Font backend implementation for Uniscribe on Windows 2000 and later.

1 files changed, 865 insertions, 0 deletions

diff --git a/src/w32uniscribe.c b/src/w32uniscribe.c
new file mode 100644
index 00000000000..fd10b9fc0f7
--- /dev/null
+++ b/src/w32uniscribe.c
@@ -0,0 +1,865 @@
+/* Font backend for the Microsoft W32 Uniscribe API.
+   Copyright (C) 2008 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
+
+#ifdef USE_FONT_BACKEND
+
+#include <config.h>
+/* Override API version - Uniscribe is only available as standard since
+   Windows 2000, though most users of older systems will have it
+   since it installs with Internet Explorer 5.0 and other software.
+   We only enable the feature if it is available, so there is no chance
+   of calling non-existant functions.  */
+#undef _WIN32_WINNT
+#define _WIN32_WINNT 0x500
+#include <windows.h>
+#include <usp10.h>
+
+#include "lisp.h"
+#include "w32term.h"
+#include "frame.h"
+#include "dispextern.h"
+#include "character.h"
+#include "charset.h"
+#include "fontset.h"
+#include "font.h"
+#include "w32font.h"
+
+struct uniscribe_font_info
+{
+  struct w32font_info w32_font;
+  SCRIPT_CACHE cache;
+};
+
+int uniscribe_available = 0;
+
+/* Defined in w32font.c, since it is required there as well.  */
+extern Lisp_Object Quniscribe;
+extern Lisp_Object Qopentype;
+
+extern int initialized;
+
+extern struct font_driver uniscribe_font_driver;
+
+/* EnumFontFamiliesEx callback.  */
+static int CALLBACK add_opentype_font_name_to_list P_ ((ENUMLOGFONTEX *,
+                                                        NEWTEXTMETRICEX *,
+                                                        DWORD, LPARAM));
+/* Used by uniscribe_otf_capability.  */
+static Lisp_Object otf_features (HDC context, char *table);
+
+static int
+memq_no_quit (elt, list)
+     Lisp_Object elt, list;
+{
+  while (CONSP (list) && ! EQ (XCAR (list), elt))
+    list = XCDR (list);
+  return (CONSP (list));
+}
+
+
+/* Font backend interface implementation.  */
+static Lisp_Object
+uniscribe_list (frame, font_spec)
+     Lisp_Object frame, font_spec;
+{
+  return w32font_list_internal (frame, font_spec, 1);
+}
+
+static Lisp_Object
+uniscribe_match (frame, font_spec)
+     Lisp_Object frame, font_spec;
+{
+  return w32font_match_internal (frame, font_spec, 1);
+}
+
+static Lisp_Object
+uniscribe_list_family (frame)
+     Lisp_Object frame;
+{
+  Lisp_Object list = Qnil;
+  LOGFONT font_match_pattern;
+  HDC dc;
+  FRAME_PTR f = XFRAME (frame);
+
+  bzero (&font_match_pattern, sizeof (font_match_pattern));
+  /* Limit enumerated fonts to outline fonts to save time.  */
+  font_match_pattern.lfOutPrecision = OUT_OUTLINE_PRECIS;
+
+  dc = get_frame_dc (f);
+
+  EnumFontFamiliesEx (dc, &font_match_pattern,
+                      (FONTENUMPROC) add_opentype_font_name_to_list,
+                      (LPARAM) &list, 0);
+  release_frame_dc (f, dc);
+
+  return list;
+}
+
+static struct font *
+uniscribe_open (f, font_entity, pixel_size)
+     FRAME_PTR f;
+     Lisp_Object font_entity;
+     int pixel_size;
+{
+  struct uniscribe_font_info *uniscribe_font
+    = xmalloc (sizeof (struct uniscribe_font_info));
+
+  if (uniscribe_font == NULL)
+    return NULL;
+
+  if (!w32font_open_internal (f, font_entity, pixel_size,
+                              (struct w32font_info *) uniscribe_font))
+    {
+      xfree (uniscribe_font);
+      return NULL;
+    }
+
+  /* Initialize the cache for this font.  */
+  uniscribe_font->cache = NULL;
+  /* Mark the format as opentype  */
+  uniscribe_font->w32_font.font.format = Qopentype;
+  uniscribe_font->w32_font.font.driver = &uniscribe_font_driver;
+
+  return (struct font *) uniscribe_font;
+}
+
+static void
+uniscribe_close (f, font)
+     FRAME_PTR f;
+     struct font *font;
+{
+  struct uniscribe_font_info *uniscribe_font
+    = (struct uniscribe_font_info *) font;
+
+  if (uniscribe_font->cache)
+    ScriptFreeCache (&uniscribe_font->cache);
+
+  w32font_close (f, font);
+}
+
+/* Return a list describing which scripts/languages FONT supports by
+   which GSUB/GPOS features of OpenType tables.  */
+static Lisp_Object
+uniscribe_otf_capability (font)
+     struct font *font;
+{
+  HDC context;
+  HFONT old_font;
+  struct frame *f;
+  Lisp_Object capability = Fcons (Qnil, Qnil);
+  Lisp_Object features;
+
+  f = XFRAME (selected_frame);
+  context = get_frame_dc (f);
+  old_font = SelectObject (context,
+                           ((W32FontStruct *) (font->font.font))->hfont);
+
+  features = otf_features (context, "GSUB");
+  XSETCAR (capability, features);
+  features = otf_features (context, "GPOS");
+  XSETCDR (capability, features);
+
+  SelectObject (context, old_font);
+  release_frame_dc (f, context);
+
+  return capability;
+}
+
+/* Uniscribe implementation of shape for font backend.
+
+   Shape text in LGSTRING.  See the docstring of `font-make-gstring'
+   for the format of LGSTRING.  If the (N+1)th element of LGSTRING
+   is nil, input of shaping is from the 1st to (N)th elements.  In
+   each input glyph, FROM, TO, CHAR, and CODE are already set.
+
+   This function updates all fields of the input glyphs.  If the
+   output glyphs (M) are more than the input glyphs (N), (N+1)th
+   through (M)th elements of LGSTRING are updated possibly by making
+   a new glyph object and storing it in LGSTRING.  If (M) is greater
+   than the length of LGSTRING, nil should be return.  In that case,
+   this function is called again with the larger LGSTRING.  */
+static Lisp_Object
+uniscribe_shape (lgstring)
+     Lisp_Object lgstring;
+{
+  struct font * font;
+  struct uniscribe_font_info * uniscribe_font;
+  EMACS_UINT nchars;
+  int nitems, max_items, i, max_glyphs, done_glyphs, done_chars;
+  wchar_t *chars;
+  WORD *glyphs, *clusters;
+  SCRIPT_ITEM *items;
+  SCRIPT_CONTROL control;
+  SCRIPT_VISATTR *attributes;
+  int *advances;
+  GOFFSET *offsets;
+  ABC overall_metrics;
+  MAT2 transform;
+  HDC context;
+  HFONT old_font;
+  HRESULT result;
+  struct frame * f;
+
+  CHECK_FONT_GET_OBJECT (LGSTRING_FONT (lgstring), font);
+  uniscribe_font = (struct uniscribe_font_info *) font;
+
+  /* Get the chars from lgstring in a form we can use with uniscribe.  */
+  max_glyphs = nchars = LGSTRING_LENGTH (lgstring);
+  done_glyphs = done_chars = 0;
+  chars = (wchar_t *) alloca (nchars * sizeof (wchar_t));
+  for (i = 0; i < nchars; i++)
+    {
+      /* lgstring can be bigger than the number of characters in it, in
+         the case where more glyphs are required to display those characters.
+         If that is the case, note the real number of characters.  */
+      if (NILP (LGSTRING_GLYPH (lgstring, i)))
+        nchars = i;
+      else
+        chars[i] = LGLYPH_CHAR (LGSTRING_GLYPH (lgstring, i));
+    }
+
+  /* First we need to break up the glyph string into runs of glyphs that
+     can be treated together.  First try a single run.  */
+  max_items = 2;
+  items = (SCRIPT_ITEM *) xmalloc (sizeof (SCRIPT_ITEM) * max_items);
+  bzero (&control, sizeof (control));
+
+  while ((result = ScriptItemize (chars, nchars, max_items, &control, NULL,
+                                  items, &nitems)) == E_OUTOFMEMORY)
+    {
+      /* If that wasn't enough, keep trying with one more run.  */
+      max_items++;
+      items = (SCRIPT_ITEM *) xrealloc (items,
+                                        sizeof (SCRIPT_ITEM) * max_items);
+    }
+
+  /* 0 = success in Microsoft's backwards world.  */
+  if (result)
+    {
+      xfree (items);
+      return Qnil;
+    }
+
+  f = XFRAME (selected_frame);
+  context = get_frame_dc (f);
+  old_font = SelectObject (context,
+                           ((W32FontStruct *) (font->font.font))->hfont);
+
+  glyphs = alloca (max_glyphs * sizeof (WORD));
+  clusters = alloca (nchars * sizeof (WORD));
+  attributes = alloca (max_glyphs * sizeof (SCRIPT_VISATTR));
+  advances = alloca (max_glyphs * sizeof (int));
+  offsets = alloca (max_glyphs * sizeof (GOFFSET));
+  bzero (&transform, sizeof (transform));
+  transform.eM11.value = 1;
+  transform.eM22.value = 1;
+
+  for (i = 0; i < nitems; i++)
+    {
+      int nglyphs, nchars_in_run;
+      nchars_in_run = items[i+1].iCharPos - items[i].iCharPos;
+
+      result = ScriptShape (context, &(uniscribe_font->cache),
+                            chars + items[i].iCharPos, nchars_in_run,
+                            max_glyphs - done_glyphs, &(items[i].a),
+                            glyphs, clusters, attributes, &nglyphs);
+      if (result == E_OUTOFMEMORY)
+        {
+          /* Need a bigger lgstring.  */
+          lgstring = Qnil;
+          break;
+        }
+      else if (result)
+        {
+          /* Can't shape this run - return results so far if any.  */
+          break;
+        }
+      else
+        {
+          result = ScriptPlace (context, &(uniscribe_font->cache),
+                                glyphs, nglyphs, attributes, &(items[i].a),
+                                advances, offsets, &overall_metrics);
+          if (!result)
+            {
+              int j, nclusters;
+
+              for (j = 0; j < nglyphs; j++)
+                {
+                  int lglyph_index = j + done_glyphs;
+                  Lisp_Object lglyph = LGSTRING_GLYPH (lgstring, lglyph_index);
+                  GLYPHMETRICS metrics;
+
+                  if (NILP (lglyph))
+                    {
+                      lglyph = Fmake_vector (make_number (LGLYPH_SIZE), Qnil);
+                      LGSTRING_SET_GLYPH (lgstring, lglyph_index, lglyph);
+                    }
+                  LGLYPH_SET_CODE (lglyph, glyphs[j]);
+                  LGLYPH_SET_WIDTH (lglyph, advances[j]);
+                  if (offsets[j].du || offsets[j].dv)
+                    {
+                      Lisp_Object vec;
+                      /* Convert from logical inches.  */
+                      int dpi = FRAME_W32_DISPLAY_INFO (f)->resy;
+                      int dx = (int)(offsets[j].du * dpi / 72.27 + 0.5);
+                      int dy = (int)(offsets[j].dv * dpi / 72.27 + 0.5);
+                      vec = Fmake_vector (make_number (3), Qnil);
+                      ASET (vec, 0, make_number (dx));
+                      ASET (vec, 1, make_number (dy));
+                      /* Based on what ftfont.c does... */
+                      ASET (vec, 2, make_number (advances[j]));
+                      LGLYPH_SET_ADJUSTMENT (lglyph, vec);
+                    }
+                  else
+                    LGLYPH_SET_ADJUSTMENT (lglyph, Qnil);
+
+                  if (GetGlyphOutlineW (context, glyphs[j],
+                                        GGO_METRICS | GGO_GLYPH_INDEX,
+                                        &metrics, 0, NULL, &transform)
+                      != GDI_ERROR)
+                    {
+                      LGLYPH_SET_LBEARING (lglyph, metrics.gmptGlyphOrigin.x);
+                      LGLYPH_SET_RBEARING (lglyph,
+                                           metrics.gmBlackBoxX
+                                           + metrics.gmptGlyphOrigin.x);
+                      LGLYPH_SET_ASCENT (lglyph, metrics.gmBlackBoxY);
+                      LGLYPH_SET_DESCENT (lglyph,
+                                          (metrics.gmCellIncY
+                                           - metrics.gmptGlyphOrigin.y
+                                           - metrics.gmBlackBoxY));
+                    }
+                  else
+                    {
+                      /* Defaults based on what we know from elsewhere.  */
+                      LGLYPH_SET_LBEARING (lglyph, 0);
+                      LGLYPH_SET_RBEARING (lglyph, advances[j]);
+                      LGLYPH_SET_ASCENT (lglyph, font->ascent);
+                      LGLYPH_SET_DESCENT (lglyph, font->descent);
+                    }
+                }
+
+              /* Set character codes as indicated in clusters.  */
+              for (j = 0; j < nchars_in_run - 1; j++)
+                {
+                  int k, start, end;
+                  wchar_t this_char = *(chars + items[i].iCharPos + j);
+
+                  start = clusters[i];
+                  end = clusters[i+1];
+                  if (start > end)
+                    {
+                      int temp = start;
+                      start = end;
+                      end = temp;
+                    }
+                  for (k = start; k < end; k++)
+                    {
+                      Lisp_Object lglyph = LGSTRING_GLYPH (lgstring,
+                                                           done_glyphs + k);
+                      LGLYPH_SET_CHAR (lglyph, this_char);
+                    }
+                }
+              /* Last one until end (or beginning) of string.  */
+              {
+                int k, start, end;
+                wchar_t last_char = *(chars + items[i].iCharPos
+                                      + nchars_in_run - 1);
+                start = clusters[nchars_in_run - 1];
+                end = nglyphs;
+                if (start < clusters[nchars_in_run - 2])
+                  {
+                    end = start + 1;
+                    start = 0;
+                  }
+                for (k = start; k < end; k++)
+                  {
+                    Lisp_Object lglyph = LGSTRING_GLYPH (lgstring,
+                                                         done_glyphs + k);
+                    LGLYPH_SET_CHAR (lglyph, last_char);
+                  }
+              }
+            }
+        }
+      done_glyphs += nglyphs;
+      done_chars += nchars_in_run;
+    }
+
+  xfree (items);
+  SelectObject (context, old_font);
+  release_frame_dc (f, context);
+
+  if (NILP (lgstring))
+    return Qnil;
+  else
+    return make_number (done_chars);
+}
+
+/* Uniscribe implementation of encode_char for font backend.
+   Return a glyph code of FONT for characer C (Unicode code point).
+   If FONT doesn't have such a glyph, return FONT_INVALID_CODE.  */
+static unsigned
+uniscribe_encode_char (font, c)
+     struct font *font;
+     int c;
+{
+  wchar_t chars[1];
+  WORD indices[1];
+  HDC context;
+  struct frame *f;
+  HFONT old_font;
+  DWORD retval;
+
+  /* TODO: surrogates.  */
+  if (c > 0xFFFF)
+    return FONT_INVALID_CODE;
+
+  chars[0] = (wchar_t) c;
+
+  /* Use selected frame until API is updated to pass the frame.  */
+  f = XFRAME (selected_frame);
+  context = get_frame_dc (f);
+  old_font = SelectObject (context,
+                           ((W32FontStruct *)(font->font.font))->hfont);
+
+  retval = GetGlyphIndicesW (context, chars, 1, indices,
+                             GGI_MARK_NONEXISTING_GLYPHS);
+
+  SelectObject (context, old_font);
+  release_frame_dc (f, context);
+
+  if (retval == 1)
+    return indices[0] == 0xFFFF ? FONT_INVALID_CODE : indices[0];
+  else
+    return FONT_INVALID_CODE;
+}
+
+/*
+   Shared with w32font:
+   Lisp_Object uniscribe_get_cache (Lisp_Object frame);
+   void uniscribe_free_entity (Lisp_Object font_entity);
+   int uniscribe_has_char (Lisp_Object entity, int c);
+   int uniscribe_text_extents (struct font *font, unsigned *code,
+                               int nglyphs, struct font_metrics *metrics);
+   int uniscribe_draw (struct glyph_string *s, int from, int to,
+                       int x, int y, int with_background);
+
+   Unused:
+   int uniscribe_prepare_face (FRAME_PTR f, struct face *face);
+   void uniscribe_done_face (FRAME_PTR f, struct face *face);
+   int uniscribe_get_bitmap (struct font *font, unsigned code,
+                             struct font_bitmap *bitmap, int bits_per_pixel);
+   void uniscribe_free_bitmap (struct font *font, struct font_bitmap *bitmap);
+   void * uniscribe_get_outline (struct font *font, unsigned code);
+   void uniscribe_free_outline (struct font *font, void *outline);
+   int uniscribe_anchor_point (struct font *font, unsigned code,
+                               int index, int *x, int *y);
+   int uniscribe_start_for_frame (FRAME_PTR f);
+   int uniscribe_end_for_frame (FRAME_PTR f);
+
+*/
+
+
+/* Callback function for EnumFontFamiliesEx.
+   Adds the name of opentype fonts to a Lisp list (passed in as the
+   lParam arg). */
+static int CALLBACK
+add_opentype_font_name_to_list (logical_font, physical_font, font_type,
+                                list_object)
+     ENUMLOGFONTEX *logical_font;
+     NEWTEXTMETRICEX *physical_font;
+     DWORD font_type;
+     LPARAM list_object;
+{
+  Lisp_Object* list = (Lisp_Object *) list_object;
+  Lisp_Object family;
+
+  /* Skip vertical fonts (intended only for printing)  */
+  if (logical_font->elfLogFont.lfFaceName[0] == '@')
+    return 1;
+
+  /* Skip non opentype fonts.  Count old truetype fonts as opentype,
+     as some of them do contain GPOS and GSUB data that Uniscribe
+     can make use of.  */
+  if (!(physical_font->ntmTm.ntmFlags & NTMFLAGS_OPENTYPE)
+      && font_type != TRUETYPE_FONTTYPE)
+    return 1;
+
+  family = intern_downcase (logical_font->elfLogFont.lfFaceName,
+                            strlen (logical_font->elfLogFont.lfFaceName));
+  if (! memq_no_quit (family, *list))
+    *list = Fcons (family, *list);
+
+  return 1;
+}
+
+
+/* :otf property handling.
+   Since the necessary Uniscribe APIs for getting font tag information
+   are only available in Vista, we need to parse the font data directly
+   according to the OpenType Specification.  */
+
+/* Push into DWORD backwards to cope with endianness.  */
+#define OTF_TAG(STR)                                          \
+  ((STR[3] << 24) | (STR[2] << 16) | (STR[1] << 8) | STR[0])
+
+#define OTF_INT16_VAL(TABLE, OFFSET, PTR)                    \
+  do {                                                       \
+    BYTE temp, data[2];                                      \
+    if (GetFontData (context, TABLE, OFFSET, data, 2) != 2)  \
+      goto font_table_error;                                 \
+    temp = data[0], data[0] = data[1], data[1] = temp;       \
+    memcpy (PTR, data, 2);                                   \
+  } while (0)
+
+/* Do not reverse the bytes, because we will compare with a OTF_TAG value
+   that has them reversed already.  */
+#define OTF_DWORDTAG_VAL(TABLE, OFFSET, PTR)                    \
+  do {                                                          \
+    if (GetFontData (context, TABLE, OFFSET, PTR, 4) != 4)      \
+      goto font_table_error;                                    \
+  } while (0)
+
+#define OTF_TAG_VAL(TABLE, OFFSET, STR)                      \
+  do {                                                       \
+    if (GetFontData (context, TABLE, OFFSET, STR, 4) != 4)   \
+      goto font_table_error;                                 \
+    STR[4] = '\0';                                           \
+  } while (0)
+
+static char* NOTHING = "    ";
+
+#define SNAME(VAL) SDATA (STRINGP (VAL) ? VAL : SYMBOL_NAME (VAL))
+
+/* Check if font supports the otf script/language/features specified.
+   OTF_SPEC is in the format
+     (script lang [(gsub_feature ...)|nil] [(gpos_feature ...)]?) */
+int uniscribe_check_otf (font, otf_spec)
+     LOGFONT *font;
+     Lisp_Object otf_spec;
+{
+  Lisp_Object script, lang, rest;
+  Lisp_Object features[2];
+  DWORD feature_tables[2];
+  DWORD script_tag, default_script, lang_tag = 0;
+  struct frame * f;
+  HDC context;
+  HFONT check_font, old_font;
+  DWORD table;
+  int i, retval = 0;
+
+  /* Break otf_spec into its components.  */
+  script = XCAR (otf_spec);
+  rest = XCDR (otf_spec);
+
+  lang = XCAR (rest);
+  rest = XCDR (rest);
+
+  features[0] = XCAR (rest);
+  rest = XCDR (rest);
+  if (NILP (rest))
+    features[1] = Qnil;
+  else
+    features[1] = XCAR (rest);
+
+  /* Set up tags we will use in the search.  */
+  feature_tables[0] = OTF_TAG ("GSUB");
+  feature_tables[1] = OTF_TAG ("GPOS");
+  default_script = OTF_TAG ("DFLT");
+  if (NILP (script))
+    script_tag = default_script;
+  else
+    script_tag = OTF_TAG (SNAME (script));
+  if (!NILP (lang))
+    lang_tag = OTF_TAG (SNAME (lang));
+
+  /* Set up graphics context so we can use the font.  */
+  f = XFRAME (selected_frame);
+  context = get_frame_dc (f);
+  check_font = CreateFontIndirect (font);
+  old_font = SelectObject (context, check_font);
+
+  /* Scan GSUB and GPOS tables.  */
+  for (i = 0; i < 2; i++)
+    {
+      int j, n_match_features;
+      unsigned short scriptlist_table, feature_table, n_scripts;
+      unsigned short script_table, langsys_table, n_langs;
+      unsigned short feature_index, n_features;
+      DWORD tbl = feature_tables[i];
+      Lisp_Object feature;
+
+      /* Skip if no features requested from this table.  */
+      if (NILP (features[i]))
+        continue;
+
+      /* Read GPOS/GSUB header.  */
+      OTF_INT16_VAL (tbl, 4, &scriptlist_table);
+      OTF_INT16_VAL (tbl, 6, &feature_table);
+      OTF_INT16_VAL (tbl, scriptlist_table, &n_scripts);
+
+      /* Find the appropriate script table.  */
+      script_table = 0;
+      for (j = 0; j < n_scripts; j++)
+        {
+          DWORD script_id;
+          OTF_DWORDTAG_VAL (tbl, scriptlist_table + 2 + j * 6, &script_id);
+          if (script_id == script_tag)
+            {
+              OTF_INT16_VAL (tbl, scriptlist_table + 6 + j * 6, &script_table);
+              break;
+            }
+          /* If there is a DFLT script defined in the font, use it
+             if the specified script is not found.  */
+          else if (script_id == default_script)
+            OTF_INT16_VAL (tbl, scriptlist_table + 6 + j * 6, &script_table);
+        }
+      /* If no specific or default script table was found, then this font
+         does not support the script.  */
+      if (!script_table)
+        goto no_support;
+
+      /* Offset is from beginning of scriptlist_table.  */
+      script_table += scriptlist_table;
+
+      /* Get default langsys table.  */
+      OTF_INT16_VAL (tbl, script_table, &langsys_table);
+
+      /* If lang was specified, see if font contains a specific entry.  */
+      if (!NILP (lang))
+        {
+          OTF_INT16_VAL (tbl, script_table + 2, &n_langs);
+
+          for (j = 0; j < n_langs; j++)
+            {
+              DWORD lang_id;
+              OTF_DWORDTAG_VAL (tbl, script_table + 4 + j * 6, &lang_id);
+              if (lang_id == lang_tag)
+                {
+                  OTF_INT16_VAL (tbl, script_table + 8 + j * 6, &langsys_table);
+                  break;
+                }
+            }
+        }
+
+      if (!langsys_table)
+        goto no_support;
+
+      /* Offset is from beginning of script table.  */
+      langsys_table += script_table;
+
+      /* Check the features.  Features may contain nil according to
+         documentation in font_prop_validate_otf, so count them.  */
+      n_match_features = 0;
+      rest = features[i];
+      for (feature = XCAR (rest); CONSP (rest); feature = XCAR (rest))
+        {
+          rest = XCDR (rest);
+          if (!NILP (feature))
+            n_match_features++;
+        }
+
+      /* If there are no features to check, skip checking.  */
+      if (!n_match_features)
+        continue;
+
+      /* First check required feature (if any).  */
+      OTF_INT16_VAL (tbl, langsys_table + 2, &feature_index);
+      if (feature_index != 0xFFFF)
+        {
+          char feature_id[5];
+          OTF_TAG_VAL (tbl, feature_table + 2 + feature_index * 6, feature_id);
+          OTF_TAG_VAL (tbl, feature_table + 2 + feature_index * 6, feature_id);
+          /* Assume no duplicates in the font table. This allows us to mark
+             the features off by simply decrementing a counter.  */
+          if (!NILP (Fmemq (intern (feature_id), features[i])))
+            n_match_features--;
+        }
+      /* Now check all the other features.  */
+      OTF_INT16_VAL (tbl, langsys_table + 4, &n_features);
+      for (j = 0; j < n_features; j++)
+        {
+          char feature_id[5];
+          OTF_INT16_VAL (tbl, langsys_table + 6 + j * 2, &feature_index);
+          OTF_TAG_VAL (tbl, feature_table + 2 + feature_index * 6, feature_id);
+          /* Assume no duplicates in the font table. This allows us to mark
+             the features off by simply decrementing a counter.  */
+          if (!NILP (Fmemq (intern (feature_id), features[i])))
+            n_match_features--;
+        }
+
+      if (n_match_features > 0)
+        goto no_support;
+    }
+
+  retval = 1;
+
+ no_support:
+ font_table_error:
+  /* restore graphics context.  */
+  SelectObject (context, old_font);
+  DeleteObject (check_font);
+  release_frame_dc (f, context);
+
+  return retval;
+}
+
+static Lisp_Object
+otf_features (HDC context, char *table)
+{
+  Lisp_Object script_list = Qnil;
+  unsigned short scriptlist_table, n_scripts, feature_table;
+  DWORD tbl = OTF_TAG (table);
+  int i, j, k;
+
+  /* Look for scripts in the table.  */
+  OTF_INT16_VAL (tbl, 4, &scriptlist_table);
+  OTF_INT16_VAL (tbl, 6, &feature_table);
+  OTF_INT16_VAL (tbl, scriptlist_table, &n_scripts);
+
+  for (i = 0; i < n_scripts; i++)
+    {
+      char script[5], lang[5];
+      unsigned short script_table, lang_count, langsys_table, feature_count;
+      Lisp_Object script_tag, langsys_list, langsys_tag, feature_list;
+      unsigned short record_offset = scriptlist_table + 2 + i * 6;
+      OTF_TAG_VAL (tbl, record_offset, script);
+      OTF_INT16_VAL (tbl, record_offset + 4, &script_table);
+
+      /* Offset is from beginning of script table.  */
+      script_table += scriptlist_table;
+
+      script_tag = intern (script);
+      langsys_list = Qnil;
+
+      /* Optional default lang.  */
+      OTF_INT16_VAL (tbl, script_table, &langsys_table);
+      if (langsys_table)
+        {
+          /* Offset is from beginning of script table.  */
+          langsys_table += script_table;
+
+          langsys_tag = Qnil;
+          feature_list = Qnil;
+          OTF_INT16_VAL (tbl, langsys_table + 4, &feature_count);
+          for (k = 0; k < feature_count; k++)
+            {
+              char feature[5];
+              unsigned short index;
+              OTF_INT16_VAL (tbl, langsys_table + 6 + k * 2, &index);
+              OTF_TAG_VAL (tbl, feature_table + 2 + index * 6, feature);
+              feature_list = Fcons (intern (feature), feature_list);
+            }
+          langsys_list = Fcons (Fcons (langsys_tag, feature_list),
+                                langsys_list);
+        }
+
+      /* List of supported languages.  */
+      OTF_INT16_VAL (tbl, script_table + 2, &lang_count);
+
+      for (j = 0; j < lang_count; j++)
+        {
+          record_offset = script_table + 4 + j * 6;
+          OTF_TAG_VAL (tbl, record_offset, lang);
+          OTF_INT16_VAL (tbl, record_offset + 4, &langsys_table);
+
+          /* Offset is from beginning of script table.  */
+          langsys_table += script_table;
+
+          langsys_tag = intern (lang);
+          feature_list = Qnil;
+          OTF_INT16_VAL (tbl, langsys_table + 4, &feature_count);
+          for (k = 0; k < feature_count; k++)
+            {
+              char feature[5];
+              unsigned short index;
+              OTF_INT16_VAL (tbl, langsys_table + 6 + k * 2, &index);
+              OTF_TAG_VAL (tbl, feature_table + 2 + index * 6, feature);
+              feature_list = Fcons (intern (feature), feature_list);
+            }
+          langsys_list = Fcons (Fcons (langsys_tag, feature_list),
+                                langsys_list);
+
+        }
+
+      script_list = Fcons (Fcons (script_tag, langsys_list), script_list);
+    }
+
+  return script_list;
+
+font_table_error:
+  return Qnil;
+}
+
+#undef OTF_INT16_VAL
+#undef OTF_TAG_VAL
+#undef OTF_TAG
+
+
+struct font_driver uniscribe_font_driver =
+  {
+    0, /* Quniscribe */
+    w32font_get_cache,
+    uniscribe_list,
+    uniscribe_match,
+    uniscribe_list_family,
+    NULL, /* free_entity */
+    uniscribe_open,
+    uniscribe_close,
+    NULL, /* prepare_face */
+    NULL, /* done_face */
+    w32font_has_char,
+    uniscribe_encode_char,
+    w32font_text_extents,
+    w32font_draw,
+    NULL, /* get_bitmap */
+    NULL, /* free_bitmap */
+    NULL, /* get_outline */
+    NULL, /* free_outline */
+    NULL, /* anchor_point */
+    uniscribe_otf_capability, /* Defined so (font-get FONTOBJ :otf) works.  */ 
+    NULL, /* otf_drive - use shape instead.  */
+    NULL, /* start_for_frame */
+    NULL, /* end_for_frame */
+    uniscribe_shape
+  };
+
+/* Note that this should be called at every startup, not just when dumping,
+   as it needs to test for the existence of the Uniscribe library.  */
+void
+syms_of_w32uniscribe ()
+{
+  HMODULE uniscribe;
+
+  /* Don't init uniscribe when dumping */
+  if (!initialized)
+    return;
+
+  /* Don't register if uniscribe is not available.  */
+  uniscribe = GetModuleHandle ("usp10");
+  if (!uniscribe)
+    return;
+
+  uniscribe_font_driver.type = Quniscribe;
+  uniscribe_available = 1;
+
+  register_font_driver (&uniscribe_font_driver, NULL);
+}
+
+#endif /* USE_FONT_BACKEND  */