From fa9b13f64b321cbfe93e340941f6d7b9c0db95cb Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Thu, 30 Apr 2020 23:32:42 +0200
Subject: [PATCH] Decrease precision for values using factor with number
 validator

Using too high precision could result in bogus digits appearing in the
displayed value, e.g. 0.058 shown in percents (with a factor of 100)
appeared as 5.800000000000001 before this change.
---
 src/common/valnum.cpp | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/common/valnum.cpp b/src/common/valnum.cpp
index ecfb6c5186..243108a388 100644
--- a/src/common/valnum.cpp
+++ b/src/common/valnum.cpp
@@ -32,6 +32,8 @@
 #include "wx/valnum.h"
 #include "wx/numformatter.h"
 
+#include <math.h>
+
 // ============================================================================
 // wxNumValidatorBase implementation
 // ============================================================================
@@ -261,8 +263,18 @@ wxIntegerValidatorBase::IsCharOk(const wxString& val, int pos, wxChar ch) const
 
 wxString wxFloatingPointValidatorBase::ToString(LongestValueType value) const
 {
+    // When using factor > 1 we're going to show more digits than are
+    // significant in the real value, so decrease precision to account for it.
+    int precision = m_precision;
+    if ( precision && m_factor > 1 )
+    {
+        precision -= static_cast<int>(log10(static_cast<double>(m_factor)));
+        if ( precision < 0 )
+            precision = 0;
+    }
+
     return wxNumberFormatter::ToString(value*m_factor,
-                                       m_precision,
+                                       precision,
                                        GetFormatFlags());
 }