X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/220d91b834f7f7252b9953460422151b86b3520c..cf5fc6dbeac10220394ab201ba3f4402e1e91faf:/src/w32uniscribe.c

diff --git a/src/w32uniscribe.c b/src/w32uniscribe.c
index 6c29e6ee2d..5d160b9d42 100644
--- a/src/w32uniscribe.c
+++ b/src/w32uniscribe.c
@@ -1,5 +1,5 @@
 /* Font backend for the Microsoft W32 Uniscribe API.
-   Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
+   Copyright (C) 2008-2012 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -27,7 +27,6 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #define _WIN32_WINNT 0x500
 #include <windows.h>
 #include <usp10.h>
-#include <setjmp.h>
 
 #include "lisp.h"
 #include "w32term.h"
@@ -52,10 +51,6 @@ int uniscribe_available = 0;
 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 (ENUMLOGFONTEX *,
                                                     NEWTEXTMETRICEX *,
@@ -235,7 +230,7 @@ uniscribe_shape (Lisp_Object lgstring)
   /* 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 + 1);
+  items = xmalloc (sizeof (SCRIPT_ITEM) * max_items + 1);
 
   while ((result = ScriptItemize (chars, nchars, max_items, NULL, NULL,
 				  items, &nitems)) == E_OUTOFMEMORY)
@@ -324,7 +319,7 @@ uniscribe_shape (Lisp_Object lgstring)
 	    }
           if (SUCCEEDED (result))
 	    {
-	      int j, nclusters, from, to;
+	      int j, from, to, adj_offset = 0;
 
 	      from = 0;
 	      to = from;
@@ -368,6 +363,32 @@ uniscribe_shape (Lisp_Object lgstring)
 				}
 			    }
 			}
+
+		      /* For RTL text, the Uniscribe shaper prepares
+			 the values in ADVANCES array for layout in
+			 reverse order, whereby "advance width" is
+			 applied to move the pen in reverse direction
+			 and _before_ drawing the glyph.  Since we
+			 draw glyphs in their normal left-to-right
+			 order, we need to adjust the coordinates of
+			 each non-base glyph in a grapheme cluster via
+			 X-OFF component of the gstring's ADJUSTMENT
+			 sub-vector.  This loop computes, for each
+			 grapheme cluster, the initial value of the
+			 adjustment for the base character, which is
+			 then updated for each successive glyph in the
+			 grapheme cluster.  */
+		      if (items[i].a.fRTL)
+			{
+			  int j1 = j;
+
+			  adj_offset = 0;
+			  while (j1 < nglyphs && !attributes[j1].fClusterStart)
+			    {
+			      adj_offset += advances[j1];
+			      j1++;
+			    }
+			}
 		    }
 
 		  LGLYPH_SET_CHAR (lglyph, chars[items[i].iCharPos
@@ -396,9 +417,11 @@ uniscribe_shape (Lisp_Object lgstring)
 
 		  if (SUCCEEDED (result))
 		    {
-		      LGLYPH_SET_LBEARING (lglyph, char_metric.abcA);
-		      LGLYPH_SET_RBEARING (lglyph, (char_metric.abcA
-						    + char_metric.abcB));
+		      int lbearing = char_metric.abcA;
+		      int rbearing = char_metric.abcA + char_metric.abcB;
+
+		      LGLYPH_SET_LBEARING (lglyph, lbearing);
+		      LGLYPH_SET_RBEARING (lglyph, rbearing);
 		    }
 		  else
 		    {
@@ -406,18 +429,47 @@ uniscribe_shape (Lisp_Object lgstring)
 		      LGLYPH_SET_RBEARING (lglyph, advances[j]);
 		    }
 
-		  if (offsets[j].du || offsets[j].dv)
+		  if (offsets[j].du || offsets[j].dv
+		      /* For non-base glyphs of RTL grapheme clusters,
+			 adjust the X offset even if both DU and DV
+			 are zero.  */
+		      || (!attributes[j].fClusterStart && items[i].a.fRTL))
 		    {
 		      Lisp_Object vec;
 		      vec = Fmake_vector (make_number (3), Qnil);
-		      ASET (vec, 0, make_number (offsets[j].du));
-		      ASET (vec, 1, make_number (offsets[j].dv));
+		      if (items[i].a.fRTL)
+			{
+			  /* Empirically, it looks like Uniscribe
+			     interprets DU in reverse direction for
+			     RTL clusters.  E.g., if we don't reverse
+			     the direction, the Hebrew point HOLAM is
+			     drawn above the right edge of the base
+			     consonant, instead of above the left edge.  */
+			  ASET (vec, 0, make_number (-offsets[j].du
+						     + adj_offset));
+			  /* Update the adjustment value for the width
+			     advance of the glyph we just emitted.  */
+			  adj_offset -= 2 * advances[j];
+			}
+		      else
+			ASET (vec, 0, make_number (offsets[j].du + adj_offset));
+		      /* In the font definition coordinate system, the
+			 Y coordinate points up, while in our screen
+			 coordinates Y grows downwards.  So we need to
+			 reverse the sign of Y-OFFSET here.  */
+		      ASET (vec, 1, make_number (-offsets[j].dv));
 		      /* Based on what ftfont.c does... */
 		      ASET (vec, 2, make_number (advances[j]));
 		      LGLYPH_SET_ADJUSTMENT (lglyph, vec);
 		    }
 		  else
-		    LGLYPH_SET_ADJUSTMENT (lglyph, Qnil);
+		    {
+		      LGLYPH_SET_ADJUSTMENT (lglyph, Qnil);
+		      /* Update the adjustment value to compensate for
+			 the width of the base character.  */
+		      if (items[i].a.fRTL)
+			adj_offset -= advances[j];
+		    }
 		}
 	    }
 	}
@@ -473,7 +525,7 @@ uniscribe_encode_char (struct font *font, int c)
 
   /* Non BMP characters must be handled by the uniscribe shaping
      engine as GDI functions (except blindly displaying lines of
-     unicode text) and the promising looking ScriptGetCMap do not
+     Unicode text) and the promising looking ScriptGetCMap do not
      convert surrogate pairs to glyph indexes correctly.  */
     {
       items = (SCRIPT_ITEM *) alloca (sizeof (SCRIPT_ITEM) * 2 + 1);
@@ -511,7 +563,7 @@ uniscribe_encode_char (struct font *font, int c)
           if (SUCCEEDED (result) && nglyphs == 1)
             {
 	      /* Some fonts return .notdef glyphs instead of failing.
-	         (Truetype spec reserves glyph code 0 for .notdef)  */
+	         (TrueType spec reserves glyph code 0 for .notdef)  */
 	      if (glyphs[0])
 		code = glyphs[0];
             }
@@ -585,7 +637,7 @@ add_opentype_font_name_to_list (ENUMLOGFONTEX *logical_font,
       && font_type != TRUETYPE_FONTTYPE)
     return 1;
 
-  /* Skip fonts that have no unicode coverage.  */
+  /* Skip fonts that have no Unicode coverage.  */
   if (!physical_font->ntmFontSig.fsUsb[3]
       && !physical_font->ntmFontSig.fsUsb[2]
       && !physical_font->ntmFontSig.fsUsb[1]
@@ -633,8 +685,6 @@ add_opentype_font_name_to_list (ENUMLOGFONTEX *logical_font,
     STR[4] = '\0';                                           \
   } while (0)
 
-static char* NOTHING = "    ";
-
 #define SNAME(VAL) SDATA (SYMBOL_NAME (VAL))
 
 /* Check if font supports the otf script/language/features specified.
@@ -650,7 +700,6 @@ uniscribe_check_otf (LOGFONT *font, Lisp_Object otf_spec)
   struct frame * f;
   HDC context;
   HFONT check_font, old_font;
-  DWORD table;
   int i, retval = 0;
   struct gcpro gcpro1;
 
@@ -940,7 +989,11 @@ struct font_driver uniscribe_font_driver =
     NULL, /* otf_drive - use shape instead.  */
     NULL, /* start_for_frame */
     NULL, /* end_for_frame */
-    uniscribe_shape
+    uniscribe_shape,
+    NULL, /* check */
+    NULL, /* get_variation_glyphs */
+    NULL, /* filter_properties */
+    NULL, /* cached_font_ok */
   };
 
 /* Note that this should be called at every startup, not just when dumping,
@@ -964,6 +1017,3 @@ syms_of_w32uniscribe (void)
 
   register_font_driver (&uniscribe_font_driver, NULL);
 }
-
-/* arch-tag: 9530f0e1-7471-47dd-a780-94330af87ea0
-   (do not change this comment) */