Bug 150883 – Unicode LRO defect

2007-07-24  Behdad Esfahbod  <behdad@gnome.org>

        Bug 150883 – Unicode LRO defect

        * modules/arabic/arabic-fc.c (arabic_engine_shape):
        * modules/arabic/arabic-ot.c (Get_Joining_Class),
        (Arabic_Assign_Properties):
        * modules/arabic/arabic-ot.h:
        Correctly handle Arabic shaping in left-to-right runs.


svn path=/trunk/; revision=2378

4 files changed, 32 insertions, 14 deletions

diff --git a/ChangeLog b/ChangeLog
index feb1c8d5..794b8c40 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2007-07-24  Behdad Esfahbod  <behdad@gnome.org>
+
+	Bug 150883 – Unicode LRO defect
+
+	* modules/arabic/arabic-fc.c (arabic_engine_shape):
+	* modules/arabic/arabic-ot.c (Get_Joining_Class),
+	(Arabic_Assign_Properties):
+	* modules/arabic/arabic-ot.h:
+	Correctly handle Arabic shaping in left-to-right runs.
+
 2007-07-21  Behdad Esfahbod  <behdad@gnome.org>
 
 	Part of Bug 347236 – provide pango_cairo_font_get_scaled_font
diff --git a/modules/arabic/arabic-fc.c b/modules/arabic/arabic-fc.c
index c311504b..5765982b 100644
--- a/modules/arabic/arabic-fc.c
+++ b/modules/arabic/arabic-fc.c
@@ -95,6 +95,7 @@ arabic_engine_shape (PangoEngineShape *engine,
   gunichar *wcs;
   const char *p;
   int cluster = 0;
+  gboolean rtl = analysis->level % 2 != 0;
   int i;
 
   g_return_if_fail (font != NULL);
@@ -108,13 +109,13 @@ arabic_engine_shape (PangoEngineShape *engine,
     return;
 
   buffer = pango_ot_buffer_new (fc_font);
-  pango_ot_buffer_set_rtl (buffer, analysis->level % 2 != 0);
+  pango_ot_buffer_set_rtl (buffer, rtl);
   pango_ot_buffer_set_zero_width_marks (buffer, TRUE);
 
   wcs = g_utf8_to_ucs4_fast (text, length, &n_chars);
   properties = g_new0 (gulong, n_chars);
 
-  Arabic_Assign_Properties (wcs, properties, n_chars);
+  Arabic_Assign_Properties (wcs, properties, n_chars, !rtl);
 
   g_free (wcs);
 
diff --git a/modules/arabic/arabic-ot.c b/modules/arabic/arabic-ot.c
index 5041bd9d..ba8e9bad 100644
--- a/modules/arabic/arabic-ot.c
+++ b/modules/arabic/arabic-ot.c
@@ -319,7 +319,8 @@ TT_Error  Build_Arabic_Glyph_Properties (TT_CharMap        char_map,
 static joining_class  Get_Joining_Class (gunichar*   string,
 					 int         pos,
 					 int         length,
-					 int         direction)
+					 int         direction,
+					 gboolean    reverse)
 {
   joining_class  j;
 
@@ -349,17 +350,22 @@ static joining_class  Get_Joining_Class (gunichar*   string,
 	return none;
 
       if (!direction || j != transparent)
-	return j;
+        {
+	  if (G_UNLIKELY (reverse))
+	    return j == right ? left : j == left ? right : j;
+	  else
+	    return j;
+	}
     }
 }
 
 
 FT_Error  Arabic_Assign_Properties (gunichar    *string,
 				    gulong      *properties,
-				    int          length)
+				    int          length,
+				    gboolean     reverse)
 {
   joining_class  previous, current, next;
-
   int      i;
 
   if (!string || !properties || length == 0)
@@ -367,9 +373,9 @@ FT_Error  Arabic_Assign_Properties (gunichar    *string,
 
   for (i = 0; i < length; i++)
     {
-      previous = Get_Joining_Class (string, i, length, -1);
-      current  = Get_Joining_Class (string, i, length,  0);
-      next     = Get_Joining_Class (string, i, length,  1);
+      previous = Get_Joining_Class (string, i, length, -1, reverse);
+      current  = Get_Joining_Class (string, i, length,  0, reverse);
+      next     = Get_Joining_Class (string, i, length,  1, reverse);
 
       /* R1 */
 
@@ -386,7 +392,7 @@ FT_Error  Arabic_Assign_Properties (gunichar    *string,
 	  previous == dual   )
 	if (current == right)
 	  {
-	    properties[i] |= final_p;
+	    properties[i] |= reverse ? initial_p : final_p;
 	    continue;
 	  }
 
@@ -397,7 +403,7 @@ FT_Error  Arabic_Assign_Properties (gunichar    *string,
 	    next == right   ||
 	    next == dual   )
 	  {
-	    properties[i] |= initial_p;
+	    properties[i] |= reverse ? final_p : initial_p;
 	    continue;
 	  }
 
@@ -425,7 +431,7 @@ FT_Error  Arabic_Assign_Properties (gunichar    *string,
 		next == right   ||
 		next == dual   ))
 	    {
-	      properties[i] |= final_p;
+	      properties[i] |= reverse ? initial_p : final_p;
 	      continue;
 	    }
 
@@ -439,7 +445,7 @@ FT_Error  Arabic_Assign_Properties (gunichar    *string,
 	      next == right   ||
 	      next == dual   )
 	    {
-	      properties[i] |= initial_p;
+	      properties[i] |= reverse ? final_p : initial_p;
 	      continue;
 	    }
 
diff --git a/modules/arabic/arabic-ot.h b/modules/arabic/arabic-ot.h
index 401279be..db9a9aa9 100644
--- a/modules/arabic/arabic-ot.h
+++ b/modules/arabic/arabic-ot.h
@@ -68,7 +68,8 @@ typedef enum joining_class_  joining_class;
 
 FT_Error  Arabic_Assign_Properties (gunichar   *string,
 				    gulong     *properties,
-				    int         length);
+				    int         length,
+				    gboolean    reverse);
 #if 0
 TT_Error  Build_Arabic_Glyph_Properties (TT_CharMap        char_map,
 					 TT_UShort         max_glyphs,