Bug 1277788 - Part 1. Set initial value of mask-position as center. r=dbaron.

MozReview-Commit-ID: BflQ6tz8ZjM

--HG--
extra : rebase_source : 01b05533f5c791da0987af81d5cca276ec36e3f0

layout/style/nsCSSParser.cpp

@@ -12083,28 +12083,33 @@ CSSParserImpl::ParseImageLayersItem(
   aState.mClip->mValue.SetIntValue(NS_STYLE_IMAGELAYER_CLIP_BORDER,
                                    eCSSUnit_Enumerated);
 
-
-
-
-  if (eCSSProperty_mask == aTable[nsStyleImageLayers::shorthand]) {
-    aState.mOrigin->mValue.SetIntValue(NS_STYLE_IMAGELAYER_ORIGIN_BORDER,
-                                       eCSSUnit_Enumerated);
-    aState.mRepeat->mXValue.SetIntValue(NS_STYLE_IMAGELAYER_REPEAT_NO_REPEAT,
-                                        eCSSUnit_Enumerated);
-  } else {
-    aState.mOrigin->mValue.SetIntValue(NS_STYLE_IMAGELAYER_ORIGIN_PADDING,
-                                       eCSSUnit_Enumerated);
-    aState.mRepeat->mXValue.SetIntValue(NS_STYLE_IMAGELAYER_REPEAT_REPEAT,
-                                        eCSSUnit_Enumerated);
-  }
+  aState.mRepeat->mXValue.SetIntValue(NS_STYLE_IMAGELAYER_REPEAT_REPEAT,
+                                      eCSSUnit_Enumerated);
   aState.mRepeat->mYValue.Reset();
 
   RefPtr<nsCSSValue::Array> positionXArr = nsCSSValue::Array::Create(2);
   RefPtr<nsCSSValue::Array> positionYArr = nsCSSValue::Array::Create(2);
   aState.mPositionX->mValue.SetArrayValue(positionXArr, eCSSUnit_Array);
   aState.mPositionY->mValue.SetArrayValue(positionYArr, eCSSUnit_Array);
-  positionXArr->Item(1).SetPercentValue(0.0f);
-  positionYArr->Item(1).SetPercentValue(0.0f);
+
+  if (eCSSProperty_mask == aTable[nsStyleImageLayers::shorthand]) {
+    aState.mOrigin->mValue.SetIntValue(NS_STYLE_IMAGELAYER_ORIGIN_BORDER,
+                                       eCSSUnit_Enumerated);
+    aState.mRepeat->mXValue.SetIntValue(NS_STYLE_IMAGELAYER_REPEAT_NO_REPEAT,
+                                        eCSSUnit_Enumerated);
+
+    positionXArr->Item(1).SetPercentValue(0.5f);
+    positionYArr->Item(1).SetPercentValue(0.5f);
+  } else {
+    aState.mOrigin->mValue.SetIntValue(NS_STYLE_IMAGELAYER_ORIGIN_PADDING,
+                                       eCSSUnit_Enumerated);
+    aState.mRepeat->mXValue.SetIntValue(NS_STYLE_IMAGELAYER_REPEAT_REPEAT,
+                                        eCSSUnit_Enumerated);
+
+    positionXArr->Item(1).SetPercentValue(0.0f);
+    positionYArr->Item(1).SetPercentValue(0.0f);
+  }
+
   aState.mSize->mXValue.SetAutoValue();
   aState.mSize->mYValue.SetAutoValue();
   aState.mComposite->mValue.SetIntValue(NS_STYLE_MASK_COMPOSITE_ADD,

layout/style/nsComputedDOMStyle.cpp

@@ -6148,7 +6148,7 @@ nsComputedDOMStyle::DoGetMask()
       firstLayer.mOrigin != NS_STYLE_IMAGELAYER_ORIGIN_BORDER ||
       firstLayer.mComposite != NS_STYLE_MASK_COMPOSITE_ADD ||
       firstLayer.mMaskMode != NS_STYLE_MASK_MODE_MATCH_SOURCE ||
-      !firstLayer.mPosition.IsInitialValue() ||
+      !firstLayer.mPosition.IsInitialValue(nsStyleImageLayers::LayerType::Mask) ||
       !firstLayer.mRepeat.IsInitialValue(nsStyleImageLayers::LayerType::Mask) ||
       !firstLayer.mSize.IsInitialValue() ||
       !(firstLayer.mImage.GetType() == eStyleImageType_Null ||

layout/style/nsStyleStruct.cpp

@@ -2488,12 +2488,21 @@ nsStyleImageLayers::HasLayerWithImage() const
 }
 
 bool
-nsStyleImageLayers::Position::IsInitialValue() const
+nsStyleImageLayers::Position::IsInitialValue(LayerType aType) const
 {
-  if (mXPosition.mPercent == 0.0 && mXPosition.mLength == 0 &&
-      mXPosition.mHasPercent && mYPosition.mPercent == 0.0 &&
-      mYPosition.mLength == 0 && mYPosition.mHasPercent) {
-    return true;
+  if (aType == LayerType::Background) {
+    if (mXPosition.mPercent == 0.0 && mXPosition.mLength == 0 &&
+        mXPosition.mHasPercent && mYPosition.mPercent == 0.0 &&
+        mYPosition.mLength == 0 && mYPosition.mHasPercent) {
+      return true;
+    }
+  } else {
+    MOZ_ASSERT(aType == LayerType::Mask);
+    if (mXPosition.mPercent == 0.5f && mXPosition.mLength == 0 &&
+        mXPosition.mHasPercent && mYPosition.mPercent == 0.5f &&
+        mYPosition.mLength == 0 && mYPosition.mHasPercent) {
+      return true;
+    }
   }
 
   return false;
@@ -2658,7 +2667,6 @@ nsStyleImageLayers::Layer::Layer()
   , mComposite(NS_STYLE_MASK_COMPOSITE_ADD)
   , mMaskMode(NS_STYLE_MASK_MODE_MATCH_SOURCE)
 {
-  mPosition.SetInitialPercentValues(0.0f); // Initial value is "0% 0%"
   mImage.SetNull();
   mSize.SetInitialValues();
 }
@@ -2674,9 +2682,11 @@ nsStyleImageLayers::Layer::Initialize(nsStyleImageLayers::LayerType aType)
 
   if (aType == LayerType::Background) {
     mOrigin = NS_STYLE_IMAGELAYER_ORIGIN_PADDING;
+    mPosition.SetInitialPercentValues(0.0f); // Initial value is "0% 0%"
   } else {
     MOZ_ASSERT(aType == LayerType::Mask, "unsupported layer type.");
     mOrigin = NS_STYLE_IMAGELAYER_ORIGIN_BORDER;
+    mPosition.SetInitialPercentValues(0.5f); // Initial value is "50% 50%"
   }
 }
 

layout/style/nsStyleStruct.h

@@ -566,7 +566,7 @@ struct nsStyleImageLayers {
     // Initialize nothing
     Position() {}
 
-    bool IsInitialValue() const;
+    bool IsInitialValue(LayerType aType) const;
 
     // Sets both mXPosition and mYPosition to the given percent value for the
     // initial property-value (e.g. 0.0f for "0% 0%", or 0.5f for "50% 50%")