Improve fix for bug #11832 with truncated/continued lines w/o margins.

 src/xdisp.c (insert_left_trunc_glyphs): Fix incorrect size in
 memmove call that removes glyphs covered by the left truncation
 glyph.  Improve commentary.
 (display_line): Fix display of continuation glyphs on GUI frames
 when the right fringe is turned off and variable-size fonts are
 used in the window.  Move the code that appends a stretch glyph to
 produce_special_glyphs, so that it could be used for truncation
 and continuation glyphs alike.
 (produce_special_glyphs) [HAVE_WINDOW_SYSTEM]: Produce a stretch
 glyph of a suitably computed width, to align the special glyphs at
 the window margin.  Code moved from display_line.

2 files changed, 62 insertions, 39 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 14428f427d5..4d4f7e006fc 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,17 @@
+2012-07-12  Eli Zaretskii  <eliz@gnu.org>
+
+        * xdisp.c (insert_left_trunc_glyphs): Fix incorrect size in
+        memmove call that removes glyphs covered by the left truncation
+        glyph.  Improve commentary.
+        (display_line): Fix display of continuation glyphs on GUI frames
+        when the right fringe is turned off and variable-size fonts are
+        used in the window.  Move the code that appends a stretch glyph to
+        produce_special_glyphs, so that it could be used for truncation
+        and continuation glyphs alike.
+        (produce_special_glyphs) [HAVE_WINDOW_SYSTEM]: Produce a stretch
+        glyph of a suitably computed width, to align the special glyphs at
+        the window margin.  Code moved from display_line.  (Bug#11832)
+
 2012-07-12  Glenn Morris  <rgm@gnu.org>
 
         * s/gnu-linux.h (UNIX98_PTYS): Let configure set it.
diff --git a/src/xdisp.c b/src/xdisp.c
index 6af0dd6e8a3..a03de37dba9 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -18257,13 +18257,12 @@ insert_left_trunc_glyphs (struct it *it)
           struct glyph *g = to;
           short used;
 
-          while (g < toend && it->glyph_row->x + w < 0)
-            {
-              w += g->pixel_width;
-              ++g;
-            }
+          /* The first glyph could be partially visible, in which case
+             it->glyph_row->x will be negative.  But we want the left
+             truncation glyphs to be aligned at the left margin of the
+             window, so we override the x coordinate at which the row
+             will begin.  */
           it->glyph_row->x = 0;
-          w = 0;
           while (g < toend && w < it->truncation_pixel_width)
             {
               w += g->pixel_width;
@@ -18271,7 +18270,7 @@ insert_left_trunc_glyphs (struct it *it)
             }
           if (g - to - tused > 0)
             {
-              memmove (to + tused, g, toend - g);
+              memmove (to + tused, g, (toend - g) * sizeof(*g));
               it->glyph_row->used[TEXT_AREA] -= g - to - tused;
             }
           used = it->glyph_row->used[TEXT_AREA];
@@ -19616,6 +19615,8 @@ display_line (struct it *it)
                       row->used[TEXT_AREA] = n_glyphs_before + i;
 
                       /* Display continuation glyphs.  */
+                      it->current_x = x_before;
+                      it->continuation_lines_width += x;
                       if (!FRAME_WINDOW_P (it->f)
                           || (row->reversed_p
                               ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
@@ -19623,8 +19624,6 @@ display_line (struct it *it)
                         produce_special_glyphs (it, IT_CONTINUATION);
                       row->continued_p = 1;
 
-                      it->current_x = x_before;
-                      it->continuation_lines_width += x;
                       extend_face_to_end_of_line (it);
 
                       if (nglyphs > 1 && i > 0)
@@ -19768,38 +19767,11 @@ display_line (struct it *it)
                       produce_special_glyphs (it, IT_TRUNCATION);
                     }
                 }
-#ifdef HAVE_WINDOW_SYSTEM
               else
                 {
-                  /* On a GUI frame, when the right fringe (left
-                     fringe for R2L rows) is turned off, we produce
-                     truncation glyphs preceded by a stretch glyph
-                     whose width is computed such that the truncation
-                     glyphs are aligned at the window margin, even
-                     when very different fonts are used in different
-                     glyph rows.  */
-                  int stretch_width = it->last_visible_x - it->current_x;
-
                   row->used[TEXT_AREA] = i;
-                  if (stretch_width > 0)
-                    {
-                      struct face *face = FACE_FROM_ID (it->f, it->face_id);
-                      struct font *font =
-                        face->font ? face->font : FRAME_FONT (it->f);
-                      int stretch_ascent =
-                        (((it->ascent + it->descent)
-                          * FONT_BASE (font)) / FONT_HEIGHT (font));
-                      struct text_pos saved_pos = it->position;
-
-                      memset (&it->position, 0, sizeof it->position);
-                      append_stretch_glyph (it, make_number (0), stretch_width,
-                                            it->ascent + it->descent,
-                                            stretch_ascent);
-                      it->position = saved_pos;
-                    }
                   produce_special_glyphs (it, IT_TRUNCATION);
                 }
-#endif
             }
           else if (IT_OVERFLOW_NEWLINE_INTO_FRINGE (it))
             {
@@ -24215,9 +24187,6 @@ produce_special_glyphs (struct it *it, enum display_element_type what)
   GLYPH glyph;
 
   temp_it = *it;
-  temp_it.dp = NULL;
-  temp_it.what = IT_CHARACTER;
-  temp_it.len = 1;
   temp_it.object = make_number (0);
   memset (&temp_it.current, 0, sizeof temp_it.current);
 
@@ -24251,6 +24220,46 @@ produce_special_glyphs (struct it *it, enum display_element_type what)
   else
     abort ();
 
+#ifdef HAVE_WINDOW_SYSTEM
+  /* On a GUI frame, when the right fringe (left fringe for R2L rows)
+     is turned off, we precede the truncation/continuation glyphs by a
+     stretch glyph whose width is computed such that these special
+     glyphs are aligned at the window margin, even when very different
+     fonts are used in different glyph rows.  */
+  if (FRAME_WINDOW_P (temp_it.f)
+      /* init_iterator calls this with it->glyph_row == NULL, and it
+         wants only the pixel width of the truncation/continuation
+         glyphs.  */
+      && temp_it.glyph_row
+      /* insert_left_trunc_glyphs calls us at the beginning of the
+         row, and it has its own calculation of the stretch glyph
+         width.  */
+      && temp_it.glyph_row->used[TEXT_AREA] > 0
+      && (temp_it.glyph_row->reversed_p
+          ? WINDOW_LEFT_FRINGE_WIDTH (temp_it.w)
+          : WINDOW_RIGHT_FRINGE_WIDTH (temp_it.w)) == 0)
+    {
+      int stretch_width = temp_it.last_visible_x - temp_it.current_x;
+
+      if (stretch_width > 0)
+        {
+          struct face *face = FACE_FROM_ID (temp_it.f, temp_it.face_id);
+          struct font *font =
+            face->font ? face->font : FRAME_FONT (temp_it.f);
+          int stretch_ascent =
+            (((temp_it.ascent + temp_it.descent)
+              * FONT_BASE (font)) / FONT_HEIGHT (font));
+
+          append_stretch_glyph (&temp_it, make_number (0), stretch_width,
+                                temp_it.ascent + temp_it.descent,
+                                stretch_ascent);
+        }
+    }
+#endif
+
+  temp_it.dp = NULL;
+  temp_it.what = IT_CHARACTER;
+  temp_it.len = 1;
   temp_it.c = temp_it.char_to_display = GLYPH_CHAR (glyph);
   temp_it.face_id = GLYPH_FACE (glyph);
   temp_it.len = CHAR_BYTES (temp_it.c);