Implement delegate for circumventing the WPF embedded font resource m…

…emory leak (https://stackoverflow.com/questions/31452443/wpf-textblock-memory-leak-when-using-font)
PingmanTools · Feb 3, 2018 · 17e37cc · 17e37cc
1 parent 6111e2d
commit 17e37cc
Show file tree

Hide file tree

Showing 2 changed files with 13 additions and 6 deletions.
diff --git a/LiteHtmlSharp.Wpf/FontInfo.cs b/LiteHtmlSharp.Wpf/FontInfo.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Text;
 using System.Windows.Media;
@@ -20,11 +20,13 @@ public class FontInfo
 
       public TextDecorationCollection Decorations = new TextDecorationCollection();
 
-      public FontInfo(string faceName, FontStyle style, FontWeight weight, int size)
+      public FontInfo(string faceName, FontStyle style, FontWeight weight, int size, FontFamily fontFamily = null)
       {
-         // Using the pack URI means we can look inside resources in addition to system fonts.
+         // Using the pack URI means we can look inside resources in addition to system fonts - this is only supported for backwards compatibility, as it causes memory leaks.
+         // https://stackoverflow.com/questions/31452443/wpf-textblock-memory-leak-when-using-font
          // FontFamily will allow comma separated font names, but does not support quotes of any kind (so don't quote it in your HTML/CSS!).
-         Family = new FontFamily(new Uri("pack://application:,,,/Fonts/"), faceName);
+
+         Family = fontFamily ?? new FontFamily(new Uri("pack://application:,,,/Fonts/"), faceName);
 
          TypeFace = new Typeface(Family, style, weight, new FontStretch());
          Size = size;

diff --git a/LiteHtmlSharp.Wpf/WPFContainer.cs b/LiteHtmlSharp.Wpf/WPFContainer.cs
@@ -39,10 +39,14 @@ public IntPoint(int x, int y)
       }
    }
 
+   public delegate FontFamily FontAbsolutePathDelegate(string fontName);
+
    public class WpfContainer : ViewportContainer
    {
       IResourceLoader _loader;
 
+      public FontAbsolutePathDelegate FontAbsolutePathDelegate;
+
       class ResourceLoader : IResourceLoader
       {
          Func<string, string> _getStringResource;
@@ -282,8 +286,9 @@ protected override void DrawText(string text, UIntPtr font, ref web_color color,
 
       protected override UIntPtr CreateFont(string faceName, int size, int weight, font_style italic, font_decoration decoration, ref font_metrics fm)
       {
-         var fontweight = FontWeight.FromOpenTypeWeight(weight);
-         FontInfo font = new FontInfo(faceName, italic == font_style.fontStyleItalic ? FontStyles.Italic : FontStyles.Normal, fontweight, size);
+         var fontweight = FontWeight.FromOpenTypeWeight(weight);    
+         FontInfo font = new FontInfo(family, italic == font_style.fontStyleItalic ? FontStyles.Italic : FontStyles.Normal, fontweight, size, FontAbsolutePathDelegate?.Invoke(family));
+
          if ((decoration & font_decoration.font_decoration_underline) != 0)
          {
             font.Decorations.Add(TextDecorations.Underline);