use float precision for screen coordinates

this should fix rounding error when the map canvas has an odd pixel size
qgis · Sep 29, 2018 · 110c8a0 · 110c8a0
1 parent 1a61885
commit 110c8a0
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/src/quickgui/qgsquickmapsettings.cpp b/src/quickgui/qgsquickmapsettings.cpp
@@ -118,7 +118,10 @@ QPointF QgsQuickMapSettings::coordinateToScreen( const QgsPoint &point ) const
 
 QgsPoint QgsQuickMapSettings::screenToCoordinate( const QPointF &point ) const
 {
-  const QgsPointXY pp = mMapSettings.mapToPixel().toMapCoordinates( point.toPoint() );
+  // use floating point precision with mapToCoordinatesF
+  // this is to avoid rounding errors with an odd screen width or height
+  // and the point being set to the exact center of it
+  const QgsPointXY pp = mMapSettings.mapToPixel().toMapCoordinatesF( point.x(), point.y() );
   return QgsPoint( pp );
 }