Underline truncated text correctly in a contrary flow

third_party/WebKit/Source/core/paint/InlineTextBoxPainter.cpp

 // 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 "core/paint/InlineTextBoxPainter.h"
 
 #include "core/editing/CompositionUnderline.h"
 #include "core/editing/Editor.h"
 #include "core/editing/markers/DocumentMarkerController.h"
 #include "core/frame/LocalFrame.h"
@@ skipping 697 matching lines @@
     if (m_inlineTextBox.truncation() == cFullTruncation)
         return;
 
     GraphicsContext& context = paintInfo.context;
     GraphicsContextStateSaver stateSaver(context);
 
     LayoutPoint localOrigin(boxOrigin);
 
     LayoutUnit width = m_inlineTextBox.logicalWidth();
     if (m_inlineTextBox.truncation() != cNoTruncation) {
-        width = LayoutUnit(m_inlineTextBox.getLineLayoutItem().width(
-            m_inlineTextBox.start(), m_inlineTextBox.truncation(), m_inlineTextBox.textPos(),
-            m_inlineTextBox.isLeftToRightDirection() ? LTR : RTL, m_inlineTextBox.isFirstLineStyle()));
-        if (!m_inlineTextBox.isLeftToRightDirection())
+        bool ltr = m_inlineTextBox.isLeftToRightDirection();
+        bool flowIsLTR = m_inlineTextBox.getLineLayoutItem().style()->isLeftToRightDirection();
+        width = LayoutUnit(m_inlineTextBox.getLineLayoutItem().width(ltr == flowIsLTR ? m_inlineTextBox.start() : m_inlineTextBox.truncation(),
+            ltr == flowIsLTR ? m_inlineTextBox.truncation() : m_inlineTextBox.len() - m_inlineTextBox.truncation(), m_inlineTextBox.textPos(),
+            flowIsLTR ? LTR : RTL, m_inlineTextBox.isFirstLineStyle()));
+        if (!flowIsLTR)
             localOrigin.move(m_inlineTextBox.logicalWidth() - width, LayoutUnit());
     }
 
     // Get the text decoration colors.
     LayoutObject::AppliedTextDecoration underline, overline, linethrough;
     LayoutObject& textBoxLayoutObject = inlineLayoutObject();
     textBoxLayoutObject.getTextDecorations(deco, underline, overline, linethrough, true);
     if (m_inlineTextBox.isFirstLineStyle())
         textBoxLayoutObject.getTextDecorations(deco, underline, overline, linethrough, true, true);
 
@@ skipping 36 matching lines @@
 {
     if (underline.color == Color::transparent)
         return;
 
     if (m_inlineTextBox.truncation() == cFullTruncation)
         return;
 
     unsigned paintStart = underlinePaintStart(underline);
     unsigned paintEnd = underlinePaintEnd(underline);
 
+    // TODO(crbug.com/636060): Handle mixed-flow contexts correctly.
     // start of line to draw
     float start = paintStart == static_cast<unsigned>(m_inlineTextBox.start()) ? 0 :
         m_inlineTextBox.getLineLayoutItem().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().toFloat() :
         m_inlineTextBox.getLineLayoutItem().width(paintStart, paintEnd - paintStart, LayoutUnit(m_inlineTextBox.textPos() + start), m_inlineTextBox.isLeftToRightDirection() ? LTR : RTL, m_inlineTextBox.isFirstLineStyle());
     // In RTL mode, start and width are computed from the right end of the text box:
     // starting at |logicalWidth| - |start| and continuing left by |width| to
     // |logicalWidth| - |start| - |width|. We will draw that line, but
     // backwards: |logicalWidth| - |start| - |width| to |logicalWidth| - |start|.
@@ skipping 57 matching lines @@
     GraphicsContext& context = paintInfo.context;
     GraphicsContextStateSaver stateSaver(context);
 
     LayoutRect boxRect(boxOrigin, LayoutSize(m_inlineTextBox.logicalWidth(), m_inlineTextBox.logicalHeight()));
     context.clip(FloatRect(boxRect));
     context.drawHighlightForText(font, run, FloatPoint(boxOrigin), boxRect.height(), color, sPos, ePos);
 }
 
 
 } // namespace blink