(display_text_line): Always store in charstart

even if at endp.  When clearing charstart, do the whole width.

(redisplay): Call verify_charstarts.

(redisplay): Don't call adjust_window_charstarts
if on last text line of window.

1 files changed, 29 insertions, 19 deletions

diff --git a/src/xdisp.c b/src/xdisp.c
index 65340f57d0e..93ca88b4bdb 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -623,23 +623,26 @@ redisplay ()
           if (cursor_vpos >= 0 && this_line_bufpos
               && this_line_endpos == tlendpos)
             {
-              int left = XFASTINT (w->left);
-              int *charstart_next_line
-                = FRAME_CURRENT_GLYPHS (XFRAME (WINDOW_FRAME (w)))->charstarts[this_line_vpos + 1];
-              int i;
-              int adjust;
-
-              if (Z - tlendpos == ZV)
-                /* This line ends at end of (accessible part of) buffer.
-                   There is no newline to count.  */
-                adjust = Z - tlendpos - charstart_next_line[left];
-              else
-                /* This line ends in a newline.
-                   Must take account of the newline and the rest of the
-                   text that follows.  */
-                adjust = Z - tlendpos + 1 - charstart_next_line[left];
-
-              adjust_window_charstarts (w, this_line_vpos, adjust);
+              if (this_line_vpos < XFASTINT (w->top) + window_internal_height (w))
+                {
+                  int left = XFASTINT (w->left);
+                  int *charstart_next_line
+                    = FRAME_CURRENT_GLYPHS (XFRAME (WINDOW_FRAME (w)))->charstarts[this_line_vpos + 1];
+                  int i;
+                  int adjust;
+
+                  if (Z - tlendpos == ZV)
+                    /* This line ends at end of (accessible part of) buffer.
+                       There is no newline to count.  */
+                    adjust = Z - tlendpos - charstart_next_line[left];
+                  else
+                    /* This line ends in a newline.
+                       Must take account of the newline and the rest of the
+                       text that follows.  */
+                    adjust = Z - tlendpos + 1 - charstart_next_line[left];
+
+                  adjust_window_charstarts (w, this_line_vpos, adjust);
+                }
 
               if (XFASTINT (w->width) != FRAME_WIDTH (XFRAME (WINDOW_FRAME (w))))
                 preserve_other_columns (w);
@@ -829,6 +832,7 @@ update:
           w->window_end_valid = Qt;
           last_arrow_position = Voverlay_arrow_position;
           last_arrow_string = Voverlay_arrow_string;
+          verify_charstarts (w);
           if (frame_up_to_date_hook != 0)
             (*frame_up_to_date_hook) (selected_frame);
         }
@@ -2071,12 +2075,15 @@ display_text_line (w, start, vpos, hpos, taboffset)
 #ifdef USE_TEXT_PROPERTIES
   next_invisible = pos;
 #endif
-  while (p1 < endp)
+  while (1)
     {
       /* Record which glyph starts a character,
          and the character position of that character.  */
       charstart[p1 - p1start] = pos;
 
+      if (p1 >= endp)
+        break;
+
       p1prev = p1;
       if (pos >= pause)
         {
@@ -2287,7 +2294,10 @@ display_text_line (w, start, vpos, hpos, taboffset)
   /* Store 0 in this charstart line for the positions where
      there is no character.  But do leave what was recorded
      for the character that ended the line.  */
-  for (i = p1 - p1start + 1; i < endp - p1start; i++)
+  /* Add 1 in the endtest to compensate for the fact that ENDP was
+     made from WIDTH, which is 1 less than the window's actual
+     internal width.  */
+  for (i = p1 - p1start + 1; i < endp - p1start + 1; i++)
     charstart[i] = 0;
 
   /* Handle continuation in middle of a character */