Merge from trunk.

[gnu-emacs] / src / dispnew.c

diff --git a/src/dispnew.c b/src/dispnew.c
index 88f75414074352920d910e4bf6fc2c3b70d949b5..e53e3fdf80db27fff7049135db9c3baba5ac2336 100644 (file)
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -431,7 +431,7 @@ margin_glyphs_to_reserve (struct window *w, int total_glyphs, Lisp_Object margin
 
 #if XASSERTS
 /* Return non-zero if ROW's hash value is correct, zero if not.  */
-static int
+int
 verify_row_hash (struct glyph_row *row)
 {
   return row->hash == row_hash (row);
@@ -608,7 +608,6 @@ adjust_glyph_matrix (struct window *w, struct glyph_matrix *matrix, int x, int y
                  row->glyphs[LAST_AREA]
                    = row->glyphs[LEFT_MARGIN_AREA] + dim.width;
                }
-             xassert (!row->enabled_p || verify_row_hash (row));
              ++row;
            }
        }
@@ -3575,12 +3574,11 @@ update_window (struct window *w, int force_p)
 
       rif->update_window_begin_hook (w);
       yb = window_text_bottom_y (w);
-
-      /* If window has a header line, update it before everything else.
-        Adjust y-positions of other rows by the header line height.  */
       row = desired_matrix->rows;
       end = row + desired_matrix->nrows - 1;
 
+      /* Take note of the header line, if there is one.  We will
+        update it below, after updating all of the window's lines.  */
       if (row->mode_line_p)
        {
          header_line_row = row;
@@ -3625,6 +3623,8 @@ update_window (struct window *w, int force_p)
 
       /* Update the rest of the lines.  */
       for (; row < end && (force_p || !input_pending); ++row)
+       /* scrolling_window resets the enabled_p flag of the rows it
+          reuses from current_matrix.  */
        if (row->enabled_p)
          {
            int vpos = MATRIX_ROW_VPOS (row, desired_matrix);
@@ -4550,18 +4550,69 @@ scrolling_window (struct window *w, int header_line_p)
          {
            rif->clear_window_mouse_face (w);
            rif->scroll_run_hook (w, r);
+         }
 
-           /* Invalidate runs that copy from where we copied to.  */
-           for (j = i + 1; j < nruns; ++j)
+       /* Truncate runs that copy to where we copied to, and
+          invalidate runs that copy from where we copied to.  */
+       for (j = nruns - 1; j > i; --j)
+         {
+           struct run *p = runs[j];
+           int truncated_p = 0;
+
+           if (p->nrows > 0
+               && p->desired_y < r->desired_y + r->height
+               && p->desired_y + p->height > r->desired_y)
              {
-               struct run *p = runs[j];
+               if (p->desired_y < r->desired_y)
+                 {
+                   p->nrows = r->desired_vpos - p->desired_vpos;
+                   p->height = r->desired_y - p->desired_y;
+                   truncated_p = 1;
+                 }
+               else
+                 {
+                   int nrows_copied = (r->desired_vpos + r->nrows
+                                       - p->desired_vpos);
+
+                   if (p->nrows <= nrows_copied)
+                     p->nrows = 0;
+                   else
+                     {
+                       int height_copied = (r->desired_y + r->height
+                                            - p->desired_y);
+
+                       p->current_vpos += nrows_copied;
+                       p->desired_vpos += nrows_copied;
+                       p->nrows -= nrows_copied;
+                       p->current_y += height_copied;
+                       p->desired_y += height_copied;
+                       p->height -= height_copied;
+                       truncated_p = 1;
+                     }
+                 }
+             }
 
-               if ((p->current_y >= r->desired_y
+           if (r->current_y != r->desired_y
+               /* The condition below is equivalent to
+                  ((p->current_y >= r->desired_y
                     && p->current_y < r->desired_y + r->height)
-                   || (p->current_y + p->height >= r->desired_y
+                   || (p->current_y + p->height > r->desired_y
                        && (p->current_y + p->height
-                           < r->desired_y + r->height)))
-                 p->nrows = 0;
+                           <= r->desired_y + r->height)))
+                  because we have 0 < p->height <= r->height.  */
+               && p->current_y < r->desired_y + r->height
+               && p->current_y + p->height > r->desired_y)
+             p->nrows = 0;
+
+           /* Reorder runs by copied pixel lines if truncated.  */
+           if (truncated_p && p->nrows > 0)
+             {
+               int k = nruns - 1;
+
+               while (runs[k]->nrows == 0 || runs[k]->height < p->height)
+                 k--;
+               memmove (runs + j, runs + j + 1, (k - j) * sizeof (*runs));
+               runs[k] = p;
              }
          }
 
@@ -4576,7 +4627,14 @@ scrolling_window (struct window *w, int header_line_p)
            to_overlapped_p = to->overlapped_p;
            from->redraw_fringe_bitmaps_p = from->fringe_bitmap_periodic_p;
            assign_row (to, from);
-           to->enabled_p = 1, from->enabled_p = 0;
+           /* The above `assign_row' actually does swap, so if we had
+              an overlap in the copy destination of two runs, then
+              the second run would assign a previously disabled bogus
+              row.  But thanks to the truncation code in the
+              preceding for-loop, we no longer have such an overlap,
+              and thus the assigned row should always be enabled.  */
+           xassert (to->enabled_p);
+           from->enabled_p = 0;
            to->overlapped_p = to_overlapped_p;
          }
       }