Transform the selection rect in vertical writing mode

In InlineTextBoxPainter and NGTextFragmentPainter, previously we
manually transpose the selection rect to convert it between the space of
the original space and the rotated space for vertical text. The code
might be inconsistent with the rotation transform. Actually
crrev.com/c/2319540 exposed the bug in InlineTextBoxPainter when the
vertical selection rect is wider than the text rect.

Now use the rotation transform to transform the selection rect to avoid
the inconsistency.

Change-Id: If75fa61539842cc32a9129391b1a32edbe631847
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2324066
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792443}

third_party/blink/renderer/core/paint/inline_text_box_painter.cc

@@ -222,7 +222,8 @@ void InlineTextBoxPainter::Paint(const PaintInfo& paint_info,
   if (inline_text_box_.HasHyphen())
     length = text_run.length();
 
-  bool should_rotate = false;
+  base::Optional<AffineTransform> rotation;
+  base::Optional<GraphicsContextStateSaver> state_saver;
   LayoutTextCombine* combined_text = nullptr;
   if (!inline_text_box_.IsHorizontal()) {
     if (style_to_use.HasTextCombine() &&
@@ -248,9 +249,10 @@ void InlineTextBoxPainter::Paint(const PaintInfo& paint_info,
         }
       }
     } else {
-      should_rotate = true;
-      context.ConcatCTM(
+      rotation.emplace(
           TextPainterBase::Rotation(box_rect, TextPainterBase::kClockwise));
+      state_saver.emplace(context);
+      context.ConcatCTM(*rotation);
     }
   }
 
@@ -298,15 +300,10 @@ void InlineTextBoxPainter::Paint(const PaintInfo& paint_info,
       }
 
       if (recorder && !box_rect.Contains(selection_rect)) {
-        if (should_rotate) {
-          // selection_rect is in the coordinates space of the rotation
-          // transform. Convert it to the non-rotated space for visual rect.
-          selection_rect.Move(-box_rect.offset);
-          std::swap(selection_rect.offset.left, selection_rect.offset.top);
-          std::swap(selection_rect.size.width, selection_rect.size.height);
-          selection_rect.Move(box_rect.offset);
-        }
-        recorder->UniteVisualRect(EnclosingIntRect(selection_rect));
+        IntRect selection_visual_rect = EnclosingIntRect(selection_rect);
+        if (rotation)
+          selection_visual_rect = rotation->MapRect(selection_visual_rect);
+        recorder->UniteVisualRect(selection_visual_rect);
       }
     }
   }
@@ -444,11 +441,6 @@ void InlineTextBoxPainter::Paint(const PaintInfo& paint_info,
                          font, DocumentMarkerPaintPhase::kForeground);
   }
 
-  if (should_rotate) {
-    context.ConcatCTM(TextPainterBase::Rotation(
-        box_rect, TextPainterBase::kCounterclockwise));
-  }
-
   if (!font.ShouldSkipDrawing())
     PaintTimingDetector::NotifyTextPaint(visual_rect);
 }

third_party/blink/renderer/core/paint/ng/ng_text_fragment_painter.cc

@@ -401,14 +401,11 @@ class SelectionPaintState {
     PaintRect(context, *selection_rect_, color);
   }
 
-  // Transposes selection_rect_. Called before we paint vertical selected text
-  // under a rotation transform.
-  void TransposeSelectionRect(const PhysicalOffset& origin) {
+  // Called before we paint vertical selected text under a rotation transform.
+  void MapSelectionRectIntoRotatedSpace(const AffineTransform& rotation) {
     DCHECK(selection_rect_);
-    selection_rect_->Move(-origin);
-    std::swap(selection_rect_->offset.top, selection_rect_->offset.left);
-    std::swap(selection_rect_->size.width, selection_rect_->size.height);
-    selection_rect_->Move(origin);
+    *selection_rect_ = PhysicalRect::EnclosingRect(
+        rotation.Inverse().MapRect(FloatRect(*selection_rect_)));
   }
 
   // Paint the selected text only.
@@ -599,8 +596,6 @@ void NGTextFragmentPainter<Cursor>::Paint(const PaintInfo& paint_info,
   const SimpleFontData* font_data = font.PrimaryFont();
   DCHECK(font_data);
 
-  base::Optional<GraphicsContextStateSaver> state_saver;
-
   // 1. Paint backgrounds behind text if needed. Examples of such backgrounds
   // include selection and composition highlights. They use physical coordinates
   // so are painted before GraphicsContext rotation.
@@ -619,6 +614,8 @@ void NGTextFragmentPainter<Cursor>::Paint(const PaintInfo& paint_info,
     }
   }
 
+  base::Optional<GraphicsContextStateSaver> state_saver;
+  base::Optional<AffineTransform> rotation;
   const WritingMode writing_mode = style.GetWritingMode();
   const bool is_horizontal = IsHorizontalWritingMode(writing_mode);
   if (!is_horizontal) {
@@ -626,10 +623,11 @@ void NGTextFragmentPainter<Cursor>::Paint(const PaintInfo& paint_info,
     // Because we rotate the GraphicsContext to match the logical direction,
     // transpose the |box_rect| to match to it.
     box_rect.size = PhysicalSize(box_rect.Height(), box_rect.Width());
-    context.ConcatCTM(TextPainterBase::Rotation(
+    rotation.emplace(TextPainterBase::Rotation(
         box_rect, writing_mode != WritingMode::kSidewaysLr
                       ? TextPainterBase::kClockwise
                       : TextPainterBase::kCounterclockwise));
+    context.ConcatCTM(*rotation);
   }
 
   // 2. Now paint the foreground, including text and decorations.
@@ -700,8 +698,8 @@ void NGTextFragmentPainter<Cursor>::Paint(const PaintInfo& paint_info,
     // Paint only the text that is selected.
     if (!selection->IsSelectionRectComputed())
       selection->ComputeSelectionRect(box_rect.offset);
-    if (!is_horizontal)
-      selection->TransposeSelectionRect(box_rect.offset);
+    if (rotation)
+      selection->MapSelectionRectIntoRotatedSpace(*rotation);
     selection->PaintSelectedText(text_painter, length, text_style, node_id);
   }
 

third_party/blink/web_tests/flag-specific/disable-layout-ng/paint/invalidation/selection/japanese-rl-selection-clear-expected.txt

@@ -7,7 +7,6 @@
       "backgroundColor": "#FFFFFF",
       "invalidations": [
         [398, 123, 375, 404],
-        [389, 123, 34, 399],
         [750, 522, 25, 5]
       ]
     }