Bug 1596513: Part 2: Allow for floating point dx/dy on feDropShadow attributes r=nical

WebRender expects drop shadow dx/dy to be in user space, which is a floating point value.
Before this, a dx/dy such as (0.2, 0.2) was truncated to (0, 0) resulting in no offset of the shadow.

Differential Revision: https://phabricator.services.mozilla.com/D63442

--HG--
extra : moz-landing-system : lando

dom/svg/SVGFEDropShadowElement.cpp

@@ -80,10 +80,10 @@ FilterPrimitiveDescription SVGFEDropShadowElement::GetPrimitiveDescription(
     return FilterPrimitiveDescription();
   }
 
-  IntPoint offset(int32_t(aInstance->GetPrimitiveNumber(
-                      SVGContentUtils::X, &mNumberAttributes[DX])),
-                  int32_t(aInstance->GetPrimitiveNumber(
-                      SVGContentUtils::Y, &mNumberAttributes[DY])));
+  Point offset(
+      aInstance->GetPrimitiveNumber(SVGContentUtils::X, &mNumberAttributes[DX]),
+      aInstance->GetPrimitiveNumber(SVGContentUtils::Y,
+                                    &mNumberAttributes[DY]));
 
   DropShadowAttributes atts;
   atts.mStdDeviation = Size(stdX, stdY);

gfx/src/FilterSupport.cpp

@@ -989,8 +989,8 @@ static already_AddRefed<FilterNode> FilterNodeFromPrimitiveDescription(
       RefPtr<FilterNode> alpha = FilterWrappers::ToAlpha(mDT, mSources[0]);
       RefPtr<FilterNode> blur =
           FilterWrappers::GaussianBlur(mDT, alpha, aDropShadow.mStdDeviation);
-      RefPtr<FilterNode> offsetBlur =
-          FilterWrappers::Offset(mDT, blur, aDropShadow.mOffset);
+      RefPtr<FilterNode> offsetBlur = FilterWrappers::Offset(
+          mDT, blur, IntPoint::Truncate(aDropShadow.mOffset));
       RefPtr<FilterNode> flood = mDT->CreateFilter(FilterType::FLOOD);
       if (!flood) {
         return nullptr;
@@ -1453,7 +1453,7 @@ static nsIntRegion ResultChangeRegionForPrimitive(
     }
 
     nsIntRegion operator()(const DropShadowAttributes& aDropShadow) {
-      IntPoint offset = aDropShadow.mOffset;
+      IntPoint offset = IntPoint::Truncate(aDropShadow.mOffset);
       nsIntRegion offsetRegion =
           mInputChangeRegions[0].MovedBy(offset.x, offset.y);
       Size stdDeviation = aDropShadow.mStdDeviation;
@@ -1833,7 +1833,7 @@ static nsIntRegion SourceNeededRegionForPrimitive(
     }
 
     nsIntRegion operator()(const DropShadowAttributes& aDropShadow) {
-      IntPoint offset = aDropShadow.mOffset;
+      IntPoint offset = IntPoint::Truncate(aDropShadow.mOffset);
       nsIntRegion offsetRegion =
           mResultNeededRegion.MovedBy(-nsIntPoint(offset.x, offset.y));
       Size stdDeviation = aDropShadow.mStdDeviation;

gfx/src/FilterSupport.h

@@ -212,7 +212,7 @@ struct GaussianBlurAttributes {
 
 struct DropShadowAttributes {
   Size mStdDeviation;
-  IntPoint mOffset;
+  Point mOffset;
   Color mColor;
 
   bool operator==(const DropShadowAttributes& aOther) const {

layout/svg/nsFilterInstance.cpp

@@ -257,7 +257,7 @@ bool nsFilterInstance::BuildWebRenderFilters(nsIFrame* aFilteredFrame,
                       gsRGBToLinearRGBMap[uint8_t(color.b * 255)], color.a);
       }
       wr::Shadow wrShadow;
-      wrShadow.offset = {(float)shadow.mOffset.x, (float)shadow.mOffset.y};
+      wrShadow.offset = {shadow.mOffset.x, shadow.mOffset.y};
       wrShadow.color = wr::ToColorF(ToDeviceColor(color));
       wrShadow.blur_radius = stdDev.width;
       wr::FilterOp filterOp = wr::FilterOp::DropShadow(wrShadow);