(Vtruncate_partial_width_windows): New Lisp_Object, replacing

truncate_partial_width_windows.
(init_iterator): If Vtruncate_partial_width_windows is an integer,
truncate only if the window width is below that integer.
(start_display. resize_mini_window, produce_stretch_glyph)
(display_string, move_it_in_display_line_to): Use line_wrap.
(back_to_previous_visible_line_start, reseat_1): Reset
string_from_display_prop_p.
(display_line): Extend default face to end of line when wrapping.
(display_line, move_it_in_display_line_to): Add ability
to wrap continued lines at word boundaries.

1 files changed, 198 insertions, 55 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 18f176e2c06..eefccefc05e 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -420,7 +420,7 @@ static struct buffer *this_line_buffer;
 /* Nonzero means truncate lines in all windows less wide than the
    frame.  */
 
-int truncate_partial_width_windows;
+Lisp_Object Vtruncate_partial_width_windows;
 
 /* A flag to control how to display unibyte 8-bit character.  */
 
@@ -2634,19 +2634,27 @@ init_iterator (it, w, charpos, bytepos, row, base_face_id)
     it->tab_width = 8;
 
   /* Are lines in the display truncated?  */
-  it->truncate_lines_p
-    = (base_face_id != DEFAULT_FACE_ID
-       || XINT (it->w->hscroll)
-       || (truncate_partial_width_windows
-           && !WINDOW_FULL_WIDTH_P (it->w))
-       || !NILP (current_buffer->truncate_lines));
+  if (base_face_id != DEFAULT_FACE_ID
+      || XINT (it->w->hscroll)
+      || (! WINDOW_FULL_WIDTH_P (it->w)
+          && ((!NILP (Vtruncate_partial_width_windows)
+               && !INTEGERP (Vtruncate_partial_width_windows))
+              || (INTEGERP (Vtruncate_partial_width_windows)
+                  && (WINDOW_TOTAL_COLS (it->w)
+                      < XINT (Vtruncate_partial_width_windows))))))
+    it->line_wrap = TRUNCATE;
+  else if (NILP (current_buffer->truncate_lines))
+    it->line_wrap = NILP (current_buffer->word_wrap)
+      ? WINDOW_WRAP : WORD_WRAP;
+  else
+    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))
     {
-      if (it->truncate_lines_p)
+      if (it->line_wrap == TRUNCATE)
         {
           /* We will need the truncation glyph.  */
           xassert (it->glyph_row == NULL);
@@ -2696,7 +2704,7 @@ init_iterator (it, w, charpos, bytepos, row, base_face_id)
          for window-based redisplay.  */
       if (!FRAME_WINDOW_P (it->f))
         {
-          if (it->truncate_lines_p)
+          if (it->line_wrap == TRUNCATE)
             it->last_visible_x -= it->truncation_pixel_width;
           else
             it->last_visible_x -= it->continuation_pixel_width;
@@ -2769,7 +2777,7 @@ start_display (it, w, pos)
 
   /* Don't reseat to previous visible line start if current start
      position is in a string or image.  */
-  if (it->method == GET_FROM_BUFFER && !it->truncate_lines_p)
+  if (it->method == GET_FROM_BUFFER && it->line_wrap != TRUNCATE)
     {
       int start_at_line_beg_p;
       int first_y = it->current_y;
@@ -2794,7 +2802,7 @@ start_display (it, w, pos)
              taken us to the start of the continuation line but to the
              end of the continued line.  */
           if (it->current_x > 0
-              && !it->truncate_lines_p /* Lines are continued.  */
+              && it->line_wrap != TRUNCATE /* Lines are continued.  */
               && (/* And glyph doesn't fit on the line.  */
                   new_x > it->last_visible_x
                   /* Or it fits exactly and we're on a window
@@ -5432,6 +5440,7 @@ back_to_previous_visible_line_start (it)
         pos = --IT_CHARPOS (it2);
         --IT_BYTEPOS (it2);
         it2.sp = 0;
+        it2.string_from_display_prop_p = 0;
         if (handle_display_prop (&it2) == HANDLED_RETURN
             && !NILP (val = get_char_property_and_overlay
                       (make_number (pos), Qdisplay, Qnil, &overlay))
@@ -5582,6 +5591,7 @@ reseat_1 (it, pos, set_stop_p)
   IT_STRING_CHARPOS (*it) = -1;
   IT_STRING_BYTEPOS (*it) = -1;
   it->string = Qnil;
+  it->string_from_display_prop_p = 0;
   it->method = GET_FROM_BUFFER;
   it->object = it->w->buffer;
   it->area = TEXT_AREA;
@@ -6643,11 +6653,20 @@ move_it_in_display_line_to (struct it *it,
 {
   enum move_it_result result = MOVE_UNDEFINED;
   struct glyph_row *saved_glyph_row;
+  struct it wrap_it, atpos_it;
+  int may_wrap = 0;
 
   /* Don't produce glyphs in produce_glyphs.  */
   saved_glyph_row = it->glyph_row;
   it->glyph_row = NULL;
 
+  /* Use wrap_it to save a copy of IT wherever a word wrap could
+     occur.  Use atpos_it to save a copy of IT at the desired
+     position, if found, so that we can scan ahead and check if the
+     word later overshoots the window edge.  */
+  wrap_it.sp = -1;
+  atpos_it.sp = -1;
+
 #define BUFFER_POS_REACHED_P()                                  \
   ((op & MOVE_TO_POS) != 0                                      \
    && BUFFERP (it->object)                                      \
@@ -6667,36 +6686,77 @@ move_it_in_display_line_to (struct it *it,
           && it->method == GET_FROM_BUFFER
           && IT_CHARPOS (*it) > to_charpos)
         {
-          result = MOVE_POS_MATCH_OR_ZV;
-          break;
+          if (it->line_wrap == WORD_WRAP)
+            {
+              /* If wrap_it is valid, the current position might be in
+                 a word that is wrapped to the next line, so continue
+                 to see if that happens.  */
+              if (wrap_it.sp < 0)
+                {
+                  result = MOVE_POS_MATCH_OR_ZV;
+                  break;
+                }
+              if (atpos_it.sp < 0)
+                atpos_it = *it;
+            }
+          else
+            {
+              result = MOVE_POS_MATCH_OR_ZV;
+              break;
+            }
         }
 
       /* Stop when ZV reached.
          We used to stop here when TO_CHARPOS reached as well, but that is
          too soon if this glyph does not fit on this line.  So we handle it
          explicitly below.  */
-      if (!get_next_display_element (it)
-          || (it->truncate_lines_p
-              && BUFFER_POS_REACHED_P ()))
+      if (!get_next_display_element (it))
         {
           result = MOVE_POS_MATCH_OR_ZV;
           break;
         }
 
-      /* The call to produce_glyphs will get the metrics of the
-         display element IT is loaded with.  We record in x the
-         x-position before this display element in case it does not
-         fit on the line.  */
-      x = it->current_x;
-
-      /* Remember the line height so far in case the next element doesn't
-         fit on the line.  */
-      if (!it->truncate_lines_p)
+      if (it->line_wrap == TRUNCATE)
+        {
+          if (BUFFER_POS_REACHED_P ())
+            {
+              result = MOVE_POS_MATCH_OR_ZV;
+              break;
+            }
+        }
+      else
         {
+          /* Remember the line height so far in case the next element
+             doesn't fit on the line.  */
           ascent = it->max_ascent;
           descent = it->max_descent;
+
+          if (it->line_wrap == WORD_WRAP)
+            {
+              if (it->what == IT_CHARACTER
+                  && (it->c == ' ' || it->c == '\t'))
+                may_wrap = 1;
+              else if (may_wrap)
+                {
+                  /* We are done if the position is already found.  */
+                  if (atpos_it.sp >= 0)
+                    {
+                      *it = atpos_it;
+                      atpos_it.sp = -1;
+                      goto buffer_pos_reached;
+                    }
+                  wrap_it = *it;
+                  may_wrap = 0;
+                }
+            }
         }
 
+      /* The call to produce_glyphs will get the metrics of the
+         display element IT is loaded with.  Record the x-position
+         before this display element, in case it doesn't fit on the
+         line.  */
+      x = it->current_x;
+
       PRODUCE_GLYPHS (it);
 
       if (it->area != TEXT_AREA)
@@ -6740,19 +6800,30 @@ move_it_in_display_line_to (struct it *it,
               if ((op & MOVE_TO_X) && new_x > to_x)
                 {
                   if (BUFFER_POS_REACHED_P ())
-                    goto buffer_pos_reached;
+                    {
+                      if (it->line_wrap == WORD_WRAP)
+                        {
+                          if (wrap_it.sp < 0)
+                            goto buffer_pos_reached;
+                          if (atpos_it.sp < 0)
+                            atpos_it = *it;
+                        }
+                      else
+                        goto buffer_pos_reached;
+                    }
                   it->current_x = x;
                   result = MOVE_X_REACHED;
                   break;
                 }
-              else if (/* Lines are continued.  */
-                       !it->truncate_lines_p
-                       && (/* And glyph doesn't fit on the line.  */
-                           new_x > it->last_visible_x
-                           /* Or it fits exactly and we're on a window
-                              system frame.  */
-                           || (new_x == it->last_visible_x
-                               && FRAME_WINDOW_P (it->f))))
+
+              if (/* Lines are continued.  */
+                  it->line_wrap != TRUNCATE
+                  && (/* And glyph doesn't fit on the line.  */
+                      new_x > it->last_visible_x
+                      /* Or it fits exactly and we're on a window
+                         system frame.  */
+                      || (new_x == it->last_visible_x
+                          && FRAME_WINDOW_P (it->f))))
                 {
                   if (/* IT->hpos == 0 means the very first glyph
                          doesn't fit on the line, e.g. a wide image.  */
@@ -6811,24 +6882,37 @@ move_it_in_display_line_to (struct it *it,
                       it->max_descent = descent;
                     }
 
+                  if (wrap_it.sp >= 0)
+                    {
+                      *it = wrap_it;
+                      atpos_it.sp = -1;
+                    }
+
                   TRACE_MOVE ((stderr, "move_it_in: continued at %d\n",
                                IT_CHARPOS (*it)));
                   result = MOVE_LINE_CONTINUED;
                   break;
                 }
-              else if (BUFFER_POS_REACHED_P ())
-                goto buffer_pos_reached;
-              else if (new_x > it->first_visible_x)
+
+              if (BUFFER_POS_REACHED_P ())
+                {
+                  if (it->line_wrap == WORD_WRAP)
+                    {
+                      if (wrap_it.sp < 0)
+                        goto buffer_pos_reached;
+                      if (atpos_it.sp < 0)
+                        atpos_it = *it;
+                    }
+                  else
+                    goto buffer_pos_reached;
+                }
+
+              if (new_x > it->first_visible_x)
                 {
                   /* Glyph is visible.  Increment number of glyphs that
                      would be displayed.  */
                   ++it->hpos;
                 }
-              else
-                {
-                  /* Glyph is completely off the left margin of the display
-                     area.  Nothing to do.  */
-                }
             }
 
           if (result != MOVE_UNDEFINED)
@@ -6867,7 +6951,7 @@ move_it_in_display_line_to (struct it *it,
 
       /* Stop if lines are truncated and IT's current x-position is
          past the right edge of the window now.  */
-      if (it->truncate_lines_p
+      if (it->line_wrap == TRUNCATE
           && it->current_x >= it->last_visible_x)
         {
 #ifdef HAVE_WINDOW_SYSTEM
@@ -6893,6 +6977,11 @@ move_it_in_display_line_to (struct it *it,
 
 #undef BUFFER_POS_REACHED_P
 
+  /* If we scanned beyond to_pos and didn't find a point to wrap at,
+     return iterator at to_pos.  */
+  if (atpos_it.sp >= 0)
+    *it = atpos_it;
+
   /* Restore the iterator settings altered at the beginning of this
      function.  */
   it->glyph_row = saved_glyph_row;
@@ -8555,7 +8644,7 @@ resize_mini_window (w, exact_p)
       max_height = min (total_height, max_height);
 
       /* Find out the height of the text in the window.  */
-      if (it.truncate_lines_p)
+      if (it.line_wrap == TRUNCATE)
         height = 1;
       else
         {
@@ -15997,7 +16086,8 @@ extend_face_to_end_of_line (it)
       && it->glyph_row->displays_text_p
       && face->box == FACE_NO_BOX
       && face->background == FRAME_BACKGROUND_PIXEL (f)
-      && !face->stipple)
+      && !face->stipple
+      && it->line_wrap != WORD_WRAP)
     return;
 
   /* Set the glyph row flag indicating that the face of the last glyph
@@ -16212,6 +16302,11 @@ display_line (it)
 {
   struct glyph_row *row = it->glyph_row;
   Lisp_Object overlay_arrow_string;
+  struct it wrap_it;
+  int may_wrap = 0, wrap_x;
+  int wrap_row_used = -1, wrap_row_ascent, wrap_row_height;
+  int wrap_row_phys_ascent, wrap_row_phys_height;
+  int wrap_row_extra_line_spacing;
 
   /* We always start displaying at hpos zero even if hscrolled.  */
   xassert (it->hpos == 0 && it->current_x == 0);
@@ -16306,12 +16401,31 @@ display_line (it)
 
       /* Remember the line height so far in case the next element doesn't
          fit on the line.  */
-      if (!it->truncate_lines_p)
+      if (it->line_wrap != TRUNCATE)
         {
           ascent = it->max_ascent;
           descent = it->max_descent;
           phys_ascent = it->max_phys_ascent;
           phys_descent = it->max_phys_descent;
+
+          if (it->line_wrap == WORD_WRAP && it->area == TEXT_AREA)
+            {
+              if (it->what == IT_CHARACTER
+                  && (it->c == ' ' || it->c == '\t'))
+                may_wrap = 1;
+              else if (may_wrap)
+                {
+                  wrap_it = *it;
+                  wrap_x = x;
+                  wrap_row_used = row->used[TEXT_AREA];
+                  wrap_row_ascent = row->ascent;
+                  wrap_row_height = row->height;
+                  wrap_row_phys_ascent = row->phys_ascent;
+                  wrap_row_phys_height = row->phys_height;
+                  wrap_row_extra_line_spacing = row->extra_line_spacing;
+                  may_wrap = 0;
+                }
+            }
         }
 
       PRODUCE_GLYPHS (it);
@@ -16371,7 +16485,7 @@ display_line (it)
               new_x = x + glyph->pixel_width;
 
               if (/* Lines are continued.  */
-                  !it->truncate_lines_p
+                  it->line_wrap != TRUNCATE
                   && (/* Glyph doesn't fit on the line.  */
                       new_x > it->last_visible_x
                       /* Or it fits exactly on a window system frame.  */
@@ -16412,6 +16526,8 @@ display_line (it)
                                 }
                             }
 #endif /* HAVE_WINDOW_SYSTEM */
+                          if (wrap_row_used > 0)
+                            goto back_to_wrap;
                         }
                     }
                   else if (CHAR_GLYPH_PADDING_P (*glyph)
@@ -16439,6 +16555,26 @@ display_line (it)
                       it->max_phys_ascent = phys_ascent;
                       it->max_phys_descent = phys_descent;
                     }
+                  else if (wrap_row_used > 0)
+                    {
+                    back_to_wrap:
+                      *it = wrap_it;
+                      it->continuation_lines_width += wrap_x;
+                      row->used[TEXT_AREA] = wrap_row_used;
+                      row->ascent = wrap_row_ascent;
+                      row->height = wrap_row_height;
+                      row->phys_ascent = wrap_row_phys_ascent;
+                      row->phys_height = wrap_row_phys_height;
+                      row->extra_line_spacing = wrap_row_extra_line_spacing;
+                      row->continued_p = 1;
+                      row->ends_at_zv_p = 0;
+                      row->exact_window_width_line_p = 0;
+                      it->continuation_lines_width += x;
+
+                      /* Make sure that a non-default face is extended
+                         up to the right margin of the window.  */
+                      extend_face_to_end_of_line (it);
+                    }
                   else if (it->c == '\t' && FRAME_WINDOW_P (it->f))
                     {
                       /* A TAB that extends past the right edge of the
@@ -16554,7 +16690,7 @@ display_line (it)
 
       /* If we truncate lines, we are done when the last displayed
          glyphs reach past the right margin of the window.  */
-      if (it->truncate_lines_p
+      if (it->line_wrap == TRUNCATE
           && (FRAME_WINDOW_P (it->f)
               ? (it->current_x >= it->last_visible_x)
               : (it->current_x > it->last_visible_x)))
@@ -18579,7 +18715,7 @@ display_string (string, lisp_string, face_string, face_string_pos,
         {
           struct glyph *glyph = row->glyphs[TEXT_AREA] + n_glyphs_before + i;
 
-          if (!it->truncate_lines_p
+          if (it->line_wrap != TRUNCATE
               && x + glyph->pixel_width > max_x)
             {
               /* End of continued line or max_x reached.  */
@@ -18635,7 +18771,7 @@ display_string (string, lisp_string, face_string, face_string_pos,
       set_iterator_to_next (it, 1);
 
       /* Stop if truncating at the right edge.  */
-      if (it->truncate_lines_p
+      if (it->line_wrap == TRUNCATE
           && it->current_x >= it->last_visible_x)
         {
           /* Add truncation mark, but don't do it if the line is
@@ -20583,7 +20719,7 @@ produce_stretch_glyph (it)
   else
     ascent = (height * FONT_BASE (font)) / FONT_HEIGHT (font);
 
-  if (width > 0 && !it->truncate_lines_p
+  if (width > 0 && it->line_wrap != TRUNCATE
       && it->current_x + width > it->last_visible_x)
     width = it->last_visible_x - it->current_x - 1;
 
@@ -24538,11 +24674,18 @@ Value is a number or a cons (WIDTH-DPI . HEIGHT-DPI).  */);
   DEFVAR_INT ("debug-end-pos", &debug_end_pos, doc: /* Don't ask.  */);
 #endif
 
-  DEFVAR_BOOL ("truncate-partial-width-windows",
-               &truncate_partial_width_windows,
-    doc: /* *Non-nil means truncate lines in all windows less than full frame wide.
+  DEFVAR_LISP ("truncate-partial-width-windows",
+               &Vtruncate_partial_width_windows,
+    doc: /* Non-nil means truncate lines in windows with less than the frame width.
+For an integer value, truncate lines in each window with less than the
+full frame width, provided the window width is less than that integer;
+otherwise, respect the value of `truncate-lines'.
+
+For any other non-nil value, truncate lines in all windows with
+less than the full frame width.
+
 Nil means to respect the value of `truncate-lines'.  */);
-  truncate_partial_width_windows = 1;
+  Vtruncate_partial_width_windows = make_number (30);
 
   DEFVAR_BOOL ("mode-line-inverse-video", &mode_line_inverse_video,
     doc: /* When nil, display the mode-line/header-line/menu-bar in the default face.