Add SkFontDescriptor for serializing fonts.

Review URL: https://codereview.appspot.com/6250080

git-svn-id: http://skia.googlecode.com/svn/trunk@4106 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 7 insertions, 2 deletions

diff --git a/include/core/SkFontHost.h b/include/core/SkFontHost.h
index 732de5c3c7..fd01b5f201 100644
--- a/include/core/SkFontHost.h
+++ b/include/core/SkFontHost.h
@@ -118,12 +118,17 @@ public:
     ///////////////////////////////////////////////////////////////////////////
 
     /** Write a unique identifier to the stream, so that the same typeface can
-        be retrieved with Deserialize().
+        be retrieved with Deserialize(). The standard format is to serialize
+        a SkFontDescriptor followed by a uint32_t length value. If the length
+        is non-zero then the following bytes (of that length) represent a
+        serialized copy of the font which can be recreated from a stream.
     */
     static void Serialize(const SkTypeface*, SkWStream*);
 
     /** Given a stream created by Serialize(), return a new typeface (like
-        CreateTypeface) or return NULL if no match is found.
+        CreateTypeface) which is either an exact match to the one serialized
+        or the best available typeface based on the data in the deserialized
+        SkFontDescriptor.
      */
     static SkTypeface* Deserialize(SkStream*);