Bug 1333685 - Eliminate CircleShapeInfo, and use EllipseShapeInfo for circle(). r=dbaron

The difference between CircleShapeInfo's constructor and EllipseShapeInfo's
is the computation of the radii. Therefore, this patch creates a factory
function to distinguish that, so shape-outside: circle() could be
implemented by using EllipseShapeInfo.

MozReview-Commit-ID: 9ZBQu8zCSrM

layout/generic/nsFloatManager.cpp

@@ -613,52 +613,8 @@ nsFloatManager::BoxShapeInfo::LineRight(WritingMode aWM,
   return mShapeBoxRect.XMost() - lineRightDiff;
 }
 
-/////////////////////////////////////////////////////////////////////////////
-// CircleShapeInfo
-
-nsFloatManager::CircleShapeInfo::CircleShapeInfo(
-  StyleBasicShape* const aBasicShape,
-  const LogicalRect& aShapeBoxRect,
-  WritingMode aWM,
-  const nsSize& aContainerSize)
-{
-  // Use physical coordinates to compute the center of the circle() since
-  // the <position> keywords such as 'left', 'top', etc. are physical.
-  // https://drafts.csswg.org/css-shapes-1/#funcdef-circle
-  nsRect physicalShapeBoxRect =
-    aShapeBoxRect.GetPhysicalRect(aWM, aContainerSize);
-  nsPoint physicalCenter =
-    ShapeUtils::ComputeCircleOrEllipseCenter(aBasicShape, physicalShapeBoxRect);
-  nscoord radius = ShapeUtils::ComputeCircleRadius(aBasicShape, physicalCenter,
-                                                   physicalShapeBoxRect);
-  mRadii = nsSize(radius, radius);
-  mCenter = ConvertPhysicalToLogical(aWM, physicalCenter, aContainerSize);
-}
-
 /////////////////////////////////////////////////////////////////////////////
 // EllipseShapeInfo
-
-nsFloatManager::EllipseShapeInfo::EllipseShapeInfo(
-  StyleBasicShape* const aBasicShape,
-  const LogicalRect& aShapeBoxRect,
-  WritingMode aWM,
-  const nsSize& aContainerSize)
-{
-  // Use physical coordinates to compute the center of the ellipse() since
-  // the <position> keywords such as 'left', 'top', etc. are physical.
-  // https://drafts.csswg.org/css-shapes-1/#funcdef-ellipse
-  nsRect physicalShapeBoxRect =
-    aShapeBoxRect.GetPhysicalRect(aWM, aContainerSize);
-  nsPoint physicalCenter =
-    ShapeUtils::ComputeCircleOrEllipseCenter(aBasicShape, physicalShapeBoxRect);
-  nsSize physicalRadii =
-    ShapeUtils::ComputeEllipseRadii(aBasicShape, physicalCenter,
-                                    physicalShapeBoxRect);
-  LogicalSize logicalRadii(aWM, physicalRadii);
-  mRadii = nsSize(logicalRadii.ISize(aWM), logicalRadii.BSize(aWM));
-  mCenter = ConvertPhysicalToLogical(aWM, physicalCenter, aContainerSize);
-}
-
 nscoord
 nsFloatManager::EllipseShapeInfo::LineLeft(WritingMode aWM,
                                            const nscoord aBStart,
@@ -749,12 +705,9 @@ nsFloatManager::FloatInfo::FloatInfo(nsIFrame* aFrame,
         // for CSS shape-outside.
         break;
       case StyleBasicShapeType::Circle:
-        mShapeInfo =
-          MakeUnique<CircleShapeInfo>(basicShape, rect, aWM, aContainerSize);
-        break;
       case StyleBasicShapeType::Ellipse:
         mShapeInfo =
-          MakeUnique<EllipseShapeInfo>(basicShape, rect, aWM, aContainerSize);
+          ShapeInfo::CreateCircleOrEllipse(basicShape, rect, aWM, aContainerSize);
         break;
       case StyleBasicShapeType::Inset:
         // Bug 1326407 - Implement the rendering of basic shape inset() for
@@ -872,6 +825,43 @@ nsFloatManager::FloatInfo::IsEmpty(ShapeType aShapeType) const
 /////////////////////////////////////////////////////////////////////////////
 // ShapeInfo
 
+/* static */ UniquePtr<nsFloatManager::ShapeInfo>
+nsFloatManager::ShapeInfo::CreateCircleOrEllipse(
+  StyleBasicShape* const aBasicShape,
+  const LogicalRect& aShapeBoxRect,
+  WritingMode aWM,
+  const nsSize& aContainerSize)
+{
+  // Use physical coordinates to compute the center of circle() or ellipse()
+  // since the <position> keywords such as 'left', 'top', etc. are physical.
+  // https://drafts.csswg.org/css-shapes-1/#funcdef-ellipse
+  nsRect physicalShapeBoxRect =
+    aShapeBoxRect.GetPhysicalRect(aWM, aContainerSize);
+  nsPoint physicalCenter =
+    ShapeUtils::ComputeCircleOrEllipseCenter(aBasicShape, physicalShapeBoxRect);
+  nsPoint center =
+    ConvertPhysicalToLogical(aWM, physicalCenter, aContainerSize);
+
+  // Compute the circle or ellipse radii.
+  nsSize radii;
+  StyleBasicShapeType type = aBasicShape->GetShapeType();
+  if (type == StyleBasicShapeType::Circle) {
+    nscoord radius = ShapeUtils::ComputeCircleRadius(aBasicShape, physicalCenter,
+                                                     physicalShapeBoxRect);
+    radii = nsSize(radius, radius);
+  } else {
+    MOZ_ASSERT(type == StyleBasicShapeType::Ellipse);
+    nsSize physicalRadii =
+      ShapeUtils::ComputeEllipseRadii(aBasicShape, physicalCenter,
+                                      physicalShapeBoxRect);
+    LogicalSize logicalRadii(aWM, physicalRadii);
+    radii = nsSize(logicalRadii.ISize(aWM), logicalRadii.BSize(aWM));
+  }
+
+  return MakeUnique<EllipseShapeInfo>(center, radii);
+}
+
+
 /* static */ nscoord
 nsFloatManager::ShapeInfo::ComputeEllipseLineInterceptDiff(
   const nscoord aShapeBoxBStart, const nscoord aShapeBoxBEnd,

layout/generic/nsFloatManager.h

@@ -361,6 +361,12 @@ private:
     // Translate the current origin by the specified offsets.
     virtual void Translate(nscoord aLineLeft, nscoord aBlockStart) = 0;
 
+    static mozilla::UniquePtr<ShapeInfo> CreateCircleOrEllipse(
+      mozilla::StyleBasicShape* const aBasicShape,
+      const mozilla::LogicalRect& aShapeBoxRect,
+      mozilla::WritingMode aWM,
+      const nsSize& aContainerSize);
+
   protected:
     // Compute the minimum line-axis difference between the bounding shape
     // box and its rounded corner within the given band (block-axis region).
@@ -420,14 +426,15 @@ private:
     nsIFrame* const mFrame;
   };
 
-  // Implements shape-outside: ellipse().
+  // Implements shape-outside: circle() and shape-outside: ellipse().
   class EllipseShapeInfo : public ShapeInfo
   {
   public:
-    EllipseShapeInfo(mozilla::StyleBasicShape* const aBasicShape,
-                     const mozilla::LogicalRect& aShapeBoxRect,
-                     mozilla::WritingMode aWM,
-                     const nsSize& aContainerSize);
+    EllipseShapeInfo(const nsPoint& aCenter,
+                     const nsSize& aRadii)
+      : mCenter(aCenter)
+      , mRadii(aRadii)
+    {}
 
     nscoord LineLeft(mozilla::WritingMode aWM,
                      const nscoord aBStart,
@@ -445,8 +452,6 @@ private:
     }
 
   protected:
-    EllipseShapeInfo() = default;
-
     // The position of the center of the ellipse. The coordinate space is the
     // same as FloatInfo::mRect.
     nsPoint mCenter;
@@ -455,16 +460,6 @@ private:
     nsSize mRadii;
   };
 
-  // Implements shape-outside: circle().
-  class CircleShapeInfo final : public EllipseShapeInfo
-  {
-  public:
-    CircleShapeInfo(mozilla::StyleBasicShape* const aBasicShape,
-                    const mozilla::LogicalRect& aShapeBoxRect,
-                    mozilla::WritingMode aWM,
-                    const nsSize& aContainerSize);
-  };
-
   struct FloatInfo {
     nsIFrame *const mFrame;
     // The lowest block-ends of left/right floats up to and including