DIALOG_PRINT_GENERIC: more easy to use user scale option. (not actual change for printing)

- fix an issue when trying to enter a scale < 1.0: such a scale starts by 0, that was rejected by the filter)
- automatic clamp to user scale limits, to avoid many warnings to users.
- if the user scale is out of bounds, warn the user before trying to print, not when opening the dialog.

common/dialogs/dialog_print_generic.cpp

@@ -30,7 +30,9 @@ static constexpr double MAX_SCALE = 100.0;
 DIALOG_PRINT_GENERIC::DIALOG_PRINT_GENERIC( EDA_DRAW_FRAME* aParent, PRINTOUT_SETTINGS* aSettings )
     : DIALOG_PRINT_GENERIC_BASE( aParent ), m_config( nullptr ), m_settings( aSettings )
 {
-    m_scaleValidator.SetRange( MIN_SCALE, MAX_SCALE );
+    // Note: for the validator, min value is 0.0, to allow typing values like 0.5
+    // that start by 0
+    m_scaleValidator.SetRange( 0.0, MAX_SCALE );
     m_scaleCustomText->SetValidator( m_scaleValidator );
 
     // We use a sdbSizer to get platform-dependent ordering of the action buttons, but
@@ -84,7 +86,7 @@ void DIALOG_PRINT_GENERIC::saveSettings()
 }
 
 
-double DIALOG_PRINT_GENERIC::getScaleValue() const
+double DIALOG_PRINT_GENERIC::getScaleValue()
 {
     if( m_scale1->GetValue() )
         return 1.0;
@@ -94,9 +96,30 @@ double DIALOG_PRINT_GENERIC::getScaleValue() const
 
     if( m_scaleCustom->GetValue() )
     {
-        double scale;
+        double scale = 1.0;;
 
-        wxCHECK( m_scaleCustomText->GetValue().ToDouble( &scale ), 1.0 );
+        if( !m_scaleCustomText->GetValue().ToDouble( &scale ) )
+        {
+            DisplayInfoMessage( nullptr, _( "Warning: Bad scale number" ) );
+            scale = 1.0;
+        }
+
+        if( scale > MAX_SCALE )
+        {
+            scale = MAX_SCALE;
+            setScaleValue( scale );
+            DisplayInfoMessage( nullptr,
+                wxString::Format( _( "Warning: Scale option set to a very large value.\n"
+                                     " Clamped to %f" ), scale ) );
+        }
+        else if( scale < MIN_SCALE )
+        {
+            scale = MIN_SCALE;
+            setScaleValue( scale );
+            DisplayInfoMessage( nullptr,
+                wxString::Format( _( "Warning: Scale option set to a very small value.\n"
+                                     " Clamped to %f" ), scale ) );
+        }
         return scale;
     }
 
@@ -118,14 +141,11 @@ void DIALOG_PRINT_GENERIC::setScaleValue( double aValue )
     }
     else
     {
+        // Silently clamp the value (it comes from the config file).
         if( aValue > MAX_SCALE )
-        {
-            DisplayInfoMessage( nullptr, _( "Warning: Scale option set to a very large value" ) );
-        }
+            aValue = MAX_SCALE;
         else if( aValue < MIN_SCALE )
-        {
-            DisplayInfoMessage( nullptr, _( "Warning: Scale option set to a very small value" ) );
-        }
+            aValue = MIN_SCALE;
 
         m_scaleCustom->SetValue( true );
         m_scaleCustomText->SetValue( wxString::Format( wxT( "%f" ), aValue ) );

common/dialogs/dialog_print_generic.h

@@ -64,8 +64,9 @@ protected:
 
     /**
      * Return scale value selected in the dialog.
+     * if this value is outside limits, it will be clamped
      */
-    double getScaleValue() const;
+    double getScaleValue();
 
     /**
     * Select a corresponding scale radio button and update custom scale value if needed.