minor fixes

com.unity.uiwidgets/Runtime/material/slider.cs

         }
     }
 
-    class _RenderSlider : RenderBox {
+    class _RenderSlider : RelayoutWhenSystemFontsChangeMixinRenderBox {
         static float _positionAnimationDurationMilliSeconds = 75;
         static float _minimumInteractionTimeMilliSeconds = 500;
 
             int? divisions = null,
             string label = null,
             SliderThemeData sliderTheme = null,
-            ThemeData theme = null,
             MediaQueryData mediaQueryData = null,
             RuntimePlatform? platform = null,
             ValueChanged<float> onChanged = null,
-            TextDirection? texDirection = null
+            TextDirection? textDirection = null
-            
+
             this.onChangeStart = onChangeStart;
             this.onChangeEnd = onChangeEnd;
             _platform = platform;
             _sliderTheme = sliderTheme;
-            _theme = theme;
+            _textDirection = textDirection.Value;
 
             _updateLabelPainter();
             GestureArenaTeam team = new GestureArenaTeam();
                 float maxValue = 0;
                 foreach (Size size in _sliderPartSizes) {
                     if (size.width > maxValue) {
-                        maxValue = size.width;
+                        maxValue = size.height;
                     }
                 }
 
         public ValueChanged<float> onChangeStart;
         public ValueChanged<float> onChangeEnd;
 
+        public TextDirection textDirection {
+            get { return _textDirection; }
+            set {
+                if (value == _textDirection) {
+                    return;
+                }
+                _textDirection = value;
+                _updateLabelPainter();
+            }
+        }
+        
+        TextDirection _textDirection;
+
         public bool showValueIndicator {
             get {
                 bool showValueIndicator = false;
             get {
                 switch (_platform) {
                     case RuntimePlatform.IPhonePlayer:
+                    case RuntimePlatform.OSXPlayer:
+                    case RuntimePlatform.OSXEditor:
                         return 0.1f;
                     default:
                         return 0.05f;
                     style: _sliderTheme.valueIndicatorTextStyle,
                     text: label
                 );
+                _labelPainter.textDirection = textDirection;
                 _labelPainter.textScaleFactor = _mediaQueryData.textScaleFactor;
                 _labelPainter.layout();
             }
 
             markNeedsLayout();
         }
+        
+        protected override void systemFontsDidChange() {
+               base.systemFontsDidChange();
+                _labelPainter.markNeedsLayout();
+                _updateLabelPainter();
+              }
 
         public override void attach(object owner) {
             base.attach(owner);
         }
 
         float _getValueFromVisualPosition(float visualPosition) {
+            switch (textDirection) {
+                case TextDirection.rtl:
+                    return 1.0f - visualPosition;
+                case TextDirection.ltr:
+                    return visualPosition;
+            }
             return visualPosition;
         }
 
         void _handleDragUpdate(DragUpdateDetails details) {
             if (isInteractive) {
                 float valueDelta = details.primaryDelta.Value / _trackRect.width;
-                _currentDragValue += valueDelta;
+                switch (textDirection) {
+                    case TextDirection.rtl:
+                        _currentDragValue -= valueDelta;
+                        break;
+                    case TextDirection.ltr:
+                        _currentDragValue += valueDelta;
+                        break;
+                }
                 onChanged(_discretize(_currentDragValue));
             }
         }
         public override void paint(PaintingContext context, Offset offset) {
             float value = _state.positionController.value;
             float visualPosition = value;
+            switch (textDirection) {
+                case TextDirection.rtl:
+                    visualPosition = 1.0f - value;
+                    break;
+                case TextDirection.ltr:
+                    visualPosition = value;
+                    break;
+            }
 
             Rect trackRect = _sliderTheme.trackShape.getPreferredRect(
                 parentBox: this,
                 parentBox: this,
                 sliderTheme: _sliderTheme,
                 enableAnimation: _enableAnimation,
+                textDirection: _textDirection,
                 thumbCenter: thumbCenter,
                 isDiscrete: isDiscrete,
                 isEnabled: isInteractive
                     labelPainter: _labelPainter,
                     parentBox: this,
                     sliderTheme: _sliderTheme,
+                    textDirection: _textDirection,
                     value: _value
                 );
             }
                             parentBox: this,
                             sliderTheme: _sliderTheme,
                             enableAnimation: _enableAnimation,
+                            textDirection: _textDirection,
                             thumbCenter: thumbCenter,
                             isEnabled: isInteractive
                         );
                         labelPainter: _labelPainter,
                         parentBox: this,
                         sliderTheme: _sliderTheme,
+                        textDirection: _textDirection,
                         value: _value
                     );
                 }
                 labelPainter: _labelPainter,
                 parentBox: this,
                 sliderTheme: _sliderTheme,
+                textDirection: _textDirection,
                 value: _value
             );
         }

com.unity.uiwidgets/Runtime/rendering/editable.cs

             markNeedsLayout();
         }
         
-        public void systemFontsDidChange() {
+        protected override void systemFontsDidChange() {
+            base.systemFontsDidChange();
             _textPainter.markNeedsLayout();
             _textLayoutLastMaxWidth = null;
             _textLayoutLastMinWidth = null;

com.unity.uiwidgets/Runtime/rendering/object.mixin.gen.cs

      
     public abstract class RelayoutWhenSystemFontsChangeMixinRenderBox : RenderBox {
     
-        protected void systemFontsDidChange() {
+        protected virtual void systemFontsDidChange() {
             markNeedsLayout();
         }
         

com.unity.uiwidgets/Runtime/rendering/object.mixin.njk

 {% macro RelayoutWhenSystemFontsChangeMixin(with) %} 
     public abstract class RelayoutWhenSystemFontsChangeMixin{{with}} : {{with}} {
     
-        protected void systemFontsDidChange() {
+        protected virtual void systemFontsDidChange() {
             markNeedsLayout();
         }