* 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.

8 files changed, 60 insertions, 1 deletions

diff --git a/alpine/addrbook.c b/alpine/addrbook.c
index 2b13ba0..2860e88 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 6e6feeb..63f9277 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 c594765..3261c63 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 dd4c6a3..1265b05 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 99cdb4c..b8d01b1 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) &&
diff --git a/pith/conf.c b/pith/conf.c
index 44854f4..e8904e4 100644
--- a/pith/conf.c
+++ b/pith/conf.c
@@ -3386,6 +3386,8 @@ feature_list(int index)
 	 F_DISABLE_SHARED_NAMESPACES, h_config_disable_shared, PREF_HIDDEN, 0},
 	{"disable-signature-edit-cmd", NULL,
 	 F_DISABLE_SIGEDIT_CMD, h_config_disable_signature_edit, PREF_HIDDEN, 0},
+	{"enable-delete-before-writing", NULL,
+	 F_ENABLE_DEL_WHEN_WRITING, h_config_delete_before_writing, PREF_HIDDEN, 0},
 	{"new-thread-on-blank-subject", "New Thread on Blank Subject",
 	 F_NEW_THREAD_ON_BLANK_SUBJECT, h_config_new_thread_blank_subject, PREF_HIDDEN, 1},
 	{"quell-personal-name-prompt", NULL,
diff --git a/pith/conftype.h b/pith/conftype.h
index 439ed88..c563126 100644
--- a/pith/conftype.h
+++ b/pith/conftype.h
@@ -374,6 +374,7 @@ typedef enum {
 	F_DISABLE_UPDATE_CMD,
 	F_DISABLE_KBLOCK_CMD,
 	F_DISABLE_SIGEDIT_CMD,
+	F_ENABLE_DEL_WHEN_WRITING,
 	F_DISABLE_ROLES_SETUP,
 	F_DISABLE_ROLES_SIGEDIT,
 	F_DISABLE_ROLES_TEMPLEDIT,
diff --git a/pith/pine.hlp b/pith/pine.hlp
index 2e7326e..060a897 100644
--- a/pith/pine.hlp
+++ b/pith/pine.hlp
@@ -183,6 +183,16 @@ it for you. Please take some time to read it and understand it.
 Since the Privacy Policy could be amended to take into consideration
 new additions to Alpine, please check it periodically.
 
+<P> These changes were added after the release of version <!--#echo var="ALPINE_VERSION"-->.
+
+<P>
+New features include:
+<UL>
+<LI> New hidden feature <a href="h_config_delete_before_writing"><!--#echo var="FEAT_enable-delete-before-writing"--></a>
+to add support for terminals that need lines to be deleted before being written. Based
+on a collaboration with Professor Martin Trusler.
+</UL>
+
 <P> The changes in version <!--#echo var="ALPINE_VERSION"--> are as follows:
 
 <P> 
@@ -4688,6 +4698,7 @@ There are also additional details on
 <li><a href="h_config_disable_collate">FEATURE: <!--#echo var="FEAT_disable-setlocale-collate"--></a>
 <li><a href="h_config_disable_shared">FEATURE: <!--#echo var="FEAT_disable-shared-namespaces"--></a>
 <li><a href="h_config_disable_signature_edit">FEATURE: <!--#echo var="FEAT_disable-signature-edit-cmd"--></a>
+<li><a href="h_config_delete_before_writing">FEATURE: <!--#echo var="FEAT_enable-delete-before-writing"--></a>
 <li><a href="h_config_take_fullname">FEATURE: <!--#echo var="FEAT_disable-take-fullname-in-addresses"--></a>
 <li><a href="h_config_take_lastfirst">FEATURE: <!--#echo var="FEAT_disable-take-last-comma-first"--></a>
 <li><a href="h_config_disable_reset_disp">FEATURE: <!--#echo var="FEAT_disable-terminal-reset-for-display-filters"--></a>
@@ -34521,6 +34532,29 @@ the Setup/Config screen.
 &lt;End of help on this topic&gt;
 </BODY>
 </HTML>
+====== h_config_delete_before_writing =====
+<HTML>
+<HEAD>
+<TITLE>FEATURE: <!--#echo var="FEAT_enable-delete-before-writing"--></TITLE>
+</HEAD>
+<BODY>
+<H1>FEATURE: <!--#echo var="FEAT_enable-delete-before-writing"--></H1>
+
+This feature controls a behavior of Alpine intended to workaround problems in
+terminals where the marker for the end of inverse video cannot be overwritten,
+but must be deleted, as a way to start inverse video again.
+
+<P>
+When this feature is enabled, Alpine will delete a line before writing it,
+therefore deleting the end of reverse video. Modern terminals do not require
+to enable this feature, but some old terminals might require it.
+<P>
+<UL>
+<LI><A HREF="h_finding_help">Finding more information and requesting help</A>
+</UL><P>
+&lt;End of help on this topic&gt;
+</BODY>
+</HTML>
 ====== h_config_disable_roles_templateedit =====
 <HTML>
 <HEAD>