wg_engine: fix shapes closing

Shapes were incorrectly closed in certain cases -
the decision to close a shape or not should be based on
path commands rather than the number of points and
their distances from each other.

src/renderer/wg_engine/tvgWgGeometry.cpp

@@ -57,6 +57,7 @@ WgPolyline::WgPolyline()
     constexpr uint32_t nPoints = 360;
     pts.reserve(nPoints);
     dist.reserve(nPoints);
+    closed = false;
 }
 
 
@@ -149,12 +150,7 @@ void WgPolyline::trim(WgPolyline* polyline, float trimBegin, float trimEnd) cons
 void WgPolyline::close()
 {
     if (pts.count > 0) appendPoint(pts[0]);
-}
+    closed = true;
-
-
-bool WgPolyline::isClosed() const
-{
-    return (pts.count >= 2) && (mathZero(pts[0].dist2(pts.last())));
 }
 
 
@@ -166,6 +162,7 @@ void WgPolyline::clear()
     // clear points and distances
     pts.clear();
     dist.clear();
+    closed = false;
 }
 
 
@@ -406,7 +403,7 @@ void WgGeometryData::appendStroke(const WgPolyline* polyline, const RenderStroke
             );
         }
     } else if (polyline->pts.count > 2) {  // multi-lined sub-path
-        if (polyline->isClosed()) {
+        if (polyline->closed) {
             WgPoint v0 = polyline->pts[polyline->pts.count - 2];
             WgPoint v1 = polyline->pts[0];
             WgPoint v2 = polyline->pts[1];

src/renderer/wg_engine/tvgWgGeometry.h

@@ -84,6 +84,7 @@ struct WgPolyline
     uint32_t imaxy{};
     // total polyline length
     float len{};
+    bool closed{};
 
     WgPolyline();
 
@@ -95,7 +96,6 @@ struct WgPolyline
     void close();
     void clear();
 
-    bool isClosed() const;
     void getBBox(WgPoint& pmin, WgPoint& pmax) const;
 };