* Add new hidden feature "Enable Delete Before Writing" that makes Alpine

     delete a line before overwriting it. It is meant to work around bugs in
     terminals that need it. Work in collaboration with professor Martin Trusler.

5 files changed, 23 insertions, 1 deletions

diff --git a/alpine/addrbook.c b/alpine/addrbook.c
index 2b13ba0b..2860e885 100644
--- a/alpine/addrbook.c
+++ b/alpine/addrbook.c
@@ -374,11 +374,15 @@ display_book(int start_disp, int cur_line, int old_line, int redraw, Pos *start_
         if(cur_line != old_line){
 
             /*--- Repaint old position to erase "cursor" ---*/
+	    if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+	       ClearLine(old_line + HEADER_ROWS(ps_global));
             paint_line(old_line + HEADER_ROWS(ps_global), as.top_ent + old_line,
                        0, &sp);
         }
 
         /*--- paint the position with the cursor ---*/
+	if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+	   ClearLine(cur_line + HEADER_ROWS(ps_global));
         paint_line(cur_line + HEADER_ROWS(ps_global), as.top_ent + cur_line,
                    1, &sp);
 	if(start_pos)
diff --git a/alpine/mailindx.c b/alpine/mailindx.c
index 6e6feeb1..63f92772 100644
--- a/alpine/mailindx.c
+++ b/alpine/mailindx.c
@@ -1846,6 +1846,8 @@ paint_index_line(ICE_S *argice, int line, long int msgno, IndexColType sfld,
       do_arrow = (afld != iNothing);
 
       MoveCursor(HEADER_ROWS(ps_global) + line, 0);
+      if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+	 CleartoEOLN();
 
       /* find the base color for the whole line */
       if(cur && !ac && !do_arrow){
diff --git a/alpine/mailpart.c b/alpine/mailpart.c
index c5947652..3261c63a 100644
--- a/alpine/mailpart.c
+++ b/alpine/mailpart.c
@@ -1006,6 +1006,8 @@ attachment_screen_updater(struct pine *ps, ATDISP_S *current, ATT_SCREEN_S *scre
 	if(!(!screen->current || ctmp == screen->current || ctmp == current))
 	  continue;
 
+	if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+	   ClearLine(dline + HEADER_ROWS(ps));
 	if(ctmp && ctmp->dstring){
 	    char *p = tmp_20k_buf;
 	    int   i, col, x = 0, totlen;
@@ -1061,7 +1063,7 @@ attachment_screen_updater(struct pine *ps, ATDISP_S *current, ATT_SCREEN_S *scre
 	       && !(F_ON(F_FORCE_LOW_SPEED,ps) || ps->low_speed))
 	      EndInverse();
 	}
-	else
+	else if(F_OFF(F_ENABLE_DEL_WHEN_WRITING, ps_global))
 	  ClearLine(dline + HEADER_ROWS(ps));
     }
 
diff --git a/alpine/mailview.c b/alpine/mailview.c
index dd4c6a38..1265b051 100644
--- a/alpine/mailview.c
+++ b/alpine/mailview.c
@@ -4431,6 +4431,8 @@ scroll_scroll_text(long int new_top_line, HANDLE_S *handle, int redraw)
 		    if(st->parms->text.src == FileStar)
 		      l -= new_top_line;
 
+		    if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+		       ClearLine(top + lp->where.row);
 		    PutLine0n8b(top + lp->where.row, 0, st->text_lines[l],
 				st->line_lengths[l], handle);
 		}
@@ -4448,6 +4450,8 @@ scroll_scroll_text(long int new_top_line, HANDLE_S *handle, int redraw)
 		       if(st->parms->text.src == FileStar)
 			 l -= new_top_line;
 
+		       if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+			  ClearLine(top + lp->where.row);
 		       PutLine0n8b(top + lp->where.row, 0, st->text_lines[l],
 				   st->line_lengths[l], handle);
 		   }
@@ -4507,6 +4511,8 @@ scroll_scroll_text(long int new_top_line, HANDLE_S *handle, int redraw)
 	       if(st->parms->text.src == FileStar)
 		 l -= new_top_line;
 
+	       if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+		  ClearLine(top + lp->where.row);
 	       PutLine0n8b(top + lp->where.row, 0, st->text_lines[l],
 			   st->line_lengths[l], handle);
 	   }
@@ -4521,6 +4527,8 @@ scroll_scroll_text(long int new_top_line, HANDLE_S *handle, int redraw)
 		      : st->top_text_line + num_display_lines;
 
 		if(l < st->num_lines){
+		  if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+		     ClearLine(st->screen.start_line + num_display_lines - 1);
 		  PutLine0n8b(st->screen.start_line + num_display_lines - 1,
 			      0, st->text_lines[l], st->line_lengths[l],
 			      handle ? handle : st->parms->text.handles);
@@ -4549,6 +4557,8 @@ scroll_scroll_text(long int new_top_line, HANDLE_S *handle, int redraw)
 		l = (st->parms->text.src == FileStar)
 		      ? st->top_text_line - new_top_line
 		      : st->top_text_line;
+		if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+		   ClearLine(st->screen.start_line);
 		PutLine0n8b(st->screen.start_line, 0, st->text_lines[l],
 			    st->line_lengths[l],
 			    handle ? handle : st->parms->text.handles);
@@ -4574,6 +4584,8 @@ scroll_scroll_text(long int new_top_line, HANDLE_S *handle, int redraw)
 	    for(lp = handle->loc; lp; lp = lp->next)
 	      if(lp->where.row >= st->top_text_line
 		 && lp->where.row < st->top_text_line + st->screen.length){
+		  if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+		     ClearLine(st->screen.start_line + (lp->where.row - st->top_text_line));
 		  PutLine0n8b(st->screen.start_line
 					 + (lp->where.row - st->top_text_line),
 			      0, st->text_lines[lp->where.row],
diff --git a/alpine/osdep/termin.gen.c b/alpine/osdep/termin.gen.c
index 99cdb4ce..b8d01b15 100644
--- a/alpine/osdep/termin.gen.c
+++ b/alpine/osdep/termin.gen.c
@@ -432,6 +432,8 @@ optionally_enter(char *utf8string, int y_base, int x_base, int utf8string_size,
 	draw_keymenu(km, bitmap, cols, 1-FOOTER_ROWS(ps_global), 0, FirstMenu);
     }
     
+    if(F_ON(F_ENABLE_DEL_WHEN_WRITING, ps_global))
+       ClearLine(real_y_base);
     if(pico_usingcolor() && VAR_PROMPT_FORE_COLOR &&
        VAR_PROMPT_BACK_COLOR &&
        pico_is_good_color(VAR_PROMPT_FORE_COLOR) &&