Common: fixup Slider's value range after loading

Author: ivan-mogilko

Common/gui/guislider.cpp

@@ -346,6 +346,10 @@ void GUISlider::ReadFromFile(Stream *in, GuiVersion gui_version)
     _cachedBar = Rect();
     _cachedHandle = Rect();
     _handleRange = 0;
+    // Clamp value range, in case the data is wrong
+    _maxValue = std::max(_minValue, _maxValue);
+    _minValue = std::min(_minValue, _maxValue);
+    _value = Math::Clamp(_value, _minValue, _maxValue);
 }
 
 void GUISlider::WriteToFile(Stream *out) const
@@ -373,6 +377,10 @@ void GUISlider::ReadFromSavegame(Stream *in, GuiSvgVersion svg_ver)
     _cachedBar = Rect();
     _cachedHandle = Rect();
     _handleRange = 0;
+    // Clamp value range, in case the data is wrong
+    _maxValue = std::max(_minValue, _maxValue);
+    _minValue = std::min(_minValue, _maxValue);
+    _value = Math::Clamp(_value, _minValue, _maxValue);
 }
 
 void GUISlider::WriteToSavegame(Stream *out) const