Cleanup InlineFlowBox::AddTextBoxVisualOverflow

In order to port/share the logic with LayoutNG, this patch cleans up
visual overflow logic for InlineTextBox.

Bug: 636993
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2
Change-Id: Ie2bd84c6f332d372b744aa0b7c6de6b9e7406bc8
Reviewed-on: https://chromium-review.googlesource.com/768592
Commit-Queue: Koji Ishii <kojii@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#517330}

third_party/WebKit/Source/core/layout/line/InlineFlowBox.cpp

@@ -1068,94 +1068,52 @@ inline void InlineFlowBox::AddTextBoxVisualOverflow(
   if (text_box->KnownToHaveNoOverflow())
     return;
 
+  LayoutRectOutsets visual_rect_outsets;
   const ComputedStyle& style =
       text_box->GetLineLayoutItem().StyleRef(IsFirstLineStyle());
 
   GlyphOverflowAndFallbackFontsMap::iterator it =
       text_box_data_map.find(text_box);
-  GlyphOverflow* glyph_overflow =
-      it == text_box_data_map.end() ? nullptr : &it->value.second;
-  bool is_flipped_line = style.IsFlippedLinesWritingMode();
-
-  float top_glyph_edge =
-      glyph_overflow
-          ? (is_flipped_line ? glyph_overflow->bottom : glyph_overflow->top)
-          : 0;
-  float bottom_glyph_edge =
-      glyph_overflow
-          ? (is_flipped_line ? glyph_overflow->top : glyph_overflow->bottom)
-          : 0;
-  float left_glyph_edge = glyph_overflow ? glyph_overflow->left : 0;
-  float right_glyph_edge = glyph_overflow ? glyph_overflow->right : 0;
-
-  float stroke_overflow = style.TextStrokeWidth() / 2.0f;
-  float top_glyph_overflow = -stroke_overflow - top_glyph_edge;
-  float bottom_glyph_overflow = stroke_overflow + bottom_glyph_edge;
-  float left_glyph_overflow = -stroke_overflow - left_glyph_edge;
-  float right_glyph_overflow = stroke_overflow + right_glyph_edge;
+  if (it != text_box_data_map.end()) {
+    const GlyphOverflow& glyph_overflow = it->value.second;
+    bool is_flipped_line = style.IsFlippedLinesWritingMode();
+    visual_rect_outsets = EnclosingLayoutRectOutsets(FloatRectOutsets(
+        is_flipped_line ? glyph_overflow.bottom : glyph_overflow.top,
+        glyph_overflow.right,
+        is_flipped_line ? glyph_overflow.top : glyph_overflow.bottom,
+        glyph_overflow.left));
+  }
+
+  if (float stroke_width = style.TextStrokeWidth()) {
+    visual_rect_outsets += LayoutUnit::FromFloatCeil(stroke_width / 2.0f);
+  }
 
   TextEmphasisPosition emphasis_mark_position;
   if (style.GetTextEmphasisMark() != TextEmphasisMark::kNone &&
       text_box->GetEmphasisMarkPosition(style, emphasis_mark_position)) {
-    float emphasis_mark_height =
-        style.GetFont().EmphasisMarkHeight(style.TextEmphasisMarkString());
-    if (HasEmphasisMarkBefore(text_box))
-      top_glyph_overflow = std::min(top_glyph_overflow, -emphasis_mark_height);
-    else
-      bottom_glyph_overflow =
-          std::max(bottom_glyph_overflow, emphasis_mark_height);
+    LayoutUnit emphasis_mark_height = LayoutUnit(
+        style.GetFont().EmphasisMarkHeight(style.TextEmphasisMarkString()));
+    if (HasEmphasisMarkBefore(text_box)) {
+      visual_rect_outsets.SetTop(
+          std::max(visual_rect_outsets.Top(), emphasis_mark_height));
+    } else {
+      visual_rect_outsets.SetBottom(
+          std::max(visual_rect_outsets.Bottom(), emphasis_mark_height));
+    }
   }
 
-  LayoutRectOutsets text_shadow_logical_outsets;
   if (ShadowList* text_shadow = style.TextShadow()) {
-    text_shadow_logical_outsets =
+    LayoutRectOutsets text_shadow_logical_outsets =
         LayoutRectOutsets(text_shadow->RectOutsetsIncludingOriginal())
             .LineOrientationOutsets(style.GetWritingMode());
+    text_shadow_logical_outsets.ClampNegativeToZero();
+    visual_rect_outsets += text_shadow_logical_outsets;
   }
 
-  // FIXME: This code currently uses negative values for expansion of the top
-  // and left edges. This should be cleaned up.
-  LayoutUnit text_shadow_logical_top = -text_shadow_logical_outsets.Top();
-  LayoutUnit text_shadow_logical_bottom = text_shadow_logical_outsets.Bottom();
-  LayoutUnit text_shadow_logical_left = -text_shadow_logical_outsets.Left();
-  LayoutUnit text_shadow_logical_right = text_shadow_logical_outsets.Right();
-
-  LayoutUnit child_overflow_logical_top(std::min(
-      text_shadow_logical_top + top_glyph_overflow, top_glyph_overflow));
-  LayoutUnit child_overflow_logical_bottom(
-      std::max(text_shadow_logical_bottom + bottom_glyph_overflow,
-               bottom_glyph_overflow));
-  LayoutUnit child_overflow_logical_left(std::min(
-      text_shadow_logical_left + left_glyph_overflow, left_glyph_overflow));
-  LayoutUnit child_overflow_logical_right(std::max(
-      text_shadow_logical_right + right_glyph_overflow, right_glyph_overflow));
-
-  int enclosing_logical_top_with_overflow =
-      (text_box->LogicalTop() + child_overflow_logical_top).Floor();
-  int enclosing_logical_bottom_with_overflow =
-      (text_box->LogicalBottom() + child_overflow_logical_bottom).Ceil();
-  int enclosing_logical_left_with_overflow =
-      (text_box->LogicalLeft() + child_overflow_logical_left).Floor();
-  int enclosing_logical_right_with_overflow =
-      (text_box->LogicalRight() + child_overflow_logical_right).Ceil();
-
-  LayoutUnit logical_top_visual_overflow =
-      std::min(LayoutUnit(enclosing_logical_top_with_overflow),
-               logical_visual_overflow.Y());
-  LayoutUnit logical_bottom_visual_overflow =
-      std::max(LayoutUnit(enclosing_logical_bottom_with_overflow),
-               logical_visual_overflow.MaxY());
-  LayoutUnit logical_left_visual_overflow =
-      std::min(LayoutUnit(enclosing_logical_left_with_overflow),
-               logical_visual_overflow.X());
-  LayoutUnit logical_right_visual_overflow =
-      std::max(LayoutUnit(enclosing_logical_right_with_overflow),
-               logical_visual_overflow.MaxX());
-
-  logical_visual_overflow =
-      LayoutRect(logical_left_visual_overflow, logical_top_visual_overflow,
-                 logical_right_visual_overflow - logical_left_visual_overflow,
-                 logical_bottom_visual_overflow - logical_top_visual_overflow);
+  LayoutRect frame_rect = text_box->LogicalFrameRect();
+  frame_rect.Expand(visual_rect_outsets);
+  frame_rect = LayoutRect(EnclosingIntRect(frame_rect));
+  logical_visual_overflow.Unite(frame_rect);
 
   if (logical_visual_overflow != text_box->LogicalFrameRect())
     text_box->SetLogicalOverflowRect(logical_visual_overflow);

third_party/WebKit/Source/platform/geometry/LayoutRectOutsets.cpp

@@ -35,6 +35,13 @@
 
 namespace blink {
 
+void LayoutRectOutsets::ClampNegativeToZero() {
+  top_ = top_.ClampNegativeToZero();
+  right_ = right_.ClampNegativeToZero();
+  bottom_ = bottom_.ClampNegativeToZero();
+  left_ = left_.ClampNegativeToZero();
+}
+
 LayoutRectOutsets LayoutRectOutsets::LineOrientationOutsets(
     WritingMode writing_mode) const {
   if (!IsHorizontalWritingMode(writing_mode))

third_party/WebKit/Source/platform/geometry/LayoutRectOutsets.h

@@ -83,6 +83,8 @@ class PLATFORM_EXPORT LayoutRectOutsets {
   void SetBottom(LayoutUnit value) { bottom_ = value; }
   void SetLeft(LayoutUnit value) { left_ = value; }
 
+  void ClampNegativeToZero();
+
   // Produces a new LayoutRectOutsets in line orientation
   // (https://www.w3.org/TR/css-writing-modes-3/#line-orientation), whose
   // - |top| is the logical 'over',
@@ -115,6 +117,14 @@ inline LayoutRectOutsets& operator+=(LayoutRectOutsets& a,
   return a;
 }
 
+inline LayoutRectOutsets& operator+=(LayoutRectOutsets& a, LayoutUnit b) {
+  a.SetTop(a.Top() + b);
+  a.SetRight(a.Right() + b);
+  a.SetBottom(a.Bottom() + b);
+  a.SetLeft(a.Left() + b);
+  return a;
+}
+
 inline LayoutRectOutsets operator+(const LayoutRectOutsets& a,
                                    const LayoutRectOutsets& b) {
   return LayoutRectOutsets(a.Top() + b.Top(), a.Right() + b.Right(),
@@ -125,6 +135,14 @@ inline LayoutRectOutsets operator-(const LayoutRectOutsets& a) {
   return LayoutRectOutsets(-a.Top(), -a.Right(), -a.Bottom(), -a.Left());
 }
 
+inline LayoutRectOutsets EnclosingLayoutRectOutsets(
+    const FloatRectOutsets& rect) {
+  return LayoutRectOutsets(LayoutUnit::FromFloatCeil(rect.Top()),
+                           LayoutUnit::FromFloatCeil(rect.Right()),
+                           LayoutUnit::FromFloatCeil(rect.Bottom()),
+                           LayoutUnit::FromFloatCeil(rect.Left()));
+}
+
 }  // namespace blink
 
 #endif  // LayoutRectOutsets_h