Fix bug #11832 with truncated lines when fringes are disabled on GUI frames.

 src/xdisp.c (init_iterator): Get dimensions of truncation and
 continuation glyphs even if on GUI frames.  Adjust
 it->last_visible_x on GUI frames when the left or right fringes,
 or both, are absent.
 (start_display, move_it_in_display_line_to): Handle the case of a
 GUI frame without a fringe to display continuation or truncation
 glyphs.
 (insert_left_trunc_glyphs): Support GUI frames: make sure
 truncation glyphs overwrite enough glyphs from the current line to
 have sufficient space in pixels.
 (display_line): Support truncation and continuation glyphs on GUI
 frames.  If some spare pixels are left on the line after inserting
 the truncation glyphs, fill that space with a stretch glyph of a
 suitably computed width.
 src/term.c (produce_special_glyphs): Call PRODUCE_GLYPHS, not
 produce_glyphs, to support GUI sessions.

3 files changed, 208 insertions, 55 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 9b76d795249..5eeace9beaf 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,25 @@
+2012-07-07  Eli Zaretskii  <eliz@gnu.org>
+
+        Support truncation and continuation glyphs on GUI frames, when
+        fringes are disabled.  (Bug#11832)
+        * xdisp.c (init_iterator): Get dimensions of truncation and
+        continuation glyphs even if on GUI frames.  Adjust
+        it->last_visible_x on GUI frames when the left or right fringes,
+        or both, are absent.
+        (start_display, move_it_in_display_line_to): Handle the case of a
+        GUI frame without a fringe to display continuation or truncation
+        glyphs.
+        (insert_left_trunc_glyphs): Support GUI frames: make sure
+        truncation glyphs overwrite enough glyphs from the current line to
+        have sufficient space in pixels.
+        (display_line): Support truncation and continuation glyphs on GUI
+        frames.  If some spare pixels are left on the line after inserting
+        the truncation glyphs, fill that space with a stretch glyph of a
+        suitably computed width.
+
+        * term.c (produce_special_glyphs): Call PRODUCE_GLYPHS, not
+        produce_glyphs, to support GUI sessions.
+
 2012-07-07  Paul Eggert  <eggert@cs.ucla.edu>
 
         * sysdep.c (ULLONG_MAX): Define if not already defined (Bug#11781).
diff --git a/src/term.c b/src/term.c
index 5e48cbbfc64..900818559cd 100644
--- a/src/term.c
+++ b/src/term.c
@@ -1940,7 +1940,7 @@ produce_special_glyphs (struct it *it, enum display_element_type what)
   temp_it.face_id = GLYPH_FACE (glyph);
   temp_it.len = CHAR_BYTES (temp_it.c);
 
-  produce_glyphs (&temp_it);
+  PRODUCE_GLYPHS (&temp_it);
   it->pixel_width = temp_it.pixel_width;
   it->nglyphs = temp_it.pixel_width;
 }
diff --git a/src/xdisp.c b/src/xdisp.c
index 0684a68444e..87f2e365198 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2731,31 +2731,28 @@ init_iterator (struct it *it, struct window *w,
     it->line_wrap = TRUNCATE;
 
   /* Get dimensions of truncation and continuation glyphs.  These are
-     displayed as fringe bitmaps under X, so we don't need them for such
-     frames.  */
-  if (!FRAME_WINDOW_P (it->f))
+     displayed as fringe bitmaps under X, but we need them for such
+     frames when the fringes are turned off.  */
+  if (it->line_wrap == TRUNCATE)
     {
-      if (it->line_wrap == TRUNCATE)
-        {
-          /* We will need the truncation glyph.  */
-          eassert (it->glyph_row == NULL);
-          produce_special_glyphs (it, IT_TRUNCATION);
-          it->truncation_pixel_width = it->pixel_width;
-        }
-      else
-        {
-          /* We will need the continuation glyph.  */
-          eassert (it->glyph_row == NULL);
-          produce_special_glyphs (it, IT_CONTINUATION);
-          it->continuation_pixel_width = it->pixel_width;
-        }
-
-      /* Reset these values to zero because the produce_special_glyphs
-         above has changed them.  */
-      it->pixel_width = it->ascent = it->descent = 0;
-      it->phys_ascent = it->phys_descent = 0;
+      /* We will need the truncation glyph.  */
+      eassert (it->glyph_row == NULL);
+      produce_special_glyphs (it, IT_TRUNCATION);
+      it->truncation_pixel_width = it->pixel_width;
+    }
+  else
+    {
+      /* We will need the continuation glyph.  */
+      eassert (it->glyph_row == NULL);
+      produce_special_glyphs (it, IT_CONTINUATION);
+      it->continuation_pixel_width = it->pixel_width;
     }
 
+  /* Reset these values to zero because the produce_special_glyphs
+     above has changed them.  */
+  it->pixel_width = it->ascent = it->descent = 0;
+  it->phys_ascent = it->phys_descent = 0;
+
   /* Set this after getting the dimensions of truncation and
      continuation glyphs, so that we don't produce glyphs when calling
      produce_special_glyphs, above.  */
@@ -2783,11 +2780,14 @@ init_iterator (struct it *it, struct window *w,
       it->last_visible_x = (it->first_visible_x
                             + window_box_width (w, TEXT_AREA));
 
-      /* If we truncate lines, leave room for the truncator glyph(s) at
+      /* If we truncate lines, leave room for the truncation glyph(s) at
          the right margin.  Otherwise, leave room for the continuation
-         glyph(s).  Truncation and continuation glyphs are not inserted
-         for window-based redisplay.  */
-      if (!FRAME_WINDOW_P (it->f))
+         glyph(s).  Done only if the window has no fringes.  Since we
+         don't know at this point whether there will be any R2L lines in
+         the window, we reserve space for truncation/continuation glyphs
+         even if only one of the fringes is absent.  */
+      if (WINDOW_RIGHT_FRINGE_WIDTH (it->w) == 0
+          || (it->bidi_p && WINDOW_LEFT_FRINGE_WIDTH (it->w) == 0))
         {
           if (it->line_wrap == TRUNCATE)
             it->last_visible_x -= it->truncation_pixel_width;
@@ -2923,7 +2923,10 @@ start_display (struct it *it, struct window *w, struct text_pos pos)
                   /* Or it fits exactly and we're on a window
                      system frame.  */
                   || (new_x == it->last_visible_x
-                      && FRAME_WINDOW_P (it->f))))
+                      && FRAME_WINDOW_P (it->f)
+                      && ((it->bidi_p && it->bidi_it.paragraph_dir == R2L)
+                          ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
+                          : WINDOW_RIGHT_FRINGE_WIDTH (it->w)))))
             {
               if ((it->current.dpvec_index >= 0
                    || it->current.overlay_string_index >= 0)
@@ -8327,7 +8330,10 @@ move_it_in_display_line_to (struct it *it,
                       /* Or it fits exactly and we're on a window
                          system frame.  */
                       || (new_x == it->last_visible_x
-                          && FRAME_WINDOW_P (it->f))))
+                          && FRAME_WINDOW_P (it->f)
+                          && ((it->bidi_p && it->bidi_it.paragraph_dir == R2L)
+                              ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
+                              : WINDOW_RIGHT_FRINGE_WIDTH (it->w)))))
                 {
                   if (/* IT->hpos == 0 means the very first glyph
                          doesn't fit on the line, e.g. a wide image.  */
@@ -8509,6 +8515,9 @@ move_it_in_display_line_to (struct it *it,
           && it->current_x >= it->last_visible_x)
         {
           if (!FRAME_WINDOW_P (it->f)
+              || ((it->bidi_p && it->bidi_it.paragraph_dir == R2L)
+                  ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
+                  : WINDOW_RIGHT_FRINGE_WIDTH (it->w))
               || IT_OVERFLOW_NEWLINE_INTO_FRINGE (it))
             {
               int at_eob_p = 0;
@@ -18203,11 +18212,8 @@ get_overlay_arrow_glyph_row (struct window *w, Lisp_Object overlay_arrow_string)
 }
 
 
-/* Insert truncation glyphs at the start of IT->glyph_row.  Truncation
-   glyphs are only inserted for terminal frames since we can't really
-   win with truncation glyphs when partially visible glyphs are
-   involved.  Which glyphs to insert is determined by
-   produce_special_glyphs.  */
+/* Insert truncation glyphs at the start of IT->glyph_row.  Which
+   glyphs to insert is determined by produce_special_glyphs.  */
 
 static void
 insert_left_trunc_glyphs (struct it *it)
@@ -18215,7 +18221,11 @@ insert_left_trunc_glyphs (struct it *it)
   struct it truncate_it;
   struct glyph *from, *end, *to, *toend;
 
-  eassert (!FRAME_WINDOW_P (it->f));
+  eassert (!FRAME_WINDOW_P (it->f)
+           || (!it->glyph_row->reversed_p
+               && WINDOW_LEFT_FRINGE_WIDTH (it->w) == 0)
+           || (it->glyph_row->reversed_p
+               && WINDOW_RIGHT_FRINGE_WIDTH (it->w) == 0));
 
   /* Get the truncation glyphs.  */
   truncate_it = *it;
@@ -18230,20 +18240,66 @@ insert_left_trunc_glyphs (struct it *it)
   /* Overwrite glyphs from IT with truncation glyphs.  */
   if (!it->glyph_row->reversed_p)
     {
+      short tused = truncate_it.glyph_row->used[TEXT_AREA];
+
       from = truncate_it.glyph_row->glyphs[TEXT_AREA];
-      end = from + truncate_it.glyph_row->used[TEXT_AREA];
+      end = from + tused;
       to = it->glyph_row->glyphs[TEXT_AREA];
       toend = to + it->glyph_row->used[TEXT_AREA];
+      if (FRAME_WINDOW_P (it->f))
+        {
+          /* On GUI frames, when variable-size fonts are displayed,
+             the truncation glyphs may need more pixels than the row's
+             glyphs they overwrite.  We overwrite more glyphs to free
+             enough screen real estate, and enlarge the stretch glyph
+             on the right (see display_line), if there is one, to
+             preserve the screen position of the truncation glyphs on
+             the right.  */
+          int w = 0;
+          struct glyph *g = to;
+          short used;
+
+          while (g < toend && it->glyph_row->x + w < 0)
+            {
+              w += g->pixel_width;
+              ++g;
+            }
+          it->glyph_row->x = 0;
+          w = 0;
+          while (g < toend && w < it->truncation_pixel_width)
+            {
+              w += g->pixel_width;
+              ++g;
+            }
+          if (g - to - tused > 0)
+            {
+              memmove (to + tused, g, toend - g);
+              it->glyph_row->used[TEXT_AREA] -= g - to - tused;
+            }
+          used = it->glyph_row->used[TEXT_AREA];
+          if (it->glyph_row->truncated_on_right_p
+              && WINDOW_RIGHT_FRINGE_WIDTH (it->w) == 0
+              && it->glyph_row->glyphs[TEXT_AREA][used - 2].type
+              == STRETCH_GLYPH)
+            {
+              int extra = w - it->truncation_pixel_width;
+
+              it->glyph_row->glyphs[TEXT_AREA][used - 2].pixel_width += extra;
+            }
+        }
 
       while (from < end)
         *to++ = *from++;
 
       /* There may be padding glyphs left over.  Overwrite them too.  */
-      while (to < toend && CHAR_GLYPH_PADDING_P (*to))
+      if (!FRAME_WINDOW_P (it->f))
         {
-          from = truncate_it.glyph_row->glyphs[TEXT_AREA];
-          while (from < end)
-            *to++ = *from++;
+          while (to < toend && CHAR_GLYPH_PADDING_P (*to))
+            {
+              from = truncate_it.glyph_row->glyphs[TEXT_AREA];
+              while (from < end)
+                *to++ = *from++;
+            }
         }
 
       if (to > toend)
@@ -18251,22 +18307,48 @@ insert_left_trunc_glyphs (struct it *it)
     }
   else
     {
+      short tused = truncate_it.glyph_row->used[TEXT_AREA];
+
       /* In R2L rows, overwrite the last (rightmost) glyphs, and do
          that back to front.  */
       end = truncate_it.glyph_row->glyphs[TEXT_AREA];
       from = end + truncate_it.glyph_row->used[TEXT_AREA] - 1;
       toend = it->glyph_row->glyphs[TEXT_AREA];
       to = toend + it->glyph_row->used[TEXT_AREA] - 1;
+      if (FRAME_WINDOW_P (it->f))
+        {
+          int w = 0;
+          struct glyph *g = to;
+
+          while (g >= toend && w < it->truncation_pixel_width)
+            {
+              w += g->pixel_width;
+              --g;
+            }
+          if (to - g - tused > 0)
+            to = g + tused;
+          if (it->glyph_row->truncated_on_right_p
+              && WINDOW_LEFT_FRINGE_WIDTH (it->w) == 0
+              && it->glyph_row->glyphs[TEXT_AREA][1].type == STRETCH_GLYPH)
+            {
+              int extra = w - it->truncation_pixel_width;
+
+              it->glyph_row->glyphs[TEXT_AREA][1].pixel_width += extra;
+            }
+        }
 
       while (from >= end && to >= toend)
         *to-- = *from--;
-      while (to >= toend && CHAR_GLYPH_PADDING_P (*to))
+      if (!FRAME_WINDOW_P (it->f))
         {
-          from =
-            truncate_it.glyph_row->glyphs[TEXT_AREA]
-            + truncate_it.glyph_row->used[TEXT_AREA] - 1;
-          while (from >= end && to >= toend)
-            *to-- = *from--;
+          while (to >= toend && CHAR_GLYPH_PADDING_P (*to))
+            {
+              from =
+                truncate_it.glyph_row->glyphs[TEXT_AREA]
+                + truncate_it.glyph_row->used[TEXT_AREA] - 1;
+              while (from >= end && to >= toend)
+                *to-- = *from--;
+            }
         }
       if (from >= end)
         {
@@ -19392,13 +19474,19 @@ display_line (struct it *it)
                       new_x > it->last_visible_x
                       /* Or it fits exactly on a window system frame.  */
                       || (new_x == it->last_visible_x
-                          && FRAME_WINDOW_P (it->f))))
+                          && FRAME_WINDOW_P (it->f)
+                          && (row->reversed_p
+                              ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
+                              : WINDOW_RIGHT_FRINGE_WIDTH (it->w)))))
                 {
                   /* End of a continued line.  */
 
                   if (it->hpos == 0
                       || (new_x == it->last_visible_x
-                          && FRAME_WINDOW_P (it->f)))
+                          && FRAME_WINDOW_P (it->f)
+                          && (row->reversed_p
+                              ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
+                              : WINDOW_RIGHT_FRINGE_WIDTH (it->w))))
                     {
                       /* Current glyph is the only one on the line or
                          fits exactly on the line.  We must continue
@@ -19509,6 +19597,10 @@ display_line (struct it *it)
                          window system frames.  We leave the glyph in
                          this row and let it fill the row, but don't
                          consume the TAB.  */
+                      if ((row->reversed_p
+                           ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
+                           : WINDOW_RIGHT_FRINGE_WIDTH (it->w)) == 0)
+                        produce_special_glyphs (it, IT_CONTINUATION);
                       it->continuation_lines_width += it->last_visible_x;
                       row->ends_in_middle_of_char_p = 1;
                       row->continued_p = 1;
@@ -19526,7 +19618,10 @@ display_line (struct it *it)
                       row->used[TEXT_AREA] = n_glyphs_before + i;
 
                       /* Display continuation glyphs.  */
-                      if (!FRAME_WINDOW_P (it->f))
+                      if (!FRAME_WINDOW_P (it->f)
+                          || (row->reversed_p
+                              ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
+                              : WINDOW_RIGHT_FRINGE_WIDTH (it->w)) == 0)
                         produce_special_glyphs (it, IT_CONTINUATION);
                       row->continued_p = 1;
 
@@ -19633,12 +19728,15 @@ display_line (struct it *it)
       /* If we truncate lines, we are done when the last displayed
          glyphs reach past the right margin of the window.  */
       if (it->line_wrap == TRUNCATE
-          && (FRAME_WINDOW_P (it->f)
+          && (FRAME_WINDOW_P (it->f) && WINDOW_RIGHT_FRINGE_WIDTH (it->w)
               ? (it->current_x >= it->last_visible_x)
               : (it->current_x > it->last_visible_x)))
         {
           /* Maybe add truncation glyphs.  */
-          if (!FRAME_WINDOW_P (it->f))
+          if (!FRAME_WINDOW_P (it->f)
+              || (row->reversed_p
+                  ? WINDOW_LEFT_FRINGE_WIDTH (it->w)
+                  : WINDOW_RIGHT_FRINGE_WIDTH (it->w)) == 0)
             {
               int i, n;
 
@@ -19663,9 +19761,36 @@ display_line (struct it *it)
                   i = row->used[TEXT_AREA] - (i + 1);
                 }
 
-              for (n = row->used[TEXT_AREA]; i < n; ++i)
+              it->current_x = x_before;
+              if (!FRAME_WINDOW_P (it->f))
+                {
+                  for (n = row->used[TEXT_AREA]; i < n; ++i)
+                    {
+                      row->used[TEXT_AREA] = i;
+                      produce_special_glyphs (it, IT_TRUNCATION);
+                    }
+                }
+              else
                 {
+                  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);
                 }
             }
@@ -19684,6 +19809,7 @@ display_line (struct it *it)
                   row->exact_window_width_line_p = 1;
                   goto at_end_of_line;
                 }
+              it->current_x = x_before;
             }
 
           row->truncated_on_right_p = 1;
@@ -19691,7 +19817,6 @@ display_line (struct it *it)
           reseat_at_next_visible_line_start (it, 0);
           row->ends_at_zv_p = FETCH_BYTE (IT_BYTEPOS (*it) - 1) != '\n';
           it->hpos = hpos_before;
-          it->current_x = x_before;
           break;
         }
     }
@@ -19704,7 +19829,10 @@ display_line (struct it *it)
   if (it->first_visible_x
       && IT_CHARPOS (*it) != CHARPOS (row->start.pos))
     {
-      if (!FRAME_WINDOW_P (it->f))
+      if (!FRAME_WINDOW_P (it->f)
+          || (row->reversed_p
+              ? WINDOW_RIGHT_FRINGE_WIDTH (it->w)
+              : WINDOW_LEFT_FRINGE_WIDTH (it->w)) == 0)
         insert_left_trunc_glyphs (it);
       row->truncated_on_left_p = 1;
     }
@@ -21913,7 +22041,10 @@ display_string (const char *string, Lisp_Object lisp_string, Lisp_Object face_st
   if (it->first_visible_x
       && it_charpos > 0)
     {
-      if (!FRAME_WINDOW_P (it->f))
+      if (!FRAME_WINDOW_P (it->f)
+          || (row->reversed_p
+              ? WINDOW_RIGHT_FRINGE_WIDTH (it->w)
+              : WINDOW_LEFT_FRINGE_WIDTH (it->w)) == 0)
         insert_left_trunc_glyphs (it);
       row->truncated_on_left_p = 1;
     }