Don't try to render non-finite points

They occur as a result of reprojection errors, and cause a line
to be extend to the top-left of the canvas.

Fixes #9392

(cherry-picked from 454cce8)

Author: nyalldawson

src/core/symbology/qgssymbol.cpp

@@ -125,6 +125,13 @@ QPolygonF QgsSymbol::_getLineString( QgsRenderContext &context, const QgsCurve &
     ct.transformPolygon( pts );
   }
 
+  // remove non-finite points, e.g. infinite or NaN points caused by reprojecting errors
+  pts.erase( std::remove_if( pts.begin(), pts.end(),
+                             []( const QPointF point )
+  {
+    return !std::isfinite( point.x() ) || !std::isfinite( point.y() );
+  } ), pts.end() );
+
   QPointF *ptr = pts.data();
   for ( int i = 0; i < pts.size(); ++i, ++ptr )
   {
@@ -161,6 +168,13 @@ QPolygonF QgsSymbol::_getPolygonRing( QgsRenderContext &context, const QgsCurve
     ct.transformPolygon( poly );
   }
 
+  // remove non-finite points, e.g. infinite or NaN points caused by reprojecting errors
+  poly.erase( std::remove_if( poly.begin(), poly.end(),
+                              []( const QPointF point )
+  {
+    return !std::isfinite( point.x() ) || !std::isfinite( point.y() );
+  } ), poly.end() );
+
   QPointF *ptr = poly.data();
   for ( int i = 0; i < poly.size(); ++i, ++ptr )
   {