Added comments

samples/ControlCatalog.Desktop/Program.cs

@@ -3,7 +3,6 @@ using System.Linq;
 using Avalonia;
 using Avalonia.Controls;
 using Avalonia.Logging.Serilog;
-using Avalonia.Media;
 using Avalonia.Platform;
 using Serilog;
 
@@ -23,13 +22,13 @@ namespace ControlCatalog
         /// This method is needed for IDE previewer infrastructure
         /// </summary>
         public static AppBuilder BuildAvaloniaApp()
-            => AppBuilder.Configure<App>().LogToDebug().UsePlatformDetect().UseSkia();
+            => AppBuilder.Configure<App>().LogToDebug().UsePlatformDetect();
 
         private static void ConfigureAssetAssembly(AppBuilder builder)
         {
             AvaloniaLocator.CurrentMutable
                 .GetService<IAssetLoader>()
-                .SetDefaultAssembly(typeof(App).Assembly);           
+                .SetDefaultAssembly(typeof(App).Assembly);
         }
     }
 }

samples/ControlCatalog/Pages/BorderPage.xaml

@@ -1,38 +1,32 @@
 <UserControl xmlns="https://github.com/avaloniaui">
-    <StackPanel Orientation="Vertical" Gap="4">
-        <TextBlock Classes="h1">Border</TextBlock>
-        <TextBlock Classes="h2">A control which decorates a child with a border and background</TextBlock>
+  <StackPanel Orientation="Vertical" Gap="4">
+    <TextBlock Classes="h1">Border</TextBlock>
+    <TextBlock Classes="h2">A control which decorates a child with a border and background</TextBlock>
 
-        <StackPanel Orientation="Vertical"
+    <StackPanel Orientation="Vertical"
                 Margin="0,16,0,0"
                 HorizontalAlignment="Center"
                 Gap="16">
-            <Border BorderBrush="{DynamicResource ThemeAccentBrush}" BorderThickness="2" Padding="16">
-                <TextBlock>Border</TextBlock>
-            </Border>
-            <Border Background="{DynamicResource ThemeAccentBrush2}"
-              BorderBrush="{DynamicResource ThemeAccentBrush}"
-              BorderThickness="4"
+      <Border BorderBrush="{DynamicResource ThemeAccentBrush}" BorderThickness="2" Padding="16">
+        <TextBlock>Border</TextBlock>
+      </Border>
+      <Border Background="{DynamicResource ThemeAccentBrush2}" 
+              BorderBrush="{DynamicResource ThemeAccentBrush}" 
+              BorderThickness="4" 
               Padding="16">
-                <TextBlock>Border and Background</TextBlock>
-            </Border>
-            <Border BorderBrush="{DynamicResource ThemeAccentBrush}"
-              BorderThickness="4"
+        <TextBlock>Border and Background</TextBlock>
+      </Border>
+      <Border BorderBrush="{DynamicResource ThemeAccentBrush}"
+              BorderThickness="4" 
               CornerRadius="8"
               Padding="16">
-                <TextBlock>Rounded Corners</TextBlock>
-            </Border>
-            <Border Background="{DynamicResource ThemeAccentBrush2}"
+        <TextBlock>Rounded Corners</TextBlock>
+      </Border>
+      <Border Background="{DynamicResource ThemeAccentBrush2}"
               CornerRadius="8"
               Padding="16">
-                <StackPanel>
-                    <TextBlock FontFamily="res:/Fonts?assembly=ControlCatalog#Pixel Operator">Rounded Corners</TextBlock>
-                    <TextBlock FontFamily="res:/Fonts?assembly=ControlCatalog#Pink Highway" FontWeight="Bold">Rounded Corners</TextBlock>
-                    <TextBlock FontFamily="res:/Fonts/Aspergit*.ttf?assembly=ControlCatalog#Aspergit" FontWeight="Bold">Rounded Corners</TextBlock>
-                    <TextBlock FontFamily="res:/Fonts/Aspergit*.ttf?assembly=ControlCatalog#Aspergit" FontWeight="Bold" FontStyle="Italic">Rounded Corners</TextBlock>
-                    <TextBlock FontFamily="res:/Fonts/Aspergit*.ttf?assembly=ControlCatalog#Aspergit" FontStyle="Italic">Rounded Corners</TextBlock>
-                </StackPanel>
-            </Border>
-        </StackPanel>
-    </StackPanel>
+        <TextBlock>Rounded Corners</TextBlock>
+      </Border>
+    </StackPanel>    
+  </StackPanel>
 </UserControl>

src/Avalonia.Visuals/Media/FontFamily.cs

@@ -8,20 +8,49 @@ namespace Avalonia.Media
 {
     public class FontFamily
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FontFamily"/> class.
+        /// </summary>
+        /// <param name="name">The name.</param>
+        /// <exception cref="ArgumentNullException">name</exception>
         public FontFamily(string name = "Courier New")
         {
             Name = name ?? throw new ArgumentNullException(nameof(name));
         }
 
+        /// <inheritdoc />
+        /// <summary>
+        /// Initializes a new instance of the <see cref="T:Avalonia.Media.FontFamily" /> class.
+        /// </summary>
+        /// <param name="name">The name.</param>
+        /// <param name="source">The source.</param>
         public FontFamily(string name, Uri source) : this(name)
         {
             Key = new FontFamilyKey(source);
         }
 
+        /// <summary>
+        /// Gets the name.
+        /// </summary>
+        /// <value>
+        /// The name.
+        /// </value>
         public string Name { get; }
 
+        /// <summary>
+        /// Gets the key.
+        /// </summary>
+        /// <value>
+        /// The key.
+        /// </value>
         public FontFamilyKey Key { get; }
 
+        /// <summary>
+        /// Returns a <see cref="string" /> that represents this instance.
+        /// </summary>
+        /// <returns>
+        /// A <see cref="string" /> that represents this instance.
+        /// </returns>
         public override string ToString()
         {
             if (Key != null)

src/Avalonia.Visuals/Media/Fonts/CachedFontFamily.cs

@@ -5,18 +5,38 @@ using System.Collections.Generic;
 
 namespace Avalonia.Media.Fonts
 {
+    /// <summary>
+    /// Holds a quantity of <see cref="FontResource"/> that belongs to a specific <see cref="FontFamilyKey"/>
+    /// </summary>
     public class CachedFontFamily
     {
         private readonly FontResourceCollection _fontResourceCollection;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CachedFontFamily"/> class.
+        /// </summary>
+        /// <param name="key">The key.</param>
+        /// <param name="fontResourceCollection">The font resource collection.</param>
         public CachedFontFamily(FontFamilyKey key, FontResourceCollection fontResourceCollection)
         {
             Key = key;
             _fontResourceCollection = fontResourceCollection;
         }
 
+        /// <summary>
+        /// Gets the key.
+        /// </summary>
+        /// <value>
+        /// The key.
+        /// </value>
         public FontFamilyKey Key { get; }
 
+        /// <summary>
+        /// Gets the font resources.
+        /// </summary>
+        /// <value>
+        /// The font resources.
+        /// </value>
         public IEnumerable<FontResource> FontResources => _fontResourceCollection.FontResources;
     }
 }

src/Avalonia.Visuals/Media/Fonts/FontFamilyCache.cs

@@ -5,15 +5,28 @@ using System.Collections.Concurrent;
 
 namespace Avalonia.Media.Fonts
 {
+    /// <summary>
+    /// Caches all <see cref="CachedFontFamily"/> instances to reduce memory usage and speed up loading times of custom font families
+    /// </summary>
     public static class FontFamilyCache
     {
         private static readonly ConcurrentDictionary<FontFamilyKey, CachedFontFamily> s_cachedFontFamilies = new ConcurrentDictionary<FontFamilyKey, CachedFontFamily>();
 
+        /// <summary>
+        /// Gets the or add cached font family.
+        /// </summary>
+        /// <param name="key">The key.</param>
+        /// <returns></returns>
         public static CachedFontFamily GetOrAddFontFamily(FontFamilyKey key)
         {
             return s_cachedFontFamilies.GetOrAdd(key, CreateCachedFontFamily);
         }
 
+        /// <summary>
+        /// Creates the cached font family.
+        /// </summary>
+        /// <param name="fontFamilyKey">The font family key.</param>
+        /// <returns></returns>
         private static CachedFontFamily CreateCachedFontFamily(FontFamilyKey fontFamilyKey)
         {
             return new CachedFontFamily(fontFamilyKey, new FontResourceCollection(fontFamilyKey));

src/Avalonia.Visuals/Media/Fonts/FontFamilyKey.cs

@@ -6,8 +6,15 @@ using System.Linq;
 
 namespace Avalonia.Media.Fonts
 {
+    /// <summary>
+    /// Unique idetifier for a quantity of <see cref="FontResource"/> that is stored at a given location.
+    /// </summary>
     public class FontFamilyKey
     {
+        /// <summary>
+        /// Creates a new instance of <see cref="FontFamilyKey"/> and extracts <see cref="Location"/> and <see cref="FileName"/> from given <see cref="Uri"/>
+        /// </summary>
+        /// <param name="source"></param>
         public FontFamilyKey(Uri source)
         {
             if (source.AbsolutePath.Contains(".ttf"))
@@ -31,8 +38,14 @@ namespace Avalonia.Media.Fonts
             }
         }
 
+        /// <summary>
+        /// Location of stored <see cref="FontResource"/> that belong to a <see cref="FontFamily"/>
+        /// </summary>
         public Uri Location { get; }
 
+        /// <summary>
+        /// Optional filename for <see cref="FontResource"/> that belong to a <see cref="FontFamily"/>
+        /// </summary>
         public string FileName { get; }
 
         public override int GetHashCode()
@@ -55,6 +68,13 @@ namespace Avalonia.Media.Fonts
             }
         }
 
+        /// <summary>
+        /// Determines whether the specified <see cref="object" />, is equal to this instance.
+        /// </summary>
+        /// <param name="obj">The <see cref="object" /> to compare with this instance.</param>
+        /// <returns>
+        ///   <c>true</c> if the specified <see cref="object" /> is equal to this instance; otherwise, <c>false</c>.
+        /// </returns>
         public override bool Equals(object obj)
         {
             if (!(obj is FontFamilyKey other)) return false;
@@ -66,6 +86,12 @@ namespace Avalonia.Media.Fonts
             return true;
         }
 
+        /// <summary>
+        /// Returns a <see cref="string" /> that represents this instance.
+        /// </summary>
+        /// <returns>
+        /// A <see cref="string" /> that represents this instance.
+        /// </returns>
         public override string ToString()
         {
             if (FileName != null)

src/Avalonia.Visuals/Media/Fonts/FontResource.cs

@@ -5,6 +5,9 @@ using System;
 
 namespace Avalonia.Media.Fonts
 {
+    /// <summary>
+    /// Represents a font resource
+    /// </summary>
     public class FontResource
     {
         public FontResource(Uri source)
@@ -12,6 +15,9 @@ namespace Avalonia.Media.Fonts
             Source = source;
         }
 
+        /// <summary>
+        /// Source of the font resource.
+        /// </summary>
         public Uri Source { get; }
     }
 }

src/Avalonia.Visuals/Media/Fonts/FontResourceCollection.cs

@@ -7,6 +7,9 @@ using System.Linq;
 
 namespace Avalonia.Media.Fonts
 {
+    /// <summary>
+    /// Represents a collection of <see cref="FontResource"/> that is identified by a unique <see cref="FontFamilyKey"/>
+    /// </summary>
     public class FontResourceCollection
     {
         private Dictionary<Uri, FontResource> _fontResources;
@@ -17,8 +20,20 @@ namespace Avalonia.Media.Fonts
             Key = key;
         }
 
+        /// <summary>
+        /// Gets the key.
+        /// </summary>
+        /// <value>
+        /// The key.
+        /// </value>
         public FontFamilyKey Key { get; }
 
+        /// <summary>
+        /// Gets the font resources.
+        /// </summary>
+        /// <value>
+        /// The font resources.
+        /// </value>
         public IEnumerable<FontResource> FontResources
         {
             get
@@ -32,6 +47,10 @@ namespace Avalonia.Media.Fonts
             }
         }
 
+        /// <summary>
+        /// Creates the font resources.
+        /// </summary>
+        /// <returns></returns>
         private Dictionary<Uri, FontResource> CreateFontResources()
         {
             return _fontResourceLoader.GetFontResources(Key).ToDictionary(x => x.Source);

src/Avalonia.Visuals/Media/Fonts/FontResourceLoader.cs

@@ -9,6 +9,10 @@ using Avalonia.Platform;
 
 namespace Avalonia.Media.Fonts
 {
+    /// <inheritdoc />
+    /// <summary>
+    /// Implementation of <see cref="T:Avalonia.Media.Fonts.IFontResourceLoader" />
+    /// </summary>
     public class FontResourceLoader : IFontResourceLoader
     {
         private static readonly Dictionary<string, AssemblyDescriptor> s_assemblyNameCache
@@ -16,6 +20,10 @@ namespace Avalonia.Media.Fonts
 
         private readonly AssemblyDescriptor _defaultAssembly;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="FontResourceLoader"/> class.
+        /// </summary>
+        /// <param name="assembly">The default assembly.</param>
         public FontResourceLoader(Assembly assembly = null)
         {
             if (assembly == null)
@@ -28,6 +36,12 @@ namespace Avalonia.Media.Fonts
             }
         }
 
+        /// <inheritdoc />
+        /// <summary>
+        /// Returns a quanity of <see cref="T:Avalonia.Media.Fonts.FontResource" /> that belongs to a given <see cref="T:Avalonia.Media.Fonts.FontFamilyKey" />
+        /// </summary>
+        /// <param name="fontFamilyKey"></param>
+        /// <returns></returns>
         public IEnumerable<FontResource> GetFontResources(FontFamilyKey fontFamilyKey)
         {
             return fontFamilyKey.FileName != null
@@ -35,6 +49,11 @@ namespace Avalonia.Media.Fonts
                 : GetFontResourcesByLocation(fontFamilyKey.Location);
         }
 
+        /// <summary>
+        /// Searches for font resources at a given location and returns a quanity of found resources
+        /// </summary>
+        /// <param name="location"></param>
+        /// <returns></returns>
         private IEnumerable<FontResource> GetFontResourcesByLocation(Uri location)
         {
             var assembly = GetAssembly(location);
@@ -46,6 +65,13 @@ namespace Avalonia.Media.Fonts
             return matchingResources.Select(x => new FontResource(GetResourceUri(x, assembly.Name)));
         }
 
+        /// <summary>
+        /// Searches for font resources at a given location and only accepts resources that fit to a given filename expression.
+        /// <para>Filenames can target multible files with * wildcard. For example "FontFile*.ttf"</para>
+        /// </summary>
+        /// <param name="location"></param>
+        /// <param name="fileName"></param>
+        /// <returns></returns>
         private IEnumerable<FontResource> GetFontResourcesByFileName(Uri location, string fileName)
         {
             var assembly = GetAssembly(location);
@@ -57,11 +83,22 @@ namespace Avalonia.Media.Fonts
             return matchingResources.Select(x => new FontResource(GetResourceUri(x, assembly.Name)));
         }
 
+        /// <summary>
+        /// Returns a valid resource <see cref="Uri"/> that follows the resm scheme
+        /// </summary>
+        /// <param name="path"></param>
+        /// <param name="assemblyName"></param>
+        /// <returns></returns>
         private static Uri GetResourceUri(string path, string assemblyName)
         {
             return new Uri("resm:" + path + "?assembly=" + assemblyName);
         }
 
+        /// <summary>
+        /// Translates a given <see cref="Uri"/> to a <see cref="Uri"/> that follows the resm scheme.
+        /// </summary>
+        /// <param name="uri"></param>
+        /// <returns></returns>
         private static string GetLocationPath(Uri uri)
         {
             if (uri.Scheme == "resm") return uri.AbsolutePath;
@@ -71,6 +108,11 @@ namespace Avalonia.Media.Fonts
             return path;
         }
 
+        /// <summary>
+        /// Extracts a <see cref="AssemblyDescriptor"/> from a given <see cref="Uri"/>
+        /// </summary>
+        /// <param name="uri"></param>
+        /// <returns></returns>
         private AssemblyDescriptor GetAssembly(Uri uri)
         {
             if (uri == null) return null;
@@ -80,6 +122,14 @@ namespace Avalonia.Media.Fonts
             return parameters.TryGetValue("assembly", out var assemblyName) ? GetAssembly(assemblyName) : null;
         }
 
+        /// <summary>
+        /// Returns a <see cref="AssemblyDescriptor"/> that is identified by a given name.
+        /// <para>
+        /// If name is <value>null</value> the default assembly is used.
+        /// </para>
+        /// </summary>
+        /// <param name="name"></param>
+        /// <returns></returns>
         private AssemblyDescriptor GetAssembly(string name)
         {
             if (name == null)
@@ -113,6 +163,11 @@ namespace Avalonia.Media.Fonts
             return rv;
         }
 
+        /// <summary>
+        /// Parses the parameters.
+        /// </summary>
+        /// <param name="uri">The URI.</param>
+        /// <returns></returns>
         private static Dictionary<string, string> ParseParameters(Uri uri)
         {
             return uri.Query.TrimStart('?')
@@ -134,8 +189,28 @@ namespace Avalonia.Media.Fonts
                 Name = Assembly.GetName().Name;
             }
 
+            /// <summary>
+            /// Gets the name.
+            /// </summary>
+            /// <value>
+            /// The name.
+            /// </value>
             public string Name { get; }
+
+            /// <summary>
+            /// Gets the assembly.
+            /// </summary>
+            /// <value>
+            /// The assembly.
+            /// </value>
             public Assembly Assembly { get; }
+
+            /// <summary>
+            /// Gets the resources.
+            /// </summary>
+            /// <value>
+            /// The resources.
+            /// </value>
             public List<string> Resources { get; }
         }
     }

src/Avalonia.Visuals/Media/Fonts/IFontResourceLoader.cs

@@ -5,8 +5,16 @@ using System.Collections.Generic;
 
 namespace Avalonia.Media.Fonts
 {
+    /// <summary>
+    /// Loads <see cref="FontResource"/> that can be identified by a given <see cref="FontFamilyKey"/>
+    /// </summary>
     public interface IFontResourceLoader
     {
+        /// <summary>
+        /// Returns a quanity of <see cref="FontResource"/> that belongs to a given <see cref="FontFamilyKey"/>
+        /// </summary>
+        /// <param name="fontFamilyKey"></param>
+        /// <returns></returns>
         IEnumerable<FontResource> GetFontResources(FontFamilyKey fontFamilyKey);
     }
 }