(try_window_id): Fix computation of window end in

the case that lines were deleted at the end of the window.
Add some more debug_method_adds.

2 files changed, 25 insertions, 10 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 2ad1892a423..bda06d04156 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,9 @@
 2001-05-11  Gerd Moellmann  <gerd@gnu.org>
 
+        * xdisp.c (try_window_id): Fix computation of window end in
+        the case that lines were deleted at the end of the window.
+        Add some more debug_method_adds.
+
         * xfaces.c (try_alternative_families): New function.
         (try_font_list): Use it.  If ATTRS specifies a family, check
         fonts from that family first.
diff --git a/src/xdisp.c b/src/xdisp.c
index 82c5dbc54d5..97f8c81f642 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -11656,6 +11656,7 @@ try_window_id (w)
       w->window_end_vpos
         = make_number (MATRIX_ROW_VPOS (row, w->current_matrix));
       xassert (w->window_end_bytepos >= 0);
+      IF_DEBUG (debug_method_add (w, "A"));
     }
   else if (last_text_row_at_end)
     {
@@ -11666,6 +11667,7 @@ try_window_id (w)
       w->window_end_vpos
         = make_number (MATRIX_ROW_VPOS (last_text_row_at_end, desired_matrix));
       xassert (w->window_end_bytepos >= 0);
+      IF_DEBUG (debug_method_add (w, "B"));
     }
   else if (last_text_row)
     {
@@ -11686,21 +11688,30 @@ try_window_id (w)
     {
       /* Displayed to end of window, but no line containing text was
          displayed.  Lines were deleted at the end of the window.  */
-      int vpos;
-      int header_line_p = WINDOW_WANTS_HEADER_LINE_P (w) ? 1 : 0;
-
-      for (vpos = XFASTINT (w->window_end_vpos); vpos > 0; --vpos)
-        if ((w->desired_matrix->rows[vpos + header_line_p].enabled_p
-             && w->desired_matrix->rows[vpos + header_line_p].displays_text_p)
-            || (!w->desired_matrix->rows[vpos + header_line_p].enabled_p
-                && w->current_matrix->rows[vpos + header_line_p].displays_text_p))
-          break;
+      int first_vpos = WINDOW_WANTS_HEADER_LINE_P (w) ? 1 : 0;
+      int vpos = XFASTINT (w->window_end_vpos);
+      struct glyph_row *current_row = current_matrix->rows + vpos;
+      struct glyph_row *desired_row = desired_matrix->rows + vpos;
+
+      for (row = NULL;
+           row == NULL && vpos >= first_vpos;
+           --vpos, --current_row, --desired_row)
+        {
+          if (desired_row->enabled_p)
+            {
+              if (desired_row->displays_text_p)
+                row = desired_row;
+            }
+          else if (current_row->displays_text_p)
+            row  = current_row;
+        }
 
+      xassert (row != NULL);
       w->window_end_vpos = make_number (vpos);
-      row = MATRIX_ROW (w->desired_matrix, vpos);
       w->window_end_pos = make_number (Z - MATRIX_ROW_END_CHARPOS (row));
       w->window_end_bytepos = Z_BYTE - MATRIX_ROW_END_BYTEPOS (row);
       xassert (w->window_end_bytepos >= 0);
+      IF_DEBUG (debug_method_add (w, "C"));
     }
   else
     abort ();