(build_frame_matrix_from_leaf_window): If a row of a

desired window matrix hasn't been displayed, use the current row
instead.  Make sure that only those frame rows are updated for
which there is a corresponding enabled desired row.

2 files changed, 29 insertions, 7 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index c0a37f53a8f..57dd1e2fca9 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2000-08-29  Gerd Moellmann  <gerd@gnu.org>
+
+        * dispnew.c (build_frame_matrix_from_leaf_window): If a row of a
+        desired window matrix hasn't been displayed, use the current row
+        instead.  Make sure that only those frame rows are updated for
+        which there exists a corresponding enabled desired row.
+        
 2000-08-29  Miles Bader  <miles@gnu.org>
 
         * xfaces.c (default_face_vector): New function.
diff --git a/src/dispnew.c b/src/dispnew.c
index 5cff07c04b9..e16296c717e 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -2454,6 +2454,7 @@ build_frame_matrix_from_leaf_window (frame_matrix, w)
     {
       struct glyph_row *frame_row = frame_matrix->rows + frame_y;
       struct glyph_row *window_row = window_matrix->rows + window_y;
+      int current_row_p = window_matrix == w->current_matrix;
 
       /* Fill up the frame row with spaces up to the left margin of the
          window row.  */
@@ -2461,19 +2462,32 @@ build_frame_matrix_from_leaf_window (frame_matrix, w)
 
       /* Fill up areas in the window matrix row with spaces.  */
       fill_up_glyph_row_with_spaces (window_row);
+
+      /* If only part of W's desired matrix has been built, and
+         window_row wasn't displayed, use the corresponding current
+         row instead.  */
+      if (window_matrix == w->desired_matrix
+          && !window_row->enabled_p)
+        {
+          window_row = w->current_matrix->rows + window_y;
+          current_row_p = 1;
+        }
       
-      if (window_matrix == w->current_matrix)
+      if (current_row_p)
         {
-          /* We have to copy W's current matrix.  Copy window
-             row to frame row.  */
+          /* Copy window row to frame row.  */
           bcopy (window_row->glyphs[0],
                  frame_row->glyphs[TEXT_AREA] + window_matrix->matrix_x,
                  window_matrix->matrix_w * sizeof (struct glyph));
         }
       else
         {
-          /* Copy W's desired matrix.  */
-
+          xassert (window_row->enabled_p);
+          
+          /* Only when a desired row has been displayed, we want
+             the corresponding frame row to be updated.  */
+          frame_row->enabled_p = 1;
+          
           /* Maybe insert a vertical border between horizontally adjacent
              windows.  */
           if (right_border_glyph)
@@ -2523,8 +2537,7 @@ build_frame_matrix_from_leaf_window (frame_matrix, w)
       frame_row->used[TEXT_AREA] 
         = window_matrix->matrix_x + window_matrix->matrix_w;
 
-      /* Or in flags.  */
-      frame_row->enabled_p |= window_row->enabled_p;
+      /* Or in other flags.  */
       frame_row->inverse_p |= window_row->inverse_p;
 
       /* Next row.  */
@@ -3443,11 +3456,13 @@ direct_output_forward_char (n)
 
   row = MATRIX_ROW (w->current_matrix, w->cursor.vpos);
 
+  /* Give up if PT is outside of the last known cursor row.  */
   if (PT <= MATRIX_ROW_START_BYTEPOS (row)
       || PT >= MATRIX_ROW_END_BYTEPOS (row))
     return 0;
 
   set_cursor_from_row (w, row, w->current_matrix, 0, 0, 0, 0);
+  
   w->last_cursor = w->cursor;
   XSETFASTINT (w->last_point, PT);