diff --git a/src/ChangeLog b/src/ChangeLog
index 4f1f087d00d..30ea46bc470 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,10 @@
 2008-04-08  Jason Rumney  <jasonr@gnu.org>
 
+	* w32font.h (struct w32_metric_cache): New struct.
+	(w32font_info): Use it.
+	(W32METRIC_NO_ATTEMPT, W32METRIC_SUCCESS, W32METRIC_FAIL)
+	(CACHE_BLOCKSIZE): New constants.
+	
 	* w32font.c (Qja, Qko, Qzh): New symbols.
 	(syms_of_w32font): Initialise them.
 	(font_matches_spec): Use them to filter by language.
diff --git a/src/w32font.h b/src/w32font.h
index 9bd7546e057..6345d59c71f 100644
--- a/src/w32font.h
+++ b/src/w32font.h
@@ -36,6 +36,16 @@ Boston, MA 02110-1301, USA.  */
 
 #define NTMFLAGS_OPENTYPE (NTM_PS_OPENTYPE | NTM_TT_OPENTYPE)
 
+struct w32_metric_cache
+{
+  short lbearing, rbearing, width;
+  unsigned char status;
+};
+
+#define W32METRIC_NO_ATTEMPT 0
+#define W32METRIC_SUCCESS 1
+#define W32METRIC_FAIL 2
+
 /* The actual structure for a w32 font, that can be cast to struct font.
    The Uniscribe backend extends this.  */
 struct w32font_info
@@ -43,9 +53,12 @@ struct w32font_info
   struct font font;
   TEXTMETRIC metrics;
   unsigned int glyph_idx;
-  struct font_metrics ascii_metrics[128];
+  struct w32_metric_cache **cached_metrics;
+  int n_cache_blocks;
 };
 
+#define CACHE_BLOCKSIZE 128
+
 Lisp_Object w32font_get_cache P_ ((FRAME_PTR fe));
 Lisp_Object w32font_list_internal P_ ((Lisp_Object frame,
                                        Lisp_Object font_spec,