[SVGDom] Add 'stroke-dashoffset' support

https://www.w3.org/TR/SVG/painting.html#StrokeDashoffsetProperty
Change-Id: Ia25d0048a56ac3835cabcb4e1794d91667367d7c
Reviewed-on: https://skia-review.googlesource.com/59820
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>

6 files changed, 24 insertions, 2 deletions

diff --git a/experimental/svg/model/SkSVGAttribute.cpp b/experimental/svg/model/SkSVGAttribute.cpp
index 41527f7497..31c6c28bb2 100644
--- a/experimental/svg/model/SkSVGAttribute.cpp
+++ b/experimental/svg/model/SkSVGAttribute.cpp
@@ -17,6 +17,7 @@ SkSVGPresentationAttributes SkSVGPresentationAttributes::MakeInitial() {
 
     result.fStroke.set(SkSVGPaint(SkSVGPaint::Type::kNone));
     result.fStrokeDashArray.set(SkSVGDashArray(SkSVGDashArray::Type::kNone));
+    result.fStrokeDashOffset.set(SkSVGLength(0));
     result.fStrokeLineCap.set(SkSVGLineCap(SkSVGLineCap::Type::kButt));
     result.fStrokeLineJoin.set(SkSVGLineJoin(SkSVGLineJoin::Type::kMiter));
     result.fStrokeMiterLimit.set(SkSVGNumberType(4));
diff --git a/experimental/svg/model/SkSVGAttribute.h b/experimental/svg/model/SkSVGAttribute.h
index 1650c3b913..333e3c98e8 100644
--- a/experimental/svg/model/SkSVGAttribute.h
+++ b/experimental/svg/model/SkSVGAttribute.h
@@ -39,6 +39,7 @@ enum class SkSVGAttribute {
     kStopOpacity,
     kStroke,
     kStrokeDashArray,
+    kStrokeDashOffset,
     kStrokeOpacity,
     kStrokeLineCap,
     kStrokeLineJoin,
@@ -70,6 +71,7 @@ struct SkSVGPresentationAttributes {
 
     SkTLazy<SkSVGPaint>      fStroke;
     SkTLazy<SkSVGDashArray>  fStrokeDashArray;
+    SkTLazy<SkSVGLength>     fStrokeDashOffset;
     SkTLazy<SkSVGLineCap>    fStrokeLineCap;
     SkTLazy<SkSVGLineJoin>   fStrokeLineJoin;
     SkTLazy<SkSVGNumberType> fStrokeMiterLimit;
diff --git a/experimental/svg/model/SkSVGDOM.cpp b/experimental/svg/model/SkSVGDOM.cpp
index b25a4d01e3..5b4dc6626f 100644
--- a/experimental/svg/model/SkSVGDOM.cpp
+++ b/experimental/svg/model/SkSVGDOM.cpp
@@ -329,6 +329,7 @@ SortedDictionaryEntry<AttrParseInfo> gAttributeParseInfo[] = {
     { "stop-opacity"     , { SkSVGAttribute::kStopOpacity      , SetNumberAttribute       }},
     { "stroke"           , { SkSVGAttribute::kStroke           , SetPaintAttribute        }},
     { "stroke-dasharray" , { SkSVGAttribute::kStrokeDashArray  , SetDashArrayAttribute    }},
+    { "stroke-dashoffset", { SkSVGAttribute::kStrokeDashOffset , SetLengthAttribute       }},
     { "stroke-linecap"   , { SkSVGAttribute::kStrokeLineCap    , SetLineCapAttribute      }},
     { "stroke-linejoin"  , { SkSVGAttribute::kStrokeLineJoin   , SetLineJoinAttribute     }},
     { "stroke-miterlimit", { SkSVGAttribute::kStrokeMiterLimit , SetNumberAttribute       }},
diff --git a/experimental/svg/model/SkSVGNode.cpp b/experimental/svg/model/SkSVGNode.cpp
index 07dc59c645..c5262a0da8 100644
--- a/experimental/svg/model/SkSVGNode.cpp
+++ b/experimental/svg/model/SkSVGNode.cpp
@@ -94,6 +94,10 @@ void SkSVGNode::setStrokeDashArray(const SkSVGDashArray& dashArray) {
     fPresentationAttributes.fStrokeDashArray.set(dashArray);
 }
 
+void SkSVGNode::setStrokeDashOffset(const SkSVGLength& dashOffset) {
+    fPresentationAttributes.fStrokeDashOffset.set(dashOffset);
+}
+
 void SkSVGNode::setStrokeOpacity(const SkSVGNumberType& opacity) {
     fPresentationAttributes.fStrokeOpacity.set(
         SkSVGNumberType(SkTPin<SkScalar>(opacity.value(), 0, 1)));
@@ -149,6 +153,11 @@ void SkSVGNode::onSetAttribute(SkSVGAttribute attr, const SkSVGValue& v) {
             this->setStrokeDashArray(*dashArray);
         }
         break;
+    case SkSVGAttribute::kStrokeDashOffset:
+        if (const SkSVGLengthValue* dashOffset= v.as<SkSVGLengthValue>()) {
+            this->setStrokeDashOffset(*dashOffset);
+        }
+        break;
     case SkSVGAttribute::kStrokeOpacity:
         if (const SkSVGNumberValue* opacity = v.as<SkSVGNumberValue>()) {
             this->setStrokeOpacity(*opacity);
diff --git a/experimental/svg/model/SkSVGNode.h b/experimental/svg/model/SkSVGNode.h
index c8de2d75f2..ffc4411bde 100644
--- a/experimental/svg/model/SkSVGNode.h
+++ b/experimental/svg/model/SkSVGNode.h
@@ -59,6 +59,7 @@ public:
     void setOpacity(const SkSVGNumberType&);
     void setStroke(const SkSVGPaint&);
     void setStrokeDashArray(const SkSVGDashArray&);
+    void setStrokeDashOffset(const SkSVGLength&);
     void setStrokeOpacity(const SkSVGNumberType&);
     void setStrokeWidth(const SkSVGLength&);
     void setVisibility(const SkSVGVisibility&);
diff --git a/experimental/svg/model/SkSVGRenderContext.cpp b/experimental/svg/model/SkSVGRenderContext.cpp
index 61551c4858..2b7ba2cf2c 100644
--- a/experimental/svg/model/SkSVGRenderContext.cpp
+++ b/experimental/svg/model/SkSVGRenderContext.cpp
@@ -179,14 +179,21 @@ void commitToPaint<SkSVGAttribute::kStrokeDashArray>(const SkSVGPresentationAttr
 
     SkASSERT((intervals.count() & 1) == 0);
 
-    // TODO: phase support
-    const SkScalar phase = 0;
+    const SkScalar phase = ctx.lengthContext().resolve(*pctx->fInherited.fStrokeDashOffset.get(),
+                                                       SkSVGLengthContext::LengthType::kOther);
     pctx->fStrokePaint.setPathEffect(SkDashPathEffect::Make(intervals.begin(),
                                                             intervals.count(),
                                                             phase));
 }
 
 template <>
+void commitToPaint<SkSVGAttribute::kStrokeDashOffset>(const SkSVGPresentationAttributes&,
+                                                      const SkSVGRenderContext&,
+                                                      SkSVGPresentationContext*) {
+    // Applied via kStrokeDashArray.
+}
+
+template <>
 void commitToPaint<SkSVGAttribute::kStrokeLineCap>(const SkSVGPresentationAttributes& attrs,
                                                    const SkSVGRenderContext&,
                                                    SkSVGPresentationContext* pctx) {
@@ -330,6 +337,7 @@ void SkSVGRenderContext::applyPresentationAttributes(const SkSVGPresentationAttr
     ApplyLazyInheritedAttribute(FillRule);
     ApplyLazyInheritedAttribute(ClipRule);
     ApplyLazyInheritedAttribute(Stroke);
+    ApplyLazyInheritedAttribute(StrokeDashOffset);
     ApplyLazyInheritedAttribute(StrokeDashArray);
     ApplyLazyInheritedAttribute(StrokeLineCap);
     ApplyLazyInheritedAttribute(StrokeLineJoin);