Introduce IGlyphTypeface2 and expose TryGetStream

AvaloniaUI · Aug 30, 2023 · f624518 · f624518
1 parent f6809ad
commit f624518
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Showing 2 changed files with 52 additions and 1 deletion.
diff --git a/src/Avalonia.Base/Media/IGlyphTypeface.cs b/src/Avalonia.Base/Media/IGlyphTypeface.cs
@@ -1,4 +1,6 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
 using Avalonia.Metadata;
 
 namespace Avalonia.Media
@@ -111,4 +113,15 @@ public interface IGlyphTypeface : IDisposable
         /// <returns>Returns <c>true</c> if the content exists, otherwise <c>false</c>.</returns>
         bool TryGetTable(uint tag, out byte[] table);
     }
+
+    internal interface IGlyphTypeface2 : IGlyphTypeface
+    {
+
+        /// <summary>
+        /// Returns the font file stream represented by the <see cref="IGlyphTypeface"/> object.
+        /// </summary>
+        /// <param name="stream">The stream.</param>
+        /// <returns>Returns <c>true</c> if the stream can be obtained, otherwise <c>false</c>.</returns>
+        bool TryGetStream([NotNullWhen(true)] out Stream? stream);
+    }
 }
diff --git a/src/Skia/Avalonia.Skia/GlyphTypefaceImpl.cs b/src/Skia/Avalonia.Skia/GlyphTypefaceImpl.cs
@@ -1,12 +1,14 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
+using System.IO;
 using System.Runtime.InteropServices;
 using Avalonia.Media;
 using HarfBuzzSharp;
 using SkiaSharp;
 
 namespace Avalonia.Skia
 {
-    internal class GlyphTypefaceImpl : IGlyphTypeface
+    internal class GlyphTypefaceImpl : IGlyphTypeface, IGlyphTypeface2
     {
         private bool _isDisposed;
         private readonly SKTypeface _typeface;
@@ -198,5 +200,41 @@ public bool TryGetTable(uint tag, out byte[] table)
         {
             return _typeface.TryGetTableData(tag, out table);
         }
+
+        public bool TryGetStream([NotNullWhen(true)] out Stream? stream)
+        {
+            try
+            {
+                var asset = _typeface.OpenStream();
+                var size = asset.Length;
+                var memoryBase = asset.GetMemoryBase();
+
+                if (memoryBase != IntPtr.Zero)
+                {
+                    unsafe
+                    {
+                        stream = new UnmanagedMemoryStream((byte*)memoryBase, size);
+
+                        return true;
+                    }
+                }
+                else
+                {
+                    var buffer = new byte[size];
+
+                    asset.Read(buffer, size);
+
+                    stream = new MemoryStream(buffer);
+
+                    return true;
+                }
+            }
+            catch
+            {
+                stream = null;
+
+                return false;
+            }
+        }
     }
 }