Added some doc comments.

And removed some tabs.

src/Avalonia.Visuals/Media/FormattedTextStyleSpan.cs

@@ -2,8 +2,17 @@
 
 namespace Avalonia.Media
 {
+    /// <summary>
+    /// Describes the formatting for a span of text in a <see cref="FormattedText"/> object.
+    /// </summary>
     public class FormattedTextStyleSpan
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FormattedTextStyleSpan"/> class.
+        /// </summary>
+        /// <param name="startIndex">The index of the first character in the span.</param>
+        /// <param name="length">The length of the span.</param>
+        /// <param name="foregroundBrush">The span's foreground brush.</param>
         public FormattedTextStyleSpan(
             int startIndex,
             int length,
@@ -14,8 +23,19 @@ namespace Avalonia.Media
             ForegroundBrush = foregroundBrush;
         }
 
+        /// <summary>
+        /// Gets the index of the first character in the span.
+        /// </summary>
         public int StartIndex { get; }
+
+        /// <summary>
+        /// Gets the length of the span.
+        /// </summary>
         public int Length { get; }
+
+        /// <summary>
+        /// Gets the span's foreground brush.
+        /// </summary>
         public IBrush ForegroundBrush { get; }
     }
 }

src/Avalonia.Visuals/Media/Typeface.cs

@@ -1,10 +1,19 @@
 using System;
-using Avalonia.Media;
 
 namespace Avalonia.Media
 {
+    /// <summary>
+    /// Represents a typeface.
+    /// </summary>
     public class Typeface
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Typeface"/> class.
+        /// </summary>
+        /// <param name="fontFamilyName">The name of the font family.</param>
+        /// <param name="fontSize">The font size, in DIPs.</param>
+        /// <param name="style">The font style.</param>
+        /// <param name="weight">The font weight.</param>
         public Typeface(
             string fontFamilyName,
             double fontSize,
@@ -27,9 +36,24 @@ namespace Avalonia.Media
             Weight = weight;
         }
 
+        /// <summary>
+        /// Gets the name of the font family.
+        /// </summary>
         public string FontFamilyName { get; }
+
+        /// <summary>
+        /// Gets the size of the font in DIPs.
+        /// </summary>
         public double FontSize { get; }
+
+        /// <summary>
+        /// Gets the font style.
+        /// </summary>
         public FontStyle Style { get; }
+
+        /// <summary>
+        /// Gets the font weight.
+        /// </summary>
         public FontWeight Weight { get; }
     }
 }

src/Gtk/Avalonia.Cairo/Media/StreamGeometryImpl.cs

@@ -52,7 +52,7 @@ namespace Avalonia.Cairo.Media
         public Rect GetRenderBounds(double strokeThickness)
         {
             // TODO: Calculate properly.
-			return Bounds.TransformToAABB(Transform).Inflate(strokeThickness);
+            return Bounds.TransformToAABB(Transform).Inflate(strokeThickness);
         }
 
         public IStreamGeometryContextImpl Open()