Make DetermineDigits() reusable in other ports

Move this function, and the associated constant, to common code.

This required moving wxSpinCtrlDouble::Create() implementation to the
source file, but there are no real changes.

include/wx/generic/spinctlg.h

@@ -382,13 +382,7 @@ public:
                 long style = wxSP_ARROW_KEYS,
                 double min = 0, double max = 100, double initial = 0,
                 double inc = 1,
-                const wxString& name = wxT("wxSpinCtrlDouble"))
-    {
-        DoSetDigits(DetermineDigits(inc));
-        return wxSpinCtrlGenericBase::Create(parent, id, value, pos, size,
-                                             style, min, max, initial,
-                                             inc, name);
-    }
+                const wxString& name = wxT("wxSpinCtrlDouble"));
 
     // accessors
     double GetValue(wxSPINCTRL_GETVALUE_FIX) const { return DoGetValue(); }
@@ -426,10 +420,6 @@ private:
         DoSetDigits(0);
     }
 
-    // Return the number of digits required to show the numbers using the
-    // specified increment without loss of precision.
-    static unsigned DetermineDigits(double inc);
-
     // Just set the number of digits and the format unconditionally.
     void DoSetDigits(unsigned digits);
 

include/wx/private/spinctrl.h

@@ -28,6 +28,14 @@ extern wxSize GetBestSize(const wxControl* spin, int minVal, int maxVal, int bas
 
 // Helper function to check if given combination of range and base is valid.
 extern bool IsBaseCompatibleWithRange(int minVal, int maxVal, int base);
+
+// Maximum number of digits returned by DetermineDigits().
+const unsigned SPINCTRLDBL_MAX_DIGITS = 20;
+
+// Return the number of digits required to show the numbers using the
+// specified increment without loss of precision.
+extern unsigned DetermineDigits(double inc);
+
 } // namespace wxSpinCtrlImpl
 
 #endif // _WX_PRIVATE_SPINCTRL_H_

src/common/spinctrlcmn.cpp

@@ -26,6 +26,8 @@
 
 #include "wx/private/spinctrl.h"
 
+#include <math.h>
+
 wxDEFINE_EVENT(wxEVT_SPINCTRL, wxSpinEvent);
 wxDEFINE_EVENT(wxEVT_SPINCTRLDOUBLE, wxSpinDoubleEvent);
 
@@ -140,4 +142,19 @@ bool wxSpinCtrlImpl::IsBaseCompatibleWithRange(int minVal, int maxVal, int base)
     return base == 10 || (minVal >= 0 && maxVal >= 0);
 }
 
+unsigned wxSpinCtrlImpl::DetermineDigits(double inc)
+{
+    // TODO-C++11: Use std::modf() to get the fractional part.
+    inc = fabs(inc);
+    inc -= static_cast<int>(inc);
+    if ( inc > 0.0 )
+    {
+        return wxMin(SPINCTRLDBL_MAX_DIGITS, -static_cast<int>(floor(log10(inc))));
+    }
+    else
+    {
+        return 0;
+    }
+}
+
 #endif // wxUSE_SPINCTRL

src/generic/spinctlg.cpp

@@ -723,10 +723,26 @@ void wxSpinCtrl::ResetTextValidator()
 // wxSpinCtrlDouble
 //-----------------------------------------------------------------------------
 
-#define SPINCTRLDBL_MAX_DIGITS 20
-
 wxIMPLEMENT_DYNAMIC_CLASS(wxSpinCtrlDouble, wxSpinCtrlGenericBase);
 
+bool
+wxSpinCtrlDouble::Create(wxWindow *parent,
+                         wxWindowID id,
+                         const wxString& value,
+                         const wxPoint& pos,
+                         const wxSize& size,
+                         long style,
+                         double min, double max, double initial,
+                         double inc,
+                         const wxString& name)
+{
+    DoSetDigits(wxSpinCtrlImpl::DetermineDigits(inc));
+
+    return wxSpinCtrlGenericBase::Create(parent, id, value, pos, size,
+                                         style, min, max, initial,
+                                         inc, name);
+}
+
 void wxSpinCtrlDouble::DoSendEvent()
 {
     wxSpinDoubleEvent event( wxEVT_SPINCTRLDOUBLE, GetId());
@@ -753,7 +769,7 @@ void wxSpinCtrlDouble::SetIncrement(double inc)
 
     DoSetIncrement(inc);
 
-    const unsigned digits = DetermineDigits(inc);
+    const unsigned digits = wxSpinCtrlImpl::DetermineDigits(inc);
 
     // We don't decrease the number of digits here, as this is unnecessary and
     // could be undesirable, but we do increase it if the current number is not
@@ -764,7 +780,8 @@ void wxSpinCtrlDouble::SetIncrement(double inc)
 
 void wxSpinCtrlDouble::SetDigits(unsigned digits)
 {
-    wxCHECK_RET( digits <= SPINCTRLDBL_MAX_DIGITS, "too many digits for wxSpinCtrlDouble" );
+    wxCHECK_RET( digits <= wxSpinCtrlImpl::SPINCTRLDBL_MAX_DIGITS,
+                 "too many digits for wxSpinCtrlDouble" );
 
     if ( digits == m_digits )
         return;
@@ -798,22 +815,6 @@ void wxSpinCtrlDouble::ResetTextValidator()
 #endif // wxUSE_VALIDATORS
 }
 
-/* static */
-unsigned wxSpinCtrlDouble::DetermineDigits(double inc)
-{
-    // TODO-C++11: Use std::modf() to get the fractional part.
-    inc = fabs(inc);
-    inc -= static_cast<int>(inc);
-    if ( inc > 0.0 )
-    {
-        return wxMin(SPINCTRLDBL_MAX_DIGITS, -static_cast<int>(floor(log10(inc))));
-    }
-    else
-    {
-        return 0;
-    }
-}
-
 #endif // wxUSE_SPINBTN
 
 #endif // !wxPort-with-native-spinctrl