Re: [ft-devel] units_per_em in CFF/CID FDArray

[Werner LEMBERG]

> Today I ran across a CFF CID font in a PDF file where the FontMatrix
> / units_per_em is 2048 instead of 1000, except FontMatrix is
> specified in the FDArray for the subfont, not in the top dict.
>
> Here is the patch against the latest CVS [...]

After some investigation I think this is the wrong approach.  Note
that each CID subfont can have a different FontMatrix value!  For the
user, only the top dict's entry should be returned.

The right approach IMHO is to select the subfont's FontMatrix in
cff_slot_load, similar to the code in the CID module.

Below is an untested patch which I ask you to verify (and fix if
necessary :-).


    Werner


======================================================================


--- cffgload.c.old      2004-05-13 23:59:17.000000000 +0200
+++ cffgload.c  2005-04-16 08:50:39.691961336 +0200
@@ -4,7 +4,7 @@
 /*                                                                         */
 /*    OpenType Glyph Loader (body).                                        */
 /*                                                                         */
-/*  Copyright 1996-2001, 2002, 2003, 2004 by                               */
+/*  Copyright 1996-2001, 2002, 2003, 2004, 2005 by                         */
 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
 /*                                                                         */
 /*  This file is part of the FreeType project, and may only be used,       */
@@ -2466,8 +2466,20 @@
 
 #endif /* FT_CONFIG_OPTION_INCREMENTAL */
 
-    font_matrix = cff->top_font.font_dict.font_matrix;
-    font_offset = cff->top_font.font_dict.font_offset;
+    /* use the subfont's font matrix if available */
+    if ( cff->num_subfonts >= 1 )
+    {
+      FT_Byte  fd_index = cff_fd_select_get( &cff->fd_select, glyph_index );
+
+
+      font_matrix = cff->subfonts[fd_index].font_dict.font_matrix;
+      font_offset = cff->subfonts[fd_index].font_dict.font_offset;
+    }
+    else
+    {
+      font_matrix = cff->top_font.font_dict.font_matrix;
+      font_offset = cff->top_font.font_dict.font_offset;
+    }
 
     /* Now, set the metrics -- this is rather simple, as   */
     /* the left side bearing is the xMin, and the top side */