From 97dbfb163b08e6e21650e249e5ecf46bbbc7c5f2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20T=C5=AFma?= <tumic@cbox.cz>
Date: Sun, 31 Jan 2021 10:30:06 +0100
Subject: [PATCH] Scale the painter, not the images for performance reasons

---
 src/map/IMG/rastertile.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/map/IMG/rastertile.cpp b/src/map/IMG/rastertile.cpp
index 6a5dc1d9..8a984882 100644
--- a/src/map/IMG/rastertile.cpp
+++ b/src/map/IMG/rastertile.cpp
@@ -227,9 +227,13 @@ void RasterTile::drawPolygons(QPainter *painter)
 
 				SubFile::Handle hdl(poly.raster.lbl());
 				QImage img(poly.raster.lbl()->readImage(hdl, poly.raster.id()));
+				qreal sx = (qreal)size.width() / (qreal)img.width();
+				qreal sy = (qreal)size.height() / (qreal)img.height();
 
-				painter->drawImage(tl, img.scaled(size, Qt::IgnoreAspectRatio,
-				  Qt::SmoothTransformation));
+				painter->save();
+				painter->scale(sx, sy);
+				painter->drawImage(QPointF(tl.x() / sx, tl.y() / sy), img);
+				painter->restore();
 
 				//painter->setPen(Qt::blue);
 				//painter->setBrush(Qt::NoBrush);