From c50e41dea1dc5aa9d0e2f5bec52c49039316daef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20T=C5=AFma?= <tumic@cbox.cz>
Date: Tue, 17 Apr 2018 22:26:20 +0200
Subject: [PATCH] Numerical instability fix

---
 src/map/onlinemap.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/map/onlinemap.cpp b/src/map/onlinemap.cpp
index 97ee3c9b..5aeaa268 100644
--- a/src/map/onlinemap.cpp
+++ b/src/map/onlinemap.cpp
@@ -8,6 +8,7 @@
 
 
 #define TILE_SIZE     256
+#define EPSILON       1e-6
 
 static QPointF ll2m(const Coordinates &c)
 {
@@ -36,7 +37,7 @@ static qreal zoom2scale(int zoom)
 
 static int scale2zoom(qreal scale)
 {
-	return (int)log2(360.0/(scale * (qreal)TILE_SIZE));
+	return (int)(log2(360.0/(scale * (qreal)TILE_SIZE)) + EPSILON);
 }