(try_cursor_movement): Exclude header line from scroll

margin at top of window.
(try_window_reusing_current_matrix): Calculate proper cursor position
after scrolling up with non-zero scroll margin, as the old cursor
position corresponds to value of PT before executing this command.
(try_window_id): Consider scroll margin at bottom of window too;
otherwise we fail to scroll when hl-line-mode is enabled.

diff --git a/src/xdisp.c b/src/xdisp.c
index 447f4dfbf79313beac0773a2e536072f8165e638..cd712ac7485ab952fc452ceeab494cc011ef65d8 100644 (file)
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -11267,7 +11267,7 @@ try_cursor_movement (window, startp, scroll_step)
       && (FRAME_WINDOW_P (f)
          || !overlay_arrow_in_current_buffer_p ()))
     {
-      int this_scroll_margin;
+      int this_scroll_margin, top_scroll_margin;
       struct glyph_row *row = NULL;
 
 #if GLYPH_DEBUG
@@ -11280,6 +11280,10 @@ try_cursor_movement (window, startp, scroll_step)
       this_scroll_margin = min (this_scroll_margin, WINDOW_TOTAL_LINES (w) / 4);
       this_scroll_margin *= FRAME_LINE_HEIGHT (f);
 
+      top_scroll_margin = this_scroll_margin;
+      if (WINDOW_WANTS_HEADER_LINE_P (w))
+       top_scroll_margin += CURRENT_HEADER_LINE_HEIGHT (w);
+
       /* Start with the row the cursor was displayed during the last
         not paused redisplay.  Give up if that row is not valid.  */
       if (w->last_cursor.vpos < 0
@@ -11340,7 +11344,7 @@ try_cursor_movement (window, startp, scroll_step)
                     && (MATRIX_ROW_START_CHARPOS (row) > PT
                         || (MATRIX_ROW_START_CHARPOS (row) == PT
                             && MATRIX_ROW_STARTS_IN_MIDDLE_OF_CHAR_P (row)))
-                    && (row->y > this_scroll_margin
+                    && (row->y > top_scroll_margin
                         || CHARPOS (startp) == BEGV))
                {
                  xassert (row->enabled_p);
@@ -11368,7 +11372,7 @@ try_cursor_movement (window, startp, scroll_step)
                ++row;
 
              /* If within the scroll margin, scroll.  */
-             if (row->y < this_scroll_margin
+             if (row->y < top_scroll_margin
                  && CHARPOS (startp) != BEGV)
                scroll_p = 1;
            }
@@ -12538,9 +12542,8 @@ try_window_reusing_current_matrix (w)
         position.  */
       if (pt_row)
        {
-         w->cursor.vpos -= MATRIX_ROW_VPOS (first_reusable_row,
-                                            w->current_matrix);
-         w->cursor.y -= first_reusable_row->y;
+         w->cursor.vpos -= nrows_scrolled;
+         w->cursor.y -= first_reusable_row->y - start_row->y;
        }
 
       /* Scroll the display.  */
@@ -12585,6 +12588,29 @@ try_window_reusing_current_matrix (w)
       for (row -= nrows_scrolled; row < bottom_row; ++row)
        row->enabled_p = 0;
 
+      /* Point may have moved to a different line, so we cannot assume that
+        the previous cursor position is valid; locate the correct row.  */
+      if (pt_row)
+       {
+         for (row = MATRIX_ROW (w->current_matrix, w->cursor.vpos);
+              row < bottom_row && PT >= MATRIX_ROW_END_CHARPOS (row);
+              row++)
+           {
+             w->cursor.vpos++;
+             w->cursor.y = row->y;
+           }
+         if (row < bottom_row)
+           {
+             struct glyph *glyph = row->glyphs[TEXT_AREA] + w->cursor.hpos;
+             while (glyph->charpos < PT)
+               {
+                 w->cursor.hpos++;
+                 w->cursor.x += glyph->pixel_width;
+                 glyph++;
+               }
+           }
+       }
+
       /* Adjust window end.  A null value of last_text_row means that
         the window end is in reused rows which in turn means that
         only its vpos can have changed.  */
@@ -13368,9 +13394,9 @@ try_window_id (w)
 
     if ((w->cursor.y < this_scroll_margin
         && CHARPOS (start) > BEGV)
-       /* Don't take scroll margin into account at the bottom because
-          old redisplay didn't do it either.  */
-       || w->cursor.y + cursor_height > it.last_visible_y)
+       /* Old redisplay didn't take scroll margin into account at the bottom,
+          but then global-hl-line-mode doesn't scroll.  KFS 2004-06-14 */
+       || w->cursor.y + cursor_height + this_scroll_margin > it.last_visible_y)
       {
        w->cursor.vpos = -1;
        clear_glyph_matrix (w->desired_matrix);