Fix line pattern fill symbol corruption with negative angles

src/core/symbology/qgsfillsymbollayer.cpp

@@ -2560,6 +2560,9 @@ void QgsLinePatternFillSymbolLayer::applyPattern( const QgsSymbolRenderContext &
 
   //create image
   int height, width;
+  lineAngle = std::fmod( lineAngle, 360 );
+  if ( lineAngle < 0 )
+    lineAngle += 360;
   if ( qgsDoubleNear( lineAngle, 0 ) || qgsDoubleNear( lineAngle, 360 ) || qgsDoubleNear( lineAngle, 180 ) )
   {
     height = outputPixelDist;
@@ -2585,7 +2588,7 @@ void QgsLinePatternFillSymbolLayer::applyPattern( const QgsSymbolRenderContext &
     height = std::abs( height );
     width = std::abs( width );
 
-    outputPixelDist = height * std::cos( lineAngle * M_PI / 180 );
+    outputPixelDist = std::abs( height * std::cos( lineAngle * M_PI / 180 ) );
 
     // Round offset to correspond to one pixel height, otherwise lines may
     // be shifted on tile border if offset falls close to pixel center

tests/src/core/testqgslinefillsymbol.cpp

@@ -56,6 +56,7 @@ class TestQgsLineFillSymbol : public QObject
     void lineFillSymbol();
     void lineFillSymbolOffset();
     void lineFillLargeOffset();
+    void lineFillNegativeAngle();
 
     void dataDefinedSubSymbol();
 
@@ -165,6 +166,17 @@ void TestQgsLineFillSymbol::lineFillLargeOffset()
   mLineFill->setOffset( 0 );
 }
 
+void TestQgsLineFillSymbol::lineFillNegativeAngle()
+{
+  mLineFill->setOffset( -8 );
+  mLineFill->setDistance( 2.2 );
+  mLineFill->setLineAngle( -130 );
+  QVERIFY( imageCheck( QStringLiteral( "symbol_linefill_negangle" ) ) );
+  mLineFill->setOffset( 0 );
+  mLineFill->setLineAngle( 45 );
+  mLineFill->setDistance( 5 );
+}
+
 void TestQgsLineFillSymbol::dataDefinedSubSymbol()
 {
   mReport += QLatin1String( "<h2>Line fill symbol data defined sub symbol test</h2>\n" );