Bug 577475 - polygon end marker should be at the same point as the start marker. r=jwatt

content/svg/content/src/nsSVGPolygonElement.cpp

@@ -112,6 +112,10 @@ nsSVGPolygonElement::GetMarkPoints(nsTArray<nsSVGMark> *aMarks)
 
     endMark->angle = nsSVGUtils::AngleBisect(angle, endMark->angle);
     startMark->angle = nsSVGUtils::AngleBisect(angle, startMark->angle);
+    // for a polygon (as opposed to a polyline) there's an implicit extra point
+    // co-located with the start point that nsSVGPolyElement::GetMarkPoints
+    // doesn't return
+    aMarks->AppendElement(nsSVGMark(startMark->x, startMark->y, startMark->angle));
   }
 }
 

layout/reftests/svg/marker-attribute-01.svg

@@ -9,9 +9,11 @@
 
     This test checks that the 'marker' presentation attribute is ignored.
   -->
-  <marker id="marker" markerWidth="40" markerHeight="40" refX="20" refY="20">
-    <circle cx="20" cy="20" r="20" fill="red"/>
-  </marker>
+  <defs>
+    <marker id="marker" markerWidth="40" markerHeight="40" refX="20" refY="20">
+      <circle cx="20" cy="20" r="20" fill="red"/>
+    </marker>
+  </defs>
   <rect width="100%" height="100%" fill="lime"/>
   <path d="M20,20 L60,20 L100,20" fill="none" stroke="none" marker="url(#marker)"/>
 </svg>

layout/reftests/svg/polygon-marker-01.svg

@@ -0,0 +1,22 @@
+<!--
+     Any copyright is dedicated to the Public Domain.
+     http://creativecommons.org/licenses/publicdomain/
+-->
+<svg xmlns="http://www.w3.org/2000/svg">
+  <title>Test that marker-start and marker-end are co-located for polygon elements</title>
+  <!--
+    From https://bugzilla.mozilla.org/show_bug.cgi?id=577475
+
+    This test checks that marker-start and marker-end are co-located for polygon elements.
+  -->
+  <defs>
+    <marker id="markerStart" markerWidth="40" markerHeight="40" refX="20" refY="20">
+      <rect width="50" height="55" fill="red"/>
+    </marker>
+    <marker id="markerEnd" markerWidth="40" markerHeight="40" refX="20" refY="20">
+      <rect width="50" height="55" fill="lime"/>
+    </marker>
+  </defs>
+  <rect width="100%" height="100%" fill="lime"/>
+  <polygon marker-start="url(#markerStart)" marker-end="url(#markerEnd)" points="250,150 200,150" />
+</svg>

layout/reftests/svg/reftest.list

@@ -124,6 +124,7 @@ fails == inline-in-xul-basic-01.xul pass.svg
 == pattern-live-01a.svg pattern-live-01-ref.svg
 == pattern-live-01b.svg pattern-live-01-ref.svg
 == pattern-live-01c.svg pattern-live-01-ref.svg
+== polygon-marker-01.svg pass.svg
 == pseudo-classes-01.svg pass.svg
 # This test depends on :visited styles (which are asynchronous), so we run
 # it in layout/style/test/test_visited_reftests.html instead of using the