Show correct part of truncated text before ellipsis in 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/editing/markers/RenderedDocumentMarker.h"
@@ skipping 80 matching lines @@
         if (DrawingRecorder::useCachedDrawingIfPossible(paintInfo.context, m_inlineTextBox, DisplayItem::paintPhaseToDrawingType(paintInfo.phase)))
             return;
         LayoutRect paintRect(logicalVisualOverflow);
         m_inlineTextBox.logicalRectToPhysicalRect(paintRect);
         if (paintInfo.phase != PaintPhaseSelection && (haveSelection || paintsMarkerHighlights(*LineLayoutAPIShim::layoutObjectFrom(m_inlineTextBox.getLineLayoutItem()))))
             paintRect.unite(m_inlineTextBox.localSelectionRect(m_inlineTextBox.start(), m_inlineTextBox.start() + m_inlineTextBox.len()));
         paintRect.moveBy(adjustedPaintOffset);
         drawingRecorder.emplace(paintInfo.context, m_inlineTextBox, DisplayItem::paintPhaseToDrawingType(paintInfo.phase), FloatRect(paintRect));
     }
 
-    if (m_inlineTextBox.truncation() != cNoTruncation) {
-        if (m_inlineTextBox.getLineLayoutItem().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 = LayoutUnit(m_inlineTextBox.getLineLayoutItem().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, LayoutUnit());
-            adjustedPaintOffset.move(m_inlineTextBox.isHorizontal() ? truncationOffset : truncationOffset.transposedSize());
-        }
-    }
-
     GraphicsContext& context = paintInfo.context;
     const ComputedStyle& styleToUse = m_inlineTextBox.getLineLayoutItem().styleRef(m_inlineTextBox.isFirstLineStyle());
 
     LayoutPoint boxOrigin(m_inlineTextBox.locationIncludingFlipping());
     boxOrigin.move(adjustedPaintOffset.x(), adjustedPaintOffset.y());
     LayoutRect boxRect(boxOrigin, LayoutSize(m_inlineTextBox.logicalWidth(), m_inlineTextBox.logicalHeight()));
 
     bool shouldRotate = false;
     LayoutTextCombine* combinedText = nullptr;
     if (!m_inlineTextBox.isHorizontal()) {
@@ skipping 66 matching lines @@
 
     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;
         }
+        // Where the text and its flow have opposite directions then our offset into the text given by |truncation| is at
+        // the start of the part that will be visible.
+        if (m_inlineTextBox.truncation() != cNoTruncation && m_inlineTextBox.getLineLayoutItem().containingBlock().style()->isLeftToRightDirection() != m_inlineTextBox.isLeftToRightDirection()) {
+            startOffset = m_inlineTextBox.truncation();
+            endOffset = textRun.length();
+        }
 
         // 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 = startOffset == 0 && endOffset == length;
         TextBlobPtr* cachedTextBlob = 0;
         if (textBlobIsCacheable)
             cachedTextBlob = addToTextBlobCache(m_inlineTextBox);
         textPainter.paint(startOffset, endOffset, length, textStyle, cachedTextBlob);
     }
@@ skipping 644 matching lines @@
 
     Color color = LayoutTheme::theme().platformTextSearchHighlightColor(marker->activeMatch());
     GraphicsContext& context = paintInfo.context;
     GraphicsContextStateSaver stateSaver(context);
     context.clip(FloatRect(boxOrigin.x().toFloat(), (boxOrigin.y() - deltaY).toFloat(), m_inlineTextBox.logicalWidth().toFloat(), selHeight));
     context.drawHighlightForText(font, run, FloatPoint(boxOrigin.x().toFloat(), (boxOrigin.y() - deltaY).toFloat()), selHeight, color, sPos, ePos);
 }
 
 
 } // namespace blink