From dab0d15d1fee7119f130c1e055bd30b5aed8d5be Mon Sep 17 00:00:00 2001
From: nirvn <nirvn.asia@gmail.com>
Date: Mon, 22 Apr 2019 07:36:26 +0000
Subject: [PATCH] Turn antialiasing flag on when rendering legend symbol
 preview

---
 src/core/layertree/qgslayertreemodellegendnode.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/core/layertree/qgslayertreemodellegendnode.cpp b/src/core/layertree/qgslayertreemodellegendnode.cpp
index 50007d4f4c41..867f421dacf8 100644
--- a/src/core/layertree/qgslayertreemodellegendnode.cpp
+++ b/src/core/layertree/qgslayertreemodellegendnode.cpp
@@ -395,6 +395,7 @@ QSizeF QgsSymbolLegendNode::drawSymbol( const QgsLegendSettings &settings, ItemC
   QgsRenderContext context;
   context.setScaleFactor( settings.dpi() / 25.4 );
   context.setRendererScale( settings.mapScale() );
+  context.setFlag( QgsRenderContext::Antialiasing, true );
   context.setMapToPixel( QgsMapToPixel( 1 / ( settings.mmPerMapUnit() * context.scaleFactor() ) ) );
   context.setForceVectorOutput( true );
   context.setPainter( ctx ? ctx->painter : nullptr );
@@ -460,6 +461,7 @@ QSizeF QgsSymbolLegendNode::drawSymbol( const QgsLegendSettings &settings, ItemC
       QImage tempImage = QImage( tempImageSize, QImage::Format_ARGB32 );
       tempImage.fill( Qt::transparent );
       QPainter imagePainter( &tempImage );
+      imagePainter.setRenderHint( QPainter::Antialiasing );
       context.setPainter( &imagePainter );
       s->drawPreviewIcon( &imagePainter, tempImageSize, &context );
       context.setPainter( ctx->painter );