some fix

Assets/UIWidgets/painting/text_painter.cs

                     ); // direction doesn't matter, text is just a space
                     if (text != null && text.style != null)
                     {
-                        builder.pushStyle(text.style.getTextStyle(textScaleFactor));
+                        builder.pushStyle(text.style);
                     }
 
                     builder.addText(" ");

Assets/UIWidgets/painting/text_span.cs

             var hasTyle = style != null;
             if (hasTyle)
             {
-                builder.pushStyle(style.getTextStyle(textScaleFactor));
+                builder.pushStyle(style);
             }
             if (!string.IsNullOrEmpty(text))
             {

Assets/UIWidgets/painting/text_style.cs

 
 namespace UIWidgets.painting
 {
-    public class TextStyle : Diagnosticable, IEquatable<TextStyle>
+    public class TextStyle : Diagnosticable, IEquatable<TextStyle>, ParagraphBuilder.ITextStyleProvider
     {
         public static readonly double _defaultFontSize = 14.0;
         public readonly bool inherit;
             this.background = background;
         }
 
-        public ui.TextStyle getTextStyle(double textScaleFactor = 1.0)
+        public  ui.TextStyle getTextStyle(ui.TextStyle currentStyle = null)
+            if (currentStyle != null)
+            {
+                return new ui.TextStyle(
+                    color:  color??currentStyle.color,
+                    fontSize: fontSize??currentStyle.fontSize,
+                    fontWeight: fontWeight??currentStyle.fontWeight,
+                    fontStyle: fontStyle??currentStyle.fontStyle,
+                    letterSpacing: letterSpacing??currentStyle.letterSpacing,
+                    wordSpacing: wordSpacing??currentStyle.wordSpacing,
+                    textBaseline: textBaseline??currentStyle.textBaseline,
+                    height: height??currentStyle.height,
+                    decoration: decoration??currentStyle.decoration,
+                    decorationColor: decorationColor??currentStyle.decorationColor,
+                    fontFamily: fontFamily??currentStyle.fontFamily,
+                    background: background??currentStyle.background
+                );
+            }
+            
-                color: color,
-                decoration: decoration,
-                decorationColor: decorationColor,
-                decorationStyle: decorationStyle,
+                color:  color,
+                fontSize: fontSize,
-                fontSize: fontSize == null ? null : fontSize * textScaleFactor,
+                decoration: decoration,
+                decorationColor: decorationColor,
                 fontFamily: fontFamily,
                 background: background
             );

Assets/UIWidgets/ui/painting/canvas_impl.cs

         public void drawTextBlob(TextBlob textBlob, double x, double y)
         {
             var mesh = MeshGenrator.generateMesh(textBlob, x, y);
-            var font = FontManager.instance.getOrCreate(textBlob.style.fontFamilyOrDefault, textBlob.style.UnityFontSize);
+            var font = FontManager.instance.getOrCreate(textBlob.style.fontFamily, textBlob.style.UnityFontSize);
             prepareGL(font.material);
             font.material.SetPass(0);
             Graphics.DrawMeshNow(mesh, Matrix4x4.identity);

Assets/UIWidgets/ui/painting/txt/mesh_generator.cs

         public static Mesh generateMesh(TextBlob textBlob, double x, double y)
         {
             var style = textBlob.style;
-            var font = FontManager.instance.getOrCreate(style.fontFamilyOrDefault, style.UnityFontSize);
+            var font = FontManager.instance.getOrCreate(style.fontFamily, style.UnityFontSize);
             var length = textBlob.end - textBlob.start;
             var vertices = new Vector3[length * 4];
             var triangles = new int[length * 6];

Assets/UIWidgets/ui/text.cs

 
     public class TextStyle : IEquatable<TextStyle>
     {
-        public static readonly string defaultFontFamily = "Helvetica";
-        public static readonly double defaultFontSize = 14.0;
-        public static readonly FontWeight defaultFontWeight = FontWeight.w400;
-        public static readonly FontStyle defaultFontStyle = FontStyle.normal;
-        public static readonly Color defaultColor = Color.fromARGB(255, 0, 0, 0);
-        public readonly Color color;
-        public readonly double? fontSize;
-        public readonly FontWeight? fontWeight;
-        public readonly FontStyle? fontStyle;
-        public readonly double? letterSpacing;
-        public readonly double? wordSpacing;
-        public readonly TextBaseline? textBaseline;
-        public readonly double? height;
-        public readonly TextDecoration decoration;
+        public readonly Color color = Color.fromARGB(255, 0, 0, 0);
+        public readonly double fontSize = 14.0;
+        public readonly FontWeight fontWeight = FontWeight.w400;
+        public readonly FontStyle fontStyle = FontStyle.normal;
+        public readonly double letterSpacing = 0.0;
+        public readonly double wordSpacing = 0.0;
+        public readonly TextBaseline textBaseline = TextBaseline.alphabetic;
+        public readonly double height = 1.0;
+        public readonly TextDecoration decoration = TextDecoration.none;
-        public readonly TextDecorationStyle? decorationStyle;
-        public readonly string fontFamily;
+        public readonly TextDecorationStyle decorationStyle = TextDecorationStyle.solid;
+        public readonly string fontFamily = "Helvetica";
-
-        public FontStyle fontStyleOrDefault
-        {
-            get { return fontStyle ?? defaultFontStyle; }
-        }
-
-        public string fontFamilyOrDefault
-        {
-            get { return fontFamily ?? defaultFontFamily; }
-        }
-
-        public double fontSizeOrDefault
-        {
-            get { return fontSize ?? defaultFontSize; }
-        }
-        public Color colorOrDefault
-        {
-            get { return color ?? defaultColor; }
-        }
-
-        public TextDecorationStyle decorationStyleOrDefault
-        {
-            get { return decorationStyle ?? TextDecorationStyle.solid; }
-        }
-
-        
-        public FontWeight safeFontWeight
-        {
-            get { return fontWeight ?? defaultFontWeight; }
-        }
-
-            get { return (color ?? defaultColor).toColor(); }
+            get { return color.toColor(); }
         }
 
         public UnityEngine.FontStyle UnityFontStyle
-                if (fontStyleOrDefault == FontStyle.italic)
+                if (fontStyle == FontStyle.italic)
-                    if (safeFontWeight == FontWeight.w700)
+                    if (fontWeight == FontWeight.w700)
                     {
                         return UnityEngine.FontStyle.BoldAndItalic;
                     }
                     }
                 }
-                else if (safeFontWeight == FontWeight.w700)
+                else if (fontWeight == FontWeight.w700)
                 {
                     return UnityEngine.FontStyle.Bold;
                 }
 
         public int UnityFontSize
         {
-            get { return (int) fontSizeOrDefault; }
-        }
-
-        public TextStyle merge(TextStyle style)
-        {
-            var ret = new TextStyle(
-                color: style.color ?? color,
-                fontSize: style.fontSize ?? fontSize,
-                fontWeight: style.fontWeight ?? fontWeight,
-                fontStyle: style.fontStyle ?? fontStyle,
-                letterSpacing: style.letterSpacing ?? letterSpacing,
-                textBaseline: style.textBaseline ?? textBaseline,
-                height: style.height ?? height,
-                decoration: style.decoration ?? decoration,
-                decorationColor: style.decorationColor ?? decorationColor,
-                decorationStyle: style.decorationStyle ?? decorationStyle,
-                background: style.background ?? background,
-                fontFamily: style.fontFamily ?? fontFamily
-            );
-
-            return ret;
+            get { return (int) fontSize; }
-
 
         public bool Equals(TextStyle other)
         {
             return !Equals(left, right);
         }
 
-        public TextStyle(Color color = null, double? fontSize = default(double?),
-            FontWeight? fontWeight = default(FontWeight?),
-            FontStyle? fontStyle = default(FontStyle?), double? letterSpacing = default(double?),
-            double? wordSpacing = default(double?), TextBaseline? textBaseline = default(TextBaseline?),
-            double? height = default(double?), TextDecoration decoration = null, Color decorationColor = null,
-            TextDecorationStyle? decorationStyle = null, string fontFamily = null, Paint background = null)
+        
+        public TextStyle(Color color = null, double? fontSize = null,
+            FontWeight? fontWeight = null, FontStyle? fontStyle = null, double? letterSpacing = null,
+            double? wordSpacing = null, TextBaseline? textBaseline = null, double? height= null, 
+            TextDecoration decoration = null, TextDecorationStyle? decorationStyle = null, Color decorationColor = null, string fontFamily = null,
+            Paint background = null
+        )
-            this.color = color;
-            this.fontSize = fontSize;
-            this.fontWeight = fontWeight;
-            this.fontStyle = fontStyle;
-            this.letterSpacing = letterSpacing;
-            this.wordSpacing = wordSpacing;
-            this.textBaseline = textBaseline;
-            this.height = height;
-            this.decoration = decoration;
-            this.fontFamily = fontFamily;
-            this.decorationStyle = decorationStyle;
-            this.decorationColor = decorationColor;
-            this.background = background;
+            this.color = color ?? this.color;
+            this.fontSize = fontSize ?? this.fontSize;
+            this.fontWeight = fontWeight ?? this.fontWeight;
+            this.fontStyle = fontStyle ?? this.fontStyle;
+            this.letterSpacing = letterSpacing ?? this.letterSpacing;
+            this.wordSpacing = wordSpacing ?? this.wordSpacing;
+            this.fontSize = fontSize ?? this.fontSize;
+            this.textBaseline = textBaseline ?? this.textBaseline;
+            this.height = height ?? this.height;
+            this.decoration = decoration ?? this.decoration;
+            this.decorationStyle = decorationStyle ?? this.decorationStyle;
+            this.decorationColor = decorationColor ?? this.decorationColor;
+            this.fontFamily = fontFamily ?? this.fontFamily;
+            this.background = background ?? this.background; 
         }
     }
 

Assets/UIWidgets/ui/txt/linebreaker.cs

             {
                 runIterator.nextTo(charIndex);
                 var run = runIterator.run;
-                var font = FontManager.instance.getOrCreate(run.style.fontFamilyOrDefault, run.style.UnityFontSize);
+                var font = FontManager.instance.getOrCreate(run.style.fontFamily, run.style.UnityFontSize);
 
                 var style = run.style;
                 var charInfo = new CharacterInfo();

Assets/UIWidgets/ui/txt/paragraph.cs

                 var run = _runs.getRun(i);
                 if (run.start < run.end)
                 {
-                    var font = FontManager.instance.getOrCreate(run.style.fontFamilyOrDefault, run.style.UnityFontSize);
+                    var font = FontManager.instance.getOrCreate(run.style.fontFamily, run.style.UnityFontSize);
                     font.RequestCharactersInTexture(_text.Substring(run.start, run.end - run.start), 0, 
                         run.style.UnityFontStyle);
                 } 
                     var run = runIndex < _runs.size ? _runs.getRun(runIndex) : null;
                     if (run != null && run.start < run.end && run.start < line.end && run.end > line.start)
                     {
-                        var font = FontManager.instance.getOrCreate(run.style.fontFamilyOrDefault, run.style.UnityFontSize);
+                        var font = FontManager.instance.getOrCreate(run.style.fontFamily, run.style.UnityFontSize);
-                        var ascent = font.ascent * (run.style.height??1.0);
-                        var descent = (font.lineHeight - font.ascent) * (run.style.height??1.0);
+                        var ascent = font.ascent * (run.style.height);
+                        var descent = (font.lineHeight - font.ascent) * (run.style.height);
                         if (metrics.ascent > maxAscent)
                         {
                             maxAscent = metrics.ascent;
             var paint = new Paint();
             if (record.style.decorationColor == null)
             {
-                paint.color = record.style.colorOrDefault;
+                paint.color = record.style.color;
             }
             else
             {
             
             var width = record.runWidth;
             var metrics = record.metrics;
-            double underLineThickness = metrics.underlineThickness ?? (record.style.fontSizeOrDefault / 14.0);
+            double underLineThickness = metrics.underlineThickness ?? (record.style.fontSize / 14.0);
             paint.strokeWidth = underLineThickness;
             var recordOffset = baseOffset + record.offset;
             var x = recordOffset.dx;
-            switch (record.style.decorationStyleOrDefault)
+            switch (record.style.decorationStyle)
             {
                    case TextDecorationStyle.doubleLine:
                        decorationCount = 2;

Assets/UIWidgets/ui/txt/paragraph_builder.cs

         private List<int>  _styleStack = new List<int>();
         private int _paragraph_style_index;
   
+        public interface ITextStyleProvider
+        {
+            TextStyle getTextStyle(TextStyle current = null);
+        }
+
         public ParagraphBuilder(ParagraphStyle style)
         {
             setParagraphStyle(style);
             return paragraph;
         }
 
-        public void pushStyle(TextStyle style)
+        public void pushStyle(ITextStyleProvider style)
-            var newStyle = peekStyle().merge(style);
+            var newStyle = style.getTextStyle(peekStyle());
+            _styleStack.Add(styleIndex);
+            _runs.startRun(styleIndex, _text.Length);
+        }
+        
+        public void pushStyle(TextStyle style)
+        {
+            var styleIndex = _runs.addStyle(style);
             _styleStack.Add(styleIndex);
             _runs.startRun(styleIndex, _text.Length);
         }