Further fix for bug #11860 with Arabic display on Windows.

 src/w32uniscribe.c (uniscribe_shape): Handle correctly the case of
 more than one grapheme cluster passed to the shaper: compute the
 offset adjustment values separately for each cluster.

diff --git a/src/ChangeLog b/src/ChangeLog
index 5b58d77e54ad4c797993d350992a4fccf56584d1..e186b8af87faec55560855eedfddb5bdc34edd29 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,9 @@
 2012-09-01  Eli Zaretskii  <eliz@gnu.org>
 
+       * w32uniscribe.c (uniscribe_shape): Handle correctly the case of
+       more than one grapheme cluster passed to the shaper: compute the
+       offset adjustment values separately for each cluster.  (Bug#11860)
+
        * image.c: Restore mistakenly removed inclusion of w32.h.  Without
        it, GCC doesn't see prototypes of w32_delayed_load, and complains
        about implicit conversions from integer to pointer.

diff --git a/src/w32uniscribe.c b/src/w32uniscribe.c
index 50532acaff3d67d53f3c5fcc96646c03fca7601e..bc45e2c648c9c9ad29ab7e5a0d391c48f325b581 100644 (file)
--- a/src/w32uniscribe.c
+++ b/src/w32uniscribe.c
@@ -322,22 +322,6 @@ uniscribe_shape (Lisp_Object lgstring)
            {
              int j, from, to, adj_offset = 0;
 
-             /* 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 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)
-               for (j = 1; j < nglyphs; j++)
-                 adj_offset += advances[j];
-
              from = 0;
              to = from;
 
@@ -380,6 +364,32 @@ 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