) {
+        DocumentMarker* marker = *markerIt;
+
+        // Paint either the background markers or the foreground markers, but not both
+        switch (marker->type()) {
+        case DocumentMarker::Grammar:
+        case DocumentMarker::Spelling:
+            if (background)
+                continue;
+            break;
+        case DocumentMarker::TextMatch:
+            if (!background)
+                continue;
+            break;
+        default:
+            continue;
+        }
+
+        if (marker->endOffset() <= m_inlineTextBox.start()) {
+            // marker is completely before this run.  This might be a marker that sits before the
+            // first run we draw, or markers that were within runs we skipped due to truncation.
+            continue;
+        }
+        if (marker->startOffset() > m_inlineTextBox.end()) {
+            // marker is completely after this run, bail.  A later run will paint it.
+            break;
+        }
+
+        // marker intersects this run.  Paint it.
+        switch (marker->type()) {
+        case DocumentMarker::Spelling:
+            m_inlineTextBox.paintDocumentMarker(pt, boxOrigin, marker, style, font, false);
+            break;
+        case DocumentMarker::Grammar:
+            m_inlineTextBox.paintDocumentMarker(pt, boxOrigin, marker, style, font, true);
+            break;
+        case DocumentMarker::TextMatch:
+            m_inlineTextBox.paintTextMatchMarker(pt, boxOrigin, marker, style, font);
+            break;
+        default:
+            ASSERT_NOT_REACHED();
+        }
+    }
+}
+
+static GraphicsContext::DocumentMarkerLineStyle lineStyleForMarkerType(DocumentMarker::MarkerType markerType)
+{
+    switch (markerType) {
+    case DocumentMarker::Spelling:
+        return GraphicsContext::DocumentMarkerSpellingLineStyle;
+    case DocumentMarker::Grammar:
+        return GraphicsContext::DocumentMarkerGrammarLineStyle;
+    default:
+        ASSERT_NOT_REACHED();
+        return GraphicsContext::DocumentMarkerSpellingLineStyle;
+    }
+}
+
+void InlineTextBoxPainter::paintDocumentMarker(GraphicsContext* pt, const FloatPoint& boxOrigin, DocumentMarker* marker, RenderStyle* style, const Font& font, bool grammar)
+{
+    // Never print spelling/grammar markers (5327887)
+    if (m_inlineTextBox.renderer().document().printing())
+        return;
+
+    if (m_inlineTextBox.truncation() == cFullTruncation)
+        return;
+
+    float start = 0; // start of line to draw, relative to tx
+    float width = m_inlineTextBox.logicalWidth(); // how much line to draw
+
+    // Determine whether we need to measure text
+    bool markerSpansWholeBox = true;
+    if (m_inlineTextBox.start() <= marker->startOffset())
+        markerSpansWholeBox = false;
+    if ((m_inlineTextBox.end() + 1) != marker->endOffset()) // end points at the last char, not past it
+        markerSpansWholeBox = false;
+    if (m_inlineTextBox.truncation() != cNoTruncation)
+        markerSpansWholeBox = false;
+
+    if (!markerSpansWholeBox || grammar) {
+        int startPosition = std::max<int>(marker->startOffset() - m_inlineTextBox.start(), 0);
+        int endPosition = std::min<int>(marker->endOffset() - static_cast<int>(m_inlineTextBox.start()), m_inlineTextBox.len());
+
+        if (m_inlineTextBox.truncation() != cNoTruncation)
+            endPosition = std::min<int>(endPosition, m_inlineTextBox.truncation());
+
+        // Calculate start & width
+        int deltaY = m_inlineTextBox.renderer().style()->isFlippedLinesWritingMode() ? m_inlineTextBox.root().selectionBottom() - m_inlineTextBox.logicalBottom() : m_inlineTextBox.logicalTop() - m_inlineTextBox.root().selectionTop();
+        int selHeight = m_inlineTextBox.root().selectionHeight();
+        FloatPoint startPoint(boxOrigin.x(), boxOrigin.y() - deltaY);
+        TextRun run = m_inlineTextBox.constructTextRun(style, font);
+
+        // FIXME: Convert the document markers to float rects.
+        IntRect markerRect = enclosingIntRect(font.selectionRectForText(run, startPoint, selHeight, startPosition, endPosition));
+        start = markerRect.x() - startPoint.x();
+        width = markerRect.width();
+
+        // Store rendered rects for bad grammar markers, so we can hit-test against it elsewhere in order to
+        // display a toolTip. We don't do this for misspelling markers.
+        if (grammar) {
+            markerRect.move(-boxOrigin.x(), -boxOrigin.y());
+            markerRect = m_inlineTextBox.renderer().localToAbsoluteQuad(FloatRect(markerRect)).enclosingBoundingBox();
+            toRenderedDocumentMarker(marker)->setRenderedRect(markerRect);
+        }
+    }
+
+    // IMPORTANT: The misspelling underline is not considered when calculating the text bounds, so we have to
+    // make sure to fit within those bounds.  This means the top pixel(s) of the underline will overlap the
+    // bottom pixel(s) of the glyphs in smaller font sizes.  The alternatives are to increase the line spacing (bad!!)
+    // or decrease the underline thickness.  The overlap is actually the most useful, and matches what AppKit does.
+    // So, we generally place the underline at the bottom of the text, but in larger fonts that's not so good so
+    // we pin to two pixels under the baseline.
+    int lineThickness = misspellingLineThickness;
+    int baseline = m_inlineTextBox.renderer().style(m_inlineTextBox.isFirstLineStyle())->fontMetrics().ascent();
+    int descent = m_inlineTextBox.logicalHeight() - baseline;
+    int underlineOffset;
+    if (descent <= (2 + lineThickness)) {
+        // Place the underline at the very bottom of the text in small/medium fonts.
+        underlineOffset = m_inlineTextBox.logicalHeight() - lineThickness;
+    } else {
+        // In larger fonts, though, place the underline up near the baseline to prevent a big gap.
+        underlineOffset = baseline + 2;
+    }
+    pt->drawLineForDocumentMarker(FloatPoint(boxOrigin.x() + start, boxOrigin.y() + underlineOffset), width, lineStyleForMarkerType(marker->type()));
+}
+
+void InlineTextBoxPainter::paintSelection(GraphicsContext* context, const FloatPoint& boxOrigin, RenderStyle* style, const Font& font, Color textColor)
+{
+    // See if we have a selection to paint at all.
+    int sPos, ePos;
+    m_inlineTextBox.selectionStartEnd(sPos, ePos);
+    if (sPos >= ePos)
+        return;
+
+    Color c = m_inlineTextBox.renderer().selectionBackgroundColor();
+    if (!c.alpha())
+        return;
+
+    // If the text color ends up being the same as the selection background, invert the selection
+    // background.
+    if (textColor == c)
+        c = Color(0xff - c.red(), 0xff - c.green(), 0xff - c.blue());
+
+    // If the text is truncated, let the thing being painted in the truncation
+    // draw its own highlight.
+    int length = m_inlineTextBox.truncation() != cNoTruncation ? m_inlineTextBox.truncation() : m_inlineTextBox.len();
+    StringView string = m_inlineTextBox.renderer().text().createView();
+
+    if (string.length() != static_cast<unsigned>(length) || m_inlineTextBox.start())
+        string.narrow(m_inlineTextBox.start(), length);
+
+    StringBuilder charactersWithHyphen;
+    bool respectHyphen = ePos == length && m_inlineTextBox.hasHyphen();
+    TextRun textRun = m_inlineTextBox.constructTextRun(style, font, string, m_inlineTextBox.renderer().textLength() - m_inlineTextBox.start(), respectHyphen ? &charactersWithHyphen : 0);
+    if (respectHyphen)
+        ePos = textRun.length();
+
+    LayoutUnit selectionBottom = m_inlineTextBox.root().selectionBottom();
+    LayoutUnit selectionTop = m_inlineTextBox.root().selectionTopAdjustedForPrecedingBlock();
+
+    int deltaY = roundToInt(m_inlineTextBox.renderer().style()->isFlippedLinesWritingMode() ? selectionBottom - m_inlineTextBox.logicalBottom() : m_inlineTextBox.logicalTop() - selectionTop);
+    int selHeight = std::max(0, roundToInt(selectionBottom - selectionTop));
+
+    FloatPoint localOrigin(boxOrigin.x(), boxOrigin.y() - deltaY);
+    FloatRect clipRect(localOrigin, FloatSize(m_inlineTextBox.logicalWidth(), selHeight));
+
+    GraphicsContextStateSaver stateSaver(*context);
+    context->clip(clipRect);
+    context->drawHighlightForText(font, textRun, localOrigin, selHeight, c, sPos, ePos);
+}
+
+static int computeUnderlineOffset(const TextUnderlinePosition underlinePosition, const FontMetrics& fontMetrics, const InlineTextBox* inlineTextBox, const float textDecorationThickness)
+{
+    // Compute the gap between the font and the underline. Use at least one
+    // pixel gap, if underline is thick then use a bigger gap.
+    int gap = 0;
+
+    // Underline position of zero means draw underline on Baseline Position,
+    // in Blink we need at least 1-pixel gap to adding following check.
+    // Positive underline Position means underline should be drawn above baselin e
+    // and negative value means drawing below baseline, negating the value as in Blink
+    // downward Y-increases.
+
+    if (fontMetrics.underlinePosition())
+        gap = -fontMetrics.underlinePosition();
+    else
+        gap = std::max<int>(1, ceilf(textDecorationThickness / 2.f));
+
+    // FIXME: We support only horizontal text for now.
+    switch (underlinePosition) {
+    case TextUnderlinePositionAuto:
+        return fontMetrics.ascent() + gap; // Position underline near the alphabetic baseline.
+    case TextUnderlinePositionUnder: {
+        // Position underline relative to the under edge of the lowest element's content box.
+        const float offset = inlineTextBox->root().maxLogicalTop() - inlineTextBox->logicalTop();
+        if (offset > 0)
+            return inlineTextBox->logicalHeight() + gap + offset;
+        return inlineTextBox->logicalHeight() + gap;
+    }
+    }
+
+    ASSERT_NOT_REACHED();
+    return fontMetrics.ascent() + gap;
+}
+
+static bool shouldSetDecorationAntialias(TextDecorationStyle decorationStyle)
+{
+    return decorationStyle == TextDecorationStyleDotted || decorationStyle == TextDecorationStyleDashed;
+}
+
+static bool shouldSetDecorationAntialias(TextDecorationStyle underline, TextDecorationStyle overline, TextDecorationStyle linethrough)
+{
+    return shouldSetDecorationAntialias(underline) || shouldSetDecorationAntialias(overline) || shouldSetDecorationAntialias(linethrough);
+}
+
+static StrokeStyle textDecorationStyleToStrokeStyle(TextDecorationStyle decorationStyle)
+{
+    StrokeStyle strokeStyle = SolidStroke;
+    switch (decorationStyle) {
+    case TextDecorationStyleSolid:
+        strokeStyle = SolidStroke;
+        break;
+    case TextDecorationStyleDouble:
+        strokeStyle = DoubleStroke;
+        break;
+    case TextDecorationStyleDotted:
+        strokeStyle = DottedStroke;
+        break;
+    case TextDecorationStyleDashed:
+        strokeStyle = DashedStroke;
+        break;
+    case TextDecorationStyleWavy:
+        strokeStyle = WavyStroke;
+        break;
+    }
+
+    return strokeStyle;
+}
+
+static void adjustStepToDecorationLength(float& step, float& controlPointDistance, float length)
+{
+    ASSERT(step > 0);
+
+    if (length <= 0)
+        return;
+
+    unsigned stepCount = static_cast<unsigned>(length / step);
+
+    // Each Bezier curve starts at the same pixel that the previous one
+    // ended. We need to subtract (stepCount - 1) pixels when calculating the
+    // length covered to account for that.
+    float uncoveredLength = length - (stepCount * step - (stepCount - 1));
+    float adjustment = uncoveredLength / stepCount;
+    step += adjustment;
+    controlPointDistance += adjustment;
+}
+
+/*
+ * Draw one cubic Bezier curve and repeat the same pattern long the the decoration's axis.
+ * The start point (p1), controlPoint1, controlPoint2 and end point (p2) of the Bezier curve
+ * form a diamond shape:
+ *
+ *                              step
+ *                         |-----------|
+ *
+ *                   controlPoint1
+ *                         +
+ *
+ *
+ *                  . .
+ *                .     .
+ *              .         .
+ * (x1, y1) p1 +           .            + p2 (x2, y2) - <--- Decoration's axis
+ *                          .         .               |
+ *                            .     .                 |
+ *                              . .                   | controlPointDistance
+ *                                                    |
+ *                                                    |
+ *                         +                          -
+ *                   controlPoint2
+ *
+ *             |-----------|
+ *                 step
+ */
+static void strokeWavyTextDecoration(GraphicsContext* context, FloatPoint p1, FloatPoint p2, float strokeThickness)
+{
+    context->adjustLineToPixelBoundaries(p1, p2, strokeThickness, context->strokeStyle());
+
+    Path path;
+    path.moveTo(p1);
+
+    // Distance between decoration's axis and Bezier curve's control points.
+    // The height of the curve is based on this distance. Use a minimum of 6 pixels distance since
+    // the actual curve passes approximately at half of that distance, that is 3 pixels.
+    // The minimum height of the curve is also approximately 3 pixels. Increases the curve's height
+    // as strockThickness increases to make the curve looks better.
+    float controlPointDistance = 3 * std::max<float>(2, strokeThickness);
+
+    // Increment used to form the diamond shape between start point (p1), control
+    // points and end point (p2) along the axis of the decoration. Makes the
+    // curve wider as strockThickness increases to make the curve looks better.
+    float step = 2 * std::max<float>(2, strokeThickness);
+
+    bool isVerticalLine = (p1.x() == p2.x());
+
+    if (isVerticalLine) {
+        ASSERT(p1.x() == p2.x());
+
+        float xAxis = p1.x();
+        float y1;
+        float y2;
+
+        if (p1.y() < p2.y()) {
+            y1 = p1.y();
+            y2 = p2.y();
+        } else {
+            y1 = p2.y();
+            y2 = p1.y();
+        }
+
+        adjustStepToDecorationLength(step, controlPointDistance, y2 - y1);
+        FloatPoint controlPoint1(xAxis + controlPointDistance, 0);
+        FloatPoint controlPoint2(xAxis - controlPointDistance, 0);
+
+        for (float y = y1; y + 2 * step <= y2;) {
+            controlPoint1.setY(y + step);
+            controlPoint2.setY(y + step);
+            y += 2 * step;
+            path.addBezierCurveTo(controlPoint1, controlPoint2, FloatPoint(xAxis, y));
+        }
+    } else {
+        ASSERT(p1.y() == p2.y());
+
+        float yAxis = p1.y();
+        float x1;
+        float x2;
+
+        if (p1.x() < p2.x()) {
+            x1 = p1.x();
+            x2 = p2.x();
+        } else {
+            x1 = p2.x();
+            x2 = p1.x();
+        }
+
+        adjustStepToDecorationLength(step, controlPointDistance, x2 - x1);
+        FloatPoint controlPoint1(0, yAxis + controlPointDistance);
+        FloatPoint controlPoint2(0, yAxis - controlPointDistance);
+
+        for (float x = x1; x + 2 * step <= x2;) {
+            controlPoint1.setX(x + step);
+            controlPoint2.setX(x + step);
+            x += 2 * step;
+            path.addBezierCurveTo(controlPoint1, controlPoint2, FloatPoint(x, yAxis));
+        }
+    }
+
+    context->setShouldAntialias(true);
+    context->strokePath(path);
+}
+
+static void paintAppliedDecoration(GraphicsContext* context, FloatPoint start, float width, float doubleOffset, int wavyOffsetFactor,
+    RenderObject::AppliedTextDecoration decoration, float thickness, bool antialiasDecoration, bool isPrinting)
+{
+    context->setStrokeStyle(textDecorationStyleToStrokeStyle(decoration.style));
+    context->setStrokeColor(decoration.color);
+
+    switch (decoration.style) {
+    case TextDecorationStyleWavy:
+        strokeWavyTextDecoration(context, start + FloatPoint(0, doubleOffset * wavyOffsetFactor), start + FloatPoint(width, doubleOffset * wavyOffsetFactor), thickness);
+        break;
+    case TextDecorationStyleDotted:
+    case TextDecorationStyleDashed:
+        context->setShouldAntialias(antialiasDecoration);
+        // Fall through
+    default:
+        context->drawLineForText(start, width, isPrinting);
+
+        if (decoration.style == TextDecorationStyleDouble)
+            context->drawLineForText(start + FloatPoint(0, doubleOffset), width, isPrinting);
+    }
+}
+
+void InlineTextBoxPainter::paintDecoration(GraphicsContext* context, const FloatPoint& boxOrigin, TextDecoration deco)
+{
+    GraphicsContextStateSaver stateSaver(*context);
+
+    if (m_inlineTextBox.truncation() == cFullTruncation)
+        return;
+
+    FloatPoint localOrigin = boxOrigin;
+
+    float width = m_inlineTextBox.logicalWidth();
+    if (m_inlineTextBox.truncation() != cNoTruncation) {
+        width = m_inlineTextBox.renderer().width(m_inlineTextBox.start(), m_inlineTextBox.truncation(), m_inlineTextBox.textPos(), m_inlineTextBox.isLeftToRightDirection() ? LTR : RTL, m_inlineTextBox.isFirstLineStyle());
+        if (!m_inlineTextBox.isLeftToRightDirection())
+            localOrigin.move(m_inlineTextBox.logicalWidth() - width, 0);
+    }
+
+    // Get the text decoration colors.
+    RenderObject::AppliedTextDecoration underline, overline, linethrough;
+    m_inlineTextBox.renderer().getTextDecorations(deco, underline, overline, linethrough, true);
+    if (m_inlineTextBox.isFirstLineStyle())
+        m_inlineTextBox.renderer().getTextDecorations(deco, underline, overline, linethrough, true, true);
+
+    // Use a special function for underlines to get the positioning exactly right.
+    bool isPrinting = m_inlineTextBox.renderer().document().printing();
+
+    RenderStyle* styleToUse = m_inlineTextBox.renderer().style(m_inlineTextBox.isFirstLineStyle());
+    int baseline = styleToUse->fontMetrics().ascent();
+
+    // Set the thick of the line to be 10% (or something else ?)of the computed font size and not less than 1px.
+    // Using computedFontSize should take care of zoom as well.
+
+    // Update Underline thickness, in case we have Faulty Font Metrics calculating underline thickness by old method.
+    float textDecorationThickness = styleToUse->fontMetrics().underlineThickness();
+    int fontHeightInt  = (int)(styleToUse->fontMetrics().floatHeight() + 0.5);
+    if ((textDecorationThickness == 0.f) || (textDecorationThickness >= (fontHeightInt >> 1)))
+        textDecorationThickness = std::max(1.f, styleToUse->computedFontSize() / 10.f);
+
+    context->setStrokeThickness(textDecorationThickness);
+
+    bool antialiasDecoration = shouldSetDecorationAntialias(overline.style, underline.style, linethrough.style)
+        && BoxPainter::shouldAntialiasLines(context);
+
+    // Offset between lines - always non-zero, so lines never cross each other.
+    float doubleOffset = textDecorationThickness + 1.f;
+
+    if (deco & TextDecorationUnderline) {
+        const int underlineOffset = computeUnderlineOffset(styleToUse->textUnderlinePosition(), styleToUse->fontMetrics(), &m_inlineTextBox, textDecorationThickness);
+        paintAppliedDecoration(context, localOrigin + FloatPoint(0, underlineOffset), width, doubleOffset, 1, underline, textDecorationThickness, antialiasDecoration, isPrinting);
+    }
+    if (deco & TextDecorationOverline) {
+        paintAppliedDecoration(context, localOrigin, width, -doubleOffset, 1, overline, textDecorationThickness, antialiasDecoration, isPrinting);
+    }
+    if (deco & TextDecorationLineThrough) {
+        const float lineThroughOffset = 2 * baseline / 3;
+        paintAppliedDecoration(context, localOrigin + FloatPoint(0, lineThroughOffset), width, doubleOffset, 0, linethrough, textDecorationThickness, antialiasDecoration, isPrinting);
+    }
+}
+
+void InlineTextBoxPainter::paintCompositionUnderline(GraphicsContext* ctx, const FloatPoint& boxOrigin, const CompositionUnderline& underline)
+{
+    if (m_inlineTextBox.truncation() == cFullTruncation)
+        return;
+
+    unsigned paintStart = underlinePaintStart(underline);
+    unsigned paintEnd = underlinePaintEnd(underline);
+
+    // start of line to draw, relative to paintOffset.
+    float start = paintStart == static_cast<unsigned>(m_inlineTextBox.start()) ? 0 :
+        m_inlineTextBox.renderer().width(m_inlineTextBox.start(), paintStart - m_inlineTextBox.start(), m_inlineTextBox.textPos(), m_inlineTextBox.isLeftToRightDirection() ? LTR : RTL, m_inlineTextBox.isFirstLineStyle());
+    // how much line to draw
+    float width = (paintStart == static_cast<unsigned>(m_inlineTextBox.start()) && paintEnd == static_cast<unsigned>(m_inlineTextBox.end()) + 1) ? m_inlineTextBox.logicalWidth() :
+        m_inlineTextBox.renderer().width(paintStart, paintEnd - paintStart, m_inlineTextBox.textPos() + start, m_inlineTextBox.isLeftToRightDirection() ? LTR : RTL, m_inlineTextBox.isFirstLineStyle());
+
+    // Thick marked text underlines are 2px thick as long as there is room for the 2px line under the baseline.
+    // All other marked text underlines are 1px thick.
+    // If there's not enough space the underline will touch or overlap characters.
+    int lineThickness = 1;
+    int baseline = m_inlineTextBox.renderer().style(m_inlineTextBox.isFirstLineStyle())->fontMetrics().ascent();
+    if (underline.thick && m_inlineTextBox.logicalHeight() - baseline >= 2)
+        lineThickness = 2;
+
+    // We need to have some space between underlines of subsequent clauses, because some input methods do not use different underline styles for those.
+    // We make each line shorter, which has a harmless side effect of shortening the first and last clauses, too.
+    start += 1;
+    width -= 2;
+
+    ctx->setStrokeColor(underline.color);
+    ctx->setStrokeThickness(lineThickness);
+    ctx->drawLineForText(FloatPoint(boxOrigin.x() + start, boxOrigin.y() + m_inlineTextBox.logicalHeight() - lineThickness), width, m_inlineTextBox.renderer().document().printing());
+}
+
+void InlineTextBoxPainter::paintTextMatchMarker(GraphicsContext* pt, const FloatPoint& boxOrigin, DocumentMarker* marker, RenderStyle* style, const Font& font)
+{
+    // Use same y positioning and height as for selection, so that when the selection and this highlight are on
+    // the same word there are no pieces sticking out.
+    int deltaY = m_inlineTextBox.renderer().style()->isFlippedLinesWritingMode() ? m_inlineTextBox.root().selectionBottom() - m_inlineTextBox.logicalBottom() : m_inlineTextBox.logicalTop() - m_inlineTextBox.root().selectionTop();
+    int selHeight = m_inlineTextBox.root().selectionHeight();
+
+    int sPos = std::max(marker->startOffset() - m_inlineTextBox.start(), (unsigned)0);
+    int ePos = std::min(marker->endOffset() - m_inlineTextBox.start(), m_inlineTextBox.len());
+    TextRun run = m_inlineTextBox.constructTextRun(style, font);
+
+    // Always compute and store the rect associated with this marker. The computed rect is in absolute coordinates.
+    IntRect markerRect = enclosingIntRect(font.selectionRectForText(run, IntPoint(m_inlineTextBox.x(), m_inlineTextBox.root().selectionTop()), selHeight, sPos, ePos));
+    markerRect = m_inlineTextBox.renderer().localToAbsoluteQuad(FloatRect(markerRect)).enclosingBoundingBox();
+    toRenderedDocumentMarker(marker)->setRenderedRect(markerRect);
+
+    // Optionally highlight the text
+    if (m_inlineTextBox.renderer().frame()->editor().markedTextMatchesAreHighlighted()) {
+        Color color = marker->activeMatch() ?
+            RenderTheme::theme().platformActiveTextSearchHighlightColor() :
+            RenderTheme::theme().platformInactiveTextSearchHighlightColor();
+        GraphicsContextStateSaver stateSaver(*pt);
+        pt->clip(FloatRect(boxOrigin.x(), boxOrigin.y() - deltaY, m_inlineTextBox.logicalWidth(), selHeight));
+        pt->drawHighlightForText(font, run, FloatPoint(boxOrigin.x(), boxOrigin.y() - deltaY), selHeight, color, sPos, ePos);
+    }
+}
+
+
+} // namespace blink